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Martina Miotto, Ricardo Martins Gouveia, Miguel González-Andrades, Che John Connon; Optimising biocompatibility of polymethyl methacrylate used for keratoprosthesis. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4346.
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© ARVO (1962-2015); The Authors (2016-present)
Prosthesis are required to be highly biocompatible for maximized integration after implantation. This is particularly important for polymethyl methacrylate (PMMA), currently being used in keratoprosthesis but showing limited capacity in promoting adhesion and proliferation of cells. As such, we investigated the potential use of self-assembling, bio-active peptide amphiphile (PA) coatings as a strategy to bio-functionalize PMMA discs, for enhanced performance.
PMMA discs were coated with different PAs: 1) comprising the RGDS cell adhesion motif (RGDS-PA); 2) RGDS-PA in a binary system with a diluent peptide (RGDS:ETTES-PA); or 3) comprising an enzyme-sensitive motif in a binary system (MMP/RGDS:ETTES-PA). After drying, topography and retention of coatings were evaluated by atomic force microscopy (AFM). Subsequently, human corneal stromal cells (hCSCs) were seeded and cultured on the coated discs in different culture conditions: with serum, serum-free, and serum-free supplemented with retinoic acid. The biocompatibility of PA-coated discs was then determined by quantifying cell growth and extracellular matrix (ECM) deposition compared to titanium discs (positive control). Cell adhesion, proliferation, and viability, were assessed through cell-tracker staining, Alamar Blue assay and live-dead double staining at day 3 and 7, respectively.
The concentration and density of each PA type used to coat PMMA discs were optimised for the subsequent cell cultures. Specifically, binary PA solutions (1.25×10-4 M) showed to promote hCSCs adhesion and proliferation at day 3 (33±2.6%), in both serum-free conditions compared to uncoated controls and single RGDS-PA; while higher PA concentrations were shown to be toxic. Moreover, the use of serum enhanced the bio-performance of all surfaces, possibly due to cell activation and/or as a source of biochemical cues promoting cell attachment to the materials. Furthermore, the synthesis of ECM quantified through the Sirius Red assay at day 16 showed (20±1.9%) increasing in collagen deposition from cells cultured on titanium discs respect to PMMA.
Our results suggested that binary PA coatings improved biocompatibility of PMMA. As such, PA coatings represent a promising strategy to bio-functionalize prosthesis. Thus, this strategy will be further tested in follow-up animal studies.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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