Abstract
Purpose: :
The purpose of this study is to design hyaluronic acid (HA) based hydrogels to differentiate ocular stem cells for ocular tissue regeneration.
Methods: :
A serial of hyaluronic acid macromers are synthesized by conjugating 2-aminoethyl methacrylate (AEMA) to hyaluronic acid with different molecular weights (i.e. 6400, 16000 and 66000). The chemical structures of these macromers are characterized using ATR-FTIR and NMR. Their cytotoxicity is tested to different cell lines such as PC-12 and ocular stem cells using the MTT assay. Hyaluronic acid hydrogels are synthesized from these macromers using photo-polymerization. The mechanical properties of these hydrogels are characterized using rheometer and dynamic mechanical analyzer (DMA). The degradation of these hydrogels is also characterized. PC-12 cells and ocular stem cells such as limbal stem cells are encapsulated into the hydrogels in situ during the photo-polymerization. The cell encapsulated hydrogels are stained using LIVE/DEAD® cell viability assays to determine the cell viability after photo-polymerization. In particular, the differential of the ocular stem cells are induced using several different growth factors. The efficiency of induced differentiation is under investigation.
Results: :
ATR-FTIR and NMR measurements confirm the successful synthesis of HA-AEMA macromers. The substitution degree can be modulated by adjusting the molecular weight of HA and the ratio of AEMA to HA. MTT data indicate that these HA-AEMA macromers are not cytotoxic. Hydrogels can be formed under mild photo-polymerization conditions, while LIVE/DEAD cell stain indicates that cells could survive under such polymerization conditions. The growth factor induced differentiation of ocular stem cells is right now under investigation.
Conclusions: :
The recently developed HA hydrogels have great potential for in situ encapsulation of ocular stem cells and differentiation of these cells for ocular tissue regeneration.
Keywords: regeneration • wound healing • cell survival