Article
Nanofibrillar Vs. Smooth: Influence Of Surface Characteristics On Cultured Human RPE Behavior
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Published: | June 29, 2009 |
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Outline
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Purpose: To explore two biocompatible substrates as candidates for Bruch’s membrane prosthetics. Common cell culture substrates are smooth surfaces. Nanofibers mimic native basement membranes. We compared the influence of these surface variants on cultured RPE behavior.
Methods: Human RPE cells from fetuses, a 23, 78 and 90 year old donor were cultured in Hu & Bok medium on either polystyrene (PS), a smooth surface, or electrospun polyamide nanofibers (EPN), a fibrillar surface. Cell cycle synchronized cells were plated at 10E4 cells/cm2 to obtain growth curves and fractions. S-phase lengths were studied using EdU/ Click it®. Floater passage cells seeded at >5x10E4 cells/cm2 were differentiated for 4+ weeks and protein expression studied with immunostaining and blotting.
Results: Cell division on EPN started earlier in all donor ages. Proliferation rates of adult cells during early log phase were increased on EPN, while growth fractions were comparable on both substrates. In fetal cultures, short pulses yielded more EdU positive cells on EPN than on PS. Aged RPE showed uniform hexagonal differentiation with development of fluid transporting capacity on EPN in contrast to PS beyond 4 wks post confluence. All longterm cultures had positive immunofluorescence for Pancytokeratin and ZO-1 on EPN. Preliminary data suggest preferential expression of RPE65 on EPN in aged cultures.
Conclusions: A nanofibrillar surface stimulates a faster S-phase progression. Aged RPE achieve differentiation nearly comparable to young donors. The nanofibrillar surface topology thus appears to rejuvenate adult RPE, making it a promising component for BM prosthetics. Further studies are underway.