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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 15, Iss. 3 — Feb. 5, 2007
  • pp: 1043–1053

Intrinsic fluorescence changes associated with the conformational state of silk fibroin in biomaterial matrices

Irene Georgakoudi, Irene Tsai, Cherry Greiner, Cheryl Wong, Jordy DeFelice, and David Kaplan  »View Author Affiliations

Optics Express, Vol. 15, Issue 3, pp. 1043-1053 (2007)

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Silk fibroin is emerging as an important biomaterial for tissue engineering applications. The ability to monitor non-invasively the structural conformation of silk matrices prior to and following cell seeding could provide important insights with regards to matrix remodeling and cell-matrix interactions that are critical for the functional development of silk-based engineered tissues. Thus, we examined the potential of intrinsic fluorescence as a tool for assessing the structural conformation of silk proteins. Specifically, we characterized the intrinsic fluorescence spectra of silk in solution, gel and scaffold configurations for excitation in the 250 to 335 nm range and emission from 265 to 600 nm. We have identified spectral components that are attributed to tyrosine, tryptophan and crosslinks based on their excitation-emission profiles. We have discovered significant spectral shifts in the emission profiles and relative contributions of these components among the silk solution, gel and scaffold samples that represent enhancements in the levels of crosslinking, hydrophobic and intermolecular interactions that are consistent with an increase in the levels of β-sheet formation and stacking. This information can be easily utilized for the development of simple, non-invasive, ratiometric methods to assess and monitor the structural conformation of silk in engineered tissues.

© 2007 Optical Society of America

OCIS Codes
(170.1580) Medical optics and biotechnology : Chemometrics
(170.6280) Medical optics and biotechnology : Spectroscopy, fluorescence and luminescence

ToC Category:
Medical Optics and Biotechnology

Original Manuscript: January 16, 2007
Manuscript Accepted: January 29, 2007
Published: February 5, 2007

Virtual Issues
Vol. 2, Iss. 3 Virtual Journal for Biomedical Optics

Irene Georgakoudi, Irene Tsai, Cherry Greiner, Cheryl Wong, Jordy DeFelice, and David Kaplan, "Intrinsic fluorescence changes associated with the conformational state of silk fibroin in biomaterial matrices," Opt. Express 15, 1043-1053 (2007)

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  1. B. D. Ratner, A. S. Hoffman, F. J. Schoen, and J. E. Lemons, Biomaterials Science, 2nd ed. (Elsevier Academic Press, San Diego, 2004).
  2. G. H. Altman, F. Diaz, C. Jakuba, T. Calabro, R. L. Horan, J. Chen, H. Lu, J. Richmond, and D. L. Kaplan, "Silk-based biomaterials," Biomaterials 24(3), 401-416 (2003). [CrossRef]
  3. G. H. Altman, R. L. Horan, H. H. Lu, J. Moreau, I. Martin, J. C. Richmond, and D. L. Kaplan, "Silk matrix for tissue engineered anterior cruciate ligaments," Biomaterials 23(20), 4131-4141 (2002). [CrossRef] [PubMed]
  4. G. H. Altman, H. H. Lu, R. L. Horan, T. Calabro, D. Ryder, D. L. Kaplan, P. Stark, I. Martin, J. C. Richmond, and G. Vunjak-Novakovic, "Advanced bioreactor with controlled application of multi-dimensional strain for tissue engineering," J Biomech Eng 124(6), 742-749 (2002). [CrossRef]
  5. H. J. Jin, J. Park, R. Valluzzi, P. Cebe, and D. L. Kaplan, "Biomaterial films of Bombyx mori silk fibroin with poly(ethylene oxide)," Biomacromolecules 5(3), 711-717 (2004). [CrossRef] [PubMed]
  6. U. J. Kim, J. Park, C. Li, H. J. Jin, R. Valluzzi, and D. L. Kaplan, "Structure and properties of silk hydrogels," Biomacromolecules 5(3), 786-792 (2004). [CrossRef] [PubMed]
  7. R. Nazarov, H. J. Jin, and D. L. Kaplan, "Porous 3-D scaffolds from regenerated silk fibroin," Biomacromolecules 5(3), 718-726 (2004). [CrossRef] [PubMed]
  8. V. Karageorgiou, L. Meinel, S. Hofmann, A. Malhotra, V. Volloch, and D. Kaplan, "Bone morphogenetic protein-2 decorated silk fibroin films induce osteogenic differentiation of human bone marrow stromal cells," J Biomed Mater Res A 71(3), 528-537 (2004). [CrossRef] [PubMed]
  9. V. Karageorgiou, M. Tomkins, R. Fajardo, L. Meinel, B. Snyder, K. Wade, J. Chen, G. Vunjak-Novakovic, and D. L. Kaplan, "Porous silk fibroin 3-D scaffolds for delivery of bone morphogenetic protein-2 in vitro and in vivo," J Biomed Mater Res A 78(2), 324-334 (2006). [PubMed]
  10. U. J. Kim, J. Park, H. J. Kim, M. Wada, and D. L. Kaplan, "Three-dimensional aqueous-derived biomaterial scaffolds from silk fibroin," Biomaterials 26(15), 2775-2785 (2005). [CrossRef]
  11. L. Meinel, R. Fajardo, S. Hofmann, R. Langer, J. Chen, B. Snyder, G. Vunjak-Novakovic, and D. Kaplan, "Silk implants for the healing of critical size bone defects," Bone 37(5), 688-698 (2005). [CrossRef] [PubMed]
  12. L. Meinel, S. Hofmann, V. Karageorgiou, C. Kirker-Head, J. McCool, G. Gronowicz, L. Zichner, R. Langer, G. Vunjak-Novakovic, and D. L. Kaplan, "The inflammatory responses to silk films in vitro and in vivo," Biomaterials 26(2), 147-155 (2005). [CrossRef]
  13. L. Meinel, S. Hofmann, V. Karageorgiou, L. Zichner, R. Langer, D. Kaplan, and G. Vunjak-Novakovic, "Engineering cartilage-like tissue using human mesenchymal stem cells and silk protein scaffolds," Biotechnol Bioeng 88(3), 379-391 (2004). [CrossRef] [PubMed]
  14. L. Meinel, V. Karageorgiou, R. Fajardo, B. Snyder, V. Shinde-Patil, L. Zichner, D. Kaplan, R. Langer, and G. Vunjak-Novakovic, "Bone tissue engineering using human mesenchymal stem cells: effects of scaffold material and medium flow," Ann Biomed Eng 32(1), 112-122 (2004). [CrossRef] [PubMed]
  15. L. Meinel, V. Karageorgiou, S. Hofmann, R. Fajardo, B. Snyder, C. Li, L. Zichner, R. Langer, G. Vunjak-Novakovic, and D. L. Kaplan, "Engineering bone-like tissue in vitro using human bone marrow stem cells and silk scaffolds," J Biomed Mater Res A 71(1), 25-34 (2004). [CrossRef] [PubMed]
  16. Y. Wang, D. J. Blasioli, H. J. Kim, H. S. Kim, and D. L. Kaplan, "Cartilage tissue engineering with silk scaffolds and human articular chondrocytes," Biomaterials 27(25), 4434-4442 (2006). [CrossRef] [PubMed]
  17. Y. Wang, U. J. Kim, D. J. Blasioli, H. J. Kim, and D. L. Kaplan, "In vitro cartilage tissue engineering with 3D porous aqueous-derived silk scaffolds and mesenchymal stem cells," Biomaterials 26(34), 7082-7094 (2005). [CrossRef] [PubMed]
  18. R. L. Horan, K. Antle, A. L. Collette, Y. Wang, J. Huang, J. E. Moreau, V. Volloch, D. L. Kaplan, and G. H. Altman, "In vitro degradation of silk fibroin," Biomaterials 26(17), 3385-3393 (2005). [CrossRef]
  19. H. J. Jin, J. Park, V. Karageorgiou, U. J. Kim, R. Valluzzi, and D. Kaplan, "Water-stable films with reduced beta-sheet content," Advanced Functional Materials 15(8), 1241-1247 (2005). [CrossRef]
  20. Y. K. Reshetnyak and E. A. Burstein, "Decomposition of protein tryptophan fluorescence spectra into log-normal components. II. The statistical proof of discreteness of tryptophan classes in proteins," Biophys J 81(3), 1710-1734 (2001). [CrossRef] [PubMed]
  21. Y. K. Reshetnyak, Y. Koshevnik, and E. A. Burstein, "Decomposition of protein tryptophan fluorescence spectra into log-normal components. III. Correlation between fluorescence and microenvironment parameters of individual tryptophan residues," Biophys J 81(3), 1735-1758 (2001). [CrossRef] [PubMed]
  22. C. Cantor and P. Schimmel, Biophysical Chemistry Part II:Techniques for the study of biological structure and function, 1st ed. (W.H. Freeman and Company, New York, 1980).
  23. T. C. Doyle, J. E. Hansen, and E. Reisler, "Tryptophan fluorescence of yeast actin resolved via conserved mutations," Biophysical Journal 80(1), 427-434 (2001). [CrossRef] [PubMed]
  24. I. M. Kuznetsova, T. A. Yakusheva, and K. K. Turoverov, "Contribution of separate tryptophan residues to intrinsic fluorescence of actin. Analysis of 3D structure," Febs Letters 452(3), 205-210 (1999). [CrossRef] [PubMed]
  25. C. Z. Zhou, F. Confalonieri, N. Medina, Y. Zivanovic, C. Esnault, T. Yang, M. Jacquet, J. Janin, M. Duguet, R. Perasso, and Z. G. Li, "Fine organization of Bombyx mori fibroin heavy chain gene," Nucleic Acids Res 28(12), 2413-2419 (2000). [CrossRef] [PubMed]
  26. H. J. Jin and D. L. Kaplan, "Mechanism of silk processing in insects and spiders," Nature 424(6952), 1057-1061 (2003). [CrossRef] [PubMed]
  27. S. Sofia, M. B. McCarthy, G. Gronowicz, and D. L. Kaplan, "Functionalized silk-based biomaterials for bone formation," J Biomed Mater Res 54(1), 139-148 (2001). [CrossRef]
  28. U. J. Kim, J. Park, H. J. Kim, M. Wada, and D. L. Kaplan, "Three-dimensional aqueous-derived biomaterial scaffolds from silk fibroin," Biomaterials 26(15), 2775-2785 (2005). [CrossRef]
  29. D. Malencik, J. Sprouse, C. Swanson, and S. Anderson, "Dityrosine: Preparation, Isolation and Analysis," Analytical Biochemistry 242, 202-213 (1996). [CrossRef] [PubMed]
  30. R. Tauler, A. Smilde, J. Henshaw, L. Burgess, and B. Kowalski, "Multicomponent determination of chlorinated hydrocarbons using a reaction-based chemical sensor. 1. Chemical speciation using multivatiate curve resolution," Analytical Chemistry 66, 3337-3344 (1994). [CrossRef]
  31. J. R. Lakowicz, Principles of Fluorescence Spectroscopy, Second ed. (Kluwer Academic/Plenum Publishers, New York, NY, 1999).
  32. B. Lotz, "Crystal structure of polyglycine I," J Mol Biol 87(2), 169-180 (1974). [CrossRef] [PubMed]
  33. R. E. Marsh, R. B. Corey, and L. Pauling, "An investigation of the structure of silk fibroin," Biochim Biophys Acta 16(1), 1-34 (1955). [CrossRef] [PubMed]
  34. D. L. Kaplan, W. Adams, B. Farmer, and C. Viney, eds., Silk Polymers: Science and Biotechnology, (American Chemical Society Symposium Series 1994), Vol. 544.
  35. E. A. Burstein, S. M. Abornev, and Y. K. Reshetnyak, "Decomposition of protein tryptophan fluorescence spectra into log-normal components. I. Decomposition algorithms," Biophys J 81(3), 1699-1709 (2001). [CrossRef] [PubMed]
  36. D. Malencik and S. Anderson, "Dityrosine as a product of oxidative stress and fluorescent probe," Amino Acids 25, 233-247 (2003). [CrossRef] [PubMed]

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