Abstract
Purpose: :
Developmant of collagen hydrogel with molecular orientation and its evaluation as an implant for tissue engineering of corneal stroma.
Methods: :
Porcine type I atelocollagen containing 5% type III collagen dissolved in aqueous HCl was adjusted at pH 3.6-4.0 by addition of aqueous NaOH, and mixed with EDC & NHS using syringe system (Liu Y. et al., Biomacromolecules, 2006). The final concentration of collagen was adjusted to 10wt%. The reaction solution was poured onto a glass plate in a specific direction and subsequently covered with another glass plate to spread the solution. Silicon rubber spacers (100-500 µm in thickness) were sandwiched between the glass plates to regulate their thickness. The obtained gels were evaluated by UV-vis transmission measurement, X-ray diffraction measurements (XRD), scanning electron microscopy (SEM),and mechanical property measurement. Their biocompatibility was evaluated by culture of porcine corneal cells and implantation in rabbit corneal stromal pockets.
Results: :
XRD and SEM analysis strongly supported that the orientation of collagen fibers (59.0 ± 14.6 nm-diameter) in the gels was same as the direction of collagen solution spreaded onto a glass plate. The tensile strength of the parallel direction was approximately two-fold higher than that of the orthogonal direction. Transparency of the obtained gels with 500 µm-thickness was 79.2 +/- 6.9 % at 550nm. This gels exibited favorable cell-adhesion and cell-proliferation in vitro. Furthermore, neither blood vessel invasion nor opacification occurred with the gel-implanted corneas for 60 days in corneal intrastromal pockets.
Conclusions: :
The obtaineded collagen hydrogels with moleculer orientation exsibited unique mechanical properties, faborable transparency and biocompatibility with cornea in vitro /in vivo, which will be useful in the field of tissue engineering of corneal stroma.
Keywords: cornea: stroma and keratocytes • extracellular matrix • transplantation