Abstract
Retinal transplantation is capable of rescuing degenerative and hereditary retinal disorders, such as age-related macular degeneration or retinitis pigmentosa. However, transplanting an intact functioning retinal sheet is very difficult, due to fragile and soft character of retina. We thus invented a novel "Sandwich and Trephination" method to transplant retinal sheet. Retinal sheet was prepared and put on a gelatin membrane, which was subsequently covered by another gelatin membrane. Then the gelatin-retina-gelatin sandwich was trephinated down altogether with a custom made device, and aspirated into a pipette carrier. Afterwards the sandwich was pushed into subretinal space of recipient eye. The gelatin membrane then dissolved and degraded soon, leaving an intact retinal sheet with proper orientation, sitting on recipient's retinal pigment epithelium. The method was patented. In this study, we compared the durable conditions for manufacturing membrane process. Then, it showed respective staining reagents added into gelatin solution resulted in insignificant difference among each group, including mechanical character, melting point, biocompatibility. However, methylene blue would induce relatively toxic effect in vitro. The results disclosed 7 % trypan blue as most suitable staining reagent. More importantly, the results concluded that gelatin of bloom number 75 ~ 100 could be the best condition for manufacturing membrane considering all the parameters together. For the sterilization, g-ray procedure was the only durable condition, and the irradiation dose is 16.6 kGy. The transplanted retinal sheet survived for more than three months and developed each lamina properly. No significant inflammation was noticed. The gelatin membrane was carefully designed and manufactured. The mechanical strength and clinical parameters were thoroughly determined. Most importantly, different sterilization method was assessed. Through the research, future human investigation might become more possible.