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Annals of Biomedical Engineering

, Volume 42, Issue 7, pp 1456–1469 | Cite as

Encapsulated Neural Stem Cell Neuronal Differentiation in Fluorinated Methacrylamide Chitosan Hydrogels

  • Hang Li
  • Asanka Wijekoon
  • Nic D. LeipzigEmail author
Article

Abstract

Neural stem/progenitor cells (NSPCs) are able to differentiate into the primary cell types (neurons, oligodendrocytes and astrocytes) of the adult nervous system. This attractive property of NSPCs offers a potential solution for neural regeneration. 3D implantable scaffolds should mimic the microstructure and dynamic properties found in vivo, enabling the natural exchange of oxygen, nutrients, and growth factors for cell survival and differentiation. We have previously reported a new class of materials consisting of perfluorocarbons (PFCs) conjugated to methacrylamide chitosan (MAC), which possess the ability to repeatedly take-up and release oxygen at beneficial levels for favorable cell metabolism and proliferation. In this study, the neuronal differentiation responses of NSPCs to fluorinated methacrylamide chitosan (MACF) hydrogels were studied for 8 days. Two treatments, with oxygen reloading or without oxygen reloading, were performed during culture. Oxygen concentration distributions within cell-seeded MACF hydrogels were found to have higher concentrations of oxygen at the edge of the hydrogels and less severe drops in O2 gradient as compared with MAC hydrogel controls. Total cell number was enhanced in MACF hydrogels as the number of conjugated fluorines via PFC substitution increased. Additionally, all MACF hydrogels supported significantly more cells than MAC controls (p < 0.001). At day 8, MACF hydrogels displayed significantly greater neuronal differentiation than MAC controls (p = 0.001), and among MACF groups methacrylamide chitosan with 15 fluorines per addition (MAC(Ali15)F) demonstrated the best ability to promote NSPC differentiation.

Keywords

Chitosan Oxygen Hydrogel Perfluorocarbons Neural stem cells Neuronal differentiation 

Notes

Acknowledgments

We are grateful for funding from the University of Akron that supported this work. The authors would also like to thank Dr. Rebecca Willits for allowing us to perform rheological measurements in her laboratory as well as assistance with interpreting mechanical and swelling results.

Supplementary material

10439_2013_925_MOESM1_ESM.pdf (736 kb)
Supplementary Fig. S1 Representative images of scaffolds with no oxygen resupplementation obtained by confocal microscope at day 8 at the center of scaffolds, each picture represents a stack of 50 images with a spacing of 200 μm. MAC(Ali15)F shows the highest cell number indicated by nuclear Hoechst 33342 stain. Corresponding 3D reconstruction movies generated from these images are presented as supplemental material (Movies 5–8). Scale bar equals 100 μm (PDF 736 kb)

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Supplementary material 9 (AVI 19439 kb)

References

  1. 1.
    Aiedeh, K., E. Gianasi, I. Orienti, and V. Zecchi. Chitosan microcapsules as controlled release systems for insulin. J. Microencapsul. 14(5):567–576, 1997.PubMedCrossRefGoogle Scholar
  2. 2.
    Arkudas, A., J. P. Beier, K. Heidner, J. Tjiawi, E. Polykandriotis, S. Srour, M. Sturzl, R. E. Horch, and U. Kneser. Axial prevascularization of porous matrices using an arteriovenous loop promotes survival and differentiation of transplanted autologous osteoblasts. Tissue Eng. 13(7):1549–1560, 2007.PubMedCrossRefGoogle Scholar
  3. 3.
    Bagheri-Khoulenjani, S., S. M. Taghizadeh, and H. Mirzadeh. An investigation on the short-term biodegradability of chitosan with various molecular weights and degrees of deacetylation. Carbohydr. Polym. 78(4):773–778, 2009.CrossRefGoogle Scholar
  4. 4.
    Campos, L. S. Beta1 integrins and neural stem cells: making sense of the extracellular environment. BioEssays 27(7):698–707, 2005.PubMedCrossRefGoogle Scholar
  5. 5.
    Castro, C. I., and J. C. Briceno. Perfluorocarbon-based oxygen carriers: review of products and trials. Artif. Organs 34(8):622–634, 2010.PubMedGoogle Scholar
  6. 6.
    Cha, C., S. Y. Kim, L. Cao, and H. Kong. Decoupled control of stiffness and permeability with a cell-encapsulating poly(ethylene glycol) dimethacrylate hydrogel. Biomaterials 31(18):4864–4871, 2010.PubMedCrossRefGoogle Scholar
  7. 7.
    Chandler, D. Structures of molecular liquids. Annu. Rev. Phys. Chem. 29:441–471, 1978.CrossRefGoogle Scholar
  8. 8.
    Chang, T. M. S. Blood Substitutes: Principles, Methods, Products, and Clinical Trials. Tissue Engineering. New York: Basel Karger Landes Systems, 1997.Google Scholar
  9. 9.
    Chin, K., S. F. Khattak, S. R. Bhatia, and S. C. Roberts. Hydrogel-perfluorocarbon composite scaffold promotes oxygen transport to immobilized cells. Biotechnol. Prog. 24(2):358–366, 2008.PubMedCrossRefGoogle Scholar
  10. 10.
    Chubb, C. Reversal of the endocrine toxicity of commercially produced perfluorochemical emulsion. Biol. Reprod. 33(4):854–858, 1985.PubMedCrossRefGoogle Scholar
  11. 11.
    Chubb, C., and P. Draper. Steroid-secretion by rat testes perfused with perfluorochemicals as oxygen carriers. Am. J. Physiol. 248(4):E432–E437, 1985.PubMedGoogle Scholar
  12. 12.
    Csete, M. Oxygen in the cultivation of stem cells. Ann. N. Y. Acad. Sci. 1–8:2005, 1049.Google Scholar
  13. 13.
    De Filippis, L., and D. Delia. Hypoxia in the regulation of neural stem cells. Cell. Mol. Life Sci. 68(17):2831–2844, 2011.PubMedCrossRefGoogle Scholar
  14. 14.
    de Vos, P., M. M. Faas, B. Strand, and R. Calafiore. Alginate-based microcapsules for immunoisolation of pancreatic islets. Biomaterials 27(32):5603–5617, 2006.PubMedCrossRefGoogle Scholar
  15. 15.
    Dias, A. M. A., C. M. B. Goncalves, J. L. Legido, J. A. P. Coutinho, and I. M. Marrucho. Solubility of oxygen in substituted perfluorocarbons. Fluid Phase Equilib. 238(1):7–12, 2005.CrossRefGoogle Scholar
  16. 16.
    Dominici, M., K. Le Blanc, I. Mueller, I. Slaper-Cortenbach, F. Marini, D. Krause, R. Deans, A. Keating, D. Prockop, and E. Horwitz. Minimal criteria for defining multipotent mesenchymal stromal cells. The International Society for Cellular Therapy position statement. Cytotherapy. 8(4):315–317, 2006.PubMedCrossRefGoogle Scholar
  17. 17.
    Drury, J. L., and D. J. Mooney. Hydrogels for tissue engineering: scaffold design variables and applications. Biomaterials 24(24):4337–4351, 2003.PubMedCrossRefGoogle Scholar
  18. 18.
    Dunn, J. C., W. Y. Chan, V. Cristini, J. S. Kim, J. Lowengrub, S. Singh, and B. M. Wu. Analysis of cell growth in three-dimensional scaffolds. Tissue Eng. 12(4):705–716, 2006.PubMedCrossRefGoogle Scholar
  19. 19.
    Engler, A. J., S. Sen, H. L. Sweeney, and D. E. Discher. Matrix elasticity directs stem cell lineage specification. Cell 126(4):677–689, 2006.PubMedCrossRefGoogle Scholar
  20. 20.
    Enzmann, V., R. M. Howard, Y. Yamauchi, S. R. Whittemore, and H. J. Kaplan. Enhanced induction of RPE lineage markers in pluripotent neural stem cells engrafted into the adult rat subretinal space. Invest. Ophthalmol. Vis. Sci. 44(12):5417–5422, 2003.PubMedCrossRefGoogle Scholar
  21. 21.
    Fitzpatrick, C. M., and J. D. Kerby. Blood substitutes: hemoglobin-based oxygen carriers. Oral Maxillofac. Surg. Clin. N. Am. 17(3):261–266, v–vi, 2005.Google Scholar
  22. 22.
    Flaim, S. F. Pharmacokinetics and side-effects of perfluorocarbon-based blood substitutes. Artif. Cells Blood Substit. Immobil. Biotechnol. 22(4):1043–1054, 1994.PubMedCrossRefGoogle Scholar
  23. 23.
    Gao, W., J. C. Lai, and S. W. Leung. Functional enhancement of chitosan and nanoparticles in cell culture, tissue engineering, and pharmaceutical applications. Front Physiol. 3:321, 2012.PubMedCentralPubMedCrossRefGoogle Scholar
  24. 24.
    Gattas-Asfura, K. M., C. A. Fraker, and C. L. Stabler. Perfluorinated alginate for cellular encapsulation. J. Biomed. Mater. Res. A 100(8):1963–1971, 2012.PubMedCrossRefGoogle Scholar
  25. 25.
    Goh, F., J. D. Gross, N. E. Simpson, and A. Sambanis. Limited beneficial effects of perfluorocarbon emulsions on encapsulated cells in culture: experimental and modeling studies. J. Biotechnol. 150(2):232–239, 2010.PubMedCentralPubMedCrossRefGoogle Scholar
  26. 26.
    Greenburg, A. G., and H. W. Kim. Hemoglobin-based oxygen carriers. Crit. Care 8(Suppl 2):S61–S64, 2004.PubMedCentralPubMedCrossRefGoogle Scholar
  27. 27.
    Gustafsson, M. V., X. Zheng, T. Pereira, K. Gradin, S. Jin, J. Lundkvist, J. L. Ruas, L. Poellinger, U. Lendahl, and M. Bondesson. Hypoxia requires notch signaling to maintain the undifferentiated cell state. Dev. Cell 9(5):617–628, 2005.PubMedCrossRefGoogle Scholar
  28. 28.
    Harrison, B. S., D. Eberli, S. J. Lee, A. Atala, and J. J. Yoo. Oxygen producing biomaterials for tissue regeneration. Biomaterials 28(31):4628–4634, 2007.PubMedCrossRefGoogle Scholar
  29. 29.
    Huang, Y., B. Zhang, G. Xu, and W. Hao. Swelling behaviours and mechanical properties of silk fibroin–polyurethane composite hydrogels. Compos. Sci. Technol. 84:15–22, 2013.CrossRefGoogle Scholar
  30. 30.
    Ifkovits, J. L., and J. A. Burdick. Review: photopolymerizable and degradable biomaterials for tissue engineering applications. Tissue Eng. 13(10):2369–2385, 2007.PubMedCrossRefGoogle Scholar
  31. 31.
    Johnson, A. S., R. J. Fisher, G. C. Weir, and C. K. Colton. Oxygen consumption and diffusion in assemblages of respiring spheres: performance enhancement of a bioartificial pancreas. Chem. Eng. Sci. 64(22):4470–4487, 2009.CrossRefGoogle Scholar
  32. 32.
    Ju, L. K., J. F. Lee, and W. B. Armiger. Enhancing oxygen-transfer in bioreactors by perfluorocarbon emulsions. Biotechnol. Prog. 7(4):323–329, 1991.CrossRefGoogle Scholar
  33. 33.
    Kanichai, M., D. Ferguson, P. J. Prendergast, and V. A. Campbell. Hypoxia promotes chondrogenesis in rat mesenchymal stem cells: a role for AKT and hypoxia-inducible factor (HIF)-1alpha. J. Cell. Physiol. 216(3):708–715, 2008.PubMedCrossRefGoogle Scholar
  34. 34.
    Khattak, S. F., K. S. Chin, S. R. Bhatia, and S. C. Roberts. Enhancing oxygen tension and cellular function in alginate cell encapsulation devices through the use of perfluorocarbons. Biotechnol. Bioeng. 96(1):156–166, 2007.PubMedCrossRefGoogle Scholar
  35. 35.
    Kimelman-Bleich, N., G. Pelled, D. Sheyn, I. Kallai, Y. Zilberman, O. Mizrahi, Y. Tal, W. Tawackoli, Z. Gazit, and D. Gazit. The use of a synthetic oxygen carrier-enriched hydrogel to enhance mesenchymal stem cell-based bone formation in vivo. Biomaterials 30(27):4639–4648, 2009.PubMedCrossRefGoogle Scholar
  36. 36.
    Kratz, G., C. Arnander, J. Swedenborg, M. Back, C. Falk, I. Gouda, and O. Larm. Heparin-chitosan complexes stimulate wound healing in human skin. Scand. J. Plast. Reconstr. Surg. Hand Surg. 31(2):119–123, 1997.PubMedCrossRefGoogle Scholar
  37. 37.
    Kresie, L. Artificial blood: an update on current red cell and platelet substitutes. Proc. (Bayl Univ. Med. Cent.) 14(2):158–161, 2001.Google Scholar
  38. 38.
    Kumar, G., P. J. Smith, and G. F. Payne. Enzymatic grafting of a natural product onto chitosan to confer water solubility under basic conditions. Biotechnol. Bioeng. 63(2):154–165, 1999.PubMedCrossRefGoogle Scholar
  39. 39.
    Langer, R., and J. P. Vacanti. Tissue engineering. Science 260(5110):920–926, 1993.PubMedCrossRefGoogle Scholar
  40. 40.
    Leipzig, N. D., and M. S. Shoichet. The effect of substrate stiffness on adult neural stem cell behavior. Biomaterials 30(36):6867–6878, 2009.PubMedCrossRefGoogle Scholar
  41. 41.
    Leipzig, N. D., R. G. Wylie, H. Kim, and M. S. Shoichet. Differentiation of neural stem cells in three-dimensional growth factor-immobilized chitosan hydrogel scaffolds. Biomaterials 32(1):57–64, 2011.PubMedCrossRefGoogle Scholar
  42. 42.
    Leung, R., D. Poncelet, and R. J. Neufeld. Enhancement of oxygen transfer rate using microencapsulated silicone oils as oxygen carriers. J. Chem. Technol. Biotechnol. 68(1):37–46, 1997.CrossRefGoogle Scholar
  43. 43.
    Lewis, M. C., B. D. Macarthur, J. Malda, G. Pettet, and C. P. Please. Heterogeneous proliferation within engineered cartilaginous tissue: the role of oxygen tension. Biotechnol. Bioeng. 91(5):607–615, 2005.PubMedCrossRefGoogle Scholar
  44. 44.
    Li, H., A. Wijekoon, and N. D. Leipzig. 3D differentiation of neural stem cells in macroporous photopolymerizable hydrogel scaffolds. PLoS ONE 7(11):e48824, 2012.PubMedCentralPubMedCrossRefGoogle Scholar
  45. 45.
    Lovett, M., K. Lee, A. Edwards, and D. L. Kaplan. Vascularization strategies for tissue engineering. Tissue Eng. B Rev. 15(3):353–370, 2009.CrossRefGoogle Scholar
  46. 46.
    Lowe, K. C. Fluorinated blood substitutes and oxygen carriers. J. Fluorine Chem. 109(1):59–65, 2001.CrossRefGoogle Scholar
  47. 47.
    Lutolf, M. P., J. L. Lauer-Fields, H. G. Schmoekel, A. T. Metters, F. E. Weber, G. B. Fields, and J. A. Hubbell. Synthetic matrix metalloproteinase-sensitive hydrogels for the conduction of tissue regeneration: engineering cell-invasion characteristics. Proc. Natl Acad. Sci. U.S.A. 100(9):5413–5418, 2003.PubMedCentralPubMedCrossRefGoogle Scholar
  48. 48.
    Madihally, S. V., and H. W. Matthew. Porous chitosan scaffolds for tissue engineering. Biomaterials 20(12):1133–1142, 1999.PubMedCrossRefGoogle Scholar
  49. 49.
    Miyazaki, S., K. Ishii, and T. Nadai. The use of chitin and chitosan as drug carriers. Chem. Pharm. Bull. 29(10):3067–3069, 1981.PubMedCrossRefGoogle Scholar
  50. 50.
    Mohyeldin, A., T. Garzon-Muvdi, and A. Quinones-Hinojosa. Oxygen in stem cell biology: a critical component of the stem cell niche. Cell Stem Cell 7(2):150–161, 2010.PubMedCrossRefGoogle Scholar
  51. 51.
    Morrison, S. J., M. Csete, A. K. Groves, W. Melega, B. Wold, and D. J. Anderson. Culture in reduced levels of oxygen promotes clonogenic sympathoadrenal differentiation by isolated neural crest stem cells. J. Neurosci. 20(19):7370–7376, 2000.PubMedGoogle Scholar
  52. 52.
    Oh, S. H., C. L. Ward, A. Atala, J. J. Yoo, and B. S. Harrison. Oxygen generating scaffolds for enhancing engineered tissue survival. Biomaterials 30(5):757–762, 2009.PubMedCrossRefGoogle Scholar
  53. 53.
    Panchision, D. M. The role of oxygen in regulating neural stem cells in development and disease. J. Cell. Physiol. 220(3):562–568, 2009.PubMedCrossRefGoogle Scholar
  54. 54.
    Park, H., C. D. Vecitis, J. Cheng, W. Choi, B. T. Mader, and M. R. Hoffmann. Reductive defluorination of aqueous perfluorinated alkyl surfactants: effects of ionic headgroup and chain length. J. Phys. Chem. A 113(4):690–696, 2009.PubMedCrossRefGoogle Scholar
  55. 55.
    Park, I. K., J. Yang, H. J. Jeong, H. S. Bom, I. Harada, T. Akaike, S. Kim, and C. S. Cho. Galactosylated chitosan as a synthetic extracellular matrix for hepatocytes attachment. Biomaterials 24(13):2331–2337, 2003.PubMedCrossRefGoogle Scholar
  56. 56.
    Pistollato, F., H. L. Chen, P. H. Schwartz, G. Basso, and D. M. Panchision. Oxygen tension controls the expansion of human CNS precursors and the generation of astrocytes and oligodendrocytes. Mol. Cell. Neurosci. 35(3):424–435, 2007.PubMedCrossRefGoogle Scholar
  57. 57.
    Portner, R., S. Nagel-Heyer, C. Goepfert, P. Adamietz, and N. M. Meenen. Bioreactor design for tissue engineering. J. Biosci. Bioeng. 100(3):235–245, 2005.PubMedCrossRefGoogle Scholar
  58. 58.
    Powers, D. E., J. R. Millman, R. B. Huang, and C. K. Colton. Effects of oxygen on mouse embryonic stem cell growth, phenotype retention, and cellular energetics. Biotechnol. Bioeng. 101(2):241–254, 2008.PubMedCrossRefGoogle Scholar
  59. 59.
    Quijano, G., S. Revah, M. Gutierrez-Rojas, L. B. Flores-Cotera, and F. Thalasso. Oxygen transfer in three-phase airlift and stirred tank reactors using silicone oil as transfer vector. Process Biochem. 44(6):619–624, 2009.CrossRefGoogle Scholar
  60. 60.
    Richardson, S. C. W., H. J. V. Kolbe, and R. Duncan. Potential of low molecular mass chitosan as a DNA delivery system: biocompatibility, body distribution and ability to complex and protect DNA. Int. J. Pharm. 178(2):231–243, 1999.PubMedCrossRefGoogle Scholar
  61. 61.
    Riess, J. G. Reassessment of criteria for the selection of perfluorochemicals for 2nd-generation blood substitutes—analysis of structure property relationships. Artif. Organs 8(1):44–56, 1984.PubMedCrossRefGoogle Scholar
  62. 62.
    Riess, J. G. Oxygen carriers (“blood substitutes”)—Raison d’Etre, chemistry, and some physiology. Chem. Rev. 101(9):2797–2919, 2001.PubMedCrossRefGoogle Scholar
  63. 63.
    Riess, J. G. Understanding the fundamentals of perfluorocarbons and perfluorocarbon emulsions relevant to in vivo oxygen delivery. Artif. Cells Blood Substit. Immobil. Biotechnol. 33(1):47–63, 2005.PubMedCrossRefGoogle Scholar
  64. 64.
    Riess, J. G. Perfluorocarbon-based oxygen delivery. Artif. Cells Blood Substit. Immobil. Biotechnol. 34(6):567–580, 2006.PubMedCrossRefGoogle Scholar
  65. 65.
    Riva, R., H. Ragelle, A. des Rieux, N. Duhem, C. Jerome, and V. Preat. Chitosan and chitosan derivatives in drug delivery and tissue engineering. Chitosan Biomater. II. 244:19–44, 2011.Google Scholar
  66. 66.
    Rouwkema, J., N. C. Rivron, and C. A. van Blitterswijk. Vascularization in tissue engineering. Trends Biotechnol. 26(8):434–441, 2008.PubMedCrossRefGoogle Scholar
  67. 67.
    Saha, K., J. Kim, E. Irwin, J. Yoon, F. Momin, V. Trujillo, D. V. Schaffer, K. E. Healy, and R. C. Hayward. Surface creasing instability of soft polyacrylamide cell culture substrates. Biophys. J. 99(12):L94–L96, 2010.PubMedCentralPubMedCrossRefGoogle Scholar
  68. 68.
    Santilli, G., G. Lamorte, L. Carlessi, D. Ferrari, L. Rota Nodari, E. Binda, D. Delia, A.L. Vescovi, and L. De Filippis. Mild hypoxia enhances proliferation and multipotency of human neural stem cells. PLoS One 5(1):e8575, 2010.Google Scholar
  69. 69.
    Sashiwa, H., and S. I. Aiba. Chemically modified chitin and chitosan as biomaterials. Prog. Polym. Sci. 29(9):887–908, 2004.CrossRefGoogle Scholar
  70. 70.
    Schroeder, J. L., J. M. Highsmith, H. F. Young, and B. E. Mathern. Reduction of hypoxia by perfluorocarbon emulsion in a traumatic spinal cord injury model. J. Neurosurg. Spine 9(2):213–220, 2008.PubMedCrossRefGoogle Scholar
  71. 71.
    Simon, M. C., and B. Keith. The role of oxygen availability in embryonic development and stem cell function. Nat. Rev. Mol. Cell Biol. 9(4):285–296, 2008.PubMedCentralPubMedCrossRefGoogle Scholar
  72. 72.
    Spiess, B. D. Perfluorocarbon emulsions as a promising technology: a review of tissue and vascular gas dynamics. J. Appl. Physiol. 106(4):1444–1452, 2009.PubMedCrossRefGoogle Scholar
  73. 73.
    Spiess, B. D., and R. P. Cochran. Perfluorocarbon emulsions and cardiopulmonary bypass: a technique for the future. J. Cardiothorac. Vasc. Anesth. 10(1):83–89; quiz 89–90, 1996.Google Scholar
  74. 74.
    Subramanian, A., U. M. Krishnan, and S. Sethuraman. Development of biomaterial scaffold for nerve tissue engineering: biomaterial mediated neural regeneration. J. Biomed. Sci. 16:108, 2009.PubMedCentralPubMedCrossRefGoogle Scholar
  75. 75.
    Tremper, K. K., and S. T. Anderson. Perfluorochemical emulsion oxygen-transport fluids—a clinical review. Annu. Rev. Med. 36:309–313, 1985.PubMedCrossRefGoogle Scholar
  76. 76.
    Turturro, M. V., M. C. Christenson, J. C. Larson, D. A. Young, E. M. Brey, and G. Papavasiliou. MMP-sensitive PEG diacrylate hydrogels with spatial variations in matrix properties stimulate directional vascular sprout formation. PLoS ONE 8(3):e58897, 2013.PubMedCentralPubMedCrossRefGoogle Scholar
  77. 77.
    Volkmer, E., I. Drosse, S. Otto, A. Stangelmayer, M. Stengele, B. C. Kallukalam, W. Mutschler, and M. Schieker. Hypoxia in static and dynamic 3D culture systems for tissue engineering of bone. Tissue Eng. A 14(8):1331–1340, 2008.CrossRefGoogle Scholar
  78. 78.
    Wang, J., Y. Zhu, H. K. Bawa, G. Ng, Y. Wu, M. Libera, H. C. van der Mei, H. J. Busscher, and X. Yu. Oxygen-generating nanofiber cell scaffolds with antimicrobial properties. ACS Appl. Mater. Interfaces 3(1):67–73, 2011.PubMedCrossRefGoogle Scholar
  79. 79.
    White, J. C., W. L. Stoppel, S. C. Roberts, and S. R. Bhatia. Addition of perfluorocarbons to alginate hydrogels significantly impacts molecular transport and fracture stress. J. Biomed. Mater. Res. A 101A(2):438–446, 2013.CrossRefGoogle Scholar
  80. 80.
    Wijekoon, A., N. Fountas-Davis, and N.D. Leipzig. Fluorinated methacrylamide chitosan hydrogel systems as adaptable oxygen carriers for wound healing. Acta Biomater. 9(3):5653–5664, 2012.Google Scholar
  81. 81.
    Yu, L. M., K. Kazazian, and M. S. Shoichet. Peptide surface modification of methacrylamide chitosan for neural tissue engineering applications. J. Biomed. Mater. Res. A 82(1):243–255, 2007.PubMedCrossRefGoogle Scholar

Copyright information

© Biomedical Engineering Society 2013

Authors and Affiliations

  1. 1.Department of Chemical and Biomolecular EngineeringThe University of AkronAkronUSA

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