Surface functionalization of tissue culture polystyrene plates with hydroxyapatite under body fluid conditions and its effect on differentiation behaviors of mesenchymal stem cells.

The surfaces of polystyrene (PS) cell culture plates were functionalized with hydroxyapatite (HAp) under body fluid conditions utilizing protein adsorption layers and a pretreatment with an alternate soaking process (ASP) using solutions containing calcium and phosphate ions. Adsorption layers of human serum albumin (HSA) formed on the surface of each well of commercial 24-well PS plates by solution processes. CaCl2 and K2HPO4 solutions were alternately added to the wells, the plates were incubated to form the precursors, and this was followed by the addition of simulated body fluid (SBF) and a further incubation for 24h. These treatments resulted in the surfaces of the PS cell culture plates being completely covered with bone-like HAp. The coating of PS plates with HAp promoted the adhesion of mesenchymal stem cells (MSCs) and maintained cell growth that was as fast as that on tissue culture-treated PS (TCPS) plates. Osteogenic differentiation was greater, whereas adipogenic and chondrogenic differentiation was less in the culture on HAp-coated PS plates than in that on TCPS plates. The present method is useful for preparing HAp-coated PS plates at clean benches without the need for any expensive apparatus. HAp coated on PS plates by this method was a bone-like apatite with high bioactivity; therefore, the present HAp-coated PS plates are promising materials for assays of bone-related cells in the bone remodeling process.