Mesoporous bioactive glass coatings on stainless steel for enhanced cell activity, cytoskeletal organization and AsMg immobilization

Abstract

Mesoporous bioactive glass (MBG) coatings with SiO₂ : CaO : P₂O₅ mol ratio of 100 : 0 : 0, 80 : 15 : 5 and 70 : 25 : 5 and a tunable pore size and pore structure were prepared on a stainless steel plate by spin-coating sol solutions containing a triblock copolymer and the inorganic precursors. The calcium content in the MBG coatings affected the mesoporous structure. With the increase in calcium content, the crystallinity of the MBG coatings increased and thus the Brunauer–Emmett–Teller (BET) surface area and pore volume decreased. The MBG coatings were evaluated on the basis of protein adsorption, cell attachment, cell proliferation, cell differentiation, cytoskeletal organization and L-ascorbic acid phosphate magnesium salt n-hydrate (AsMg) immobilization for their potential in improving implant-bone integration. The results showed that the osteoblast MC3T3-E1 cells were stimulated by the mesoporous structure and chemical composition of the MBG coatings, with enhanced cell attachment, proliferation, differentiation and better developed cytoskeleton. Moreover, AsMg was successfully immobilized on the MBG coatings by using an AsMg-containing supersaturated calcium phosphate solution. The AsMg immobilized on the MBG coatings was not denatured and showed high activity enhancing the fibroblast NIH3T3 proliferation in vitro. An appropriate range of pore size and a preferred alignment of the mesochannels of the MBG coatings on stainless steel are promising to improve the implant-bone integration.