Biocompatibility of Various Kinds of Polymer Microspheres Estimated from Their Effect on Gap Junctional Intercellular Communication of Fibroblasts

Gap junctional intercellular communication is a function that plays an important role in maintaining cell and tissue homeostasis and in regulating cell growth, development and differentiation. Change in this function when contacting fibroblasts with various polymer microspheres was estimated using the fluorescence recovery after photobleaching (FRAP) assay system. When the cells were in contact on test dishes, the inhibition level increased as the diameters of polystyrene microspheres decreased, except for a microsphere with 0.5 μm diameter. The function was inclined to be recovered with the increase of the incubation time, while it was not recovered when the cells were cultured with pre-coated polystyrene microspheres. As well as inhibitory activities of the function, cytotoxicity potentials of tested microspheres depended on their diameter and their composition. These findings suggest that the size and the physico-chemical character of polymer microspheres, and how cells recognize them plays important roles in causing influences of the microspheres on both gap junctional intercellular communication and their cytotoxicity. Therefore, estimating the inhibitory effect of biomaterials on the gap junctional intercellular communication will provide valuable information about the biocompatibility of materials even in the form of particles.