Human Corneal Keratocyte Response to Micro- and Nano-Gratings on Chitosan and PDMS
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Corneal stroma accounts for major refractive power and the transparency of cornea. This transparency is contributed mainly by the highly ordered arrangement of the extracellular matrix (ECM), particularly the collagen fibrils. Shortage and complications of cornea transplantation have remained an issue for decades. Attempts to produce tissue-engineered cornea are met with challenges, one of which is to induce alignment of stromal ECM produced by keratocytes. In this study, human corneal keratocyte response toward substrate topography on two different materials was examined. Primary human keratocytes were cultured on chitosan and polydimethylsiloxane (PDMS) surface patterned with anisotopic topography of gratings in various widths. Cell response in the form of alignment, elongation and proliferation were analyzed. Collagen I deposition was imaged and the gene expression analysis of keratocytes cultured on PDMS were studied. On both chitosan and PDMS, keratocytes were found to be aligned and elongated in grating direction. Proliferation rate was reduced as grating width decreased. Aldehyde-3-dehydrogenase (ALDH3) expression was increased on nanogratings. Deposited collagen I followed the keratocyte orientation, which was aligned along the direction of gratings. In conclusion, keratocytes responded similarly to topographical cues when presented on materials with different surface chemistry and stiffness and nanogratings were observed to be more efficient in inducing these responses than microgratings.
KeywordsNanotopography Corneal stroma Keratocyte Extracellular matrix alignment Response to topography Chitosan
This work is supported by National Medical Research Council Singapore NMRC/NIG/0037/2008, and partly supported by the Mechanobiology Institute Singapore for SK. The authors would like to thank E. L. S. Fong for her assistance and helpful discussions.
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