Conformation changes of albumin and lysozyme on electrospun TiO2 nanofibers and its effects on MSC behaviors.

Protein adsorption plays a key role in bone repair and regeneration by affecting cell behavior. In this study, TiO2 nanofibers (TiO2 NFs) with different structures, including anatase TiO2 nanofibers (A-NFs), anatase TiO2 nanofibers with beads (B-NFs), anatase-rutile TiO2 nanofibers (AR-NFs) and rutile TiO2 nanofibers (R-NFs), were prepared by electrospinning method. Bovine serum albumin (BSA) and lysozyme (LYZ) were used to explore the adsorption behaviors of TiO2 NFs and then the effects of materials with protein on bone marrow mesenchymal stem cells (MSCs) were studied. Pure titanium metal (PT) was used as control. The results displayed that the adsorption amounts of BSA on samples were B-NFs > AR-NFs > A-NFs ≈ R-NFs > PT, and that for LYZ were B-NFs > AR-NFs > R-NFs > A-NFs > PT. The conformation of proteins changed remarkably when they were adsorbed on meterials. Soaking the TiO2 NFs with and without protein into SBF revealed that the BSA and LYZ on B-NFs, A-NFs and AR-NFs could accelerate the HA deposition on its surface, but it had no promoting effect on HA deposition on B-NFs. MTT and PCR tests showed that the BSA and LYZ adsorbed on materials could promote the proliferation and osteogenic differentiation of MSCs to different degrees due to their different adsorption amount and conformation changes on different TiO2 NFs. The current work demonstrated that the surface properties and crystal structure of TiO2 NFs could influence the adsorption behavior and conformational change of BSA and LYZ, and then further regulate MSCs biological behavior.