Abstract

We demonstrate that terahertz (THz) spectroscopy can be used to differentiate soft protein microstructures. Differentiation of soft microstructures in gels has to date been performed using optical imaging techniques (e.g. electron microscope) and Fourier Transform Infra-Red (FTIR) spectroscopy for the mid-IR range, but a differentiation tool for the THz frequency range is lacking. Particulate and fine-stranded (fibrillar) soft protein microstructures are of interest, particularly to medical researchers, because they form from naturally occurring proteins that are thought to be involved in several human diseases, such as Alzheimer’s disease. In this study, globular β-lactoglobulin structures with diameters of 2 µm, and fibrillar structures with diameters less than 0.03 µm are observed between 0.8 and 1.5 THz. Results show that the globular structures have a decline in THz transmission when compared to the fibrillar ones. The cause of this decline is possibly due to Rayleigh scattering from the globular microstructures.

© 2009 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. A. G. Markelz, A. Roitberg, and E. J. Heilweil, “Pulsed terahertz spectroscopy of DNA, bovine serum albumin and collagen between 0.1 and 2.0 THz,” Chemical Physics Letters 320, 42–48 (2000).
    [CrossRef]
  2. B. M. Fischer, M. Walther, and P. U. Jepsen, “Far-infrared vibrational modes of DNA components studied by terahertz time-domain spectroscopy,” Physics in Medicine and Biology 47, 3807–3814 (2002).
    [CrossRef] [PubMed]
  3. S. E. Whitmire, D. Wolpert, A. G. Markelz, J. R. Hillebrecht, J. Galan, and R. R. Birge, “Protein flexibility and conformational state: A comparison of collective vibrational modes of wild-type and D96N bacteriorhodopsin,” Biophysical Journal 85, 1269–1277 (2003).
    [CrossRef]
  4. K. Siegrist, C. R. Bucher, I. Mandelbaum, A. R. H. Walker, R. Balu, S. K. Gregurick, and D. F. Plusquellic, “High-resolution terahertz spectroscopy of crystalline trialanine: Extreme sensitivity to β-sheet structure and cocrystallized water,” Journal of the American Chemical Society 128, 5764–5775 (2006).
    [CrossRef] [PubMed]
  5. A. G. Markelz, J. R. Knab, J. Y. Chen, and Y. He, “Protein dynamical transition in terahertz dielectric response,” Chemical Physics Letters 442, 413–417 (2007).
    [CrossRef]
  6. C. Zhang, E. Tarhan, A. K. Ramdas, A.M. Weiner, and S.M. Durbin, “Broadened far-infrared absorption spectra for hydrated and dehydrated myoglobin,” Journal of Physical Chemistry B 108, 10,077–10,082 (2004).
    [CrossRef]
  7. J. Knab, B. Shah, J.-Y. Chen, and A. Markelz, “Critical hydration and temperature effects on terahertz biomolecular sensing,” in Chemical and Biological Standoff Detection III, J. O. Jensen and J.-M. Thériault, eds., Proc. SPIE 5995, 59950P (2005).
    [CrossRef]
  8. J. Knab, J.-Y. Chen, and A. Markelz, “Hydration dependence of conformational dielectric relaxation of lysozyme,” Biophysical Journal 90, 2576–2581 (2006).
    [CrossRef] [PubMed]
  9. C. Kistner, A. Andre, T. Fischer, A. Thoma, C. Janke, A. Bartels, T. Gisler, G. Maret, and T. Dekorsy, “Hydration dynamics of oriented DNA films investigated by time-domain terahertz spectroscopy,” Applied Physics Letters 90, 233902 (2007).
    [CrossRef]
  10. A. G. Markelz, “Terahertz dielectric sensitivity to biomolecular structure and function,” IEEE Journal of Selected Topics in Quantum Electronics 14, 180–190 (2008).
    [CrossRef]
  11. S. Ebbinghaus, S. J. Kim, M. Heyden, X. Yu, M. Gruebele, D. M. Leitner, and M. Havenith, “Protein sequence-and pH-dependent hydration probed by terahertz spectroscopy,” Journal of the American Chemical Society 130, 2374–2375 (2008).
    [CrossRef] [PubMed]
  12. K. G. de Kruif, M. A. M. Hoffmann, M. E. van Marle, P. J. J. M. van Mil, S. P. F. M. Roefs, M. Verheul, and N. Zoon, “Gelation of proteins from milk,” Faraday Discussions 101, 185–200 (1995).
    [CrossRef] [PubMed]
  13. R. Mercadé-Prieto and X. D. Chen, “Dissolution of whey protein concentrate gels in alkali,” American Institute of Chemical Engineers (AIChE) Journal 52, 792–803 (2006).
  14. D. J. Selkoe, “Folding proteins in fatal ways,” Nature 426, 900–904 (2003).
    [CrossRef] [PubMed]
  15. J. Näslund, V. Haroutunian, R. Mohs, K. L. Davis, P. Davies, P. Greengard, and J. D. Buxbaum, “Correlation between elevated levels of amyloid β-peptide in the brain and cognitive decline,” Journal of the American Medical Association 283, 1571–1577 (2000).
    [CrossRef] [PubMed]
  16. S. Y. Tan and M. B. Pepys, “Amyloidosis,” Histopathology 25, 403–414 (1994).
    [CrossRef] [PubMed]
  17. W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-Lactoglobulin gels: Part 1. Fibril formation and structure,” Biomacromolecules 5, 2408–2419 (2004).
    [CrossRef] [PubMed]
  18. J. J. Resch, C. R. Daubert, and E. A. Foegeding, “β-Lactoglobulin gelation and modification: Effect of selected acidulants and heating conditions,” Journal of Food Science 70, C79–C86 (2005).
    [CrossRef]
  19. T. Lefèvre and M. Subirade, “Molecular differences in the formation and structure of fine-stranded and particulate β-lactoglobulin gels,” Biopolymers 54, 578–586 (2000).
    [CrossRef] [PubMed]
  20. E. A. Foegeding, P. R. Kuhn, and C. C. Hardin, “Specific divalent cation-induced changes during gelation of β-lactoglobulin,” Journal of Agricultural and Food Chemistry 40, 2092–2097 (1992).
    [CrossRef]
  21. H. M. Hudson, C. R. Daubert, and E. A. Foegeding, “Rheological and physical properties of derivitized whey protein isolate powders,” Journal of Agricultural and Food Chemistry 48, 3112–3119 (2000).
    [CrossRef] [PubMed]
  22. M. Verheul, J. S. Pedersen, S. P. F.M. Roefs, and K. G. de Kruif, “Association behavior of native β-lactoglobulin,” Biopolymers 49, 11–20 (1999).
    [CrossRef] [PubMed]
  23. M. E. Hines and E. A. Foegeding, “Interactions ofa-lactalbumin and bovine serum-albumin with β-lactoglobulin in thermally induced gelation,” Journal of Agricultural and Food Chemistry 41, 341–346 (1993).
    [CrossRef]
  24. B. Y. Qin, M. C. Bewley, L. K. Creamer, H. M. Baker, E. N. Baker, and G. B. Jameson, “Structural basis of the Tanford transition of bovine β-lactoglobulin,” Biochemistry 37, 14,014–14,023 (1998).
    [CrossRef]
  25. E. H. C. Bromley, M. R. H. Krebs, and A. M. Donald, “Aggregation across the length-scales in β-lactoglobulin,” Faraday Discussions 128, 13–27 (2005).
    [CrossRef] [PubMed]
  26. M. R. H. Krebs, G. L. Devlin, and A. M. Donald, “Protein particulates: Another generic form of protein aggregation?” Biophysical Journal 92, 1336–1342 (2007).
    [CrossRef]
  27. G. M. Kavanagh, A. H. Clark, and S. B. Ross-Murphy, “Heat-induced gelation of globular proteins: Part 3. Molecular studies on low pH β-lactoglobulin gels,” International Journal of Biological Macromolecules 28, 41–50 (2000).
    [CrossRef] [PubMed]
  28. S. I. Takata, T. Norisuye, N. Tanaka, and M. Shibayama, “Heat-induced gelation of β-lactoglobulin. 1. Time-resolved dynamic light scattering,” Macromolecules 33, 5470–5475 (2000).
    [CrossRef]
  29. J. I. Boye, C. Y. Ma, A. Ismail, V. R. Harwalkar, and M. Kalab, “Molecular and microstructural studies of thermal denaturation and gelation of β-lactoglobulins A and B,” Journal of Agricultural and Food Chemistry 45, 1608–1618 (1997).
    [CrossRef]
  30. E. H. C. Bromley, M. R. H. Krebs, and A. M. Donald, “Mechanisms of structure formation in particulate gels of β-lactoglobulin formed near the isoelectric point,” European Physical Journal E 21, 145–152 (2006).
    [CrossRef]
  31. C. Le Bon, T. Nicolai, and D. Durand, “Kinetics of aggregation and gelation of globular proteins after heat-induced denaturation,” Macromolecules 32, 6120–6127 (1999).
    [CrossRef]
  32. C. M. Bryant and D. J. McClements, “Molecular basis of protein functionality with special consideration of cold-set gels derived from heat-denatured whey,” Trends in Food Science & Technology 9, 143–151 (1998).
    [CrossRef]
  33. W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-Lactoglobulin gels: Part 2. Dynamic mechanical characterization of heat-set systems,” Biomacromolecules 5, 2420–2429 (2004).
    [CrossRef] [PubMed]
  34. W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-lactoglobulin gels: Part 3. Dynamic mechanical characterization of solvent-induced systems,” Biomacromolecules 5, 2430–2438 (2004).
    [CrossRef] [PubMed]
  35. P. C. Ashworth, J. A. Zeitler, M. Pepper, and V. P. Wallace, “Terahertz spectroscopy of biologically relevant liquids at low temperatures,” in Proceedings of Joint 31st International Conference on Infrared and Millimeter Waves and 14th International Conference on Terahertz Electronics (IRMMW-THz) (IEEE, Shanghai, China, 2006), p. 184.
  36. M. A. de la Fuente, H. Singh, and Y. Hemar, “Recent advances in the characterisation of heat-induced aggregates and intermediates of whey proteins,” Trends in Food Science & Technology 13, 262–274 (2002).
    [CrossRef]
  37. L. N. Arnaudov and R. de Vries, “Thermally induced fibrillar aggregation of hen egg white lysozyme,” Biophysical Journal 88, 515–526 (2005).
    [CrossRef]
  38. P. H. Siegel “Terahertz technology,” IEEE Transactions on Microwave Theory and Techniques 50, 910–928 (2002).
    [CrossRef]
  39. A. J. Fitzgerald, E. Berry, N. N. Zinov’ev, S. Homer-Vanniasinkam, R. E. Miles, J. M. Chamberlain, and M. A. Smith, “Catalogue of human tissue optical properties at terahertz frequencies,” Journal of Biological Physics 129, 123–128 (2003).
    [CrossRef]
  40. G. M. Png, J.-W. Choi, B. W.-H. Ng, S. P. Mickan, D. Abbott, and X.-C. Zhang, “The impact of hydration changes in fresh bio-tissue on THz spectroscopic measurements,” Physics in Medicine and Biology 53, 3501–3517 (2008).
    [CrossRef] [PubMed]
  41. C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles, Wiley science paperback series (John Wiley & Sons, New York, NY, USA, 1983).
  42. H. C. van de Hulst, Light Scattering by Small Particles (John Wiley & Sons, Inc., New York, USA, 1957).
  43. E. F. Knott, J. F. Shaeffer, and M. T. Tuley, Radar Cross Section, The SciTech radar and defense series, 2nd ed. (SciTech Publishing Inc., Rayleigh, NC, USA, 2004).
  44. H. T. Meryman, “Mechanics of freezing in living cells and tissues,” Science 124, 515–521 (1956).
    [CrossRef] [PubMed]
  45. M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
    [CrossRef] [PubMed]

2008 (3)

A. G. Markelz, “Terahertz dielectric sensitivity to biomolecular structure and function,” IEEE Journal of Selected Topics in Quantum Electronics 14, 180–190 (2008).
[CrossRef]

S. Ebbinghaus, S. J. Kim, M. Heyden, X. Yu, M. Gruebele, D. M. Leitner, and M. Havenith, “Protein sequence-and pH-dependent hydration probed by terahertz spectroscopy,” Journal of the American Chemical Society 130, 2374–2375 (2008).
[CrossRef] [PubMed]

G. M. Png, J.-W. Choi, B. W.-H. Ng, S. P. Mickan, D. Abbott, and X.-C. Zhang, “The impact of hydration changes in fresh bio-tissue on THz spectroscopic measurements,” Physics in Medicine and Biology 53, 3501–3517 (2008).
[CrossRef] [PubMed]

2007 (3)

C. Kistner, A. Andre, T. Fischer, A. Thoma, C. Janke, A. Bartels, T. Gisler, G. Maret, and T. Dekorsy, “Hydration dynamics of oriented DNA films investigated by time-domain terahertz spectroscopy,” Applied Physics Letters 90, 233902 (2007).
[CrossRef]

A. G. Markelz, J. R. Knab, J. Y. Chen, and Y. He, “Protein dynamical transition in terahertz dielectric response,” Chemical Physics Letters 442, 413–417 (2007).
[CrossRef]

M. R. H. Krebs, G. L. Devlin, and A. M. Donald, “Protein particulates: Another generic form of protein aggregation?” Biophysical Journal 92, 1336–1342 (2007).
[CrossRef]

2006 (5)

E. H. C. Bromley, M. R. H. Krebs, and A. M. Donald, “Mechanisms of structure formation in particulate gels of β-lactoglobulin formed near the isoelectric point,” European Physical Journal E 21, 145–152 (2006).
[CrossRef]

P. C. Ashworth, J. A. Zeitler, M. Pepper, and V. P. Wallace, “Terahertz spectroscopy of biologically relevant liquids at low temperatures,” in Proceedings of Joint 31st International Conference on Infrared and Millimeter Waves and 14th International Conference on Terahertz Electronics (IRMMW-THz) (IEEE, Shanghai, China, 2006), p. 184.

J. Knab, J.-Y. Chen, and A. Markelz, “Hydration dependence of conformational dielectric relaxation of lysozyme,” Biophysical Journal 90, 2576–2581 (2006).
[CrossRef] [PubMed]

K. Siegrist, C. R. Bucher, I. Mandelbaum, A. R. H. Walker, R. Balu, S. K. Gregurick, and D. F. Plusquellic, “High-resolution terahertz spectroscopy of crystalline trialanine: Extreme sensitivity to β-sheet structure and cocrystallized water,” Journal of the American Chemical Society 128, 5764–5775 (2006).
[CrossRef] [PubMed]

R. Mercadé-Prieto and X. D. Chen, “Dissolution of whey protein concentrate gels in alkali,” American Institute of Chemical Engineers (AIChE) Journal 52, 792–803 (2006).

2005 (4)

J. Knab, B. Shah, J.-Y. Chen, and A. Markelz, “Critical hydration and temperature effects on terahertz biomolecular sensing,” in Chemical and Biological Standoff Detection III, J. O. Jensen and J.-M. Thériault, eds., Proc. SPIE 5995, 59950P (2005).
[CrossRef]

E. H. C. Bromley, M. R. H. Krebs, and A. M. Donald, “Aggregation across the length-scales in β-lactoglobulin,” Faraday Discussions 128, 13–27 (2005).
[CrossRef] [PubMed]

J. J. Resch, C. R. Daubert, and E. A. Foegeding, “β-Lactoglobulin gelation and modification: Effect of selected acidulants and heating conditions,” Journal of Food Science 70, C79–C86 (2005).
[CrossRef]

L. N. Arnaudov and R. de Vries, “Thermally induced fibrillar aggregation of hen egg white lysozyme,” Biophysical Journal 88, 515–526 (2005).
[CrossRef]

2004 (5)

E. F. Knott, J. F. Shaeffer, and M. T. Tuley, Radar Cross Section, The SciTech radar and defense series, 2nd ed. (SciTech Publishing Inc., Rayleigh, NC, USA, 2004).

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-Lactoglobulin gels: Part 2. Dynamic mechanical characterization of heat-set systems,” Biomacromolecules 5, 2420–2429 (2004).
[CrossRef] [PubMed]

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-lactoglobulin gels: Part 3. Dynamic mechanical characterization of solvent-induced systems,” Biomacromolecules 5, 2430–2438 (2004).
[CrossRef] [PubMed]

C. Zhang, E. Tarhan, A. K. Ramdas, A.M. Weiner, and S.M. Durbin, “Broadened far-infrared absorption spectra for hydrated and dehydrated myoglobin,” Journal of Physical Chemistry B 108, 10,077–10,082 (2004).
[CrossRef]

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-Lactoglobulin gels: Part 1. Fibril formation and structure,” Biomacromolecules 5, 2408–2419 (2004).
[CrossRef] [PubMed]

2003 (3)

D. J. Selkoe, “Folding proteins in fatal ways,” Nature 426, 900–904 (2003).
[CrossRef] [PubMed]

S. E. Whitmire, D. Wolpert, A. G. Markelz, J. R. Hillebrecht, J. Galan, and R. R. Birge, “Protein flexibility and conformational state: A comparison of collective vibrational modes of wild-type and D96N bacteriorhodopsin,” Biophysical Journal 85, 1269–1277 (2003).
[CrossRef]

A. J. Fitzgerald, E. Berry, N. N. Zinov’ev, S. Homer-Vanniasinkam, R. E. Miles, J. M. Chamberlain, and M. A. Smith, “Catalogue of human tissue optical properties at terahertz frequencies,” Journal of Biological Physics 129, 123–128 (2003).
[CrossRef]

2002 (4)

M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
[CrossRef] [PubMed]

P. H. Siegel “Terahertz technology,” IEEE Transactions on Microwave Theory and Techniques 50, 910–928 (2002).
[CrossRef]

B. M. Fischer, M. Walther, and P. U. Jepsen, “Far-infrared vibrational modes of DNA components studied by terahertz time-domain spectroscopy,” Physics in Medicine and Biology 47, 3807–3814 (2002).
[CrossRef] [PubMed]

M. A. de la Fuente, H. Singh, and Y. Hemar, “Recent advances in the characterisation of heat-induced aggregates and intermediates of whey proteins,” Trends in Food Science & Technology 13, 262–274 (2002).
[CrossRef]

2000 (6)

T. Lefèvre and M. Subirade, “Molecular differences in the formation and structure of fine-stranded and particulate β-lactoglobulin gels,” Biopolymers 54, 578–586 (2000).
[CrossRef] [PubMed]

H. M. Hudson, C. R. Daubert, and E. A. Foegeding, “Rheological and physical properties of derivitized whey protein isolate powders,” Journal of Agricultural and Food Chemistry 48, 3112–3119 (2000).
[CrossRef] [PubMed]

G. M. Kavanagh, A. H. Clark, and S. B. Ross-Murphy, “Heat-induced gelation of globular proteins: Part 3. Molecular studies on low pH β-lactoglobulin gels,” International Journal of Biological Macromolecules 28, 41–50 (2000).
[CrossRef] [PubMed]

S. I. Takata, T. Norisuye, N. Tanaka, and M. Shibayama, “Heat-induced gelation of β-lactoglobulin. 1. Time-resolved dynamic light scattering,” Macromolecules 33, 5470–5475 (2000).
[CrossRef]

A. G. Markelz, A. Roitberg, and E. J. Heilweil, “Pulsed terahertz spectroscopy of DNA, bovine serum albumin and collagen between 0.1 and 2.0 THz,” Chemical Physics Letters 320, 42–48 (2000).
[CrossRef]

J. Näslund, V. Haroutunian, R. Mohs, K. L. Davis, P. Davies, P. Greengard, and J. D. Buxbaum, “Correlation between elevated levels of amyloid β-peptide in the brain and cognitive decline,” Journal of the American Medical Association 283, 1571–1577 (2000).
[CrossRef] [PubMed]

1999 (2)

M. Verheul, J. S. Pedersen, S. P. F.M. Roefs, and K. G. de Kruif, “Association behavior of native β-lactoglobulin,” Biopolymers 49, 11–20 (1999).
[CrossRef] [PubMed]

C. Le Bon, T. Nicolai, and D. Durand, “Kinetics of aggregation and gelation of globular proteins after heat-induced denaturation,” Macromolecules 32, 6120–6127 (1999).
[CrossRef]

1998 (2)

C. M. Bryant and D. J. McClements, “Molecular basis of protein functionality with special consideration of cold-set gels derived from heat-denatured whey,” Trends in Food Science & Technology 9, 143–151 (1998).
[CrossRef]

B. Y. Qin, M. C. Bewley, L. K. Creamer, H. M. Baker, E. N. Baker, and G. B. Jameson, “Structural basis of the Tanford transition of bovine β-lactoglobulin,” Biochemistry 37, 14,014–14,023 (1998).
[CrossRef]

1997 (1)

J. I. Boye, C. Y. Ma, A. Ismail, V. R. Harwalkar, and M. Kalab, “Molecular and microstructural studies of thermal denaturation and gelation of β-lactoglobulins A and B,” Journal of Agricultural and Food Chemistry 45, 1608–1618 (1997).
[CrossRef]

1995 (1)

K. G. de Kruif, M. A. M. Hoffmann, M. E. van Marle, P. J. J. M. van Mil, S. P. F. M. Roefs, M. Verheul, and N. Zoon, “Gelation of proteins from milk,” Faraday Discussions 101, 185–200 (1995).
[CrossRef] [PubMed]

1994 (1)

S. Y. Tan and M. B. Pepys, “Amyloidosis,” Histopathology 25, 403–414 (1994).
[CrossRef] [PubMed]

1993 (1)

M. E. Hines and E. A. Foegeding, “Interactions ofa-lactalbumin and bovine serum-albumin with β-lactoglobulin in thermally induced gelation,” Journal of Agricultural and Food Chemistry 41, 341–346 (1993).
[CrossRef]

1992 (1)

E. A. Foegeding, P. R. Kuhn, and C. C. Hardin, “Specific divalent cation-induced changes during gelation of β-lactoglobulin,” Journal of Agricultural and Food Chemistry 40, 2092–2097 (1992).
[CrossRef]

1956 (1)

H. T. Meryman, “Mechanics of freezing in living cells and tissues,” Science 124, 515–521 (1956).
[CrossRef] [PubMed]

Abbott, D.

G. M. Png, J.-W. Choi, B. W.-H. Ng, S. P. Mickan, D. Abbott, and X.-C. Zhang, “The impact of hydration changes in fresh bio-tissue on THz spectroscopic measurements,” Physics in Medicine and Biology 53, 3501–3517 (2008).
[CrossRef] [PubMed]

Andre, A.

C. Kistner, A. Andre, T. Fischer, A. Thoma, C. Janke, A. Bartels, T. Gisler, G. Maret, and T. Dekorsy, “Hydration dynamics of oriented DNA films investigated by time-domain terahertz spectroscopy,” Applied Physics Letters 90, 233902 (2007).
[CrossRef]

Arnaudov, L. N.

L. N. Arnaudov and R. de Vries, “Thermally induced fibrillar aggregation of hen egg white lysozyme,” Biophysical Journal 88, 515–526 (2005).
[CrossRef]

Ashworth, P. C.

P. C. Ashworth, J. A. Zeitler, M. Pepper, and V. P. Wallace, “Terahertz spectroscopy of biologically relevant liquids at low temperatures,” in Proceedings of Joint 31st International Conference on Infrared and Millimeter Waves and 14th International Conference on Terahertz Electronics (IRMMW-THz) (IEEE, Shanghai, China, 2006), p. 184.

Baker, E. N.

B. Y. Qin, M. C. Bewley, L. K. Creamer, H. M. Baker, E. N. Baker, and G. B. Jameson, “Structural basis of the Tanford transition of bovine β-lactoglobulin,” Biochemistry 37, 14,014–14,023 (1998).
[CrossRef]

Baker, H. M.

B. Y. Qin, M. C. Bewley, L. K. Creamer, H. M. Baker, E. N. Baker, and G. B. Jameson, “Structural basis of the Tanford transition of bovine β-lactoglobulin,” Biochemistry 37, 14,014–14,023 (1998).
[CrossRef]

Balu, R.

K. Siegrist, C. R. Bucher, I. Mandelbaum, A. R. H. Walker, R. Balu, S. K. Gregurick, and D. F. Plusquellic, “High-resolution terahertz spectroscopy of crystalline trialanine: Extreme sensitivity to β-sheet structure and cocrystallized water,” Journal of the American Chemical Society 128, 5764–5775 (2006).
[CrossRef] [PubMed]

Baroni, F.

M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
[CrossRef] [PubMed]

Bartels, A.

C. Kistner, A. Andre, T. Fischer, A. Thoma, C. Janke, A. Bartels, T. Gisler, G. Maret, and T. Dekorsy, “Hydration dynamics of oriented DNA films investigated by time-domain terahertz spectroscopy,” Applied Physics Letters 90, 233902 (2007).
[CrossRef]

Berry, E.

A. J. Fitzgerald, E. Berry, N. N. Zinov’ev, S. Homer-Vanniasinkam, R. E. Miles, J. M. Chamberlain, and M. A. Smith, “Catalogue of human tissue optical properties at terahertz frequencies,” Journal of Biological Physics 129, 123–128 (2003).
[CrossRef]

Bewley, M. C.

B. Y. Qin, M. C. Bewley, L. K. Creamer, H. M. Baker, E. N. Baker, and G. B. Jameson, “Structural basis of the Tanford transition of bovine β-lactoglobulin,” Biochemistry 37, 14,014–14,023 (1998).
[CrossRef]

Birge, R. R.

S. E. Whitmire, D. Wolpert, A. G. Markelz, J. R. Hillebrecht, J. Galan, and R. R. Birge, “Protein flexibility and conformational state: A comparison of collective vibrational modes of wild-type and D96N bacteriorhodopsin,” Biophysical Journal 85, 1269–1277 (2003).
[CrossRef]

Bohren, C. F.

C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles, Wiley science paperback series (John Wiley & Sons, New York, NY, USA, 1983).

Boye, J. I.

J. I. Boye, C. Y. Ma, A. Ismail, V. R. Harwalkar, and M. Kalab, “Molecular and microstructural studies of thermal denaturation and gelation of β-lactoglobulins A and B,” Journal of Agricultural and Food Chemistry 45, 1608–1618 (1997).
[CrossRef]

Bromley, E. H. C.

E. H. C. Bromley, M. R. H. Krebs, and A. M. Donald, “Mechanisms of structure formation in particulate gels of β-lactoglobulin formed near the isoelectric point,” European Physical Journal E 21, 145–152 (2006).
[CrossRef]

E. H. C. Bromley, M. R. H. Krebs, and A. M. Donald, “Aggregation across the length-scales in β-lactoglobulin,” Faraday Discussions 128, 13–27 (2005).
[CrossRef] [PubMed]

Bryant, C. M.

C. M. Bryant and D. J. McClements, “Molecular basis of protein functionality with special consideration of cold-set gels derived from heat-denatured whey,” Trends in Food Science & Technology 9, 143–151 (1998).
[CrossRef]

Bucciantini, M.

M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
[CrossRef] [PubMed]

Bucher, C. R.

K. Siegrist, C. R. Bucher, I. Mandelbaum, A. R. H. Walker, R. Balu, S. K. Gregurick, and D. F. Plusquellic, “High-resolution terahertz spectroscopy of crystalline trialanine: Extreme sensitivity to β-sheet structure and cocrystallized water,” Journal of the American Chemical Society 128, 5764–5775 (2006).
[CrossRef] [PubMed]

Buxbaum, J. D.

J. Näslund, V. Haroutunian, R. Mohs, K. L. Davis, P. Davies, P. Greengard, and J. D. Buxbaum, “Correlation between elevated levels of amyloid β-peptide in the brain and cognitive decline,” Journal of the American Medical Association 283, 1571–1577 (2000).
[CrossRef] [PubMed]

Chamberlain, J. M.

A. J. Fitzgerald, E. Berry, N. N. Zinov’ev, S. Homer-Vanniasinkam, R. E. Miles, J. M. Chamberlain, and M. A. Smith, “Catalogue of human tissue optical properties at terahertz frequencies,” Journal of Biological Physics 129, 123–128 (2003).
[CrossRef]

Chen, J. Y.

A. G. Markelz, J. R. Knab, J. Y. Chen, and Y. He, “Protein dynamical transition in terahertz dielectric response,” Chemical Physics Letters 442, 413–417 (2007).
[CrossRef]

Chen, J.-Y.

J. Knab, J.-Y. Chen, and A. Markelz, “Hydration dependence of conformational dielectric relaxation of lysozyme,” Biophysical Journal 90, 2576–2581 (2006).
[CrossRef] [PubMed]

J. Knab, B. Shah, J.-Y. Chen, and A. Markelz, “Critical hydration and temperature effects on terahertz biomolecular sensing,” in Chemical and Biological Standoff Detection III, J. O. Jensen and J.-M. Thériault, eds., Proc. SPIE 5995, 59950P (2005).
[CrossRef]

Chen, X. D.

R. Mercadé-Prieto and X. D. Chen, “Dissolution of whey protein concentrate gels in alkali,” American Institute of Chemical Engineers (AIChE) Journal 52, 792–803 (2006).

Chiti, F.

M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
[CrossRef] [PubMed]

Choi, J.-W.

G. M. Png, J.-W. Choi, B. W.-H. Ng, S. P. Mickan, D. Abbott, and X.-C. Zhang, “The impact of hydration changes in fresh bio-tissue on THz spectroscopic measurements,” Physics in Medicine and Biology 53, 3501–3517 (2008).
[CrossRef] [PubMed]

Clark, A. H.

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-Lactoglobulin gels: Part 2. Dynamic mechanical characterization of heat-set systems,” Biomacromolecules 5, 2420–2429 (2004).
[CrossRef] [PubMed]

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-lactoglobulin gels: Part 3. Dynamic mechanical characterization of solvent-induced systems,” Biomacromolecules 5, 2430–2438 (2004).
[CrossRef] [PubMed]

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-Lactoglobulin gels: Part 1. Fibril formation and structure,” Biomacromolecules 5, 2408–2419 (2004).
[CrossRef] [PubMed]

G. M. Kavanagh, A. H. Clark, and S. B. Ross-Murphy, “Heat-induced gelation of globular proteins: Part 3. Molecular studies on low pH β-lactoglobulin gels,” International Journal of Biological Macromolecules 28, 41–50 (2000).
[CrossRef] [PubMed]

Creamer, L. K.

B. Y. Qin, M. C. Bewley, L. K. Creamer, H. M. Baker, E. N. Baker, and G. B. Jameson, “Structural basis of the Tanford transition of bovine β-lactoglobulin,” Biochemistry 37, 14,014–14,023 (1998).
[CrossRef]

Daubert, C. R.

J. J. Resch, C. R. Daubert, and E. A. Foegeding, “β-Lactoglobulin gelation and modification: Effect of selected acidulants and heating conditions,” Journal of Food Science 70, C79–C86 (2005).
[CrossRef]

H. M. Hudson, C. R. Daubert, and E. A. Foegeding, “Rheological and physical properties of derivitized whey protein isolate powders,” Journal of Agricultural and Food Chemistry 48, 3112–3119 (2000).
[CrossRef] [PubMed]

Davies, P.

J. Näslund, V. Haroutunian, R. Mohs, K. L. Davis, P. Davies, P. Greengard, and J. D. Buxbaum, “Correlation between elevated levels of amyloid β-peptide in the brain and cognitive decline,” Journal of the American Medical Association 283, 1571–1577 (2000).
[CrossRef] [PubMed]

Davis, K. L.

J. Näslund, V. Haroutunian, R. Mohs, K. L. Davis, P. Davies, P. Greengard, and J. D. Buxbaum, “Correlation between elevated levels of amyloid β-peptide in the brain and cognitive decline,” Journal of the American Medical Association 283, 1571–1577 (2000).
[CrossRef] [PubMed]

de Kruif, K. G.

M. Verheul, J. S. Pedersen, S. P. F.M. Roefs, and K. G. de Kruif, “Association behavior of native β-lactoglobulin,” Biopolymers 49, 11–20 (1999).
[CrossRef] [PubMed]

K. G. de Kruif, M. A. M. Hoffmann, M. E. van Marle, P. J. J. M. van Mil, S. P. F. M. Roefs, M. Verheul, and N. Zoon, “Gelation of proteins from milk,” Faraday Discussions 101, 185–200 (1995).
[CrossRef] [PubMed]

de la Fuente, M. A.

M. A. de la Fuente, H. Singh, and Y. Hemar, “Recent advances in the characterisation of heat-induced aggregates and intermediates of whey proteins,” Trends in Food Science & Technology 13, 262–274 (2002).
[CrossRef]

de Vries, R.

L. N. Arnaudov and R. de Vries, “Thermally induced fibrillar aggregation of hen egg white lysozyme,” Biophysical Journal 88, 515–526 (2005).
[CrossRef]

Dekorsy, T.

C. Kistner, A. Andre, T. Fischer, A. Thoma, C. Janke, A. Bartels, T. Gisler, G. Maret, and T. Dekorsy, “Hydration dynamics of oriented DNA films investigated by time-domain terahertz spectroscopy,” Applied Physics Letters 90, 233902 (2007).
[CrossRef]

Devlin, G. L.

M. R. H. Krebs, G. L. Devlin, and A. M. Donald, “Protein particulates: Another generic form of protein aggregation?” Biophysical Journal 92, 1336–1342 (2007).
[CrossRef]

Dobson, C. M.

M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
[CrossRef] [PubMed]

Donald, A. M.

M. R. H. Krebs, G. L. Devlin, and A. M. Donald, “Protein particulates: Another generic form of protein aggregation?” Biophysical Journal 92, 1336–1342 (2007).
[CrossRef]

E. H. C. Bromley, M. R. H. Krebs, and A. M. Donald, “Mechanisms of structure formation in particulate gels of β-lactoglobulin formed near the isoelectric point,” European Physical Journal E 21, 145–152 (2006).
[CrossRef]

E. H. C. Bromley, M. R. H. Krebs, and A. M. Donald, “Aggregation across the length-scales in β-lactoglobulin,” Faraday Discussions 128, 13–27 (2005).
[CrossRef] [PubMed]

Durand, D.

C. Le Bon, T. Nicolai, and D. Durand, “Kinetics of aggregation and gelation of globular proteins after heat-induced denaturation,” Macromolecules 32, 6120–6127 (1999).
[CrossRef]

Durbin, S.M.

C. Zhang, E. Tarhan, A. K. Ramdas, A.M. Weiner, and S.M. Durbin, “Broadened far-infrared absorption spectra for hydrated and dehydrated myoglobin,” Journal of Physical Chemistry B 108, 10,077–10,082 (2004).
[CrossRef]

Ebbinghaus, S.

S. Ebbinghaus, S. J. Kim, M. Heyden, X. Yu, M. Gruebele, D. M. Leitner, and M. Havenith, “Protein sequence-and pH-dependent hydration probed by terahertz spectroscopy,” Journal of the American Chemical Society 130, 2374–2375 (2008).
[CrossRef] [PubMed]

Fischer, B. M.

B. M. Fischer, M. Walther, and P. U. Jepsen, “Far-infrared vibrational modes of DNA components studied by terahertz time-domain spectroscopy,” Physics in Medicine and Biology 47, 3807–3814 (2002).
[CrossRef] [PubMed]

Fischer, T.

C. Kistner, A. Andre, T. Fischer, A. Thoma, C. Janke, A. Bartels, T. Gisler, G. Maret, and T. Dekorsy, “Hydration dynamics of oriented DNA films investigated by time-domain terahertz spectroscopy,” Applied Physics Letters 90, 233902 (2007).
[CrossRef]

Fitzgerald, A. J.

A. J. Fitzgerald, E. Berry, N. N. Zinov’ev, S. Homer-Vanniasinkam, R. E. Miles, J. M. Chamberlain, and M. A. Smith, “Catalogue of human tissue optical properties at terahertz frequencies,” Journal of Biological Physics 129, 123–128 (2003).
[CrossRef]

Foegeding, E. A.

J. J. Resch, C. R. Daubert, and E. A. Foegeding, “β-Lactoglobulin gelation and modification: Effect of selected acidulants and heating conditions,” Journal of Food Science 70, C79–C86 (2005).
[CrossRef]

H. M. Hudson, C. R. Daubert, and E. A. Foegeding, “Rheological and physical properties of derivitized whey protein isolate powders,” Journal of Agricultural and Food Chemistry 48, 3112–3119 (2000).
[CrossRef] [PubMed]

M. E. Hines and E. A. Foegeding, “Interactions ofa-lactalbumin and bovine serum-albumin with β-lactoglobulin in thermally induced gelation,” Journal of Agricultural and Food Chemistry 41, 341–346 (1993).
[CrossRef]

E. A. Foegeding, P. R. Kuhn, and C. C. Hardin, “Specific divalent cation-induced changes during gelation of β-lactoglobulin,” Journal of Agricultural and Food Chemistry 40, 2092–2097 (1992).
[CrossRef]

Formigli, L.

M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
[CrossRef] [PubMed]

Galan, J.

S. E. Whitmire, D. Wolpert, A. G. Markelz, J. R. Hillebrecht, J. Galan, and R. R. Birge, “Protein flexibility and conformational state: A comparison of collective vibrational modes of wild-type and D96N bacteriorhodopsin,” Biophysical Journal 85, 1269–1277 (2003).
[CrossRef]

Giannoni, E.

M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
[CrossRef] [PubMed]

Gisler, T.

C. Kistner, A. Andre, T. Fischer, A. Thoma, C. Janke, A. Bartels, T. Gisler, G. Maret, and T. Dekorsy, “Hydration dynamics of oriented DNA films investigated by time-domain terahertz spectroscopy,” Applied Physics Letters 90, 233902 (2007).
[CrossRef]

Gosal, W. S.

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-Lactoglobulin gels: Part 1. Fibril formation and structure,” Biomacromolecules 5, 2408–2419 (2004).
[CrossRef] [PubMed]

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-lactoglobulin gels: Part 3. Dynamic mechanical characterization of solvent-induced systems,” Biomacromolecules 5, 2430–2438 (2004).
[CrossRef] [PubMed]

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-Lactoglobulin gels: Part 2. Dynamic mechanical characterization of heat-set systems,” Biomacromolecules 5, 2420–2429 (2004).
[CrossRef] [PubMed]

Greengard, P.

J. Näslund, V. Haroutunian, R. Mohs, K. L. Davis, P. Davies, P. Greengard, and J. D. Buxbaum, “Correlation between elevated levels of amyloid β-peptide in the brain and cognitive decline,” Journal of the American Medical Association 283, 1571–1577 (2000).
[CrossRef] [PubMed]

Gregurick, S. K.

K. Siegrist, C. R. Bucher, I. Mandelbaum, A. R. H. Walker, R. Balu, S. K. Gregurick, and D. F. Plusquellic, “High-resolution terahertz spectroscopy of crystalline trialanine: Extreme sensitivity to β-sheet structure and cocrystallized water,” Journal of the American Chemical Society 128, 5764–5775 (2006).
[CrossRef] [PubMed]

Gruebele, M.

S. Ebbinghaus, S. J. Kim, M. Heyden, X. Yu, M. Gruebele, D. M. Leitner, and M. Havenith, “Protein sequence-and pH-dependent hydration probed by terahertz spectroscopy,” Journal of the American Chemical Society 130, 2374–2375 (2008).
[CrossRef] [PubMed]

Hardin, C. C.

E. A. Foegeding, P. R. Kuhn, and C. C. Hardin, “Specific divalent cation-induced changes during gelation of β-lactoglobulin,” Journal of Agricultural and Food Chemistry 40, 2092–2097 (1992).
[CrossRef]

Haroutunian, V.

J. Näslund, V. Haroutunian, R. Mohs, K. L. Davis, P. Davies, P. Greengard, and J. D. Buxbaum, “Correlation between elevated levels of amyloid β-peptide in the brain and cognitive decline,” Journal of the American Medical Association 283, 1571–1577 (2000).
[CrossRef] [PubMed]

Harwalkar, V. R.

J. I. Boye, C. Y. Ma, A. Ismail, V. R. Harwalkar, and M. Kalab, “Molecular and microstructural studies of thermal denaturation and gelation of β-lactoglobulins A and B,” Journal of Agricultural and Food Chemistry 45, 1608–1618 (1997).
[CrossRef]

Havenith, M.

S. Ebbinghaus, S. J. Kim, M. Heyden, X. Yu, M. Gruebele, D. M. Leitner, and M. Havenith, “Protein sequence-and pH-dependent hydration probed by terahertz spectroscopy,” Journal of the American Chemical Society 130, 2374–2375 (2008).
[CrossRef] [PubMed]

He, Y.

A. G. Markelz, J. R. Knab, J. Y. Chen, and Y. He, “Protein dynamical transition in terahertz dielectric response,” Chemical Physics Letters 442, 413–417 (2007).
[CrossRef]

Heilweil, E. J.

A. G. Markelz, A. Roitberg, and E. J. Heilweil, “Pulsed terahertz spectroscopy of DNA, bovine serum albumin and collagen between 0.1 and 2.0 THz,” Chemical Physics Letters 320, 42–48 (2000).
[CrossRef]

Hemar, Y.

M. A. de la Fuente, H. Singh, and Y. Hemar, “Recent advances in the characterisation of heat-induced aggregates and intermediates of whey proteins,” Trends in Food Science & Technology 13, 262–274 (2002).
[CrossRef]

Heyden, M.

S. Ebbinghaus, S. J. Kim, M. Heyden, X. Yu, M. Gruebele, D. M. Leitner, and M. Havenith, “Protein sequence-and pH-dependent hydration probed by terahertz spectroscopy,” Journal of the American Chemical Society 130, 2374–2375 (2008).
[CrossRef] [PubMed]

Hillebrecht, J. R.

S. E. Whitmire, D. Wolpert, A. G. Markelz, J. R. Hillebrecht, J. Galan, and R. R. Birge, “Protein flexibility and conformational state: A comparison of collective vibrational modes of wild-type and D96N bacteriorhodopsin,” Biophysical Journal 85, 1269–1277 (2003).
[CrossRef]

Hines, M. E.

M. E. Hines and E. A. Foegeding, “Interactions ofa-lactalbumin and bovine serum-albumin with β-lactoglobulin in thermally induced gelation,” Journal of Agricultural and Food Chemistry 41, 341–346 (1993).
[CrossRef]

Hoffmann, M. A. M.

K. G. de Kruif, M. A. M. Hoffmann, M. E. van Marle, P. J. J. M. van Mil, S. P. F. M. Roefs, M. Verheul, and N. Zoon, “Gelation of proteins from milk,” Faraday Discussions 101, 185–200 (1995).
[CrossRef] [PubMed]

Homer-Vanniasinkam, S.

A. J. Fitzgerald, E. Berry, N. N. Zinov’ev, S. Homer-Vanniasinkam, R. E. Miles, J. M. Chamberlain, and M. A. Smith, “Catalogue of human tissue optical properties at terahertz frequencies,” Journal of Biological Physics 129, 123–128 (2003).
[CrossRef]

Hudson, H. M.

H. M. Hudson, C. R. Daubert, and E. A. Foegeding, “Rheological and physical properties of derivitized whey protein isolate powders,” Journal of Agricultural and Food Chemistry 48, 3112–3119 (2000).
[CrossRef] [PubMed]

Huffman, D. R.

C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles, Wiley science paperback series (John Wiley & Sons, New York, NY, USA, 1983).

Ismail, A.

J. I. Boye, C. Y. Ma, A. Ismail, V. R. Harwalkar, and M. Kalab, “Molecular and microstructural studies of thermal denaturation and gelation of β-lactoglobulins A and B,” Journal of Agricultural and Food Chemistry 45, 1608–1618 (1997).
[CrossRef]

Jameson, G. B.

B. Y. Qin, M. C. Bewley, L. K. Creamer, H. M. Baker, E. N. Baker, and G. B. Jameson, “Structural basis of the Tanford transition of bovine β-lactoglobulin,” Biochemistry 37, 14,014–14,023 (1998).
[CrossRef]

Janke, C.

C. Kistner, A. Andre, T. Fischer, A. Thoma, C. Janke, A. Bartels, T. Gisler, G. Maret, and T. Dekorsy, “Hydration dynamics of oriented DNA films investigated by time-domain terahertz spectroscopy,” Applied Physics Letters 90, 233902 (2007).
[CrossRef]

Jepsen, P. U.

B. M. Fischer, M. Walther, and P. U. Jepsen, “Far-infrared vibrational modes of DNA components studied by terahertz time-domain spectroscopy,” Physics in Medicine and Biology 47, 3807–3814 (2002).
[CrossRef] [PubMed]

Kalab, M.

J. I. Boye, C. Y. Ma, A. Ismail, V. R. Harwalkar, and M. Kalab, “Molecular and microstructural studies of thermal denaturation and gelation of β-lactoglobulins A and B,” Journal of Agricultural and Food Chemistry 45, 1608–1618 (1997).
[CrossRef]

Kavanagh, G. M.

G. M. Kavanagh, A. H. Clark, and S. B. Ross-Murphy, “Heat-induced gelation of globular proteins: Part 3. Molecular studies on low pH β-lactoglobulin gels,” International Journal of Biological Macromolecules 28, 41–50 (2000).
[CrossRef] [PubMed]

Kim, S. J.

S. Ebbinghaus, S. J. Kim, M. Heyden, X. Yu, M. Gruebele, D. M. Leitner, and M. Havenith, “Protein sequence-and pH-dependent hydration probed by terahertz spectroscopy,” Journal of the American Chemical Society 130, 2374–2375 (2008).
[CrossRef] [PubMed]

Kistner, C.

C. Kistner, A. Andre, T. Fischer, A. Thoma, C. Janke, A. Bartels, T. Gisler, G. Maret, and T. Dekorsy, “Hydration dynamics of oriented DNA films investigated by time-domain terahertz spectroscopy,” Applied Physics Letters 90, 233902 (2007).
[CrossRef]

Knab, J.

J. Knab, J.-Y. Chen, and A. Markelz, “Hydration dependence of conformational dielectric relaxation of lysozyme,” Biophysical Journal 90, 2576–2581 (2006).
[CrossRef] [PubMed]

J. Knab, B. Shah, J.-Y. Chen, and A. Markelz, “Critical hydration and temperature effects on terahertz biomolecular sensing,” in Chemical and Biological Standoff Detection III, J. O. Jensen and J.-M. Thériault, eds., Proc. SPIE 5995, 59950P (2005).
[CrossRef]

Knab, J. R.

A. G. Markelz, J. R. Knab, J. Y. Chen, and Y. He, “Protein dynamical transition in terahertz dielectric response,” Chemical Physics Letters 442, 413–417 (2007).
[CrossRef]

Knott, E. F.

E. F. Knott, J. F. Shaeffer, and M. T. Tuley, Radar Cross Section, The SciTech radar and defense series, 2nd ed. (SciTech Publishing Inc., Rayleigh, NC, USA, 2004).

Krebs, M. R. H.

M. R. H. Krebs, G. L. Devlin, and A. M. Donald, “Protein particulates: Another generic form of protein aggregation?” Biophysical Journal 92, 1336–1342 (2007).
[CrossRef]

E. H. C. Bromley, M. R. H. Krebs, and A. M. Donald, “Mechanisms of structure formation in particulate gels of β-lactoglobulin formed near the isoelectric point,” European Physical Journal E 21, 145–152 (2006).
[CrossRef]

E. H. C. Bromley, M. R. H. Krebs, and A. M. Donald, “Aggregation across the length-scales in β-lactoglobulin,” Faraday Discussions 128, 13–27 (2005).
[CrossRef] [PubMed]

Kuhn, P. R.

E. A. Foegeding, P. R. Kuhn, and C. C. Hardin, “Specific divalent cation-induced changes during gelation of β-lactoglobulin,” Journal of Agricultural and Food Chemistry 40, 2092–2097 (1992).
[CrossRef]

Le Bon, C.

C. Le Bon, T. Nicolai, and D. Durand, “Kinetics of aggregation and gelation of globular proteins after heat-induced denaturation,” Macromolecules 32, 6120–6127 (1999).
[CrossRef]

Lefèvre, T.

T. Lefèvre and M. Subirade, “Molecular differences in the formation and structure of fine-stranded and particulate β-lactoglobulin gels,” Biopolymers 54, 578–586 (2000).
[CrossRef] [PubMed]

Leitner, D. M.

S. Ebbinghaus, S. J. Kim, M. Heyden, X. Yu, M. Gruebele, D. M. Leitner, and M. Havenith, “Protein sequence-and pH-dependent hydration probed by terahertz spectroscopy,” Journal of the American Chemical Society 130, 2374–2375 (2008).
[CrossRef] [PubMed]

Ma, C. Y.

J. I. Boye, C. Y. Ma, A. Ismail, V. R. Harwalkar, and M. Kalab, “Molecular and microstructural studies of thermal denaturation and gelation of β-lactoglobulins A and B,” Journal of Agricultural and Food Chemistry 45, 1608–1618 (1997).
[CrossRef]

Mandelbaum, I.

K. Siegrist, C. R. Bucher, I. Mandelbaum, A. R. H. Walker, R. Balu, S. K. Gregurick, and D. F. Plusquellic, “High-resolution terahertz spectroscopy of crystalline trialanine: Extreme sensitivity to β-sheet structure and cocrystallized water,” Journal of the American Chemical Society 128, 5764–5775 (2006).
[CrossRef] [PubMed]

Maret, G.

C. Kistner, A. Andre, T. Fischer, A. Thoma, C. Janke, A. Bartels, T. Gisler, G. Maret, and T. Dekorsy, “Hydration dynamics of oriented DNA films investigated by time-domain terahertz spectroscopy,” Applied Physics Letters 90, 233902 (2007).
[CrossRef]

Markelz, A.

J. Knab, J.-Y. Chen, and A. Markelz, “Hydration dependence of conformational dielectric relaxation of lysozyme,” Biophysical Journal 90, 2576–2581 (2006).
[CrossRef] [PubMed]

J. Knab, B. Shah, J.-Y. Chen, and A. Markelz, “Critical hydration and temperature effects on terahertz biomolecular sensing,” in Chemical and Biological Standoff Detection III, J. O. Jensen and J.-M. Thériault, eds., Proc. SPIE 5995, 59950P (2005).
[CrossRef]

Markelz, A. G.

A. G. Markelz, “Terahertz dielectric sensitivity to biomolecular structure and function,” IEEE Journal of Selected Topics in Quantum Electronics 14, 180–190 (2008).
[CrossRef]

A. G. Markelz, J. R. Knab, J. Y. Chen, and Y. He, “Protein dynamical transition in terahertz dielectric response,” Chemical Physics Letters 442, 413–417 (2007).
[CrossRef]

S. E. Whitmire, D. Wolpert, A. G. Markelz, J. R. Hillebrecht, J. Galan, and R. R. Birge, “Protein flexibility and conformational state: A comparison of collective vibrational modes of wild-type and D96N bacteriorhodopsin,” Biophysical Journal 85, 1269–1277 (2003).
[CrossRef]

A. G. Markelz, A. Roitberg, and E. J. Heilweil, “Pulsed terahertz spectroscopy of DNA, bovine serum albumin and collagen between 0.1 and 2.0 THz,” Chemical Physics Letters 320, 42–48 (2000).
[CrossRef]

McClements, D. J.

C. M. Bryant and D. J. McClements, “Molecular basis of protein functionality with special consideration of cold-set gels derived from heat-denatured whey,” Trends in Food Science & Technology 9, 143–151 (1998).
[CrossRef]

Mercadé-Prieto, R.

R. Mercadé-Prieto and X. D. Chen, “Dissolution of whey protein concentrate gels in alkali,” American Institute of Chemical Engineers (AIChE) Journal 52, 792–803 (2006).

Meryman, H. T.

H. T. Meryman, “Mechanics of freezing in living cells and tissues,” Science 124, 515–521 (1956).
[CrossRef] [PubMed]

Mickan, S. P.

G. M. Png, J.-W. Choi, B. W.-H. Ng, S. P. Mickan, D. Abbott, and X.-C. Zhang, “The impact of hydration changes in fresh bio-tissue on THz spectroscopic measurements,” Physics in Medicine and Biology 53, 3501–3517 (2008).
[CrossRef] [PubMed]

Miles, R. E.

A. J. Fitzgerald, E. Berry, N. N. Zinov’ev, S. Homer-Vanniasinkam, R. E. Miles, J. M. Chamberlain, and M. A. Smith, “Catalogue of human tissue optical properties at terahertz frequencies,” Journal of Biological Physics 129, 123–128 (2003).
[CrossRef]

Mohs, R.

J. Näslund, V. Haroutunian, R. Mohs, K. L. Davis, P. Davies, P. Greengard, and J. D. Buxbaum, “Correlation between elevated levels of amyloid β-peptide in the brain and cognitive decline,” Journal of the American Medical Association 283, 1571–1577 (2000).
[CrossRef] [PubMed]

Näslund, J.

J. Näslund, V. Haroutunian, R. Mohs, K. L. Davis, P. Davies, P. Greengard, and J. D. Buxbaum, “Correlation between elevated levels of amyloid β-peptide in the brain and cognitive decline,” Journal of the American Medical Association 283, 1571–1577 (2000).
[CrossRef] [PubMed]

Ng, B. W.-H.

G. M. Png, J.-W. Choi, B. W.-H. Ng, S. P. Mickan, D. Abbott, and X.-C. Zhang, “The impact of hydration changes in fresh bio-tissue on THz spectroscopic measurements,” Physics in Medicine and Biology 53, 3501–3517 (2008).
[CrossRef] [PubMed]

Nicolai, T.

C. Le Bon, T. Nicolai, and D. Durand, “Kinetics of aggregation and gelation of globular proteins after heat-induced denaturation,” Macromolecules 32, 6120–6127 (1999).
[CrossRef]

Norisuye, T.

S. I. Takata, T. Norisuye, N. Tanaka, and M. Shibayama, “Heat-induced gelation of β-lactoglobulin. 1. Time-resolved dynamic light scattering,” Macromolecules 33, 5470–5475 (2000).
[CrossRef]

Pedersen, J. S.

M. Verheul, J. S. Pedersen, S. P. F.M. Roefs, and K. G. de Kruif, “Association behavior of native β-lactoglobulin,” Biopolymers 49, 11–20 (1999).
[CrossRef] [PubMed]

Pepper, M.

P. C. Ashworth, J. A. Zeitler, M. Pepper, and V. P. Wallace, “Terahertz spectroscopy of biologically relevant liquids at low temperatures,” in Proceedings of Joint 31st International Conference on Infrared and Millimeter Waves and 14th International Conference on Terahertz Electronics (IRMMW-THz) (IEEE, Shanghai, China, 2006), p. 184.

Pepys, M. B.

S. Y. Tan and M. B. Pepys, “Amyloidosis,” Histopathology 25, 403–414 (1994).
[CrossRef] [PubMed]

Plusquellic, D. F.

K. Siegrist, C. R. Bucher, I. Mandelbaum, A. R. H. Walker, R. Balu, S. K. Gregurick, and D. F. Plusquellic, “High-resolution terahertz spectroscopy of crystalline trialanine: Extreme sensitivity to β-sheet structure and cocrystallized water,” Journal of the American Chemical Society 128, 5764–5775 (2006).
[CrossRef] [PubMed]

Png, G. M.

G. M. Png, J.-W. Choi, B. W.-H. Ng, S. P. Mickan, D. Abbott, and X.-C. Zhang, “The impact of hydration changes in fresh bio-tissue on THz spectroscopic measurements,” Physics in Medicine and Biology 53, 3501–3517 (2008).
[CrossRef] [PubMed]

Qin, B. Y.

B. Y. Qin, M. C. Bewley, L. K. Creamer, H. M. Baker, E. N. Baker, and G. B. Jameson, “Structural basis of the Tanford transition of bovine β-lactoglobulin,” Biochemistry 37, 14,014–14,023 (1998).
[CrossRef]

Ramdas, A. K.

C. Zhang, E. Tarhan, A. K. Ramdas, A.M. Weiner, and S.M. Durbin, “Broadened far-infrared absorption spectra for hydrated and dehydrated myoglobin,” Journal of Physical Chemistry B 108, 10,077–10,082 (2004).
[CrossRef]

Ramponi, G.

M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
[CrossRef] [PubMed]

Resch, J. J.

J. J. Resch, C. R. Daubert, and E. A. Foegeding, “β-Lactoglobulin gelation and modification: Effect of selected acidulants and heating conditions,” Journal of Food Science 70, C79–C86 (2005).
[CrossRef]

Roefs, S. P. F. M.

K. G. de Kruif, M. A. M. Hoffmann, M. E. van Marle, P. J. J. M. van Mil, S. P. F. M. Roefs, M. Verheul, and N. Zoon, “Gelation of proteins from milk,” Faraday Discussions 101, 185–200 (1995).
[CrossRef] [PubMed]

Roefs, S. P. F.M.

M. Verheul, J. S. Pedersen, S. P. F.M. Roefs, and K. G. de Kruif, “Association behavior of native β-lactoglobulin,” Biopolymers 49, 11–20 (1999).
[CrossRef] [PubMed]

Roitberg, A.

A. G. Markelz, A. Roitberg, and E. J. Heilweil, “Pulsed terahertz spectroscopy of DNA, bovine serum albumin and collagen between 0.1 and 2.0 THz,” Chemical Physics Letters 320, 42–48 (2000).
[CrossRef]

Ross-Murphy, S. B.

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-Lactoglobulin gels: Part 2. Dynamic mechanical characterization of heat-set systems,” Biomacromolecules 5, 2420–2429 (2004).
[CrossRef] [PubMed]

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-Lactoglobulin gels: Part 1. Fibril formation and structure,” Biomacromolecules 5, 2408–2419 (2004).
[CrossRef] [PubMed]

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-lactoglobulin gels: Part 3. Dynamic mechanical characterization of solvent-induced systems,” Biomacromolecules 5, 2430–2438 (2004).
[CrossRef] [PubMed]

G. M. Kavanagh, A. H. Clark, and S. B. Ross-Murphy, “Heat-induced gelation of globular proteins: Part 3. Molecular studies on low pH β-lactoglobulin gels,” International Journal of Biological Macromolecules 28, 41–50 (2000).
[CrossRef] [PubMed]

Selkoe, D. J.

D. J. Selkoe, “Folding proteins in fatal ways,” Nature 426, 900–904 (2003).
[CrossRef] [PubMed]

Shaeffer, J. F.

E. F. Knott, J. F. Shaeffer, and M. T. Tuley, Radar Cross Section, The SciTech radar and defense series, 2nd ed. (SciTech Publishing Inc., Rayleigh, NC, USA, 2004).

Shah, B.

J. Knab, B. Shah, J.-Y. Chen, and A. Markelz, “Critical hydration and temperature effects on terahertz biomolecular sensing,” in Chemical and Biological Standoff Detection III, J. O. Jensen and J.-M. Thériault, eds., Proc. SPIE 5995, 59950P (2005).
[CrossRef]

Shibayama, M.

S. I. Takata, T. Norisuye, N. Tanaka, and M. Shibayama, “Heat-induced gelation of β-lactoglobulin. 1. Time-resolved dynamic light scattering,” Macromolecules 33, 5470–5475 (2000).
[CrossRef]

Siegel, P. H.

P. H. Siegel “Terahertz technology,” IEEE Transactions on Microwave Theory and Techniques 50, 910–928 (2002).
[CrossRef]

Siegrist, K.

K. Siegrist, C. R. Bucher, I. Mandelbaum, A. R. H. Walker, R. Balu, S. K. Gregurick, and D. F. Plusquellic, “High-resolution terahertz spectroscopy of crystalline trialanine: Extreme sensitivity to β-sheet structure and cocrystallized water,” Journal of the American Chemical Society 128, 5764–5775 (2006).
[CrossRef] [PubMed]

Singh, H.

M. A. de la Fuente, H. Singh, and Y. Hemar, “Recent advances in the characterisation of heat-induced aggregates and intermediates of whey proteins,” Trends in Food Science & Technology 13, 262–274 (2002).
[CrossRef]

Smith, M. A.

A. J. Fitzgerald, E. Berry, N. N. Zinov’ev, S. Homer-Vanniasinkam, R. E. Miles, J. M. Chamberlain, and M. A. Smith, “Catalogue of human tissue optical properties at terahertz frequencies,” Journal of Biological Physics 129, 123–128 (2003).
[CrossRef]

Stefani, M.

M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
[CrossRef] [PubMed]

Subirade, M.

T. Lefèvre and M. Subirade, “Molecular differences in the formation and structure of fine-stranded and particulate β-lactoglobulin gels,” Biopolymers 54, 578–586 (2000).
[CrossRef] [PubMed]

Taddei, N.

M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
[CrossRef] [PubMed]

Takata, S. I.

S. I. Takata, T. Norisuye, N. Tanaka, and M. Shibayama, “Heat-induced gelation of β-lactoglobulin. 1. Time-resolved dynamic light scattering,” Macromolecules 33, 5470–5475 (2000).
[CrossRef]

Tan, S. Y.

S. Y. Tan and M. B. Pepys, “Amyloidosis,” Histopathology 25, 403–414 (1994).
[CrossRef] [PubMed]

Tanaka, N.

S. I. Takata, T. Norisuye, N. Tanaka, and M. Shibayama, “Heat-induced gelation of β-lactoglobulin. 1. Time-resolved dynamic light scattering,” Macromolecules 33, 5470–5475 (2000).
[CrossRef]

Tarhan, E.

C. Zhang, E. Tarhan, A. K. Ramdas, A.M. Weiner, and S.M. Durbin, “Broadened far-infrared absorption spectra for hydrated and dehydrated myoglobin,” Journal of Physical Chemistry B 108, 10,077–10,082 (2004).
[CrossRef]

Thoma, A.

C. Kistner, A. Andre, T. Fischer, A. Thoma, C. Janke, A. Bartels, T. Gisler, G. Maret, and T. Dekorsy, “Hydration dynamics of oriented DNA films investigated by time-domain terahertz spectroscopy,” Applied Physics Letters 90, 233902 (2007).
[CrossRef]

Tuley, M. T.

E. F. Knott, J. F. Shaeffer, and M. T. Tuley, Radar Cross Section, The SciTech radar and defense series, 2nd ed. (SciTech Publishing Inc., Rayleigh, NC, USA, 2004).

van de Hulst, H. C.

H. C. van de Hulst, Light Scattering by Small Particles (John Wiley & Sons, Inc., New York, USA, 1957).

van Marle, M. E.

K. G. de Kruif, M. A. M. Hoffmann, M. E. van Marle, P. J. J. M. van Mil, S. P. F. M. Roefs, M. Verheul, and N. Zoon, “Gelation of proteins from milk,” Faraday Discussions 101, 185–200 (1995).
[CrossRef] [PubMed]

van Mil, P. J. J. M.

K. G. de Kruif, M. A. M. Hoffmann, M. E. van Marle, P. J. J. M. van Mil, S. P. F. M. Roefs, M. Verheul, and N. Zoon, “Gelation of proteins from milk,” Faraday Discussions 101, 185–200 (1995).
[CrossRef] [PubMed]

Verheul, M.

M. Verheul, J. S. Pedersen, S. P. F.M. Roefs, and K. G. de Kruif, “Association behavior of native β-lactoglobulin,” Biopolymers 49, 11–20 (1999).
[CrossRef] [PubMed]

K. G. de Kruif, M. A. M. Hoffmann, M. E. van Marle, P. J. J. M. van Mil, S. P. F. M. Roefs, M. Verheul, and N. Zoon, “Gelation of proteins from milk,” Faraday Discussions 101, 185–200 (1995).
[CrossRef] [PubMed]

Walker, A. R. H.

K. Siegrist, C. R. Bucher, I. Mandelbaum, A. R. H. Walker, R. Balu, S. K. Gregurick, and D. F. Plusquellic, “High-resolution terahertz spectroscopy of crystalline trialanine: Extreme sensitivity to β-sheet structure and cocrystallized water,” Journal of the American Chemical Society 128, 5764–5775 (2006).
[CrossRef] [PubMed]

Wallace, V. P.

P. C. Ashworth, J. A. Zeitler, M. Pepper, and V. P. Wallace, “Terahertz spectroscopy of biologically relevant liquids at low temperatures,” in Proceedings of Joint 31st International Conference on Infrared and Millimeter Waves and 14th International Conference on Terahertz Electronics (IRMMW-THz) (IEEE, Shanghai, China, 2006), p. 184.

Walther, M.

B. M. Fischer, M. Walther, and P. U. Jepsen, “Far-infrared vibrational modes of DNA components studied by terahertz time-domain spectroscopy,” Physics in Medicine and Biology 47, 3807–3814 (2002).
[CrossRef] [PubMed]

Weiner, A.M.

C. Zhang, E. Tarhan, A. K. Ramdas, A.M. Weiner, and S.M. Durbin, “Broadened far-infrared absorption spectra for hydrated and dehydrated myoglobin,” Journal of Physical Chemistry B 108, 10,077–10,082 (2004).
[CrossRef]

Whitmire, S. E.

S. E. Whitmire, D. Wolpert, A. G. Markelz, J. R. Hillebrecht, J. Galan, and R. R. Birge, “Protein flexibility and conformational state: A comparison of collective vibrational modes of wild-type and D96N bacteriorhodopsin,” Biophysical Journal 85, 1269–1277 (2003).
[CrossRef]

Wolpert, D.

S. E. Whitmire, D. Wolpert, A. G. Markelz, J. R. Hillebrecht, J. Galan, and R. R. Birge, “Protein flexibility and conformational state: A comparison of collective vibrational modes of wild-type and D96N bacteriorhodopsin,” Biophysical Journal 85, 1269–1277 (2003).
[CrossRef]

Yu, X.

S. Ebbinghaus, S. J. Kim, M. Heyden, X. Yu, M. Gruebele, D. M. Leitner, and M. Havenith, “Protein sequence-and pH-dependent hydration probed by terahertz spectroscopy,” Journal of the American Chemical Society 130, 2374–2375 (2008).
[CrossRef] [PubMed]

Zeitler, J. A.

P. C. Ashworth, J. A. Zeitler, M. Pepper, and V. P. Wallace, “Terahertz spectroscopy of biologically relevant liquids at low temperatures,” in Proceedings of Joint 31st International Conference on Infrared and Millimeter Waves and 14th International Conference on Terahertz Electronics (IRMMW-THz) (IEEE, Shanghai, China, 2006), p. 184.

Zhang, C.

C. Zhang, E. Tarhan, A. K. Ramdas, A.M. Weiner, and S.M. Durbin, “Broadened far-infrared absorption spectra for hydrated and dehydrated myoglobin,” Journal of Physical Chemistry B 108, 10,077–10,082 (2004).
[CrossRef]

Zhang, X.-C.

G. M. Png, J.-W. Choi, B. W.-H. Ng, S. P. Mickan, D. Abbott, and X.-C. Zhang, “The impact of hydration changes in fresh bio-tissue on THz spectroscopic measurements,” Physics in Medicine and Biology 53, 3501–3517 (2008).
[CrossRef] [PubMed]

Zinov’ev, N. N.

A. J. Fitzgerald, E. Berry, N. N. Zinov’ev, S. Homer-Vanniasinkam, R. E. Miles, J. M. Chamberlain, and M. A. Smith, “Catalogue of human tissue optical properties at terahertz frequencies,” Journal of Biological Physics 129, 123–128 (2003).
[CrossRef]

Zoon, N.

K. G. de Kruif, M. A. M. Hoffmann, M. E. van Marle, P. J. J. M. van Mil, S. P. F. M. Roefs, M. Verheul, and N. Zoon, “Gelation of proteins from milk,” Faraday Discussions 101, 185–200 (1995).
[CrossRef] [PubMed]

Zurdo, J.

M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
[CrossRef] [PubMed]

American Institute of Chemical Engineers (AIChE) Journal (1)

R. Mercadé-Prieto and X. D. Chen, “Dissolution of whey protein concentrate gels in alkali,” American Institute of Chemical Engineers (AIChE) Journal 52, 792–803 (2006).

Applied Physics Letters (1)

C. Kistner, A. Andre, T. Fischer, A. Thoma, C. Janke, A. Bartels, T. Gisler, G. Maret, and T. Dekorsy, “Hydration dynamics of oriented DNA films investigated by time-domain terahertz spectroscopy,” Applied Physics Letters 90, 233902 (2007).
[CrossRef]

Biochemistry (1)

B. Y. Qin, M. C. Bewley, L. K. Creamer, H. M. Baker, E. N. Baker, and G. B. Jameson, “Structural basis of the Tanford transition of bovine β-lactoglobulin,” Biochemistry 37, 14,014–14,023 (1998).
[CrossRef]

Biomacromolecules (3)

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-Lactoglobulin gels: Part 2. Dynamic mechanical characterization of heat-set systems,” Biomacromolecules 5, 2420–2429 (2004).
[CrossRef] [PubMed]

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-lactoglobulin gels: Part 3. Dynamic mechanical characterization of solvent-induced systems,” Biomacromolecules 5, 2430–2438 (2004).
[CrossRef] [PubMed]

W. S. Gosal, A. H. Clark, and S. B. Ross-Murphy, “Fibrillar β-Lactoglobulin gels: Part 1. Fibril formation and structure,” Biomacromolecules 5, 2408–2419 (2004).
[CrossRef] [PubMed]

Biophysical Journal (3)

J. Knab, J.-Y. Chen, and A. Markelz, “Hydration dependence of conformational dielectric relaxation of lysozyme,” Biophysical Journal 90, 2576–2581 (2006).
[CrossRef] [PubMed]

L. N. Arnaudov and R. de Vries, “Thermally induced fibrillar aggregation of hen egg white lysozyme,” Biophysical Journal 88, 515–526 (2005).
[CrossRef]

M. R. H. Krebs, G. L. Devlin, and A. M. Donald, “Protein particulates: Another generic form of protein aggregation?” Biophysical Journal 92, 1336–1342 (2007).
[CrossRef]

Biophysical Journal 85 (1)

S. E. Whitmire, D. Wolpert, A. G. Markelz, J. R. Hillebrecht, J. Galan, and R. R. Birge, “Protein flexibility and conformational state: A comparison of collective vibrational modes of wild-type and D96N bacteriorhodopsin,” Biophysical Journal 85, 1269–1277 (2003).
[CrossRef]

Biopolymers (2)

T. Lefèvre and M. Subirade, “Molecular differences in the formation and structure of fine-stranded and particulate β-lactoglobulin gels,” Biopolymers 54, 578–586 (2000).
[CrossRef] [PubMed]

M. Verheul, J. S. Pedersen, S. P. F.M. Roefs, and K. G. de Kruif, “Association behavior of native β-lactoglobulin,” Biopolymers 49, 11–20 (1999).
[CrossRef] [PubMed]

Chemical Physics Letters (2)

A. G. Markelz, A. Roitberg, and E. J. Heilweil, “Pulsed terahertz spectroscopy of DNA, bovine serum albumin and collagen between 0.1 and 2.0 THz,” Chemical Physics Letters 320, 42–48 (2000).
[CrossRef]

A. G. Markelz, J. R. Knab, J. Y. Chen, and Y. He, “Protein dynamical transition in terahertz dielectric response,” Chemical Physics Letters 442, 413–417 (2007).
[CrossRef]

European Physical Journal E (1)

E. H. C. Bromley, M. R. H. Krebs, and A. M. Donald, “Mechanisms of structure formation in particulate gels of β-lactoglobulin formed near the isoelectric point,” European Physical Journal E 21, 145–152 (2006).
[CrossRef]

Faraday Discussions (2)

E. H. C. Bromley, M. R. H. Krebs, and A. M. Donald, “Aggregation across the length-scales in β-lactoglobulin,” Faraday Discussions 128, 13–27 (2005).
[CrossRef] [PubMed]

K. G. de Kruif, M. A. M. Hoffmann, M. E. van Marle, P. J. J. M. van Mil, S. P. F. M. Roefs, M. Verheul, and N. Zoon, “Gelation of proteins from milk,” Faraday Discussions 101, 185–200 (1995).
[CrossRef] [PubMed]

Histopathology (1)

S. Y. Tan and M. B. Pepys, “Amyloidosis,” Histopathology 25, 403–414 (1994).
[CrossRef] [PubMed]

IEEE Journal of Selected Topics in Quantum Electronics (1)

A. G. Markelz, “Terahertz dielectric sensitivity to biomolecular structure and function,” IEEE Journal of Selected Topics in Quantum Electronics 14, 180–190 (2008).
[CrossRef]

IEEE Transactions on Microwave Theory and Techniques (1)

P. H. Siegel “Terahertz technology,” IEEE Transactions on Microwave Theory and Techniques 50, 910–928 (2002).
[CrossRef]

International Journal of Biological Macromolecules (1)

G. M. Kavanagh, A. H. Clark, and S. B. Ross-Murphy, “Heat-induced gelation of globular proteins: Part 3. Molecular studies on low pH β-lactoglobulin gels,” International Journal of Biological Macromolecules 28, 41–50 (2000).
[CrossRef] [PubMed]

Journal of Agricultural and Food Chemistry (4)

M. E. Hines and E. A. Foegeding, “Interactions ofa-lactalbumin and bovine serum-albumin with β-lactoglobulin in thermally induced gelation,” Journal of Agricultural and Food Chemistry 41, 341–346 (1993).
[CrossRef]

E. A. Foegeding, P. R. Kuhn, and C. C. Hardin, “Specific divalent cation-induced changes during gelation of β-lactoglobulin,” Journal of Agricultural and Food Chemistry 40, 2092–2097 (1992).
[CrossRef]

H. M. Hudson, C. R. Daubert, and E. A. Foegeding, “Rheological and physical properties of derivitized whey protein isolate powders,” Journal of Agricultural and Food Chemistry 48, 3112–3119 (2000).
[CrossRef] [PubMed]

J. I. Boye, C. Y. Ma, A. Ismail, V. R. Harwalkar, and M. Kalab, “Molecular and microstructural studies of thermal denaturation and gelation of β-lactoglobulins A and B,” Journal of Agricultural and Food Chemistry 45, 1608–1618 (1997).
[CrossRef]

Journal of Biological Physics (1)

A. J. Fitzgerald, E. Berry, N. N. Zinov’ev, S. Homer-Vanniasinkam, R. E. Miles, J. M. Chamberlain, and M. A. Smith, “Catalogue of human tissue optical properties at terahertz frequencies,” Journal of Biological Physics 129, 123–128 (2003).
[CrossRef]

Journal of Food Science (1)

J. J. Resch, C. R. Daubert, and E. A. Foegeding, “β-Lactoglobulin gelation and modification: Effect of selected acidulants and heating conditions,” Journal of Food Science 70, C79–C86 (2005).
[CrossRef]

Journal of Physical Chemistry B (1)

C. Zhang, E. Tarhan, A. K. Ramdas, A.M. Weiner, and S.M. Durbin, “Broadened far-infrared absorption spectra for hydrated and dehydrated myoglobin,” Journal of Physical Chemistry B 108, 10,077–10,082 (2004).
[CrossRef]

Journal of the American Chemical Society (2)

S. Ebbinghaus, S. J. Kim, M. Heyden, X. Yu, M. Gruebele, D. M. Leitner, and M. Havenith, “Protein sequence-and pH-dependent hydration probed by terahertz spectroscopy,” Journal of the American Chemical Society 130, 2374–2375 (2008).
[CrossRef] [PubMed]

K. Siegrist, C. R. Bucher, I. Mandelbaum, A. R. H. Walker, R. Balu, S. K. Gregurick, and D. F. Plusquellic, “High-resolution terahertz spectroscopy of crystalline trialanine: Extreme sensitivity to β-sheet structure and cocrystallized water,” Journal of the American Chemical Society 128, 5764–5775 (2006).
[CrossRef] [PubMed]

Journal of the American Medical Association (1)

J. Näslund, V. Haroutunian, R. Mohs, K. L. Davis, P. Davies, P. Greengard, and J. D. Buxbaum, “Correlation between elevated levels of amyloid β-peptide in the brain and cognitive decline,” Journal of the American Medical Association 283, 1571–1577 (2000).
[CrossRef] [PubMed]

Macromolecules (2)

C. Le Bon, T. Nicolai, and D. Durand, “Kinetics of aggregation and gelation of globular proteins after heat-induced denaturation,” Macromolecules 32, 6120–6127 (1999).
[CrossRef]

S. I. Takata, T. Norisuye, N. Tanaka, and M. Shibayama, “Heat-induced gelation of β-lactoglobulin. 1. Time-resolved dynamic light scattering,” Macromolecules 33, 5470–5475 (2000).
[CrossRef]

Nature (2)

D. J. Selkoe, “Folding proteins in fatal ways,” Nature 426, 900–904 (2003).
[CrossRef] [PubMed]

M. Bucciantini, E. Giannoni, F. Chiti, F. Baroni, L. Formigli, J. Zurdo, N. Taddei, G. Ramponi, C. M. Dobson, and M. Stefani, “Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases,” Nature 416, 507–511 (2002).
[CrossRef] [PubMed]

Physics in Medicine and Biology (2)

B. M. Fischer, M. Walther, and P. U. Jepsen, “Far-infrared vibrational modes of DNA components studied by terahertz time-domain spectroscopy,” Physics in Medicine and Biology 47, 3807–3814 (2002).
[CrossRef] [PubMed]

G. M. Png, J.-W. Choi, B. W.-H. Ng, S. P. Mickan, D. Abbott, and X.-C. Zhang, “The impact of hydration changes in fresh bio-tissue on THz spectroscopic measurements,” Physics in Medicine and Biology 53, 3501–3517 (2008).
[CrossRef] [PubMed]

Proc. SPIE (1)

J. Knab, B. Shah, J.-Y. Chen, and A. Markelz, “Critical hydration and temperature effects on terahertz biomolecular sensing,” in Chemical and Biological Standoff Detection III, J. O. Jensen and J.-M. Thériault, eds., Proc. SPIE 5995, 59950P (2005).
[CrossRef]

Science (1)

H. T. Meryman, “Mechanics of freezing in living cells and tissues,” Science 124, 515–521 (1956).
[CrossRef] [PubMed]

Trends in Food Science & Technology (2)

M. A. de la Fuente, H. Singh, and Y. Hemar, “Recent advances in the characterisation of heat-induced aggregates and intermediates of whey proteins,” Trends in Food Science & Technology 13, 262–274 (2002).
[CrossRef]

C. M. Bryant and D. J. McClements, “Molecular basis of protein functionality with special consideration of cold-set gels derived from heat-denatured whey,” Trends in Food Science & Technology 9, 143–151 (1998).
[CrossRef]

Other (4)

P. C. Ashworth, J. A. Zeitler, M. Pepper, and V. P. Wallace, “Terahertz spectroscopy of biologically relevant liquids at low temperatures,” in Proceedings of Joint 31st International Conference on Infrared and Millimeter Waves and 14th International Conference on Terahertz Electronics (IRMMW-THz) (IEEE, Shanghai, China, 2006), p. 184.

C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles, Wiley science paperback series (John Wiley & Sons, New York, NY, USA, 1983).

H. C. van de Hulst, Light Scattering by Small Particles (John Wiley & Sons, Inc., New York, USA, 1957).

E. F. Knott, J. F. Shaeffer, and M. T. Tuley, Radar Cross Section, The SciTech radar and defense series, 2nd ed. (SciTech Publishing Inc., Rayleigh, NC, USA, 2004).

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (10)

Fig. 1.
Fig. 1.

(a) Cartoon diagram of a β-lg molecule obtained from the Protein Data Bank (PDB), and rendered using Rasmol (PDB ID: 1BSY). This molecule is colored according to its secondary structures: eight antiparallel β-pleated sheets (yellow), α-helix segments (magenta), and other residues (white). After [24]; (b) Succession of steps leading to the formation of fibrillar and globular β-lg gels in a solution environment at >65–70°C. The process starts off with β-lg dimers (a dimer contains two β-lg molecules, each with structure as shown by the cartoon diagram on the left). Depending on the acidity of the solution environment, the dimer aggregates to form either fine fibrils (pH 2) or globules (pH 4). Coarse fibrils are formed at pH 7. Adapted from [19].

Fig. 2.
Fig. 2.

(a and b) At pH 2, the β-lg monomers form chains that look “worm-like”, being typically between 100–200 nm in length and ~4 nm in diameter. Alternatively at pH 7, the β-lg monomers tend to stick to each other, resulting in fractal aggregate formation. The fibrils also look “worm-like” but are thicker than the ones seen at pH 2, being typically ~30 nm in diameter. After [17,28]; (c) This schematic of pH 4 globules is not drawn to the same scale as the figures to the left. The globules clearly resemble balls with diameter that varies with the rate of heating. Diameters reported in literature vary between 100 nm and 2 µm. After [30, 31].

Fig. 3.
Fig. 3.

Frozen pH 2 gel shown here as an example of the appearance of the gels. All the frozen gels appear turbid and opaque. For illustrative purpose, the frozen gel on the right is shown in its dish but without the sealed lid.

Fig. 4.
Fig. 4.

Electron micrographs of the gels synthesized in this study. The white scale bar at the bottom of each figure represents 2 µm. (a) Transmission electron micrograph (TEM) of pH 2 gel reveals fine fibrillar aggregates that are scattered loosely throughout the gel; (b) Scanning electron micrograph (SEM) of pH 4 gel reveals globular aggregates that cluster to form layers of balls; (c) TEM of pH 7 gel also reveals the presence of fibrillar aggregates but these fibrils are coarser than those at pH 2. Like the pH 4 globules, the pH 7 fibrils also cluster to form clumps.

Fig. 5.
Fig. 5.

The Picometrix T-ray-2000 system used in this study, shown without the nitrogen-purged chamber. The upright arrangement of this system allows the dishes to be mounted quickly and easily on a horizontal platform without the need for clamps. A hole in the platform is wide enough to allow unobstructed THz transmission through the sample.

Fig. 6.
Fig. 6.

The custom PCA system used in this study, shown with its nitrogen-purged chamber. The THz beam propagates in a path that is parallel to the optical bench, thus the samples are mounted perpendicular to the optical bench (unlike the case for the Picometrix system).

Fig. 7.
Fig. 7.

The distinct rise in the THz extinction coefficient of pH 4 gel is likely due to the globular microstructure in the gel. The two different fibrillar structures in the pH 2 and 7 gels are indistinguishable from each other. Furthermore, the fibrils have the same THz response as the solutions, which lack any microstructures.

Fig. 8.
Fig. 8.

The refractive indices n(ω) of both the gels and solutions do not vary much with frequency since their profiles are relatively flat over the system bandwidth. This means that there is no evidence of dispersion of the THz signal inside the samples. The error bars are generated based on ±0.1 mm uncertainty in the measurement of sample thickness.

Fig. 9.
Fig. 9.

Rayleigh scattering efficiencies Q sca(ω) versus extinction coefficients α(ω) of fibrils and globules. Rayleigh scattering is a special case of Mie scattering, and is applicable in this study due to the small dimensions of the microstructures. (a) The plot of Q sca(ω) for a single sphere model of a pH 4 globule, and the plot of Q sca(ω) for clusters of wide cylinders modeling the pH 7 coarse fibrils reveal that the steep rise in the extinction coefficient of the pH 4 gel could be due to scattering; (b) There is good agreement between Q sca(ω) for clusters of wide cylinders and the extinction coefficient of the coarse fibrils at pH 7, but no agreement between Q sca(ω) for clusters of narrow cylinders and the extinction coefficient of fine fibrils at pH 2. This indicates that the existing resolution of a THz-TDS system is insufficient for differentiating between the fine and coarse fibrils.

Fig. 10.
Fig. 10.

The frequency bandwidth and dynamic range of the pH 4 gel measurements improve with decreasing temperatures, but begin to convergence at 180 K. There is no significant difference between the measurements made at 120 K and 20 K.

Equations (13)

Equations on this page are rendered with MathJax. Learn more.

Eref(ω)=Eref(ω)e(iωt+ϕref(ω))
Esample+ref(ω)=Esample+ref(ω)e(iωt+ϕsample+ref(ω))
Esample(ω)=Esample+ref(ω)Eref(ω)
ϕsample(ω)=ϕsample+ref(ω)ϕref(ω),
nsample(ω)=cϕsample(ω)ωd+1
αsample(ω)=2dln(Esample(ω)[1+nsample(ω)][ndish(ω)+nsample(ω)]2nsample(ω)[1+ndish(ω)]),
Qsca(ω)=8Lx43 m21m2+22
wherem(ω)=n̂microstructure(ω)n̂surroundingmedium(ω)
x(ω)=2πn̂microstructure(ω)rλ
n̂microstructure(ω)=nmicrostructure(ω)+iκmicrostructure(ω)=nmicrostructure(ω)+iαmicrostructure(ω)c2ω,
Qsca(ω)=2Px[b0(ω)2+2b1(ω)2]
whereb0(ω)iπx2(m21)4
b1(ω)iπx4(m21)32.

Metrics