Abstract

A Multimode nonlinear optical imaging technique based on the combination of multichannel mode and Lambda mode is developed to investigate human dermis. Our findings show that this technique not only improves the image contrast of the structural proteins of extracellular matrix (ECM) but also provides an image-guided spectral analysis method to identify both cellular and ECM intrinsic components including collagen, elastin, NAD(P)H and flavin. By the combined use of multichannel mode and Lambda mode in tandem, the obtained in-depth two photon-excited fluorescence (TPEF) and second-harmonic generation (SHG) imaging and TPEF/SHG signals depth-dependence decay can offer a sensitive tool for obtaining quantitative tissue structural and biochemical information. These results suggest that the technique has the potential to provide more accurate information for determining tissue physiological and pathological states.

© 2006 Optical Society of America

1. Introduction

An emerging application of multiphoton microscopy (MPM) is the observation of unstained samples based on intrinsic sources of nonlinear signals [1, 2] such as two photon-excited fluorescence (TPEF) and second-harmonic generation (SHG). It can provide high contrast and optical sectioning capabilities for involving nonlinear light-matter interactions. The ability of MPM to produce images deep in optically thick preparations is crucial for intravital tissue microscopy. Moreover, SHG enables direct imaging of anisotropic biological structures, such as collagen [3–5]. SHG can produce high-resolution, high contrast images of tissue morphology [2, 6] and has also be applied to study dynamics in tissue physiology, such as monitoring collagen modification in tumor growth [7], and optically recording action potential change in neuron cells [8]. Recently, because these imaging (TPEF and SHG) modalities involve different contrast mechanisms and can provide in tandem complementary information about tissue structure and function, the combination of TPEF and SHG has attracted more attention. These imaging modalities are easy to implement simultaneously and differ only in optical filter selection and detector placement. The combination of TPEF and SHG has been implemented for the study of cells [9, 10], thin tissue sections [11], and for the more practical case of thick, unstained living specimens [6, 12].

In addition to structural imaging, spectral analysis can provide complementary functional information. Spectral analysis is a powerful method to identify intrinsic biochemical species. The relative abundance of intrinsic components is related to tissue physiological and pathological states [13]. Spectral analysis has been used to characterize tissue type, monitor the physiological and pathological states of tissue [13–16]. However, the traditional tissue spectroscopy mostly bases on the overall spectrum resulting from a mixture of many different intrinsic components. It is apparent that the interpretation of the bulk spectrum is difficult, and it is nearly impossible to identify all the chemical components present within the tissue or determine their concentration. This fact prompts further investigation into the spectra and distribution of each biochemical species. By linking the spectroscopic information to tissue morphological structures, it is possible to study the spectral properties and distributions of each biochemical species [17]. The method is significant for tissue biochemical analysis.

Collagen and elastin are important structural proteins of extracellular matrix (ECM). Collagen plays an important structural role in skin, interstitial tissue and basal laminae. Modifications of the collagen fibrillar matrix structure are associated with various physiologic processes, such as wound healing, photoaging, cornea diseases, osteoarthritis, liver fibrosis, and cancer [4, 18–22]. Elastin is the protein responsible for the characteristic elastic properties of many tissues [23–25]. The elastic function complements collagen fibrils, which impart tensile strength. However, to understand the healthy and diseased tissues, a complete understanding of the arrangement and modification of the major structural proteins, such as collagen and elastin, is crucial. Thus, the visualization of the major structural proteins of the extracellular matrix (ECM), such as collagen and elastin, is of great value in gaining structural and diagnostic information. Cellular NAD(P)H and flavin carry information of cellular metabolism. It is reported in previous work that the ratio of NAD(P)H over flavin fluorescence, a parameter related to the tissue pathology [26–28]. The investigation of NAD(P)H and flavin fluorescence is of significance for evaluating the redox ratio and monitoring the metabolic state in tissue. To date, few techniques can accomplish the selective visualization of the major structural proteins of ECM and the identification of tissue intrinsic components.

In this study, we demonstrate for the first time the multimode nonlinear imaging technique to carry out the selective visualization of ECM and the identification of dermis intrinsic components by combining multichannel mode with Lambda mode. The technique is illustrated by imaging human dermis using a mode-locked femtosecond Ti: sapphire laser coupled to a Zeiss LSM 510 META laser scanning microscopy. We also show that the technique can provide some quantitative tissue structural and biochemical information. Furthermore, we qualitatively interpret the origin of the backward SHG signals from tissue.

2. Materials and methods

All the experiments described in this paper were based on ex-vivo human skin. Human skin was obtained from Affiliated Xiehe Hospital of Fujian Medical University. The specimens were stored at a bottle of liquid nitrogen (-196°C) before they were used. The skin samples were excided perpendicular to the epidermal layer so that each section comprised a complete transverse cross-section of the epidermal and dermal layers and sandwiched between the microscope slide and a piece of the cover glass. To avoid dehydration or shrinkage during the whole imaging process, the specimen was sprinkled with PBS solution (PH 7.4). The dermal part of ex-vivo human skin is our region of interest.

In this study, the multimode nonlinear optical imaging based on the combination of multichannel mode and Lambda mode was performed on a Zeiss LSM 510 META laser scanning microscopy equipped with a mode-locked femtosecond Ti: sapphire laser (110fs, 76MHz), tunable from 700nm to 980nm (Coherent Mira 900-F), as shown in Fig. 1.

 

Fig. 1. Schematic of multimode nonlinear optical imaging experimental setup.

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The polarization direction of the laser light is the horizontal polarization. An Acousto-Optic Modulator (AOM) is used to control the laser intensity attenuation. A Plan-Apochromat 63× (N.A.=1.4) oil immersion objective (Zeiss) was employed for focusing the excitation beam and for collecting of the backward signals. We detected all signals in the backward direction. The signals were directed by a main dichroic beam splitter (MDBS) to the META detector. The META detector with 32-gated photon counting module is used to collect x-y images at a series of emission wavelengths, covering from 377nm to 716nm. Each photon counting module can cover a spectral range of 10.7nm. An IR beam block filters ( Zeiss KP650), which is in front of META detector, was be used to ensure that excitation light was filtered out and only emission signals were recorded. The LSM 510 META laser scanning microscopy is controlled via a standard high-end Pentium PC and linked to the electronic control system via an ultrafast SCSi interface. This system has two especial imaging modes: multichannel mode and Lambda mode. These two modes use the same detector that is META detector to acquire the imaging. The multichannel mode has eight independent-channels and each channel can selectively be set to detect emission signals within the random range from 377 to 716nm to achieve imaging. The Lambda mode permits to simultaneously record the spectral resolved image and the corresponding spectra by creating emission lambda stacks. In this study, we have combined multichannel mode with Lambda mode to carry out multimode nonlinear imaging. In multichannel mode, we selected two independent-channels from eight channels to achieve SHG (387–409nm) and TPEF (447–628nm) imaging of human dermis, respectively. The SHG/TPEF images were subsequently recorded and generally attained within a few seconds. In our experiments, if the two channels (SHG and TPEF) were recorded simultaneously, which they bear the same system parameters, we found that the integrated total intensity of SHG is about 1/5 of that of TPEF (as indicated in the Fig. 5 b). Thus, when SHG imaging is on optimal, it is more likely that the much higher relative TPEF intensity obscure the SHG signal; when TPEF imaging is on optimal, the SHG signal will become much weaker. The acquired SHG/TPEF image bears low contrast and signal-to-background. So, in this study we used two independent channels and they can acquire images with the optimal system parameters, including the laser intensity, the detection gain, amplifier offset, and amplifier gain, which can enhance the image contrast. This is an advantage of the multichannel mode. At the same time, in Lambda mode we acquire the spectral resolved TPEF/SHG image and the corresponding spectra in the same region as using the multichannel mode. Using our setting, about 1s of exposure were necessary for the alternation of two modes. The acquisition of a single 512×512 pixels image was generally achieved within a few seconds. But, note that all the images presented in this article are not 512×512 pixels in size because of taking into account the size of images and discussed contents. The average laser power at the specimen was maintained at <6mW and no photobleaching was observed at this low power level.

3. Results and discussion

3.1. Multimode nonlinear optical imaging of human skin

In order to demonstrate multimode nonlinear imaging technique, we have examined samples of human skin. Human skin is comprised of two layers: the epidermis and the dermis. The epidermis is the outermost portion of the skin and is a stratified squamous epithelium composed mainly of keratinocytes. The dermis provides structural support for the epidermis and is primarily composed of a collagen and elastin matrix with a sparse population of cells such as fibroblasts. In this study, we mainly focus on the dermis. Figure 2 shows a TPEF/SHG image of human dermis using the multichannel mode. As can be seen from Fig. 2 a, the collagen mesh of dermis can be imaged alone by one channel (387–409nm, green color-coded). Similarly, in the Fig. 2 b the elastin and fibroblasts components of dermis can be isolated from collagen using another channel (447–628nm, red color-coded). Overlaying two channels yields a high-contrast TPEF/SHG image of human dermis, where structural details of the sample can be readily distinguished, as shown in Fig. 2 c. The image (green color-coded) shows a fine mesh morphology which corresponds to collagen and probes the distribution and orientation of collagen. Collagen is the predominant structural protein in most biological tissues, as well as an efficient source of SHG [3–5]. Modifications of the collagen fibrillar matrix structure are associated with various physiologic processes, such as wound healing, aging, diabetes, and cancer. Therefore, SHG is very promising as a sensitive probe in tissue morphology and physiology studies. The image (red color-coded) displays the morphology of thick ropes that corresponds to elastin fibers with diameters of ≈ 1.94μm. Elastin that coil and recoils like a spring within the elastic fibers of connective tissue and accounts for the elasticity of structures such the skin, blood vessels, heart, lungs, intestines, tendons, and ligaments. However, no cells can be visualized in the dermis. This may be responsible for two factors. It is possible that the cells are relatively sparse. It is more likely that the much higher relative fluorescence intensity of elastic fibers obscure the much dimmer fluorescence from the fibroblasts. Note that the image contrast is significantly improved in the present study as compared with the previous study [12, 25]. Since two channels are independent and can possess different system parameters as shown in Table 1, they can acquire images with the optimal system parameters which can enhance the image contrast. The method is effective in improving the image (SHG and TPEF) contrast.

 

Fig. 2. TPEF/SHG nonlinear imaging of human dermis using the multichannel mode. The images were acquired by using two independent-channels: (a) Typical SHG image (green color-coded, 387 – 409nm) for excitation power PSHG = 6.0mW. The signal mainly arises from collagen and (b) TPEF image (red color-coded, 447 – 628nm) for PTPEF = 2.6mW. Elastin, NAD(P)H and flavin are responsible for the signals. (c) TPEF/SHG image was obtained by overlaying two channels, in which the contrast has been enhanced to outline the various structures seen in the image. The excitation wavelength λex was 800nm. The images are 135×315 pixels in size 12-bit pixel depth.

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Tables Icon

Table 1. System parameters of two independent-channels in the multihannel mode

Multichannel mode has also capability to generate high-contrast structural images deep inside highly scattering tissues. It was found that detailed, high-contrast features could be resolved in TPEF/SHG optical sections throughout the full ~ 60μm thickness of a freshly dissected, unfixed sample of human dermis (Fig. 3 a). Figures 3 b–h shows TPEF/SHG images from human dermis at depths of 0, 10, 20, 30, 40, 50, 60 μm, for λex =800nm. As represented in Fig. 3 b–h, the distribution and content of ECM components are visible. Optical sections at various depths can better reveal fine details of the internal tissue structure. The signal progressively degrades with increasing depth, but the TPEF/SHG images still bear high-contrast. However, the maximum imaging depth reached here is only limited by the working distance of microscopy objective and the low value of excitation power used (PSHG = 6.0mw, PTPEF = 2.6mw). Recently, some groups have reported the maximum depth of two-photon imaging can reach up to one millimeter [29], while leaving the tissue intact. Further improving our system may permit deeper imaging.

 

Fig. 3. TPEF/SHG images obtained from human dermis at various depths using the multichannel mode. A dissected sample of human dermis was optically sectioned through its full thickness of ~60μm. (a) Graphic representation of the image volume of tissue. xy (top), yz (left), and xz (right) sections from the boundaries of the volume are shown. Note that dimensions are indicated, and are not portrayed proportionally. (b–h) TPEF/SHG images of human dermis at depths of 0, 10, 20, 30, 40, 50 and 60 μm. The images are 265×320 pixels in size 12-bit pixel depth. Scale bar = 20μm. (λex = 800nm, PSHG = 6.0mW, PTPEF = 2.6mW).

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At the same time, in the Lambda-mode we obtain the spectral resolved TPEF/SHG image of human dermis from the same region as using the multichannel mode and the corresponding spectra from regions of interest (ROI), as shown in the Fig. 4. The spectral resolved TPEF/SHG image could provide visual identification between the different tissue structures attributed to the differences in their biochemical components. It was obvious that in the Fig. 4 there are two main color structures: blue and purple. The blue-fluorescing rope-like structures are likely to be elastin. The purple color refers to the second-harmonic signal generated by collagen. Thus, we can select our ROI, including certain intrinsic component, based on the structural information. Then the emission spectra of different ROI can be obtained by taking the image of ROI and averaging the intensity from each pixel with this region. In the Fig. 4, we obtained the spectra from our ROI and each spectrum is normalized to the maximal peak intensity. In the ROI 1, the emission spectra reveals strong SHG signals manifested by a narrow peak at half the excitation and a bandwidth (full width a half-maximum) in accordance with the excitation laser spectral width. Moreover, the signal intensity exhibited a quadratic dependence on the laser power. Collagen is well known to produce SHG and is responsible for this signal [3, 5]. However, almost no TPEF signal was observed. The result was in accordance with previous study, which no TPEF signal from collage was detected for excitation wavelength of 800nm [6].

 

Fig. 4. The spectral resolved TPEF/SHG image of human dermis from the same region in Fig. 2 and the corresponding spectra from regions of interest (ROI). They simultaneously were obtained by using the Lambda mode. The image is 135×315 pixels in size 12-bit pixel depth. (λex = 800nm, P = 5mW)

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In the ROI 2, there are two distinct peaks at 470nm and 500nm. It was reported in previous work that cellular contributions (NAD(P)H and flavin) and elastin emit this band [13–15, 17, 26–28]. Thus, we believe that the corresponding to NAD(P)H and flavin in the fibroblasts, and elastin contribute to two peaks, respectively. Specifically, the 470nm peak corresponds to the combination of NAD(P)H and flavin fluorescence. The 500nm peak is associated with the presence of elastin. ROI 3 displays the overall spectrum from NAD(P)H and flavin in the fibroblasts, collagen, and elastin. It is apparent that this spectral analysis method can better identify tissue intrinsic components to analysis different components spectra. It is so-called the image-guided spectral analysis method. In addition, because cellular NAD(P)H and flavin not only carry information of cellular metabolism but also relate to the tissue pathology, the method can be used for evaluating the redox ratio and monitoring the metabolic state in tissue.

In the Lambda-mode, we could also investigate the dependence of the SHG and TPEF signals intensity on imaging depth in turbid tissues. The spectral resolved TPEF/SHG images from human dermis at various depths were acquired. The emission spectra were obtained by taking the image of the whole optical section plane and averaging the intensity from each pixel within the image. To suppress the 470 nm autofluorescence peak of NAD(P)H, 830 nm excitation wavelength was used instead of 800 nm. Figure 5 (a) shows the emission spectra from human dermis at depths 0, 20, 40, 60 μm, while Fig. 5 (b) gives integrated total intensity of SHG and TPEF spectra versus penetration depth, z, for λex = 830nm. To ensure the reproducibility of the results, the experiment was repeated three times. The SHG and TPEF signals were observed to decay exponentially with depth. Multiple light scattering decreases the number of excitation photons reaching the focus plane. Multiple light scattering also decreases the number of SHG and TPEF photons collected by the objective lens. Thus, the SHG and TPEF signals decay with depth. The detected signal intensity, I, decays as a function of depth, z, according to:

(I)z=(I)0exp(Az)

where A is an attenuation coefficient that is a function of the sample absorption and scattering properties at the both the excitation and emission wavelengths. The inverse of A yields an attenuation length, latt . Figure 5 (c) and (d) show the plot of the natural logarithm of SHG and TPEF integrated total intensity versus depth, z, with latt(SHG) and latt(TPEF) ≈ 25.6μm. The SHG (purple light) wavelength is shorter than that of TPEF (blue light), the sample absorption and scattering properties of SHG is bigger [30, 31]. So, the attenuation of SHG is more significant than TPEF, which is consistent with the above results. In addition, it is well known that refractive index mismatch induced spherical aberration is a ubiquitous problem for in-depth optical biological imaging. However, recently Dong’s group has used it to determine the refractive indices of uniformly luminescent specimens by measuring the signals decay profile as a function of imaging depth [32]. In other words, the signals decay profile as a function of imaging depth can reflect changes of the refractive indices of specimens. Here, the SHG and TPEF signals decay profile as a function of imaging depth also can use to monitor changes of the refractive indices of biological tissue. These finding suggest that the SHG and TPEF depth-dependent decay can provide a general estimate of optical properties, which are critical parameter for deep-tissue imaging and reflect various physiologic processes [33]. The SHG and TPEF depth-dependent decay may have the potential to be as sensitive tools for obtaining quantitative tissue information.

 

Fig. 5. Emission spectra obtained from human dermis at various depths using the Lambda mode. Each spectrum is the average of measurement acquired at the whole optical section plane. (a)SHG and TPEF spectra obtained at depths of 0, 20, 40, 60μm. (b) Integrated total intensity of SHG and TPEF spectra versus penetration depth. (c, d)Plot of the natural logarithm of SHG and TPEF integrated total intensity versus penetration depth, Z, respectively. Error bars represent calculated standard deviations. (λex=830nm, P = 5mW).

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To sum up, the multimode nonlinear optical imaging technique can allow direct visualization of ECM components and the identification of both cellular and ECM intrinsic components. The combined use of multichannel mode and Lambda mode in tandem can obtain quantitative information regarding the biomorphology and biochemistry of tissue.

3.2. Origin of the backward SHG signal

Our study collects SHG signals in a backward geometry and the excitation light power is relatively lower. Because SHG is the coherent process and the majority of the second-harmonic wave copropagates with the excitation laser beam, it is necessary to understand the origin of the backward SHG signal from the sample. Three main sources, we believe, contribute to the backward SHG signals. Firstly, the backward SHG signals are directly emitted from the dermis collagen fibril. Emitted SHG is generally anisotropic because phase matching constraints of coherent scattering. As indicated by recent theoretical and experimental works[5, 34], objects with the axial size on the order of the second harmonic wavelength exhibits forward directed SHG, while objects with a axial size less than λ/10 (approx. 40nm)are estimated to produce nearly equal backward and forward SHG signals. As proposed by the previous investigation of tendon collagen fibrils [35], the dermis collagen fibrils seem possess inhomogeneous tubelike structures. The collagen microfibrils might be randomly arranged in the core but are well aligned in the shell (thickness < 40nm) the dermis fibril, generating evenly distributed forward/backward SHG. Secondly, because human dermis is opaque, the backward SHG signals may be attributed to the backscattering of the forward-generated SHG signals. Thirdly, the backscattering of ballistic excitation photons as the excitation light induces the ‘forward SHG signals’, that is, the backward SHG signals. The existence of backward SHG signals in tissue is fortuitous for in vivo tissue imaging because collecting forward propagating signals is impractical in many cases.

4. Conclusion

We have developed a multimode nonlinear optical imaging technique based on the combination of multichannel mode and Lambda mode and applied it to image human skin. The experimental results demonstrates that the technique can permit high-contrast visualization of ECM intrinsic components, and identify both cellular and ECM intrinsic components including collagen, elastin, NAD(P)H and flavin. Our findings indicate that in-depth TPEF/SHG imaging and TPEF/SHG signals depth-dependence decay provide a means for extracting quantitative structural and biochemical information from tissue by the combined use of multichannel mode and Lambda mode in tandem.

A major advantage of the technique can provide unique contrast enhancement to the previous study in TPEF/SHG image by using two-independent channels with the optimal system parameters. Another major advantage is that it is a noninvasive technique that relies exclusively on intrinsic signals, and does not required extrinsic probes, which can change the physiologic state of the tissue. Third, the technique can offer an image-guided spectral analysis method to identify tissue biochemical components.

Until now, few other techniques can provide a direct visualization of ECM intrinsic components, and identify both cellular and ECM intrinsic components. The technique reported here opens many possibilities of studying physiological activity of intact tissues. The technique provides a new tool to map the distribution of ECM components and monitor cellular redox state in intact tissue, providing quantitative information regarding biomorphology and biochemistry of tissue, and may prove useful to clinical diagnostics as well as to basic biological research.

Acknowledgments

The project was supported by the National Natural Science Foundation of China (No. 60508017), Program for New Century Excellent Talents in Fujian Province University, the Natural Science Foundation of Fujian Province of China (No. A0510015), the Innovation Foundation for Young Technological Talents of Fujian Province (NO.2003J027), and the Scientific Program of the Educational Hall of Fujian Province (NO.JA05215).

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  1. W.R. Zipfel, R.M. Williams, and W.W. Webb, “Nonlinear magic: multiphoton microscopy in the biosciences,” Nat. Biotechnol. 21, 1369–1377 (2003).
    [Crossref] [PubMed]
  2. W.R. Zipfel, R.M. Williams, R. Christie, A.Y. Nikitin, B.T. Hyman, and W.W. Webb, “Live tissue intrinsic emission microscopy using multiphoton-excited native fluorescence and second harmonic generation,” Proc. Natl. Acad. Sci. USA. 100, 7075–7080 (2003).
    [Crossref] [PubMed]
  3. P.J Campagnola and L.M. Loew, “Second-harmonic imaging microscopy for visualizing biomolecular arrays in cells, tissues and organisms,” Nat. Biotechnol. 21, 1356–1360 (2003).
    [Crossref] [PubMed]
  4. M. Han, G. Giese, and J.F. Bille, “Second harmonic generation imaging of collagen fibrils in cornea and sclera,” Opt. Express. 13, 5791–5797 (2005).
    [Crossref] [PubMed]
  5. R.M. Williams, W.R. Zipfel, and W.W. Webb, “Interpreting second harmonic generation images of collagen I fibrils,” Biophys. J. 88, 1377–1386 (2005).
    [Crossref]
  6. A. Zoumi, A. Yeh, and B.J. Tromberg, “Imaging cells and extracellular matrix in vivo by using second-harmonic generation and two-photon excited fluorescence,” Proc. Natl. Acad. Sci. USA. 99, 11014–11019 (2002).
    [Crossref] [PubMed]
  7. E. Brown, T McKee, E. diTomaso, A. Pluen, B. Seed, Y. Boucher, and R.K. Jain, “Dynamic imaging of collagen and its modulation in tumors in vivo using second-harmonic generation,” Nat. Med. 9, 796–800 (2003).
    [Crossref] [PubMed]
  8. D.A. Dombeck, M. Blanchard-Desce, and W.W. Webb, “Optical recording of action potentials with second-harmonic generation microscopy,” J. Neurosci. 24, 999–1003 (2004).
    [Crossref] [PubMed]
  9. P.J. Campagnola, M.D Wei, A. Lewis, and L.M. Loew, “High-resolution nonlinear optical imaging of live cells by second harmonic generation,” Biophys. J. 77, 3341–3349 (1999).
    [Crossref] [PubMed]
  10. P.J. Campagnola, H.A. Clark, W.A. Mohler, A. Lewis, and L.M. Loew, “Second-harmonic imaging microscopy of living cells,” J. Biomed. Opt. 6, 227–286 (2001).
    [Crossref]
  11. P.J. Campagnola, A.C. Millard, M. Terasaki, P.E. Hoppe, C.J. Malone, and W.A. Mohle, “Three-dimensional high-resolution second-harmonic generation imaging of endogenous structural proteins in biological tissues,” Biophys. J. 81, 493–508 (2002).
    [Crossref]
  12. Y.C. Guo, H.E. Savage, F. Liu, S.P. Schantz, P.P. Ho, and R.R. Alfano, “Subsurface tumor progression investigated by noninvasive optical second harmonic tomography,” Proc. Natl. Acad. Sci. USA. 96, 10854–10856 (1999).
    [Crossref] [PubMed]
  13. R.K. Rebecca and S.M. Eva, “Quantitative optical spectroscopy for tissue diagnosis,” Annu. Rev. Phys. Chem. 47, 555–606 (1996).
    [Crossref]
  14. I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
    [PubMed]
  15. Y. Wu, P. Xi, J.Y. Qu, T.H. Cheung, and M.Y. Yu, “Depth-resolved fluorescence spectroscopy of normal and dysplastic cervical tissue,” Opt. Express. 13,382–388 (2005).
    [Crossref] [PubMed]
  16. M.C. Skala, J.M. Squirrell, K.M. Vrotsos, J.C. Eickhoff, A. Gendron-Fitzpatrick, K.W. Eliceiri, and N. Ramanujam, “Multiphoton microscopy of endogenous fluorescence differentiates normal, precancerous, and cancerous squamous,” Cancer. Res. 65, 1180–1186 (2005).
    [Crossref] [PubMed]
  17. L.H. Laiho, S. Plete, T.M. Hancewicz, P.D. Kaplan, and P.T.C. So, “Two-photon 3-D mapping of ex vivo human skin endogenous fluorescence species based on fluorescence emission spectra,” J. Biomed. Opt. 10, 0240161–10 (2005).
    [Crossref] [PubMed]
  18. B.M. Kim, J. Eichler, K.M. Reiser, A.M. Rubenchik, and L.B.D. Silva, “Collagen structure and nonlinear susceptibility: effects of heat, glycation, and enzymatic cleavage on second harmonic signal intensity,” Lasers Surg. Med. 27, 329–335 (2000).
    [Crossref] [PubMed]
  19. S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
    [Crossref]
  20. A.T. Yeh, M.J. Hammer-Wilson, D.C.V. Sickle, H.P. Benton, A. Zoumi, B.J. Tromberg, and G.M. Peavy, “Nonlinear optical microscopy of articular cartilage,” Osteoarthritis and Cartilage. 13, 345–352 (2005).
    [Crossref] [PubMed]
  21. H.S. Lee, Y. Liu, H.C. Chen, L.L. Chiou, G.T. Huang, W. Lo, and C.Y. Dong, “Optical biopsy of liver fibrosis by use of multiphoton microscopy,” Opt. Lett. 29, 2615–2616 (2004).
    [Crossref]
  22. J. Condeelis and J.E. Segall, “Intravital imaging of cell movement in tumours,” Nat.Rev. 3, 921–930 (2003).
    [Crossref]
  23. D.Y. Li, B. Brooke, E.C. Davis, R.P. Mecham, L.K. Sorensen, B.B. Boak, E. Eichwald, and M.T. Keating, “Elastin is an essential determinant of arterial morphogenesis,” Nature. 393, 276–280 (1998).
    [Crossref] [PubMed]
  24. L. Debelle and A.M. Tamburro, “Elastin: molecular description and function,” Int. J. Biochem. Cell. Biol. 31, 261–272 (1999).
    [Crossref] [PubMed]
  25. A. Zoumi, X. Lu, G.S. Kassab, and B.J. Tromberg, “Imaging coronary artery microstructure using second-harmonic and two-photon fluorescence microscopy,” Biophys. J. 87, 2278–2286 (2004).
    [Crossref]
  26. Y.C. Wu and J.A.Y. Qu, “Two-photon autofluorescence spectroscopy and second-harmonic generation of epithelial tissue,” Opt. Lett. 30, 3045–3047 (2005).
    [Crossref] [PubMed]
  27. S. Huang, A.A. Heikal, and W.W. Webb, “Two-photon fluorescence spectroscopy and microscopy of NAD(P)H and flavoprotein,” Biophys. J. 82, 2811–2825 (2002).
    [Crossref] [PubMed]
  28. B.R. Masters, P.T.C. So, and E. Gratton, “Multiphoton excitation fluorescence microscopy and spectroscopy of in vivo human skin,” Biophys. J. 72, 2405–2412 (1997).
    [Crossref] [PubMed]
  29. P. Theer, M.T. Hasan, and W. Denk, “Two-photon imaging to a depth of 1000 microns in living brains by use of a Ti:Al203 regenerative amplifier,” Opt. Lett. 28, 1022–1024 (2003).
    [Crossref] [PubMed]
  30. H.J. van Staveren, C.J.M. Moes, J. van Marie, S.A. Prahl, and M.J.C. van Gemert, “Light scattering in intralipid-10% in the wavelength range of 400–1100 nm,” Appl .Opt. 30, 4057–4514 (1991).
  31. A.K. Dunn, V.P. Wallace, M. Coleno, M.W. Berns, and B.J. Tromberg, “Influence of optical properties on two-photon fluorescence imaging in turbid samples,” Appl. Opt. 39, 1194–1201 (2000).
    [Crossref]
  32. P.T. Fwua, W. Loa, and C.Y. Dong, “Refractive index determination from multiphoton and confocal spherical aberration microscopy,” in Multiphoton Microscopy in the Biomedical Sciences V, A. Periasamy and P.T.C. So, eds., Proc. SPIE. 5700, 70–77 (2005).
    [Crossref]
  33. T. Collier, D. Arifler, A. Malpica, M. Follen, and R. Richards-Kortum, “Determination of epithelial tissue scattering coefficient using confocal microscopy,” IEEE J.Sele.Top. Qua. Elec. 9, 307–313 (2003).
    [Crossref]
  34. L. Moreaux, O. Saadre, and J. Mertz, “Membrane imaging by second-harmonic generation microscopy,” J. Opt. Soc. Am B, 17, 1685–1694(2000).
    [Crossref]
  35. T. Gutsmann, G. E. Fantner, and M. Venturoni, “Evidence that collagen fibrils in tendons are inhomogeneously structured in a tubelike manner,” Biophys. J. 84, 2593–2598(2003).
    [Crossref] [PubMed]

2005 (9)

M. Han, G. Giese, and J.F. Bille, “Second harmonic generation imaging of collagen fibrils in cornea and sclera,” Opt. Express. 13, 5791–5797 (2005).
[Crossref] [PubMed]

R.M. Williams, W.R. Zipfel, and W.W. Webb, “Interpreting second harmonic generation images of collagen I fibrils,” Biophys. J. 88, 1377–1386 (2005).
[Crossref]

Y. Wu, P. Xi, J.Y. Qu, T.H. Cheung, and M.Y. Yu, “Depth-resolved fluorescence spectroscopy of normal and dysplastic cervical tissue,” Opt. Express. 13,382–388 (2005).
[Crossref] [PubMed]

M.C. Skala, J.M. Squirrell, K.M. Vrotsos, J.C. Eickhoff, A. Gendron-Fitzpatrick, K.W. Eliceiri, and N. Ramanujam, “Multiphoton microscopy of endogenous fluorescence differentiates normal, precancerous, and cancerous squamous,” Cancer. Res. 65, 1180–1186 (2005).
[Crossref] [PubMed]

L.H. Laiho, S. Plete, T.M. Hancewicz, P.D. Kaplan, and P.T.C. So, “Two-photon 3-D mapping of ex vivo human skin endogenous fluorescence species based on fluorescence emission spectra,” J. Biomed. Opt. 10, 0240161–10 (2005).
[Crossref] [PubMed]

S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
[Crossref]

A.T. Yeh, M.J. Hammer-Wilson, D.C.V. Sickle, H.P. Benton, A. Zoumi, B.J. Tromberg, and G.M. Peavy, “Nonlinear optical microscopy of articular cartilage,” Osteoarthritis and Cartilage. 13, 345–352 (2005).
[Crossref] [PubMed]

P.T. Fwua, W. Loa, and C.Y. Dong, “Refractive index determination from multiphoton and confocal spherical aberration microscopy,” in Multiphoton Microscopy in the Biomedical Sciences V, A. Periasamy and P.T.C. So, eds., Proc. SPIE. 5700, 70–77 (2005).
[Crossref]

Y.C. Wu and J.A.Y. Qu, “Two-photon autofluorescence spectroscopy and second-harmonic generation of epithelial tissue,” Opt. Lett. 30, 3045–3047 (2005).
[Crossref] [PubMed]

2004 (3)

A. Zoumi, X. Lu, G.S. Kassab, and B.J. Tromberg, “Imaging coronary artery microstructure using second-harmonic and two-photon fluorescence microscopy,” Biophys. J. 87, 2278–2286 (2004).
[Crossref]

H.S. Lee, Y. Liu, H.C. Chen, L.L. Chiou, G.T. Huang, W. Lo, and C.Y. Dong, “Optical biopsy of liver fibrosis by use of multiphoton microscopy,” Opt. Lett. 29, 2615–2616 (2004).
[Crossref]

D.A. Dombeck, M. Blanchard-Desce, and W.W. Webb, “Optical recording of action potentials with second-harmonic generation microscopy,” J. Neurosci. 24, 999–1003 (2004).
[Crossref] [PubMed]

2003 (8)

E. Brown, T McKee, E. diTomaso, A. Pluen, B. Seed, Y. Boucher, and R.K. Jain, “Dynamic imaging of collagen and its modulation in tumors in vivo using second-harmonic generation,” Nat. Med. 9, 796–800 (2003).
[Crossref] [PubMed]

W.R. Zipfel, R.M. Williams, and W.W. Webb, “Nonlinear magic: multiphoton microscopy in the biosciences,” Nat. Biotechnol. 21, 1369–1377 (2003).
[Crossref] [PubMed]

W.R. Zipfel, R.M. Williams, R. Christie, A.Y. Nikitin, B.T. Hyman, and W.W. Webb, “Live tissue intrinsic emission microscopy using multiphoton-excited native fluorescence and second harmonic generation,” Proc. Natl. Acad. Sci. USA. 100, 7075–7080 (2003).
[Crossref] [PubMed]

P.J Campagnola and L.M. Loew, “Second-harmonic imaging microscopy for visualizing biomolecular arrays in cells, tissues and organisms,” Nat. Biotechnol. 21, 1356–1360 (2003).
[Crossref] [PubMed]

J. Condeelis and J.E. Segall, “Intravital imaging of cell movement in tumours,” Nat.Rev. 3, 921–930 (2003).
[Crossref]

P. Theer, M.T. Hasan, and W. Denk, “Two-photon imaging to a depth of 1000 microns in living brains by use of a Ti:Al203 regenerative amplifier,” Opt. Lett. 28, 1022–1024 (2003).
[Crossref] [PubMed]

T. Collier, D. Arifler, A. Malpica, M. Follen, and R. Richards-Kortum, “Determination of epithelial tissue scattering coefficient using confocal microscopy,” IEEE J.Sele.Top. Qua. Elec. 9, 307–313 (2003).
[Crossref]

T. Gutsmann, G. E. Fantner, and M. Venturoni, “Evidence that collagen fibrils in tendons are inhomogeneously structured in a tubelike manner,” Biophys. J. 84, 2593–2598(2003).
[Crossref] [PubMed]

2002 (4)

S. Huang, A.A. Heikal, and W.W. Webb, “Two-photon fluorescence spectroscopy and microscopy of NAD(P)H and flavoprotein,” Biophys. J. 82, 2811–2825 (2002).
[Crossref] [PubMed]

P.J. Campagnola, A.C. Millard, M. Terasaki, P.E. Hoppe, C.J. Malone, and W.A. Mohle, “Three-dimensional high-resolution second-harmonic generation imaging of endogenous structural proteins in biological tissues,” Biophys. J. 81, 493–508 (2002).
[Crossref]

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

A. Zoumi, A. Yeh, and B.J. Tromberg, “Imaging cells and extracellular matrix in vivo by using second-harmonic generation and two-photon excited fluorescence,” Proc. Natl. Acad. Sci. USA. 99, 11014–11019 (2002).
[Crossref] [PubMed]

2001 (1)

P.J. Campagnola, H.A. Clark, W.A. Mohler, A. Lewis, and L.M. Loew, “Second-harmonic imaging microscopy of living cells,” J. Biomed. Opt. 6, 227–286 (2001).
[Crossref]

2000 (3)

B.M. Kim, J. Eichler, K.M. Reiser, A.M. Rubenchik, and L.B.D. Silva, “Collagen structure and nonlinear susceptibility: effects of heat, glycation, and enzymatic cleavage on second harmonic signal intensity,” Lasers Surg. Med. 27, 329–335 (2000).
[Crossref] [PubMed]

A.K. Dunn, V.P. Wallace, M. Coleno, M.W. Berns, and B.J. Tromberg, “Influence of optical properties on two-photon fluorescence imaging in turbid samples,” Appl. Opt. 39, 1194–1201 (2000).
[Crossref]

L. Moreaux, O. Saadre, and J. Mertz, “Membrane imaging by second-harmonic generation microscopy,” J. Opt. Soc. Am B, 17, 1685–1694(2000).
[Crossref]

1999 (3)

L. Debelle and A.M. Tamburro, “Elastin: molecular description and function,” Int. J. Biochem. Cell. Biol. 31, 261–272 (1999).
[Crossref] [PubMed]

Y.C. Guo, H.E. Savage, F. Liu, S.P. Schantz, P.P. Ho, and R.R. Alfano, “Subsurface tumor progression investigated by noninvasive optical second harmonic tomography,” Proc. Natl. Acad. Sci. USA. 96, 10854–10856 (1999).
[Crossref] [PubMed]

P.J. Campagnola, M.D Wei, A. Lewis, and L.M. Loew, “High-resolution nonlinear optical imaging of live cells by second harmonic generation,” Biophys. J. 77, 3341–3349 (1999).
[Crossref] [PubMed]

1998 (1)

D.Y. Li, B. Brooke, E.C. Davis, R.P. Mecham, L.K. Sorensen, B.B. Boak, E. Eichwald, and M.T. Keating, “Elastin is an essential determinant of arterial morphogenesis,” Nature. 393, 276–280 (1998).
[Crossref] [PubMed]

1997 (1)

B.R. Masters, P.T.C. So, and E. Gratton, “Multiphoton excitation fluorescence microscopy and spectroscopy of in vivo human skin,” Biophys. J. 72, 2405–2412 (1997).
[Crossref] [PubMed]

1996 (1)

R.K. Rebecca and S.M. Eva, “Quantitative optical spectroscopy for tissue diagnosis,” Annu. Rev. Phys. Chem. 47, 555–606 (1996).
[Crossref]

1991 (1)

H.J. van Staveren, C.J.M. Moes, J. van Marie, S.A. Prahl, and M.J.C. van Gemert, “Light scattering in intralipid-10% in the wavelength range of 400–1100 nm,” Appl .Opt. 30, 4057–4514 (1991).

Alfano, R.R.

Y.C. Guo, H.E. Savage, F. Liu, S.P. Schantz, P.P. Ho, and R.R. Alfano, “Subsurface tumor progression investigated by noninvasive optical second harmonic tomography,” Proc. Natl. Acad. Sci. USA. 96, 10854–10856 (1999).
[Crossref] [PubMed]

Arifler, D.

T. Collier, D. Arifler, A. Malpica, M. Follen, and R. Richards-Kortum, “Determination of epithelial tissue scattering coefficient using confocal microscopy,” IEEE J.Sele.Top. Qua. Elec. 9, 307–313 (2003).
[Crossref]

Badizadegan, K.

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

Benton, H.P.

A.T. Yeh, M.J. Hammer-Wilson, D.C.V. Sickle, H.P. Benton, A. Zoumi, B.J. Tromberg, and G.M. Peavy, “Nonlinear optical microscopy of articular cartilage,” Osteoarthritis and Cartilage. 13, 345–352 (2005).
[Crossref] [PubMed]

Berns, M.W.

Bille, J.F.

M. Han, G. Giese, and J.F. Bille, “Second harmonic generation imaging of collagen fibrils in cornea and sclera,” Opt. Express. 13, 5791–5797 (2005).
[Crossref] [PubMed]

Blanchard-Desce, M.

D.A. Dombeck, M. Blanchard-Desce, and W.W. Webb, “Optical recording of action potentials with second-harmonic generation microscopy,” J. Neurosci. 24, 999–1003 (2004).
[Crossref] [PubMed]

Boak, B.B.

D.Y. Li, B. Brooke, E.C. Davis, R.P. Mecham, L.K. Sorensen, B.B. Boak, E. Eichwald, and M.T. Keating, “Elastin is an essential determinant of arterial morphogenesis,” Nature. 393, 276–280 (1998).
[Crossref] [PubMed]

Boone, C.W.

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

Boucher, Y.

E. Brown, T McKee, E. diTomaso, A. Pluen, B. Seed, Y. Boucher, and R.K. Jain, “Dynamic imaging of collagen and its modulation in tumors in vivo using second-harmonic generation,” Nat. Med. 9, 796–800 (2003).
[Crossref] [PubMed]

Brooke, B.

D.Y. Li, B. Brooke, E.C. Davis, R.P. Mecham, L.K. Sorensen, B.B. Boak, E. Eichwald, and M.T. Keating, “Elastin is an essential determinant of arterial morphogenesis,” Nature. 393, 276–280 (1998).
[Crossref] [PubMed]

Brown, E.

E. Brown, T McKee, E. diTomaso, A. Pluen, B. Seed, Y. Boucher, and R.K. Jain, “Dynamic imaging of collagen and its modulation in tumors in vivo using second-harmonic generation,” Nat. Med. 9, 796–800 (2003).
[Crossref] [PubMed]

Campagnola, P.J

P.J Campagnola and L.M. Loew, “Second-harmonic imaging microscopy for visualizing biomolecular arrays in cells, tissues and organisms,” Nat. Biotechnol. 21, 1356–1360 (2003).
[Crossref] [PubMed]

Campagnola, P.J.

P.J. Campagnola, A.C. Millard, M. Terasaki, P.E. Hoppe, C.J. Malone, and W.A. Mohle, “Three-dimensional high-resolution second-harmonic generation imaging of endogenous structural proteins in biological tissues,” Biophys. J. 81, 493–508 (2002).
[Crossref]

P.J. Campagnola, H.A. Clark, W.A. Mohler, A. Lewis, and L.M. Loew, “Second-harmonic imaging microscopy of living cells,” J. Biomed. Opt. 6, 227–286 (2001).
[Crossref]

P.J. Campagnola, M.D Wei, A. Lewis, and L.M. Loew, “High-resolution nonlinear optical imaging of live cells by second harmonic generation,” Biophys. J. 77, 3341–3349 (1999).
[Crossref] [PubMed]

Chen, H.C.

H.S. Lee, Y. Liu, H.C. Chen, L.L. Chiou, G.T. Huang, W. Lo, and C.Y. Dong, “Optical biopsy of liver fibrosis by use of multiphoton microscopy,” Opt. Lett. 29, 2615–2616 (2004).
[Crossref]

Chen, J.S.

S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
[Crossref]

Cheung, T.H.

Y. Wu, P. Xi, J.Y. Qu, T.H. Cheung, and M.Y. Yu, “Depth-resolved fluorescence spectroscopy of normal and dysplastic cervical tissue,” Opt. Express. 13,382–388 (2005).
[Crossref] [PubMed]

Chiou, L.L.

H.S. Lee, Y. Liu, H.C. Chen, L.L. Chiou, G.T. Huang, W. Lo, and C.Y. Dong, “Optical biopsy of liver fibrosis by use of multiphoton microscopy,” Opt. Lett. 29, 2615–2616 (2004).
[Crossref]

Christie, R.

W.R. Zipfel, R.M. Williams, R. Christie, A.Y. Nikitin, B.T. Hyman, and W.W. Webb, “Live tissue intrinsic emission microscopy using multiphoton-excited native fluorescence and second harmonic generation,” Proc. Natl. Acad. Sci. USA. 100, 7075–7080 (2003).
[Crossref] [PubMed]

Clark, H.A.

P.J. Campagnola, H.A. Clark, W.A. Mohler, A. Lewis, and L.M. Loew, “Second-harmonic imaging microscopy of living cells,” J. Biomed. Opt. 6, 227–286 (2001).
[Crossref]

Coleno, M.

Collier, T.

T. Collier, D. Arifler, A. Malpica, M. Follen, and R. Richards-Kortum, “Determination of epithelial tissue scattering coefficient using confocal microscopy,” IEEE J.Sele.Top. Qua. Elec. 9, 307–313 (2003).
[Crossref]

Condeelis, J.

J. Condeelis and J.E. Segall, “Intravital imaging of cell movement in tumours,” Nat.Rev. 3, 921–930 (2003).
[Crossref]

Crum, C.P.

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

Dam, J.V.

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

Dasari, R. R.

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

Davis, E.C.

D.Y. Li, B. Brooke, E.C. Davis, R.P. Mecham, L.K. Sorensen, B.B. Boak, E. Eichwald, and M.T. Keating, “Elastin is an essential determinant of arterial morphogenesis,” Nature. 393, 276–280 (1998).
[Crossref] [PubMed]

Debelle, L.

L. Debelle and A.M. Tamburro, “Elastin: molecular description and function,” Int. J. Biochem. Cell. Biol. 31, 261–272 (1999).
[Crossref] [PubMed]

Denk, W.

diTomaso, E.

E. Brown, T McKee, E. diTomaso, A. Pluen, B. Seed, Y. Boucher, and R.K. Jain, “Dynamic imaging of collagen and its modulation in tumors in vivo using second-harmonic generation,” Nat. Med. 9, 796–800 (2003).
[Crossref] [PubMed]

Dombeck, D.A.

D.A. Dombeck, M. Blanchard-Desce, and W.W. Webb, “Optical recording of action potentials with second-harmonic generation microscopy,” J. Neurosci. 24, 999–1003 (2004).
[Crossref] [PubMed]

Dong, C.Y.

S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
[Crossref]

P.T. Fwua, W. Loa, and C.Y. Dong, “Refractive index determination from multiphoton and confocal spherical aberration microscopy,” in Multiphoton Microscopy in the Biomedical Sciences V, A. Periasamy and P.T.C. So, eds., Proc. SPIE. 5700, 70–77 (2005).
[Crossref]

H.S. Lee, Y. Liu, H.C. Chen, L.L. Chiou, G.T. Huang, W. Lo, and C.Y. Dong, “Optical biopsy of liver fibrosis by use of multiphoton microscopy,” Opt. Lett. 29, 2615–2616 (2004).
[Crossref]

Dunn, A.K.

Eichler, J.

B.M. Kim, J. Eichler, K.M. Reiser, A.M. Rubenchik, and L.B.D. Silva, “Collagen structure and nonlinear susceptibility: effects of heat, glycation, and enzymatic cleavage on second harmonic signal intensity,” Lasers Surg. Med. 27, 329–335 (2000).
[Crossref] [PubMed]

Eichwald, E.

D.Y. Li, B. Brooke, E.C. Davis, R.P. Mecham, L.K. Sorensen, B.B. Boak, E. Eichwald, and M.T. Keating, “Elastin is an essential determinant of arterial morphogenesis,” Nature. 393, 276–280 (1998).
[Crossref] [PubMed]

Eickhoff, J.C.

M.C. Skala, J.M. Squirrell, K.M. Vrotsos, J.C. Eickhoff, A. Gendron-Fitzpatrick, K.W. Eliceiri, and N. Ramanujam, “Multiphoton microscopy of endogenous fluorescence differentiates normal, precancerous, and cancerous squamous,” Cancer. Res. 65, 1180–1186 (2005).
[Crossref] [PubMed]

Eliceiri, K.W.

M.C. Skala, J.M. Squirrell, K.M. Vrotsos, J.C. Eickhoff, A. Gendron-Fitzpatrick, K.W. Eliceiri, and N. Ramanujam, “Multiphoton microscopy of endogenous fluorescence differentiates normal, precancerous, and cancerous squamous,” Cancer. Res. 65, 1180–1186 (2005).
[Crossref] [PubMed]

Eva, S.M.

R.K. Rebecca and S.M. Eva, “Quantitative optical spectroscopy for tissue diagnosis,” Annu. Rev. Phys. Chem. 47, 555–606 (1996).
[Crossref]

Fantner, G. E.

T. Gutsmann, G. E. Fantner, and M. Venturoni, “Evidence that collagen fibrils in tendons are inhomogeneously structured in a tubelike manner,” Biophys. J. 84, 2593–2598(2003).
[Crossref] [PubMed]

Feld, M.S.

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

Follen, M.

T. Collier, D. Arifler, A. Malpica, M. Follen, and R. Richards-Kortum, “Determination of epithelial tissue scattering coefficient using confocal microscopy,” IEEE J.Sele.Top. Qua. Elec. 9, 307–313 (2003).
[Crossref]

Fwua, P.T.

P.T. Fwua, W. Loa, and C.Y. Dong, “Refractive index determination from multiphoton and confocal spherical aberration microscopy,” in Multiphoton Microscopy in the Biomedical Sciences V, A. Periasamy and P.T.C. So, eds., Proc. SPIE. 5700, 70–77 (2005).
[Crossref]

Gemert, M.J.C. van

H.J. van Staveren, C.J.M. Moes, J. van Marie, S.A. Prahl, and M.J.C. van Gemert, “Light scattering in intralipid-10% in the wavelength range of 400–1100 nm,” Appl .Opt. 30, 4057–4514 (1991).

Gendron-Fitzpatrick, A.

M.C. Skala, J.M. Squirrell, K.M. Vrotsos, J.C. Eickhoff, A. Gendron-Fitzpatrick, K.W. Eliceiri, and N. Ramanujam, “Multiphoton microscopy of endogenous fluorescence differentiates normal, precancerous, and cancerous squamous,” Cancer. Res. 65, 1180–1186 (2005).
[Crossref] [PubMed]

Georgakoudi, I.

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

Giese, G.

M. Han, G. Giese, and J.F. Bille, “Second harmonic generation imaging of collagen fibrils in cornea and sclera,” Opt. Express. 13, 5791–5797 (2005).
[Crossref] [PubMed]

Gratton, E.

B.R. Masters, P.T.C. So, and E. Gratton, “Multiphoton excitation fluorescence microscopy and spectroscopy of in vivo human skin,” Biophys. J. 72, 2405–2412 (1997).
[Crossref] [PubMed]

Guo, Y.C.

Y.C. Guo, H.E. Savage, F. Liu, S.P. Schantz, P.P. Ho, and R.R. Alfano, “Subsurface tumor progression investigated by noninvasive optical second harmonic tomography,” Proc. Natl. Acad. Sci. USA. 96, 10854–10856 (1999).
[Crossref] [PubMed]

Gutsmann, T.

T. Gutsmann, G. E. Fantner, and M. Venturoni, “Evidence that collagen fibrils in tendons are inhomogeneously structured in a tubelike manner,” Biophys. J. 84, 2593–2598(2003).
[Crossref] [PubMed]

Hammer-Wilson, M.J.

A.T. Yeh, M.J. Hammer-Wilson, D.C.V. Sickle, H.P. Benton, A. Zoumi, B.J. Tromberg, and G.M. Peavy, “Nonlinear optical microscopy of articular cartilage,” Osteoarthritis and Cartilage. 13, 345–352 (2005).
[Crossref] [PubMed]

Han, M.

M. Han, G. Giese, and J.F. Bille, “Second harmonic generation imaging of collagen fibrils in cornea and sclera,” Opt. Express. 13, 5791–5797 (2005).
[Crossref] [PubMed]

Hancewicz, T.M.

L.H. Laiho, S. Plete, T.M. Hancewicz, P.D. Kaplan, and P.T.C. So, “Two-photon 3-D mapping of ex vivo human skin endogenous fluorescence species based on fluorescence emission spectra,” J. Biomed. Opt. 10, 0240161–10 (2005).
[Crossref] [PubMed]

Hasan, M.T.

Heikal, A.A.

S. Huang, A.A. Heikal, and W.W. Webb, “Two-photon fluorescence spectroscopy and microscopy of NAD(P)H and flavoprotein,” Biophys. J. 82, 2811–2825 (2002).
[Crossref] [PubMed]

Ho, P.P.

Y.C. Guo, H.E. Savage, F. Liu, S.P. Schantz, P.P. Ho, and R.R. Alfano, “Subsurface tumor progression investigated by noninvasive optical second harmonic tomography,” Proc. Natl. Acad. Sci. USA. 96, 10854–10856 (1999).
[Crossref] [PubMed]

Hoppe, P.E.

P.J. Campagnola, A.C. Millard, M. Terasaki, P.E. Hoppe, C.J. Malone, and W.A. Mohle, “Three-dimensional high-resolution second-harmonic generation imaging of endogenous structural proteins in biological tissues,” Biophys. J. 81, 493–508 (2002).
[Crossref]

Hsu, C.J.

S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
[Crossref]

Huang, G.T.

H.S. Lee, Y. Liu, H.C. Chen, L.L. Chiou, G.T. Huang, W. Lo, and C.Y. Dong, “Optical biopsy of liver fibrosis by use of multiphoton microscopy,” Opt. Lett. 29, 2615–2616 (2004).
[Crossref]

Huang, S.

S. Huang, A.A. Heikal, and W.W. Webb, “Two-photon fluorescence spectroscopy and microscopy of NAD(P)H and flavoprotein,” Biophys. J. 82, 2811–2825 (2002).
[Crossref] [PubMed]

Hyman, B.T.

W.R. Zipfel, R.M. Williams, R. Christie, A.Y. Nikitin, B.T. Hyman, and W.W. Webb, “Live tissue intrinsic emission microscopy using multiphoton-excited native fluorescence and second harmonic generation,” Proc. Natl. Acad. Sci. USA. 100, 7075–7080 (2003).
[Crossref] [PubMed]

Jacobson, B.C.

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

Jain, R.K.

E. Brown, T McKee, E. diTomaso, A. Pluen, B. Seed, Y. Boucher, and R.K. Jain, “Dynamic imaging of collagen and its modulation in tumors in vivo using second-harmonic generation,” Nat. Med. 9, 796–800 (2003).
[Crossref] [PubMed]

Jee, S.H.

S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
[Crossref]

Kaplan, P.D.

L.H. Laiho, S. Plete, T.M. Hancewicz, P.D. Kaplan, and P.T.C. So, “Two-photon 3-D mapping of ex vivo human skin endogenous fluorescence species based on fluorescence emission spectra,” J. Biomed. Opt. 10, 0240161–10 (2005).
[Crossref] [PubMed]

Kassab, G.S.

A. Zoumi, X. Lu, G.S. Kassab, and B.J. Tromberg, “Imaging coronary artery microstructure using second-harmonic and two-photon fluorescence microscopy,” Biophys. J. 87, 2278–2286 (2004).
[Crossref]

Keating, M.T.

D.Y. Li, B. Brooke, E.C. Davis, R.P. Mecham, L.K. Sorensen, B.B. Boak, E. Eichwald, and M.T. Keating, “Elastin is an essential determinant of arterial morphogenesis,” Nature. 393, 276–280 (1998).
[Crossref] [PubMed]

Kim, B.M.

B.M. Kim, J. Eichler, K.M. Reiser, A.M. Rubenchik, and L.B.D. Silva, “Collagen structure and nonlinear susceptibility: effects of heat, glycation, and enzymatic cleavage on second harmonic signal intensity,” Lasers Surg. Med. 27, 329–335 (2000).
[Crossref] [PubMed]

Laiho, L.H.

L.H. Laiho, S. Plete, T.M. Hancewicz, P.D. Kaplan, and P.T.C. So, “Two-photon 3-D mapping of ex vivo human skin endogenous fluorescence species based on fluorescence emission spectra,” J. Biomed. Opt. 10, 0240161–10 (2005).
[Crossref] [PubMed]

Lee, H.S.

H.S. Lee, Y. Liu, H.C. Chen, L.L. Chiou, G.T. Huang, W. Lo, and C.Y. Dong, “Optical biopsy of liver fibrosis by use of multiphoton microscopy,” Opt. Lett. 29, 2615–2616 (2004).
[Crossref]

Lewis, A.

P.J. Campagnola, H.A. Clark, W.A. Mohler, A. Lewis, and L.M. Loew, “Second-harmonic imaging microscopy of living cells,” J. Biomed. Opt. 6, 227–286 (2001).
[Crossref]

P.J. Campagnola, M.D Wei, A. Lewis, and L.M. Loew, “High-resolution nonlinear optical imaging of live cells by second harmonic generation,” Biophys. J. 77, 3341–3349 (1999).
[Crossref] [PubMed]

Li, D.Y.

D.Y. Li, B. Brooke, E.C. Davis, R.P. Mecham, L.K. Sorensen, B.B. Boak, E. Eichwald, and M.T. Keating, “Elastin is an essential determinant of arterial morphogenesis,” Nature. 393, 276–280 (1998).
[Crossref] [PubMed]

Lin, S.J.

S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
[Crossref]

Lin, W.C.

S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
[Crossref]

Liu, F.

Y.C. Guo, H.E. Savage, F. Liu, S.P. Schantz, P.P. Ho, and R.R. Alfano, “Subsurface tumor progression investigated by noninvasive optical second harmonic tomography,” Proc. Natl. Acad. Sci. USA. 96, 10854–10856 (1999).
[Crossref] [PubMed]

Liu, Y.

H.S. Lee, Y. Liu, H.C. Chen, L.L. Chiou, G.T. Huang, W. Lo, and C.Y. Dong, “Optical biopsy of liver fibrosis by use of multiphoton microscopy,” Opt. Lett. 29, 2615–2616 (2004).
[Crossref]

Lo, W.

S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
[Crossref]

H.S. Lee, Y. Liu, H.C. Chen, L.L. Chiou, G.T. Huang, W. Lo, and C.Y. Dong, “Optical biopsy of liver fibrosis by use of multiphoton microscopy,” Opt. Lett. 29, 2615–2616 (2004).
[Crossref]

Loa, W.

P.T. Fwua, W. Loa, and C.Y. Dong, “Refractive index determination from multiphoton and confocal spherical aberration microscopy,” in Multiphoton Microscopy in the Biomedical Sciences V, A. Periasamy and P.T.C. So, eds., Proc. SPIE. 5700, 70–77 (2005).
[Crossref]

Locke, D.L. C.

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

Loew, L.M.

P.J Campagnola and L.M. Loew, “Second-harmonic imaging microscopy for visualizing biomolecular arrays in cells, tissues and organisms,” Nat. Biotechnol. 21, 1356–1360 (2003).
[Crossref] [PubMed]

P.J. Campagnola, H.A. Clark, W.A. Mohler, A. Lewis, and L.M. Loew, “Second-harmonic imaging microscopy of living cells,” J. Biomed. Opt. 6, 227–286 (2001).
[Crossref]

P.J. Campagnola, M.D Wei, A. Lewis, and L.M. Loew, “High-resolution nonlinear optical imaging of live cells by second harmonic generation,” Biophys. J. 77, 3341–3349 (1999).
[Crossref] [PubMed]

Lu, X.

A. Zoumi, X. Lu, G.S. Kassab, and B.J. Tromberg, “Imaging coronary artery microstructure using second-harmonic and two-photon fluorescence microscopy,” Biophys. J. 87, 2278–2286 (2004).
[Crossref]

Malone, C.J.

P.J. Campagnola, A.C. Millard, M. Terasaki, P.E. Hoppe, C.J. Malone, and W.A. Mohle, “Three-dimensional high-resolution second-harmonic generation imaging of endogenous structural proteins in biological tissues,” Biophys. J. 81, 493–508 (2002).
[Crossref]

Malpica, A.

T. Collier, D. Arifler, A. Malpica, M. Follen, and R. Richards-Kortum, “Determination of epithelial tissue scattering coefficient using confocal microscopy,” IEEE J.Sele.Top. Qua. Elec. 9, 307–313 (2003).
[Crossref]

Marie, J. van

H.J. van Staveren, C.J.M. Moes, J. van Marie, S.A. Prahl, and M.J.C. van Gemert, “Light scattering in intralipid-10% in the wavelength range of 400–1100 nm,” Appl .Opt. 30, 4057–4514 (1991).

Masters, B.R.

B.R. Masters, P.T.C. So, and E. Gratton, “Multiphoton excitation fluorescence microscopy and spectroscopy of in vivo human skin,” Biophys. J. 72, 2405–2412 (1997).
[Crossref] [PubMed]

McKee, T

E. Brown, T McKee, E. diTomaso, A. Pluen, B. Seed, Y. Boucher, and R.K. Jain, “Dynamic imaging of collagen and its modulation in tumors in vivo using second-harmonic generation,” Nat. Med. 9, 796–800 (2003).
[Crossref] [PubMed]

Mecham, R.P.

D.Y. Li, B. Brooke, E.C. Davis, R.P. Mecham, L.K. Sorensen, B.B. Boak, E. Eichwald, and M.T. Keating, “Elastin is an essential determinant of arterial morphogenesis,” Nature. 393, 276–280 (1998).
[Crossref] [PubMed]

Mertz, J.

L. Moreaux, O. Saadre, and J. Mertz, “Membrane imaging by second-harmonic generation microscopy,” J. Opt. Soc. Am B, 17, 1685–1694(2000).
[Crossref]

Millard, A.C.

P.J. Campagnola, A.C. Millard, M. Terasaki, P.E. Hoppe, C.J. Malone, and W.A. Mohle, “Three-dimensional high-resolution second-harmonic generation imaging of endogenous structural proteins in biological tissues,” Biophys. J. 81, 493–508 (2002).
[Crossref]

Moes, C.J.M.

H.J. van Staveren, C.J.M. Moes, J. van Marie, S.A. Prahl, and M.J.C. van Gemert, “Light scattering in intralipid-10% in the wavelength range of 400–1100 nm,” Appl .Opt. 30, 4057–4514 (1991).

Mohle, W.A.

P.J. Campagnola, A.C. Millard, M. Terasaki, P.E. Hoppe, C.J. Malone, and W.A. Mohle, “Three-dimensional high-resolution second-harmonic generation imaging of endogenous structural proteins in biological tissues,” Biophys. J. 81, 493–508 (2002).
[Crossref]

Mohler, W.A.

P.J. Campagnola, H.A. Clark, W.A. Mohler, A. Lewis, and L.M. Loew, “Second-harmonic imaging microscopy of living cells,” J. Biomed. Opt. 6, 227–286 (2001).
[Crossref]

Moreaux, L.

L. Moreaux, O. Saadre, and J. Mertz, “Membrane imaging by second-harmonic generation microscopy,” J. Opt. Soc. Am B, 17, 1685–1694(2000).
[Crossref]

Muller, M.G.

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

Nikitin, A.Y.

W.R. Zipfel, R.M. Williams, R. Christie, A.Y. Nikitin, B.T. Hyman, and W.W. Webb, “Live tissue intrinsic emission microscopy using multiphoton-excited native fluorescence and second harmonic generation,” Proc. Natl. Acad. Sci. USA. 100, 7075–7080 (2003).
[Crossref] [PubMed]

Peavy, G.M.

A.T. Yeh, M.J. Hammer-Wilson, D.C.V. Sickle, H.P. Benton, A. Zoumi, B.J. Tromberg, and G.M. Peavy, “Nonlinear optical microscopy of articular cartilage,” Osteoarthritis and Cartilage. 13, 345–352 (2005).
[Crossref] [PubMed]

Plete, S.

L.H. Laiho, S. Plete, T.M. Hancewicz, P.D. Kaplan, and P.T.C. So, “Two-photon 3-D mapping of ex vivo human skin endogenous fluorescence species based on fluorescence emission spectra,” J. Biomed. Opt. 10, 0240161–10 (2005).
[Crossref] [PubMed]

Pluen, A.

E. Brown, T McKee, E. diTomaso, A. Pluen, B. Seed, Y. Boucher, and R.K. Jain, “Dynamic imaging of collagen and its modulation in tumors in vivo using second-harmonic generation,” Nat. Med. 9, 796–800 (2003).
[Crossref] [PubMed]

Prahl, S.A.

H.J. van Staveren, C.J.M. Moes, J. van Marie, S.A. Prahl, and M.J.C. van Gemert, “Light scattering in intralipid-10% in the wavelength range of 400–1100 nm,” Appl .Opt. 30, 4057–4514 (1991).

Qu, J.A.Y.

Qu, J.Y.

Y. Wu, P. Xi, J.Y. Qu, T.H. Cheung, and M.Y. Yu, “Depth-resolved fluorescence spectroscopy of normal and dysplastic cervical tissue,” Opt. Express. 13,382–388 (2005).
[Crossref] [PubMed]

Ramanujam, N.

M.C. Skala, J.M. Squirrell, K.M. Vrotsos, J.C. Eickhoff, A. Gendron-Fitzpatrick, K.W. Eliceiri, and N. Ramanujam, “Multiphoton microscopy of endogenous fluorescence differentiates normal, precancerous, and cancerous squamous,” Cancer. Res. 65, 1180–1186 (2005).
[Crossref] [PubMed]

Rebecca, R.K.

R.K. Rebecca and S.M. Eva, “Quantitative optical spectroscopy for tissue diagnosis,” Annu. Rev. Phys. Chem. 47, 555–606 (1996).
[Crossref]

Reiser, K.M.

B.M. Kim, J. Eichler, K.M. Reiser, A.M. Rubenchik, and L.B.D. Silva, “Collagen structure and nonlinear susceptibility: effects of heat, glycation, and enzymatic cleavage on second harmonic signal intensity,” Lasers Surg. Med. 27, 329–335 (2000).
[Crossref] [PubMed]

Richards-Kortum, R.

T. Collier, D. Arifler, A. Malpica, M. Follen, and R. Richards-Kortum, “Determination of epithelial tissue scattering coefficient using confocal microscopy,” IEEE J.Sele.Top. Qua. Elec. 9, 307–313 (2003).
[Crossref]

Rubenchik, A.M.

B.M. Kim, J. Eichler, K.M. Reiser, A.M. Rubenchik, and L.B.D. Silva, “Collagen structure and nonlinear susceptibility: effects of heat, glycation, and enzymatic cleavage on second harmonic signal intensity,” Lasers Surg. Med. 27, 329–335 (2000).
[Crossref] [PubMed]

Saadre, O.

L. Moreaux, O. Saadre, and J. Mertz, “Membrane imaging by second-harmonic generation microscopy,” J. Opt. Soc. Am B, 17, 1685–1694(2000).
[Crossref]

Savage, H.E.

Y.C. Guo, H.E. Savage, F. Liu, S.P. Schantz, P.P. Ho, and R.R. Alfano, “Subsurface tumor progression investigated by noninvasive optical second harmonic tomography,” Proc. Natl. Acad. Sci. USA. 96, 10854–10856 (1999).
[Crossref] [PubMed]

Schantz, S.P.

Y.C. Guo, H.E. Savage, F. Liu, S.P. Schantz, P.P. Ho, and R.R. Alfano, “Subsurface tumor progression investigated by noninvasive optical second harmonic tomography,” Proc. Natl. Acad. Sci. USA. 96, 10854–10856 (1999).
[Crossref] [PubMed]

Seed, B.

E. Brown, T McKee, E. diTomaso, A. Pluen, B. Seed, Y. Boucher, and R.K. Jain, “Dynamic imaging of collagen and its modulation in tumors in vivo using second-harmonic generation,” Nat. Med. 9, 796–800 (2003).
[Crossref] [PubMed]

Segall, J.E.

J. Condeelis and J.E. Segall, “Intravital imaging of cell movement in tumours,” Nat.Rev. 3, 921–930 (2003).
[Crossref]

Sheets, E.E.

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

Sickle, D.C.V.

A.T. Yeh, M.J. Hammer-Wilson, D.C.V. Sickle, H.P. Benton, A. Zoumi, B.J. Tromberg, and G.M. Peavy, “Nonlinear optical microscopy of articular cartilage,” Osteoarthritis and Cartilage. 13, 345–352 (2005).
[Crossref] [PubMed]

Silva, L.B.D.

B.M. Kim, J. Eichler, K.M. Reiser, A.M. Rubenchik, and L.B.D. Silva, “Collagen structure and nonlinear susceptibility: effects of heat, glycation, and enzymatic cleavage on second harmonic signal intensity,” Lasers Surg. Med. 27, 329–335 (2000).
[Crossref] [PubMed]

Skala, M.C.

M.C. Skala, J.M. Squirrell, K.M. Vrotsos, J.C. Eickhoff, A. Gendron-Fitzpatrick, K.W. Eliceiri, and N. Ramanujam, “Multiphoton microscopy of endogenous fluorescence differentiates normal, precancerous, and cancerous squamous,” Cancer. Res. 65, 1180–1186 (2005).
[Crossref] [PubMed]

So, P.T.C.

L.H. Laiho, S. Plete, T.M. Hancewicz, P.D. Kaplan, and P.T.C. So, “Two-photon 3-D mapping of ex vivo human skin endogenous fluorescence species based on fluorescence emission spectra,” J. Biomed. Opt. 10, 0240161–10 (2005).
[Crossref] [PubMed]

B.R. Masters, P.T.C. So, and E. Gratton, “Multiphoton excitation fluorescence microscopy and spectroscopy of in vivo human skin,” Biophys. J. 72, 2405–2412 (1997).
[Crossref] [PubMed]

Sorensen, L.K.

D.Y. Li, B. Brooke, E.C. Davis, R.P. Mecham, L.K. Sorensen, B.B. Boak, E. Eichwald, and M.T. Keating, “Elastin is an essential determinant of arterial morphogenesis,” Nature. 393, 276–280 (1998).
[Crossref] [PubMed]

Squirrell, J.M.

M.C. Skala, J.M. Squirrell, K.M. Vrotsos, J.C. Eickhoff, A. Gendron-Fitzpatrick, K.W. Eliceiri, and N. Ramanujam, “Multiphoton microscopy of endogenous fluorescence differentiates normal, precancerous, and cancerous squamous,” Cancer. Res. 65, 1180–1186 (2005).
[Crossref] [PubMed]

Staveren, H.J. van

H.J. van Staveren, C.J.M. Moes, J. van Marie, S.A. Prahl, and M.J.C. van Gemert, “Light scattering in intralipid-10% in the wavelength range of 400–1100 nm,” Appl .Opt. 30, 4057–4514 (1991).

Tamburro, A.M.

L. Debelle and A.M. Tamburro, “Elastin: molecular description and function,” Int. J. Biochem. Cell. Biol. 31, 261–272 (1999).
[Crossref] [PubMed]

Tan, H.Y.

S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
[Crossref]

Terasaki, M.

P.J. Campagnola, A.C. Millard, M. Terasaki, P.E. Hoppe, C.J. Malone, and W.A. Mohle, “Three-dimensional high-resolution second-harmonic generation imaging of endogenous structural proteins in biological tissues,” Biophys. J. 81, 493–508 (2002).
[Crossref]

Theer, P.

Tromberg, B.J.

A.T. Yeh, M.J. Hammer-Wilson, D.C.V. Sickle, H.P. Benton, A. Zoumi, B.J. Tromberg, and G.M. Peavy, “Nonlinear optical microscopy of articular cartilage,” Osteoarthritis and Cartilage. 13, 345–352 (2005).
[Crossref] [PubMed]

A. Zoumi, X. Lu, G.S. Kassab, and B.J. Tromberg, “Imaging coronary artery microstructure using second-harmonic and two-photon fluorescence microscopy,” Biophys. J. 87, 2278–2286 (2004).
[Crossref]

A. Zoumi, A. Yeh, and B.J. Tromberg, “Imaging cells and extracellular matrix in vivo by using second-harmonic generation and two-photon excited fluorescence,” Proc. Natl. Acad. Sci. USA. 99, 11014–11019 (2002).
[Crossref] [PubMed]

A.K. Dunn, V.P. Wallace, M. Coleno, M.W. Berns, and B.J. Tromberg, “Influence of optical properties on two-photon fluorescence imaging in turbid samples,” Appl. Opt. 39, 1194–1201 (2000).
[Crossref]

Venturoni, M.

T. Gutsmann, G. E. Fantner, and M. Venturoni, “Evidence that collagen fibrils in tendons are inhomogeneously structured in a tubelike manner,” Biophys. J. 84, 2593–2598(2003).
[Crossref] [PubMed]

Vrotsos, K.M.

M.C. Skala, J.M. Squirrell, K.M. Vrotsos, J.C. Eickhoff, A. Gendron-Fitzpatrick, K.W. Eliceiri, and N. Ramanujam, “Multiphoton microscopy of endogenous fluorescence differentiates normal, precancerous, and cancerous squamous,” Cancer. Res. 65, 1180–1186 (2005).
[Crossref] [PubMed]

Wallace, V.P.

Webb, W.W.

R.M. Williams, W.R. Zipfel, and W.W. Webb, “Interpreting second harmonic generation images of collagen I fibrils,” Biophys. J. 88, 1377–1386 (2005).
[Crossref]

D.A. Dombeck, M. Blanchard-Desce, and W.W. Webb, “Optical recording of action potentials with second-harmonic generation microscopy,” J. Neurosci. 24, 999–1003 (2004).
[Crossref] [PubMed]

W.R. Zipfel, R.M. Williams, R. Christie, A.Y. Nikitin, B.T. Hyman, and W.W. Webb, “Live tissue intrinsic emission microscopy using multiphoton-excited native fluorescence and second harmonic generation,” Proc. Natl. Acad. Sci. USA. 100, 7075–7080 (2003).
[Crossref] [PubMed]

W.R. Zipfel, R.M. Williams, and W.W. Webb, “Nonlinear magic: multiphoton microscopy in the biosciences,” Nat. Biotechnol. 21, 1369–1377 (2003).
[Crossref] [PubMed]

S. Huang, A.A. Heikal, and W.W. Webb, “Two-photon fluorescence spectroscopy and microscopy of NAD(P)H and flavoprotein,” Biophys. J. 82, 2811–2825 (2002).
[Crossref] [PubMed]

Wei, M.D

P.J. Campagnola, M.D Wei, A. Lewis, and L.M. Loew, “High-resolution nonlinear optical imaging of live cells by second harmonic generation,” Biophys. J. 77, 3341–3349 (1999).
[Crossref] [PubMed]

Williams, R.M.

R.M. Williams, W.R. Zipfel, and W.W. Webb, “Interpreting second harmonic generation images of collagen I fibrils,” Biophys. J. 88, 1377–1386 (2005).
[Crossref]

W.R. Zipfel, R.M. Williams, R. Christie, A.Y. Nikitin, B.T. Hyman, and W.W. Webb, “Live tissue intrinsic emission microscopy using multiphoton-excited native fluorescence and second harmonic generation,” Proc. Natl. Acad. Sci. USA. 100, 7075–7080 (2003).
[Crossref] [PubMed]

W.R. Zipfel, R.M. Williams, and W.W. Webb, “Nonlinear magic: multiphoton microscopy in the biosciences,” Nat. Biotechnol. 21, 1369–1377 (2003).
[Crossref] [PubMed]

Wu, R.J.

S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
[Crossref]

Wu, Y.

Y. Wu, P. Xi, J.Y. Qu, T.H. Cheung, and M.Y. Yu, “Depth-resolved fluorescence spectroscopy of normal and dysplastic cervical tissue,” Opt. Express. 13,382–388 (2005).
[Crossref] [PubMed]

Wu, Y.C.

Xi, P.

Y. Wu, P. Xi, J.Y. Qu, T.H. Cheung, and M.Y. Yu, “Depth-resolved fluorescence spectroscopy of normal and dysplastic cervical tissue,” Opt. Express. 13,382–388 (2005).
[Crossref] [PubMed]

Yeh, A.

A. Zoumi, A. Yeh, and B.J. Tromberg, “Imaging cells and extracellular matrix in vivo by using second-harmonic generation and two-photon excited fluorescence,” Proc. Natl. Acad. Sci. USA. 99, 11014–11019 (2002).
[Crossref] [PubMed]

Yeh, A.T.

A.T. Yeh, M.J. Hammer-Wilson, D.C.V. Sickle, H.P. Benton, A. Zoumi, B.J. Tromberg, and G.M. Peavy, “Nonlinear optical microscopy of articular cartilage,” Osteoarthritis and Cartilage. 13, 345–352 (2005).
[Crossref] [PubMed]

Young, T.H.

S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
[Crossref]

Yu, M.Y.

Y. Wu, P. Xi, J.Y. Qu, T.H. Cheung, and M.Y. Yu, “Depth-resolved fluorescence spectroscopy of normal and dysplastic cervical tissue,” Opt. Express. 13,382–388 (2005).
[Crossref] [PubMed]

Zipfel, W.R.

R.M. Williams, W.R. Zipfel, and W.W. Webb, “Interpreting second harmonic generation images of collagen I fibrils,” Biophys. J. 88, 1377–1386 (2005).
[Crossref]

W.R. Zipfel, R.M. Williams, and W.W. Webb, “Nonlinear magic: multiphoton microscopy in the biosciences,” Nat. Biotechnol. 21, 1369–1377 (2003).
[Crossref] [PubMed]

W.R. Zipfel, R.M. Williams, R. Christie, A.Y. Nikitin, B.T. Hyman, and W.W. Webb, “Live tissue intrinsic emission microscopy using multiphoton-excited native fluorescence and second harmonic generation,” Proc. Natl. Acad. Sci. USA. 100, 7075–7080 (2003).
[Crossref] [PubMed]

Zoumi, A.

A.T. Yeh, M.J. Hammer-Wilson, D.C.V. Sickle, H.P. Benton, A. Zoumi, B.J. Tromberg, and G.M. Peavy, “Nonlinear optical microscopy of articular cartilage,” Osteoarthritis and Cartilage. 13, 345–352 (2005).
[Crossref] [PubMed]

A. Zoumi, X. Lu, G.S. Kassab, and B.J. Tromberg, “Imaging coronary artery microstructure using second-harmonic and two-photon fluorescence microscopy,” Biophys. J. 87, 2278–2286 (2004).
[Crossref]

A. Zoumi, A. Yeh, and B.J. Tromberg, “Imaging cells and extracellular matrix in vivo by using second-harmonic generation and two-photon excited fluorescence,” Proc. Natl. Acad. Sci. USA. 99, 11014–11019 (2002).
[Crossref] [PubMed]

Annu. Rev. Phys. Chem. (1)

R.K. Rebecca and S.M. Eva, “Quantitative optical spectroscopy for tissue diagnosis,” Annu. Rev. Phys. Chem. 47, 555–606 (1996).
[Crossref]

Appl .Opt. (1)

H.J. van Staveren, C.J.M. Moes, J. van Marie, S.A. Prahl, and M.J.C. van Gemert, “Light scattering in intralipid-10% in the wavelength range of 400–1100 nm,” Appl .Opt. 30, 4057–4514 (1991).

Appl. Opt. (1)

Biophys. J. (7)

S. Huang, A.A. Heikal, and W.W. Webb, “Two-photon fluorescence spectroscopy and microscopy of NAD(P)H and flavoprotein,” Biophys. J. 82, 2811–2825 (2002).
[Crossref] [PubMed]

B.R. Masters, P.T.C. So, and E. Gratton, “Multiphoton excitation fluorescence microscopy and spectroscopy of in vivo human skin,” Biophys. J. 72, 2405–2412 (1997).
[Crossref] [PubMed]

T. Gutsmann, G. E. Fantner, and M. Venturoni, “Evidence that collagen fibrils in tendons are inhomogeneously structured in a tubelike manner,” Biophys. J. 84, 2593–2598(2003).
[Crossref] [PubMed]

A. Zoumi, X. Lu, G.S. Kassab, and B.J. Tromberg, “Imaging coronary artery microstructure using second-harmonic and two-photon fluorescence microscopy,” Biophys. J. 87, 2278–2286 (2004).
[Crossref]

R.M. Williams, W.R. Zipfel, and W.W. Webb, “Interpreting second harmonic generation images of collagen I fibrils,” Biophys. J. 88, 1377–1386 (2005).
[Crossref]

P.J. Campagnola, M.D Wei, A. Lewis, and L.M. Loew, “High-resolution nonlinear optical imaging of live cells by second harmonic generation,” Biophys. J. 77, 3341–3349 (1999).
[Crossref] [PubMed]

P.J. Campagnola, A.C. Millard, M. Terasaki, P.E. Hoppe, C.J. Malone, and W.A. Mohle, “Three-dimensional high-resolution second-harmonic generation imaging of endogenous structural proteins in biological tissues,” Biophys. J. 81, 493–508 (2002).
[Crossref]

Cancer Res. (1)

I. Georgakoudi, B.C. Jacobson, M.G. Muller, E.E. Sheets, K. Badizadegan, D.L. C. Locke, C.P. Crum, C.W. Boone, R. R. Dasari, J.V. Dam, and M.S. Feld, “NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes,” Cancer Res. 62, 682–687(2002).
[PubMed]

Cancer. Res. (1)

M.C. Skala, J.M. Squirrell, K.M. Vrotsos, J.C. Eickhoff, A. Gendron-Fitzpatrick, K.W. Eliceiri, and N. Ramanujam, “Multiphoton microscopy of endogenous fluorescence differentiates normal, precancerous, and cancerous squamous,” Cancer. Res. 65, 1180–1186 (2005).
[Crossref] [PubMed]

IEEE J.Sele.Top. Qua. Elec. (1)

T. Collier, D. Arifler, A. Malpica, M. Follen, and R. Richards-Kortum, “Determination of epithelial tissue scattering coefficient using confocal microscopy,” IEEE J.Sele.Top. Qua. Elec. 9, 307–313 (2003).
[Crossref]

Int. J. Biochem. Cell. Biol. (1)

L. Debelle and A.M. Tamburro, “Elastin: molecular description and function,” Int. J. Biochem. Cell. Biol. 31, 261–272 (1999).
[Crossref] [PubMed]

J. Biomed. Opt. (2)

L.H. Laiho, S. Plete, T.M. Hancewicz, P.D. Kaplan, and P.T.C. So, “Two-photon 3-D mapping of ex vivo human skin endogenous fluorescence species based on fluorescence emission spectra,” J. Biomed. Opt. 10, 0240161–10 (2005).
[Crossref] [PubMed]

P.J. Campagnola, H.A. Clark, W.A. Mohler, A. Lewis, and L.M. Loew, “Second-harmonic imaging microscopy of living cells,” J. Biomed. Opt. 6, 227–286 (2001).
[Crossref]

J. Neurosci. (1)

D.A. Dombeck, M. Blanchard-Desce, and W.W. Webb, “Optical recording of action potentials with second-harmonic generation microscopy,” J. Neurosci. 24, 999–1003 (2004).
[Crossref] [PubMed]

J. Opt. Soc. Am B, (1)

L. Moreaux, O. Saadre, and J. Mertz, “Membrane imaging by second-harmonic generation microscopy,” J. Opt. Soc. Am B, 17, 1685–1694(2000).
[Crossref]

Lasers Surg. Med. (1)

B.M. Kim, J. Eichler, K.M. Reiser, A.M. Rubenchik, and L.B.D. Silva, “Collagen structure and nonlinear susceptibility: effects of heat, glycation, and enzymatic cleavage on second harmonic signal intensity,” Lasers Surg. Med. 27, 329–335 (2000).
[Crossref] [PubMed]

Nat. Biotechnol. (2)

W.R. Zipfel, R.M. Williams, and W.W. Webb, “Nonlinear magic: multiphoton microscopy in the biosciences,” Nat. Biotechnol. 21, 1369–1377 (2003).
[Crossref] [PubMed]

P.J Campagnola and L.M. Loew, “Second-harmonic imaging microscopy for visualizing biomolecular arrays in cells, tissues and organisms,” Nat. Biotechnol. 21, 1356–1360 (2003).
[Crossref] [PubMed]

Nat. Med. (1)

E. Brown, T McKee, E. diTomaso, A. Pluen, B. Seed, Y. Boucher, and R.K. Jain, “Dynamic imaging of collagen and its modulation in tumors in vivo using second-harmonic generation,” Nat. Med. 9, 796–800 (2003).
[Crossref] [PubMed]

Nat.Rev. (1)

J. Condeelis and J.E. Segall, “Intravital imaging of cell movement in tumours,” Nat.Rev. 3, 921–930 (2003).
[Crossref]

Nature. (1)

D.Y. Li, B. Brooke, E.C. Davis, R.P. Mecham, L.K. Sorensen, B.B. Boak, E. Eichwald, and M.T. Keating, “Elastin is an essential determinant of arterial morphogenesis,” Nature. 393, 276–280 (1998).
[Crossref] [PubMed]

Opt. Express. (2)

Y. Wu, P. Xi, J.Y. Qu, T.H. Cheung, and M.Y. Yu, “Depth-resolved fluorescence spectroscopy of normal and dysplastic cervical tissue,” Opt. Express. 13,382–388 (2005).
[Crossref] [PubMed]

M. Han, G. Giese, and J.F. Bille, “Second harmonic generation imaging of collagen fibrils in cornea and sclera,” Opt. Express. 13, 5791–5797 (2005).
[Crossref] [PubMed]

Opt. Lett. (4)

S.J. Lin, R.J. Wu, H.Y. Tan, W. Lo, W.C. Lin, T.H. Young, C.J. Hsu, J.S. Chen, S.H. Jee, and C.Y. Dong, “Evaluating cutaneous photoaging by use of multiphoton fluorescence and second-harmonic generation microscopy,” Opt. Lett. 17, 2275–2277 (2005).
[Crossref]

H.S. Lee, Y. Liu, H.C. Chen, L.L. Chiou, G.T. Huang, W. Lo, and C.Y. Dong, “Optical biopsy of liver fibrosis by use of multiphoton microscopy,” Opt. Lett. 29, 2615–2616 (2004).
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Y.C. Wu and J.A.Y. Qu, “Two-photon autofluorescence spectroscopy and second-harmonic generation of epithelial tissue,” Opt. Lett. 30, 3045–3047 (2005).
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P. Theer, M.T. Hasan, and W. Denk, “Two-photon imaging to a depth of 1000 microns in living brains by use of a Ti:Al203 regenerative amplifier,” Opt. Lett. 28, 1022–1024 (2003).
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Osteoarthritis and Cartilage. (1)

A.T. Yeh, M.J. Hammer-Wilson, D.C.V. Sickle, H.P. Benton, A. Zoumi, B.J. Tromberg, and G.M. Peavy, “Nonlinear optical microscopy of articular cartilage,” Osteoarthritis and Cartilage. 13, 345–352 (2005).
[Crossref] [PubMed]

Proc. Natl. Acad. Sci. USA. (3)

Y.C. Guo, H.E. Savage, F. Liu, S.P. Schantz, P.P. Ho, and R.R. Alfano, “Subsurface tumor progression investigated by noninvasive optical second harmonic tomography,” Proc. Natl. Acad. Sci. USA. 96, 10854–10856 (1999).
[Crossref] [PubMed]

W.R. Zipfel, R.M. Williams, R. Christie, A.Y. Nikitin, B.T. Hyman, and W.W. Webb, “Live tissue intrinsic emission microscopy using multiphoton-excited native fluorescence and second harmonic generation,” Proc. Natl. Acad. Sci. USA. 100, 7075–7080 (2003).
[Crossref] [PubMed]

A. Zoumi, A. Yeh, and B.J. Tromberg, “Imaging cells and extracellular matrix in vivo by using second-harmonic generation and two-photon excited fluorescence,” Proc. Natl. Acad. Sci. USA. 99, 11014–11019 (2002).
[Crossref] [PubMed]

Proc. SPIE. (1)

P.T. Fwua, W. Loa, and C.Y. Dong, “Refractive index determination from multiphoton and confocal spherical aberration microscopy,” in Multiphoton Microscopy in the Biomedical Sciences V, A. Periasamy and P.T.C. So, eds., Proc. SPIE. 5700, 70–77 (2005).
[Crossref]

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Figures (5)

Fig. 1.
Fig. 1.

Schematic of multimode nonlinear optical imaging experimental setup.

Fig. 2.
Fig. 2.

TPEF/SHG nonlinear imaging of human dermis using the multichannel mode. The images were acquired by using two independent-channels: (a) Typical SHG image (green color-coded, 387 – 409nm) for excitation power PSHG = 6.0mW. The signal mainly arises from collagen and (b) TPEF image (red color-coded, 447 – 628nm) for PTPEF = 2.6mW. Elastin, NAD(P)H and flavin are responsible for the signals. (c) TPEF/SHG image was obtained by overlaying two channels, in which the contrast has been enhanced to outline the various structures seen in the image. The excitation wavelength λex was 800nm. The images are 135×315 pixels in size 12-bit pixel depth.

Fig. 3.
Fig. 3.

TPEF/SHG images obtained from human dermis at various depths using the multichannel mode. A dissected sample of human dermis was optically sectioned through its full thickness of ~60μm. (a) Graphic representation of the image volume of tissue. xy (top), yz (left), and xz (right) sections from the boundaries of the volume are shown. Note that dimensions are indicated, and are not portrayed proportionally. (b–h) TPEF/SHG images of human dermis at depths of 0, 10, 20, 30, 40, 50 and 60 μm. The images are 265×320 pixels in size 12-bit pixel depth. Scale bar = 20μm. (λex = 800nm, PSHG = 6.0mW, PTPEF = 2.6mW).

Fig. 4.
Fig. 4.

The spectral resolved TPEF/SHG image of human dermis from the same region in Fig. 2 and the corresponding spectra from regions of interest (ROI). They simultaneously were obtained by using the Lambda mode. The image is 135×315 pixels in size 12-bit pixel depth. (λex = 800nm, P = 5mW)

Fig. 5.
Fig. 5.

Emission spectra obtained from human dermis at various depths using the Lambda mode. Each spectrum is the average of measurement acquired at the whole optical section plane. (a)SHG and TPEF spectra obtained at depths of 0, 20, 40, 60μm. (b) Integrated total intensity of SHG and TPEF spectra versus penetration depth. (c, d)Plot of the natural logarithm of SHG and TPEF integrated total intensity versus penetration depth, Z, respectively. Error bars represent calculated standard deviations. (λex=830nm, P = 5mW).

Tables (1)

Tables Icon

Table 1. System parameters of two independent-channels in the multihannel mode

Equations (1)

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( I ) z = ( I ) 0 exp ( Az )

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