Isolation of polysaccharides alpha- and beta-glucans of Pleurotus ostreatus and evaluation of their biocompatibility after surface coating

Glucans, which are polysaccharides in the fungal cell wall, are formed by glucose monomers linked by O-glycosidic bonds. Besides of their medical applications, one of the most promising features of glucans is the stimulatory effect on the immune system of beta-glucans, in which glucose units are linked by beta-1,3 and -1,6 glycosidic bonds. In this study, it was aimed to investigate the effect of alpha- and beta-glucans on the cell viability and proliferation, which were derived from Pleurotus ostreatus by hot water/caustic extraction. Total glucan was quantified by the phenol-sulphuric acid method, and alpha/beta-glucan purity was determined by the enzymatic method. After coating the surface of culture flask with the glucans, their effects on mesenchymal stem cells were examined by toxicity and cell proliferation assays. Alpha- and beta-glucans from P. ostreatus were obtained with a purity of 97.87% ±1.45 and 97.79% ±0.28, respectively. In cell adhesion analysis, alpha-glucans were found to support the attachment (88.10-95.75%), while the adhesion ratio on beta-glucan-coated surfaces decreased to 61.26% ±8.04. The cells on alpha-glucan-coated surfaces were proliferated 1.44 times faster than those on beta-glucan, and 1.56 times faster than those on the uncoated surface. As a result, alpha- and beta-glucan, obtained by hot water/caustic extraction processes, have been shown to have no toxic effects on the cells, and both glucans were demonstrated to be biocompatible biomaterials by in vitro tests. However, the cell adhesion on beta-glucan coated surfaces was observed to be low. Alpha-glucan was shown to promote both cell adhesion and proliferation. Therefore, alpha-glucan may have potential applications in cell culture and tissue engineering studies