Resorbable scaffolds modified with collagen type I or hydroxyapatite : in vitro studies on human mesenchymal stem cells

Poly(L-lactide-co-glycolide) (PLGA) scaffolds of pore size within the range of 250–320 μm were produced by solvent casting/ porogen leaching method. Afterwards, they were modified through adsorption of collagen type I and incubation in simulated body fluid (SBF) to allow deposition of hydroxyapatite (HAp). The wettability of the scaffolds was measured by sessile drop test. Scanning electron microscopy (SEM) evaluation and energy dispersive X-ray analysis (EDX) were also performed. SEM evaluation and EDX analysis depicted the presence of HAp deposits and a collagen layer on the pore walls on the surface and in the bulk of the scaffolds. Wettability and water droplets penetration time within the scaffolds decreased considerably after applying modifications. Human mesenchymal stem cells (hMSC) were cultured on the scaffolds for 28 days and cell morphology, proliferation and differentiation as well as calcium deposition were evaluated. Lactate dehydrogenase (LDH) activity results revealed that cells cultured on tissue culture polystyrene (TCPS) exhibited high proliferation capacity. Cell growth on the scaffolds was slower in comparison to TCPS and did not depend on modification applied. On the other hand, osteogenic differentiation of hMSC as confirmed by alkaline phosphatase (ALP) activity and mineralization results was enhanced on the scaffolds modified with hydroxyapatite and collagen.