Abstract
Purpose :
The cellulose produced by Acetobacter xylinum has a three-dimensional fibrillar interconnected structure in nanoscale with intrinsic properties that make it widely used in tissue engineering. We characterized the hemicellulose film (Nanoskin) analyzing the surface, transparency, immunogenicity and mesenchymal stem cell adhesion, essential qualities of an ideal scaffold for stem cell transplantation into injured corneas.
Methods :
Bacterial cellulose films were produced by culturing Gluconacetobacter xylinus in green tea as nutrient medium, supplemented with hyaluronic acid. The Nanoskin surface was analyzed by scanning electron microscopy. The percentage of light transmittance was measured in a UV-Vis spectrophotometer comparing it with amniotic membrane and soft contact lenses. The immunogenicity was accessed by culturing carboxyfluorescein diacetate N-succinimidyl ester (CFSE)-labeled lymphocytes over Nanoskin, with analysis by flow cytometry. Cytotoxicity was evaluated by labeling lymphocytes with Annexin V and 7-aminoactinomycin D (7-AAD) with analysis by flow cytometry after 1, 3 and 5 days. For the adherence study, mesenchymal stem cells (MSC) were seeded over Nanoskins that were submitted for scanning electron microscopy after 6 hours, 1, 3, 7, 10 and 14 days.
Results :
Nanoskin exhibited slightly lower transmittance than amniotic membrane at 400- to 700-nm wavelength. The study of lymphoproliferation and labeling with CFSE demonstrated that Nanoskin did not induced immunogenicity. The labeling with Annexin and 7-AAD after 1 day showed no difference in the viability of the control lymphocytes compared to those exposed to Nanoskin. After 3 days, Nanoskin showed an increase of the number of viable lymphocytes, with statistical significance (p=0.0146) and after 5 days Nanoskin caused an increase of viable cells, with statistical significance (p=0.0071). MSC adhered to the Nanoskins surface was observed only after 10 days of incubation, by scanning electron microscopy.
Conclusions :
Nanoskin showed several characteristics necessary to be considered a good scaffold including a protective effect on cell viability. We can conclude that it is a promising biomaterial for the stem cell transplantation.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.