Abstract

Narrow dispersity organically modified silica nanoparticles (SiNPs), diameter ~30 nm, entrapping a hydrophobic two-photon absorbing fluorenyl dye, were synthesized by hydrolysis of triethoxyvinylsilane and (3-aminopropyl)triethoxysilane in the nonpolar core of Aerosol-OT micelles. The surface of the SiNPs were functionalized with folic acid, to specifically deliver the probe to folate receptor (FR) over-expressing Hela cells, making these folate two-photon dye-doped SiNPs potential candidates as probes for two-photon fluorescence microscopy (2PFM) bioimaging. In vitro studies using FR over-expressing Hela cells and low FR expressing MG63 cells demonstrated specific cellular uptake of the functionalized nanoparticles. One-photon fluorescence microscopy (1PFM) imaging, 2PFM imaging, and two-photon fluorescence lifetime microscopy (2P-FLIM) imaging of Hela cells incubated with folate-modified two-photon dye-doped SiNPs were demonstrated.

© 2010 OSA

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2010 (5)

C. D. Andrade, C. O. Yanez, L. Rodriguez, and K. D. Belfield, “A series of fluorene-based two-photon absorbing molecules: synthesis, linear and nonlinear characterization, and bioimaging,” J. Org. Chem. 75(12), 3975–3982 (2010).
[CrossRef] [PubMed]

E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Targeting of drugs and nanoparticles to tumors,” J. Cell Biol. 188(6), 759–768 (2010).
[CrossRef] [PubMed]

T. Y. Ohulchanskyy, I. Roy, K. T. Yong, H. E. Pudavar, and P. N. Prasad, “High-resolution light microscopy using luminescent nanoparticles,” Wiley Interdiscip Rev Nanomed Nanobiotechnol 2(2), 162–175 (2010).
[PubMed]

S. Yao, H. Y. Ahn, X. Wang, J. Fu, E. W. Van Stryland, D. J. Hagan, and K. D. Belfield, “Donor-acceptor-donor fluorene derivatives for two-photon fluorescence lysosomal imaging,” J. Org. Chem. 75(12), 3965–3974 (2010).
[CrossRef] [PubMed]

H. Shi, X. He, Y. Yuan, K. Wang, and D. Liu, “Nanoparticle-based biocompatible and long-life marker for lysosome labeling and tracking,” Anal. Chem. 82(6), 2213–2220 (2010).
[CrossRef] [PubMed]

2009 (3)

J. H. Park, L. Gu, G. von Maltzahn, E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Biodegradable luminescent porous silicon nanoparticles for in vivo applications,” Nat. Mater. 8(4), 331–336 (2009).
[CrossRef] [PubMed]

K. D. Belfield, M. V. Bondar, C. O. Yanez, F. E. Hernandez, and O. V. Przhonska, “One- and two-photon stimulated emission depletion of a sulfonyl-containing fluorene derivative,” J. Phys. Chem. B 113(20), 7101–7106 (2009).
[CrossRef] [PubMed]

A. R. Morales, C. O. Yanez, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Biomolecule labeling and imaging with a new fluorenyl Two-photon fluorescent probe,” Bioconjug. Chem. 20(10), 1992–2000 (2009).
[CrossRef] [PubMed]

2008 (4)

R. Kumar, I. Roy, T. Y. Ohulchanskyy, L. N. Goswami, A. C. Bonoiu, E. J. Bergey, K. M. Tramposch, A. Maitra, and P. N. Prasad, “Covalently dye-linked, surface-controlled, and bioconjugated organically modified silica nanoparticles as targeted probes for optical imaging,” ACS Nano 2(3), 449–456 (2008).
[CrossRef] [PubMed]

A. R. Morales, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Amine-reactive fluorene probes: synthesis, optical characterization, bioconjugation, and two-photon fluorescence imaging,” Bioconjug. Chem. 19(12), 2559–2567 (2008).
[CrossRef] [PubMed]

E. I. Sega and P. S. Low, “Tumor detection using folate receptor-targeted imaging agents,” Cancer Metastasis Rev. 27(4), 655–664 (2008).
[CrossRef] [PubMed]

J. Qian, X. Li, M. Wei, X. Gao, Z. Xu, and S. He, “Bio-molecule-conjugated fluorescent organically modified silica nanoparticles as optical probes for cancer cell imaging,” Opt. Express 16(24), 19568–19578 (2008).
[CrossRef] [PubMed]

2007 (2)

T. Y. Ohulchanskyy, I. Roy, L. N. Goswami, Y. H. Chen, E. J. Bergey, R. K. Pandey, A. R. Oseroff, and P. N. Prasad, “Organically modified silica nanoparticles with covalently incorporated photosensitizer for photodynamic therapy of cancer,” Nano Lett. 7(9), 2835–2842 (2007).
[CrossRef] [PubMed]

S. Kim, T. Y. Ohulchanskyy, H. E. Pudavar, R. K. Pandey, and P. N. Prasad, “Organically modified silica nanoparticles co-encapsulating photosensitizing drug and aggregation-enhanced two-photon absorbing fluorescent dye aggregates for two-photon photodynamic therapy,” J. Am. Chem. Soc. 129(9), 2669–2675 (2007).
[CrossRef] [PubMed]

2006 (2)

C. Sun, R. Sze, and M. Zhang, “Folic acid-PEG conjugated superparamagnetic nanoparticles for targeted cellular uptake and detection by MRI,” J. Biomed. Mater. Res. A 78(3), 550–557 (2006).
[CrossRef] [PubMed]

C. C. Corredor, K. D. Belfield, M. V. Bondar, O. V. Przhonska, and S. Yao, “One- and two-photon photochemical stability of linear and branched fluorene derivatives,” J. Photochem. Photobiol. Chem. 184(1-2), 105–112 (2006).
[CrossRef]

2005 (2)

M. Ferrari, “Cancer nanotechnology: opportunities and challenges,” Nat. Rev. Cancer 5(3), 161–171 (2005).
[CrossRef] [PubMed]

D. J. Bharali, I. Klejbor, E. K. Stachowiak, P. Dutta, I. Roy, N. Kaur, E. J. Bergey, P. N. Prasad, and M. K. Stachowiak, “Organically modified silica nanoparticles: a nonviral vector for in vivo gene delivery and expression in the brain,” Proc. Natl. Acad. Sci. U.S.A. 102(32), 11539–11544 (2005).
[CrossRef] [PubMed]

2004 (1)

C. P. Leamon and J. A. Reddy, “Folate-targeted chemotherapy,” Adv. Drug Deliv. Rev. 56(8), 1127–1141 (2004).
[CrossRef] [PubMed]

2002 (2)

Y. Lu and P. S. Low, “Folate-mediated delivery of macromolecular anticancer therapeutic agents,” Adv. Drug Deliv. Rev. 54(5), 675–693 (2002).
[CrossRef] [PubMed]

I. Brigger, C. Dubernet, and P. Couvreur, “Nanoparticles in cancer therapy and diagnosis,” Adv. Drug Deliv. Rev. 54(5), 631–651 (2002).
[CrossRef] [PubMed]

2001 (1)

R. M. Williams, W. R. Zipfel, and W. W. Webb, “Multiphoton microscopy in biological research,” Curr. Opin. Chem. Biol. 5(5), 603–608 (2001).
[CrossRef] [PubMed]

1999 (1)

J. M. Squirrell, D. L. Wokosin, J. G. White, and B. D. Bavister, “Long-term two-photon fluorescence imaging of mammalian embryos without compromising viability,” Nat. Biotechnol. 17(8), 763–767 (1999).
[CrossRef] [PubMed]

1998 (1)

V. E. Centonze and J. G. White, “Multiphoton excitation provides optical sections from deeper within scattering specimens than confocal imaging,” Biophys. J. 75(4), 2015–2024 (1998).
[CrossRef] [PubMed]

1996 (1)

A. C. Antony, “Folate receptors,” Annu. Rev. Nutr. 16(1), 501–521 (1996).
[CrossRef] [PubMed]

1990 (1)

W. Denk, J. H. Strickler, and W. W. Webb, “Two-photon laser scanning fluorescence microscopy,” Science 248(4951), 73–76 (1990).
[CrossRef] [PubMed]

Ahn, H. Y.

S. Yao, H. Y. Ahn, X. Wang, J. Fu, E. W. Van Stryland, D. J. Hagan, and K. D. Belfield, “Donor-acceptor-donor fluorene derivatives for two-photon fluorescence lysosomal imaging,” J. Org. Chem. 75(12), 3965–3974 (2010).
[CrossRef] [PubMed]

Andrade, C. D.

C. D. Andrade, C. O. Yanez, L. Rodriguez, and K. D. Belfield, “A series of fluorene-based two-photon absorbing molecules: synthesis, linear and nonlinear characterization, and bioimaging,” J. Org. Chem. 75(12), 3975–3982 (2010).
[CrossRef] [PubMed]

Antony, A. C.

A. C. Antony, “Folate receptors,” Annu. Rev. Nutr. 16(1), 501–521 (1996).
[CrossRef] [PubMed]

Bavister, B. D.

J. M. Squirrell, D. L. Wokosin, J. G. White, and B. D. Bavister, “Long-term two-photon fluorescence imaging of mammalian embryos without compromising viability,” Nat. Biotechnol. 17(8), 763–767 (1999).
[CrossRef] [PubMed]

Belfield, K. D.

C. D. Andrade, C. O. Yanez, L. Rodriguez, and K. D. Belfield, “A series of fluorene-based two-photon absorbing molecules: synthesis, linear and nonlinear characterization, and bioimaging,” J. Org. Chem. 75(12), 3975–3982 (2010).
[CrossRef] [PubMed]

S. Yao, H. Y. Ahn, X. Wang, J. Fu, E. W. Van Stryland, D. J. Hagan, and K. D. Belfield, “Donor-acceptor-donor fluorene derivatives for two-photon fluorescence lysosomal imaging,” J. Org. Chem. 75(12), 3965–3974 (2010).
[CrossRef] [PubMed]

A. R. Morales, C. O. Yanez, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Biomolecule labeling and imaging with a new fluorenyl Two-photon fluorescent probe,” Bioconjug. Chem. 20(10), 1992–2000 (2009).
[CrossRef] [PubMed]

K. D. Belfield, M. V. Bondar, C. O. Yanez, F. E. Hernandez, and O. V. Przhonska, “One- and two-photon stimulated emission depletion of a sulfonyl-containing fluorene derivative,” J. Phys. Chem. B 113(20), 7101–7106 (2009).
[CrossRef] [PubMed]

A. R. Morales, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Amine-reactive fluorene probes: synthesis, optical characterization, bioconjugation, and two-photon fluorescence imaging,” Bioconjug. Chem. 19(12), 2559–2567 (2008).
[CrossRef] [PubMed]

C. C. Corredor, K. D. Belfield, M. V. Bondar, O. V. Przhonska, and S. Yao, “One- and two-photon photochemical stability of linear and branched fluorene derivatives,” J. Photochem. Photobiol. Chem. 184(1-2), 105–112 (2006).
[CrossRef]

Bergey, E. J.

R. Kumar, I. Roy, T. Y. Ohulchanskyy, L. N. Goswami, A. C. Bonoiu, E. J. Bergey, K. M. Tramposch, A. Maitra, and P. N. Prasad, “Covalently dye-linked, surface-controlled, and bioconjugated organically modified silica nanoparticles as targeted probes for optical imaging,” ACS Nano 2(3), 449–456 (2008).
[CrossRef] [PubMed]

T. Y. Ohulchanskyy, I. Roy, L. N. Goswami, Y. H. Chen, E. J. Bergey, R. K. Pandey, A. R. Oseroff, and P. N. Prasad, “Organically modified silica nanoparticles with covalently incorporated photosensitizer for photodynamic therapy of cancer,” Nano Lett. 7(9), 2835–2842 (2007).
[CrossRef] [PubMed]

D. J. Bharali, I. Klejbor, E. K. Stachowiak, P. Dutta, I. Roy, N. Kaur, E. J. Bergey, P. N. Prasad, and M. K. Stachowiak, “Organically modified silica nanoparticles: a nonviral vector for in vivo gene delivery and expression in the brain,” Proc. Natl. Acad. Sci. U.S.A. 102(32), 11539–11544 (2005).
[CrossRef] [PubMed]

Bharali, D. J.

D. J. Bharali, I. Klejbor, E. K. Stachowiak, P. Dutta, I. Roy, N. Kaur, E. J. Bergey, P. N. Prasad, and M. K. Stachowiak, “Organically modified silica nanoparticles: a nonviral vector for in vivo gene delivery and expression in the brain,” Proc. Natl. Acad. Sci. U.S.A. 102(32), 11539–11544 (2005).
[CrossRef] [PubMed]

Bhatia, S. N.

E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Targeting of drugs and nanoparticles to tumors,” J. Cell Biol. 188(6), 759–768 (2010).
[CrossRef] [PubMed]

J. H. Park, L. Gu, G. von Maltzahn, E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Biodegradable luminescent porous silicon nanoparticles for in vivo applications,” Nat. Mater. 8(4), 331–336 (2009).
[CrossRef] [PubMed]

Bondar, M. V.

K. D. Belfield, M. V. Bondar, C. O. Yanez, F. E. Hernandez, and O. V. Przhonska, “One- and two-photon stimulated emission depletion of a sulfonyl-containing fluorene derivative,” J. Phys. Chem. B 113(20), 7101–7106 (2009).
[CrossRef] [PubMed]

C. C. Corredor, K. D. Belfield, M. V. Bondar, O. V. Przhonska, and S. Yao, “One- and two-photon photochemical stability of linear and branched fluorene derivatives,” J. Photochem. Photobiol. Chem. 184(1-2), 105–112 (2006).
[CrossRef]

Bonoiu, A. C.

R. Kumar, I. Roy, T. Y. Ohulchanskyy, L. N. Goswami, A. C. Bonoiu, E. J. Bergey, K. M. Tramposch, A. Maitra, and P. N. Prasad, “Covalently dye-linked, surface-controlled, and bioconjugated organically modified silica nanoparticles as targeted probes for optical imaging,” ACS Nano 2(3), 449–456 (2008).
[CrossRef] [PubMed]

Brigger, I.

I. Brigger, C. Dubernet, and P. Couvreur, “Nanoparticles in cancer therapy and diagnosis,” Adv. Drug Deliv. Rev. 54(5), 631–651 (2002).
[CrossRef] [PubMed]

Centonze, V. E.

V. E. Centonze and J. G. White, “Multiphoton excitation provides optical sections from deeper within scattering specimens than confocal imaging,” Biophys. J. 75(4), 2015–2024 (1998).
[CrossRef] [PubMed]

Chen, Y. H.

T. Y. Ohulchanskyy, I. Roy, L. N. Goswami, Y. H. Chen, E. J. Bergey, R. K. Pandey, A. R. Oseroff, and P. N. Prasad, “Organically modified silica nanoparticles with covalently incorporated photosensitizer for photodynamic therapy of cancer,” Nano Lett. 7(9), 2835–2842 (2007).
[CrossRef] [PubMed]

Corredor, C. C.

C. C. Corredor, K. D. Belfield, M. V. Bondar, O. V. Przhonska, and S. Yao, “One- and two-photon photochemical stability of linear and branched fluorene derivatives,” J. Photochem. Photobiol. Chem. 184(1-2), 105–112 (2006).
[CrossRef]

Couvreur, P.

I. Brigger, C. Dubernet, and P. Couvreur, “Nanoparticles in cancer therapy and diagnosis,” Adv. Drug Deliv. Rev. 54(5), 631–651 (2002).
[CrossRef] [PubMed]

Denk, W.

W. Denk, J. H. Strickler, and W. W. Webb, “Two-photon laser scanning fluorescence microscopy,” Science 248(4951), 73–76 (1990).
[CrossRef] [PubMed]

Dubernet, C.

I. Brigger, C. Dubernet, and P. Couvreur, “Nanoparticles in cancer therapy and diagnosis,” Adv. Drug Deliv. Rev. 54(5), 631–651 (2002).
[CrossRef] [PubMed]

Dutta, P.

D. J. Bharali, I. Klejbor, E. K. Stachowiak, P. Dutta, I. Roy, N. Kaur, E. J. Bergey, P. N. Prasad, and M. K. Stachowiak, “Organically modified silica nanoparticles: a nonviral vector for in vivo gene delivery and expression in the brain,” Proc. Natl. Acad. Sci. U.S.A. 102(32), 11539–11544 (2005).
[CrossRef] [PubMed]

Ferrari, M.

M. Ferrari, “Cancer nanotechnology: opportunities and challenges,” Nat. Rev. Cancer 5(3), 161–171 (2005).
[CrossRef] [PubMed]

Fu, J.

S. Yao, H. Y. Ahn, X. Wang, J. Fu, E. W. Van Stryland, D. J. Hagan, and K. D. Belfield, “Donor-acceptor-donor fluorene derivatives for two-photon fluorescence lysosomal imaging,” J. Org. Chem. 75(12), 3965–3974 (2010).
[CrossRef] [PubMed]

Gao, X.

Goswami, L. N.

R. Kumar, I. Roy, T. Y. Ohulchanskyy, L. N. Goswami, A. C. Bonoiu, E. J. Bergey, K. M. Tramposch, A. Maitra, and P. N. Prasad, “Covalently dye-linked, surface-controlled, and bioconjugated organically modified silica nanoparticles as targeted probes for optical imaging,” ACS Nano 2(3), 449–456 (2008).
[CrossRef] [PubMed]

T. Y. Ohulchanskyy, I. Roy, L. N. Goswami, Y. H. Chen, E. J. Bergey, R. K. Pandey, A. R. Oseroff, and P. N. Prasad, “Organically modified silica nanoparticles with covalently incorporated photosensitizer for photodynamic therapy of cancer,” Nano Lett. 7(9), 2835–2842 (2007).
[CrossRef] [PubMed]

Gu, L.

J. H. Park, L. Gu, G. von Maltzahn, E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Biodegradable luminescent porous silicon nanoparticles for in vivo applications,” Nat. Mater. 8(4), 331–336 (2009).
[CrossRef] [PubMed]

Hagan, D. J.

S. Yao, H. Y. Ahn, X. Wang, J. Fu, E. W. Van Stryland, D. J. Hagan, and K. D. Belfield, “Donor-acceptor-donor fluorene derivatives for two-photon fluorescence lysosomal imaging,” J. Org. Chem. 75(12), 3965–3974 (2010).
[CrossRef] [PubMed]

He, S.

He, X.

H. Shi, X. He, Y. Yuan, K. Wang, and D. Liu, “Nanoparticle-based biocompatible and long-life marker for lysosome labeling and tracking,” Anal. Chem. 82(6), 2213–2220 (2010).
[CrossRef] [PubMed]

Hernandez, F. E.

K. D. Belfield, M. V. Bondar, C. O. Yanez, F. E. Hernandez, and O. V. Przhonska, “One- and two-photon stimulated emission depletion of a sulfonyl-containing fluorene derivative,” J. Phys. Chem. B 113(20), 7101–7106 (2009).
[CrossRef] [PubMed]

Kaur, N.

D. J. Bharali, I. Klejbor, E. K. Stachowiak, P. Dutta, I. Roy, N. Kaur, E. J. Bergey, P. N. Prasad, and M. K. Stachowiak, “Organically modified silica nanoparticles: a nonviral vector for in vivo gene delivery and expression in the brain,” Proc. Natl. Acad. Sci. U.S.A. 102(32), 11539–11544 (2005).
[CrossRef] [PubMed]

Kim, S.

S. Kim, T. Y. Ohulchanskyy, H. E. Pudavar, R. K. Pandey, and P. N. Prasad, “Organically modified silica nanoparticles co-encapsulating photosensitizing drug and aggregation-enhanced two-photon absorbing fluorescent dye aggregates for two-photon photodynamic therapy,” J. Am. Chem. Soc. 129(9), 2669–2675 (2007).
[CrossRef] [PubMed]

Klejbor, I.

D. J. Bharali, I. Klejbor, E. K. Stachowiak, P. Dutta, I. Roy, N. Kaur, E. J. Bergey, P. N. Prasad, and M. K. Stachowiak, “Organically modified silica nanoparticles: a nonviral vector for in vivo gene delivery and expression in the brain,” Proc. Natl. Acad. Sci. U.S.A. 102(32), 11539–11544 (2005).
[CrossRef] [PubMed]

Kumar, R.

R. Kumar, I. Roy, T. Y. Ohulchanskyy, L. N. Goswami, A. C. Bonoiu, E. J. Bergey, K. M. Tramposch, A. Maitra, and P. N. Prasad, “Covalently dye-linked, surface-controlled, and bioconjugated organically modified silica nanoparticles as targeted probes for optical imaging,” ACS Nano 2(3), 449–456 (2008).
[CrossRef] [PubMed]

Leamon, C. P.

C. P. Leamon and J. A. Reddy, “Folate-targeted chemotherapy,” Adv. Drug Deliv. Rev. 56(8), 1127–1141 (2004).
[CrossRef] [PubMed]

Li, X.

Liu, D.

H. Shi, X. He, Y. Yuan, K. Wang, and D. Liu, “Nanoparticle-based biocompatible and long-life marker for lysosome labeling and tracking,” Anal. Chem. 82(6), 2213–2220 (2010).
[CrossRef] [PubMed]

Low, P. S.

E. I. Sega and P. S. Low, “Tumor detection using folate receptor-targeted imaging agents,” Cancer Metastasis Rev. 27(4), 655–664 (2008).
[CrossRef] [PubMed]

Y. Lu and P. S. Low, “Folate-mediated delivery of macromolecular anticancer therapeutic agents,” Adv. Drug Deliv. Rev. 54(5), 675–693 (2002).
[CrossRef] [PubMed]

Lu, Y.

Y. Lu and P. S. Low, “Folate-mediated delivery of macromolecular anticancer therapeutic agents,” Adv. Drug Deliv. Rev. 54(5), 675–693 (2002).
[CrossRef] [PubMed]

Maitra, A.

R. Kumar, I. Roy, T. Y. Ohulchanskyy, L. N. Goswami, A. C. Bonoiu, E. J. Bergey, K. M. Tramposch, A. Maitra, and P. N. Prasad, “Covalently dye-linked, surface-controlled, and bioconjugated organically modified silica nanoparticles as targeted probes for optical imaging,” ACS Nano 2(3), 449–456 (2008).
[CrossRef] [PubMed]

Marcus, A. I.

A. R. Morales, C. O. Yanez, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Biomolecule labeling and imaging with a new fluorenyl Two-photon fluorescent probe,” Bioconjug. Chem. 20(10), 1992–2000 (2009).
[CrossRef] [PubMed]

A. R. Morales, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Amine-reactive fluorene probes: synthesis, optical characterization, bioconjugation, and two-photon fluorescence imaging,” Bioconjug. Chem. 19(12), 2559–2567 (2008).
[CrossRef] [PubMed]

Morales, A. R.

A. R. Morales, C. O. Yanez, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Biomolecule labeling and imaging with a new fluorenyl Two-photon fluorescent probe,” Bioconjug. Chem. 20(10), 1992–2000 (2009).
[CrossRef] [PubMed]

A. R. Morales, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Amine-reactive fluorene probes: synthesis, optical characterization, bioconjugation, and two-photon fluorescence imaging,” Bioconjug. Chem. 19(12), 2559–2567 (2008).
[CrossRef] [PubMed]

Ohulchanskyy, T. Y.

T. Y. Ohulchanskyy, I. Roy, K. T. Yong, H. E. Pudavar, and P. N. Prasad, “High-resolution light microscopy using luminescent nanoparticles,” Wiley Interdiscip Rev Nanomed Nanobiotechnol 2(2), 162–175 (2010).
[PubMed]

R. Kumar, I. Roy, T. Y. Ohulchanskyy, L. N. Goswami, A. C. Bonoiu, E. J. Bergey, K. M. Tramposch, A. Maitra, and P. N. Prasad, “Covalently dye-linked, surface-controlled, and bioconjugated organically modified silica nanoparticles as targeted probes for optical imaging,” ACS Nano 2(3), 449–456 (2008).
[CrossRef] [PubMed]

S. Kim, T. Y. Ohulchanskyy, H. E. Pudavar, R. K. Pandey, and P. N. Prasad, “Organically modified silica nanoparticles co-encapsulating photosensitizing drug and aggregation-enhanced two-photon absorbing fluorescent dye aggregates for two-photon photodynamic therapy,” J. Am. Chem. Soc. 129(9), 2669–2675 (2007).
[CrossRef] [PubMed]

T. Y. Ohulchanskyy, I. Roy, L. N. Goswami, Y. H. Chen, E. J. Bergey, R. K. Pandey, A. R. Oseroff, and P. N. Prasad, “Organically modified silica nanoparticles with covalently incorporated photosensitizer for photodynamic therapy of cancer,” Nano Lett. 7(9), 2835–2842 (2007).
[CrossRef] [PubMed]

Oseroff, A. R.

T. Y. Ohulchanskyy, I. Roy, L. N. Goswami, Y. H. Chen, E. J. Bergey, R. K. Pandey, A. R. Oseroff, and P. N. Prasad, “Organically modified silica nanoparticles with covalently incorporated photosensitizer for photodynamic therapy of cancer,” Nano Lett. 7(9), 2835–2842 (2007).
[CrossRef] [PubMed]

Pandey, R. K.

T. Y. Ohulchanskyy, I. Roy, L. N. Goswami, Y. H. Chen, E. J. Bergey, R. K. Pandey, A. R. Oseroff, and P. N. Prasad, “Organically modified silica nanoparticles with covalently incorporated photosensitizer for photodynamic therapy of cancer,” Nano Lett. 7(9), 2835–2842 (2007).
[CrossRef] [PubMed]

S. Kim, T. Y. Ohulchanskyy, H. E. Pudavar, R. K. Pandey, and P. N. Prasad, “Organically modified silica nanoparticles co-encapsulating photosensitizing drug and aggregation-enhanced two-photon absorbing fluorescent dye aggregates for two-photon photodynamic therapy,” J. Am. Chem. Soc. 129(9), 2669–2675 (2007).
[CrossRef] [PubMed]

Park, J. H.

J. H. Park, L. Gu, G. von Maltzahn, E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Biodegradable luminescent porous silicon nanoparticles for in vivo applications,” Nat. Mater. 8(4), 331–336 (2009).
[CrossRef] [PubMed]

Prasad, P. N.

T. Y. Ohulchanskyy, I. Roy, K. T. Yong, H. E. Pudavar, and P. N. Prasad, “High-resolution light microscopy using luminescent nanoparticles,” Wiley Interdiscip Rev Nanomed Nanobiotechnol 2(2), 162–175 (2010).
[PubMed]

R. Kumar, I. Roy, T. Y. Ohulchanskyy, L. N. Goswami, A. C. Bonoiu, E. J. Bergey, K. M. Tramposch, A. Maitra, and P. N. Prasad, “Covalently dye-linked, surface-controlled, and bioconjugated organically modified silica nanoparticles as targeted probes for optical imaging,” ACS Nano 2(3), 449–456 (2008).
[CrossRef] [PubMed]

S. Kim, T. Y. Ohulchanskyy, H. E. Pudavar, R. K. Pandey, and P. N. Prasad, “Organically modified silica nanoparticles co-encapsulating photosensitizing drug and aggregation-enhanced two-photon absorbing fluorescent dye aggregates for two-photon photodynamic therapy,” J. Am. Chem. Soc. 129(9), 2669–2675 (2007).
[CrossRef] [PubMed]

T. Y. Ohulchanskyy, I. Roy, L. N. Goswami, Y. H. Chen, E. J. Bergey, R. K. Pandey, A. R. Oseroff, and P. N. Prasad, “Organically modified silica nanoparticles with covalently incorporated photosensitizer for photodynamic therapy of cancer,” Nano Lett. 7(9), 2835–2842 (2007).
[CrossRef] [PubMed]

D. J. Bharali, I. Klejbor, E. K. Stachowiak, P. Dutta, I. Roy, N. Kaur, E. J. Bergey, P. N. Prasad, and M. K. Stachowiak, “Organically modified silica nanoparticles: a nonviral vector for in vivo gene delivery and expression in the brain,” Proc. Natl. Acad. Sci. U.S.A. 102(32), 11539–11544 (2005).
[CrossRef] [PubMed]

Przhonska, O. V.

K. D. Belfield, M. V. Bondar, C. O. Yanez, F. E. Hernandez, and O. V. Przhonska, “One- and two-photon stimulated emission depletion of a sulfonyl-containing fluorene derivative,” J. Phys. Chem. B 113(20), 7101–7106 (2009).
[CrossRef] [PubMed]

C. C. Corredor, K. D. Belfield, M. V. Bondar, O. V. Przhonska, and S. Yao, “One- and two-photon photochemical stability of linear and branched fluorene derivatives,” J. Photochem. Photobiol. Chem. 184(1-2), 105–112 (2006).
[CrossRef]

Pudavar, H. E.

T. Y. Ohulchanskyy, I. Roy, K. T. Yong, H. E. Pudavar, and P. N. Prasad, “High-resolution light microscopy using luminescent nanoparticles,” Wiley Interdiscip Rev Nanomed Nanobiotechnol 2(2), 162–175 (2010).
[PubMed]

S. Kim, T. Y. Ohulchanskyy, H. E. Pudavar, R. K. Pandey, and P. N. Prasad, “Organically modified silica nanoparticles co-encapsulating photosensitizing drug and aggregation-enhanced two-photon absorbing fluorescent dye aggregates for two-photon photodynamic therapy,” J. Am. Chem. Soc. 129(9), 2669–2675 (2007).
[CrossRef] [PubMed]

Qian, J.

Reddy, J. A.

C. P. Leamon and J. A. Reddy, “Folate-targeted chemotherapy,” Adv. Drug Deliv. Rev. 56(8), 1127–1141 (2004).
[CrossRef] [PubMed]

Rodriguez, L.

C. D. Andrade, C. O. Yanez, L. Rodriguez, and K. D. Belfield, “A series of fluorene-based two-photon absorbing molecules: synthesis, linear and nonlinear characterization, and bioimaging,” J. Org. Chem. 75(12), 3975–3982 (2010).
[CrossRef] [PubMed]

Roy, I.

T. Y. Ohulchanskyy, I. Roy, K. T. Yong, H. E. Pudavar, and P. N. Prasad, “High-resolution light microscopy using luminescent nanoparticles,” Wiley Interdiscip Rev Nanomed Nanobiotechnol 2(2), 162–175 (2010).
[PubMed]

R. Kumar, I. Roy, T. Y. Ohulchanskyy, L. N. Goswami, A. C. Bonoiu, E. J. Bergey, K. M. Tramposch, A. Maitra, and P. N. Prasad, “Covalently dye-linked, surface-controlled, and bioconjugated organically modified silica nanoparticles as targeted probes for optical imaging,” ACS Nano 2(3), 449–456 (2008).
[CrossRef] [PubMed]

T. Y. Ohulchanskyy, I. Roy, L. N. Goswami, Y. H. Chen, E. J. Bergey, R. K. Pandey, A. R. Oseroff, and P. N. Prasad, “Organically modified silica nanoparticles with covalently incorporated photosensitizer for photodynamic therapy of cancer,” Nano Lett. 7(9), 2835–2842 (2007).
[CrossRef] [PubMed]

D. J. Bharali, I. Klejbor, E. K. Stachowiak, P. Dutta, I. Roy, N. Kaur, E. J. Bergey, P. N. Prasad, and M. K. Stachowiak, “Organically modified silica nanoparticles: a nonviral vector for in vivo gene delivery and expression in the brain,” Proc. Natl. Acad. Sci. U.S.A. 102(32), 11539–11544 (2005).
[CrossRef] [PubMed]

Ruoslahti, E.

E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Targeting of drugs and nanoparticles to tumors,” J. Cell Biol. 188(6), 759–768 (2010).
[CrossRef] [PubMed]

J. H. Park, L. Gu, G. von Maltzahn, E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Biodegradable luminescent porous silicon nanoparticles for in vivo applications,” Nat. Mater. 8(4), 331–336 (2009).
[CrossRef] [PubMed]

Sailor, M. J.

E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Targeting of drugs and nanoparticles to tumors,” J. Cell Biol. 188(6), 759–768 (2010).
[CrossRef] [PubMed]

J. H. Park, L. Gu, G. von Maltzahn, E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Biodegradable luminescent porous silicon nanoparticles for in vivo applications,” Nat. Mater. 8(4), 331–336 (2009).
[CrossRef] [PubMed]

Schafer-Hales, K. J.

A. R. Morales, C. O. Yanez, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Biomolecule labeling and imaging with a new fluorenyl Two-photon fluorescent probe,” Bioconjug. Chem. 20(10), 1992–2000 (2009).
[CrossRef] [PubMed]

A. R. Morales, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Amine-reactive fluorene probes: synthesis, optical characterization, bioconjugation, and two-photon fluorescence imaging,” Bioconjug. Chem. 19(12), 2559–2567 (2008).
[CrossRef] [PubMed]

Sega, E. I.

E. I. Sega and P. S. Low, “Tumor detection using folate receptor-targeted imaging agents,” Cancer Metastasis Rev. 27(4), 655–664 (2008).
[CrossRef] [PubMed]

Shi, H.

H. Shi, X. He, Y. Yuan, K. Wang, and D. Liu, “Nanoparticle-based biocompatible and long-life marker for lysosome labeling and tracking,” Anal. Chem. 82(6), 2213–2220 (2010).
[CrossRef] [PubMed]

Squirrell, J. M.

J. M. Squirrell, D. L. Wokosin, J. G. White, and B. D. Bavister, “Long-term two-photon fluorescence imaging of mammalian embryos without compromising viability,” Nat. Biotechnol. 17(8), 763–767 (1999).
[CrossRef] [PubMed]

Stachowiak, E. K.

D. J. Bharali, I. Klejbor, E. K. Stachowiak, P. Dutta, I. Roy, N. Kaur, E. J. Bergey, P. N. Prasad, and M. K. Stachowiak, “Organically modified silica nanoparticles: a nonviral vector for in vivo gene delivery and expression in the brain,” Proc. Natl. Acad. Sci. U.S.A. 102(32), 11539–11544 (2005).
[CrossRef] [PubMed]

Stachowiak, M. K.

D. J. Bharali, I. Klejbor, E. K. Stachowiak, P. Dutta, I. Roy, N. Kaur, E. J. Bergey, P. N. Prasad, and M. K. Stachowiak, “Organically modified silica nanoparticles: a nonviral vector for in vivo gene delivery and expression in the brain,” Proc. Natl. Acad. Sci. U.S.A. 102(32), 11539–11544 (2005).
[CrossRef] [PubMed]

Strickler, J. H.

W. Denk, J. H. Strickler, and W. W. Webb, “Two-photon laser scanning fluorescence microscopy,” Science 248(4951), 73–76 (1990).
[CrossRef] [PubMed]

Sun, C.

C. Sun, R. Sze, and M. Zhang, “Folic acid-PEG conjugated superparamagnetic nanoparticles for targeted cellular uptake and detection by MRI,” J. Biomed. Mater. Res. A 78(3), 550–557 (2006).
[CrossRef] [PubMed]

Sze, R.

C. Sun, R. Sze, and M. Zhang, “Folic acid-PEG conjugated superparamagnetic nanoparticles for targeted cellular uptake and detection by MRI,” J. Biomed. Mater. Res. A 78(3), 550–557 (2006).
[CrossRef] [PubMed]

Tramposch, K. M.

R. Kumar, I. Roy, T. Y. Ohulchanskyy, L. N. Goswami, A. C. Bonoiu, E. J. Bergey, K. M. Tramposch, A. Maitra, and P. N. Prasad, “Covalently dye-linked, surface-controlled, and bioconjugated organically modified silica nanoparticles as targeted probes for optical imaging,” ACS Nano 2(3), 449–456 (2008).
[CrossRef] [PubMed]

Van Stryland, E. W.

S. Yao, H. Y. Ahn, X. Wang, J. Fu, E. W. Van Stryland, D. J. Hagan, and K. D. Belfield, “Donor-acceptor-donor fluorene derivatives for two-photon fluorescence lysosomal imaging,” J. Org. Chem. 75(12), 3965–3974 (2010).
[CrossRef] [PubMed]

von Maltzahn, G.

J. H. Park, L. Gu, G. von Maltzahn, E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Biodegradable luminescent porous silicon nanoparticles for in vivo applications,” Nat. Mater. 8(4), 331–336 (2009).
[CrossRef] [PubMed]

Wang, K.

H. Shi, X. He, Y. Yuan, K. Wang, and D. Liu, “Nanoparticle-based biocompatible and long-life marker for lysosome labeling and tracking,” Anal. Chem. 82(6), 2213–2220 (2010).
[CrossRef] [PubMed]

Wang, X.

S. Yao, H. Y. Ahn, X. Wang, J. Fu, E. W. Van Stryland, D. J. Hagan, and K. D. Belfield, “Donor-acceptor-donor fluorene derivatives for two-photon fluorescence lysosomal imaging,” J. Org. Chem. 75(12), 3965–3974 (2010).
[CrossRef] [PubMed]

Webb, W. W.

R. M. Williams, W. R. Zipfel, and W. W. Webb, “Multiphoton microscopy in biological research,” Curr. Opin. Chem. Biol. 5(5), 603–608 (2001).
[CrossRef] [PubMed]

W. Denk, J. H. Strickler, and W. W. Webb, “Two-photon laser scanning fluorescence microscopy,” Science 248(4951), 73–76 (1990).
[CrossRef] [PubMed]

Wei, M.

White, J. G.

J. M. Squirrell, D. L. Wokosin, J. G. White, and B. D. Bavister, “Long-term two-photon fluorescence imaging of mammalian embryos without compromising viability,” Nat. Biotechnol. 17(8), 763–767 (1999).
[CrossRef] [PubMed]

V. E. Centonze and J. G. White, “Multiphoton excitation provides optical sections from deeper within scattering specimens than confocal imaging,” Biophys. J. 75(4), 2015–2024 (1998).
[CrossRef] [PubMed]

Williams, R. M.

R. M. Williams, W. R. Zipfel, and W. W. Webb, “Multiphoton microscopy in biological research,” Curr. Opin. Chem. Biol. 5(5), 603–608 (2001).
[CrossRef] [PubMed]

Wokosin, D. L.

J. M. Squirrell, D. L. Wokosin, J. G. White, and B. D. Bavister, “Long-term two-photon fluorescence imaging of mammalian embryos without compromising viability,” Nat. Biotechnol. 17(8), 763–767 (1999).
[CrossRef] [PubMed]

Xu, Z.

Yanez, C. O.

C. D. Andrade, C. O. Yanez, L. Rodriguez, and K. D. Belfield, “A series of fluorene-based two-photon absorbing molecules: synthesis, linear and nonlinear characterization, and bioimaging,” J. Org. Chem. 75(12), 3975–3982 (2010).
[CrossRef] [PubMed]

A. R. Morales, C. O. Yanez, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Biomolecule labeling and imaging with a new fluorenyl Two-photon fluorescent probe,” Bioconjug. Chem. 20(10), 1992–2000 (2009).
[CrossRef] [PubMed]

K. D. Belfield, M. V. Bondar, C. O. Yanez, F. E. Hernandez, and O. V. Przhonska, “One- and two-photon stimulated emission depletion of a sulfonyl-containing fluorene derivative,” J. Phys. Chem. B 113(20), 7101–7106 (2009).
[CrossRef] [PubMed]

Yao, S.

S. Yao, H. Y. Ahn, X. Wang, J. Fu, E. W. Van Stryland, D. J. Hagan, and K. D. Belfield, “Donor-acceptor-donor fluorene derivatives for two-photon fluorescence lysosomal imaging,” J. Org. Chem. 75(12), 3965–3974 (2010).
[CrossRef] [PubMed]

C. C. Corredor, K. D. Belfield, M. V. Bondar, O. V. Przhonska, and S. Yao, “One- and two-photon photochemical stability of linear and branched fluorene derivatives,” J. Photochem. Photobiol. Chem. 184(1-2), 105–112 (2006).
[CrossRef]

Yong, K. T.

T. Y. Ohulchanskyy, I. Roy, K. T. Yong, H. E. Pudavar, and P. N. Prasad, “High-resolution light microscopy using luminescent nanoparticles,” Wiley Interdiscip Rev Nanomed Nanobiotechnol 2(2), 162–175 (2010).
[PubMed]

Yuan, Y.

H. Shi, X. He, Y. Yuan, K. Wang, and D. Liu, “Nanoparticle-based biocompatible and long-life marker for lysosome labeling and tracking,” Anal. Chem. 82(6), 2213–2220 (2010).
[CrossRef] [PubMed]

Zhang, M.

C. Sun, R. Sze, and M. Zhang, “Folic acid-PEG conjugated superparamagnetic nanoparticles for targeted cellular uptake and detection by MRI,” J. Biomed. Mater. Res. A 78(3), 550–557 (2006).
[CrossRef] [PubMed]

Zipfel, W. R.

R. M. Williams, W. R. Zipfel, and W. W. Webb, “Multiphoton microscopy in biological research,” Curr. Opin. Chem. Biol. 5(5), 603–608 (2001).
[CrossRef] [PubMed]

ACS Nano (1)

R. Kumar, I. Roy, T. Y. Ohulchanskyy, L. N. Goswami, A. C. Bonoiu, E. J. Bergey, K. M. Tramposch, A. Maitra, and P. N. Prasad, “Covalently dye-linked, surface-controlled, and bioconjugated organically modified silica nanoparticles as targeted probes for optical imaging,” ACS Nano 2(3), 449–456 (2008).
[CrossRef] [PubMed]

Adv. Drug Deliv. Rev. (3)

I. Brigger, C. Dubernet, and P. Couvreur, “Nanoparticles in cancer therapy and diagnosis,” Adv. Drug Deliv. Rev. 54(5), 631–651 (2002).
[CrossRef] [PubMed]

C. P. Leamon and J. A. Reddy, “Folate-targeted chemotherapy,” Adv. Drug Deliv. Rev. 56(8), 1127–1141 (2004).
[CrossRef] [PubMed]

Y. Lu and P. S. Low, “Folate-mediated delivery of macromolecular anticancer therapeutic agents,” Adv. Drug Deliv. Rev. 54(5), 675–693 (2002).
[CrossRef] [PubMed]

Anal. Chem. (1)

H. Shi, X. He, Y. Yuan, K. Wang, and D. Liu, “Nanoparticle-based biocompatible and long-life marker for lysosome labeling and tracking,” Anal. Chem. 82(6), 2213–2220 (2010).
[CrossRef] [PubMed]

Annu. Rev. Nutr. (1)

A. C. Antony, “Folate receptors,” Annu. Rev. Nutr. 16(1), 501–521 (1996).
[CrossRef] [PubMed]

Bioconjug. Chem. (2)

A. R. Morales, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Amine-reactive fluorene probes: synthesis, optical characterization, bioconjugation, and two-photon fluorescence imaging,” Bioconjug. Chem. 19(12), 2559–2567 (2008).
[CrossRef] [PubMed]

A. R. Morales, C. O. Yanez, K. J. Schafer-Hales, A. I. Marcus, and K. D. Belfield, “Biomolecule labeling and imaging with a new fluorenyl Two-photon fluorescent probe,” Bioconjug. Chem. 20(10), 1992–2000 (2009).
[CrossRef] [PubMed]

Biophys. J. (1)

V. E. Centonze and J. G. White, “Multiphoton excitation provides optical sections from deeper within scattering specimens than confocal imaging,” Biophys. J. 75(4), 2015–2024 (1998).
[CrossRef] [PubMed]

Cancer Metastasis Rev. (1)

E. I. Sega and P. S. Low, “Tumor detection using folate receptor-targeted imaging agents,” Cancer Metastasis Rev. 27(4), 655–664 (2008).
[CrossRef] [PubMed]

Curr. Opin. Chem. Biol. (1)

R. M. Williams, W. R. Zipfel, and W. W. Webb, “Multiphoton microscopy in biological research,” Curr. Opin. Chem. Biol. 5(5), 603–608 (2001).
[CrossRef] [PubMed]

J. Am. Chem. Soc. (1)

S. Kim, T. Y. Ohulchanskyy, H. E. Pudavar, R. K. Pandey, and P. N. Prasad, “Organically modified silica nanoparticles co-encapsulating photosensitizing drug and aggregation-enhanced two-photon absorbing fluorescent dye aggregates for two-photon photodynamic therapy,” J. Am. Chem. Soc. 129(9), 2669–2675 (2007).
[CrossRef] [PubMed]

J. Biomed. Mater. Res. A (1)

C. Sun, R. Sze, and M. Zhang, “Folic acid-PEG conjugated superparamagnetic nanoparticles for targeted cellular uptake and detection by MRI,” J. Biomed. Mater. Res. A 78(3), 550–557 (2006).
[CrossRef] [PubMed]

J. Cell Biol. (1)

E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Targeting of drugs and nanoparticles to tumors,” J. Cell Biol. 188(6), 759–768 (2010).
[CrossRef] [PubMed]

J. Org. Chem. (2)

C. D. Andrade, C. O. Yanez, L. Rodriguez, and K. D. Belfield, “A series of fluorene-based two-photon absorbing molecules: synthesis, linear and nonlinear characterization, and bioimaging,” J. Org. Chem. 75(12), 3975–3982 (2010).
[CrossRef] [PubMed]

S. Yao, H. Y. Ahn, X. Wang, J. Fu, E. W. Van Stryland, D. J. Hagan, and K. D. Belfield, “Donor-acceptor-donor fluorene derivatives for two-photon fluorescence lysosomal imaging,” J. Org. Chem. 75(12), 3965–3974 (2010).
[CrossRef] [PubMed]

J. Photochem. Photobiol. Chem. (1)

C. C. Corredor, K. D. Belfield, M. V. Bondar, O. V. Przhonska, and S. Yao, “One- and two-photon photochemical stability of linear and branched fluorene derivatives,” J. Photochem. Photobiol. Chem. 184(1-2), 105–112 (2006).
[CrossRef]

J. Phys. Chem. B (1)

K. D. Belfield, M. V. Bondar, C. O. Yanez, F. E. Hernandez, and O. V. Przhonska, “One- and two-photon stimulated emission depletion of a sulfonyl-containing fluorene derivative,” J. Phys. Chem. B 113(20), 7101–7106 (2009).
[CrossRef] [PubMed]

Nano Lett. (1)

T. Y. Ohulchanskyy, I. Roy, L. N. Goswami, Y. H. Chen, E. J. Bergey, R. K. Pandey, A. R. Oseroff, and P. N. Prasad, “Organically modified silica nanoparticles with covalently incorporated photosensitizer for photodynamic therapy of cancer,” Nano Lett. 7(9), 2835–2842 (2007).
[CrossRef] [PubMed]

Nat. Biotechnol. (1)

J. M. Squirrell, D. L. Wokosin, J. G. White, and B. D. Bavister, “Long-term two-photon fluorescence imaging of mammalian embryos without compromising viability,” Nat. Biotechnol. 17(8), 763–767 (1999).
[CrossRef] [PubMed]

Nat. Mater. (1)

J. H. Park, L. Gu, G. von Maltzahn, E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Biodegradable luminescent porous silicon nanoparticles for in vivo applications,” Nat. Mater. 8(4), 331–336 (2009).
[CrossRef] [PubMed]

Nat. Rev. Cancer (1)

M. Ferrari, “Cancer nanotechnology: opportunities and challenges,” Nat. Rev. Cancer 5(3), 161–171 (2005).
[CrossRef] [PubMed]

Opt. Express (1)

Proc. Natl. Acad. Sci. U.S.A. (1)

D. J. Bharali, I. Klejbor, E. K. Stachowiak, P. Dutta, I. Roy, N. Kaur, E. J. Bergey, P. N. Prasad, and M. K. Stachowiak, “Organically modified silica nanoparticles: a nonviral vector for in vivo gene delivery and expression in the brain,” Proc. Natl. Acad. Sci. U.S.A. 102(32), 11539–11544 (2005).
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Science (1)

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[CrossRef] [PubMed]

Wiley Interdiscip Rev Nanomed Nanobiotechnol (1)

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[PubMed]

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Figures (6)

Fig. 1
Fig. 1

Schematic illustration of the synthesis of silica nanoparticles and their bioconjugation with folic acid.

Fig. 2
Fig. 2

TEM images of silica nanoparticles (a) SNP-NH2, (b) SNP-DBF-NH2, and (c) their particle size distribution, (d) SNP-NHFA, (e) SNP-DBF-NHFA, and (f) their particle size distribution. Scale bar: 100 nm.

Fig. 3
Fig. 3

(a) Normalized absorption of DBF in THF and SiNPs in water, (b) normalized excitation spectra of DBF in THF and SiNPs in water, the maximum excitation of SNP-NH2 and SNP-NHFA were normalized to 0.1 (Em: 490 nm), (c) normalized fluorescence emission spectra of DBF in THF and SiNPs in water, the maximum fluorescence of SNP-NH2 and SNP-NHFA were normalized to 0.1 (Ex: 410 nm), and (d) fluorescence anisotropy of DBF in THF and SiNPs in water (Em: 490 nm).

Fig. 4
Fig. 4

(a) 2PA cross sections of DBF (fs excitation). (b) Viability of Hela and MG63 cells with SNP-DBF-NHFA.

Fig. 5
Fig. 5

Images of Hela cells (top row), MG63 cells (middle row), and folate receptor blocked Hela cells (bottom row) incubated with SNP-DBF-NHFA (20 µM, 2 h). Left column: DIC, 40 ms. Middle column: one-photon fluorescence image, 200 ms (filter cube Ex: 377/50 DM: 409 Em: 525/40). Right column: 3D reconstruction from overlaid two-photon fluorescence images (Ex: 740 nm; Power: 30 mW; Em. short-pass filter 690 nm) 10 µm grid.

Fig. 6
Fig. 6

Images of Hela cells incubated with SNP-DBF-NHFA (20 µM, 2 h). (a) DIC, 20 ms, (b) 3D reconstruction from overlaid two-photon fluorescence images (Ex: 740 nm; Power: 30 mW; Em. short-pass filter 690 nm) 10 µm grid, (c) 2P-FLIM image (Ex: 740 nm; Power: 30 mW).

Tables (1)

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Table 1 Photophysical properties of the DBF in THF, SNP-DBF-NHFA in water and fluorescein in 0.1 M NaOH aqueous solution

Equations (1)

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Φ = ( A 1 A 0 ) N A 10 3 × ε × Ι × ( 1 10 ( A 1 + A 0 ) / 2 ) ( t 1 t 0 )

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