Lubrication and drug release behaviors of mesoporous silica nanoparticles grafted with sulfobetaine-based zwitterionic polymer

Osteoarthritis, which is characterized by irreversible destruction of articular cartilage and severe inflammation of joint capsule, may be effectively treated via the synergistic therapy of lubrication restoration and local drug intervention. In this study, zwitterionic polymer-grafted mesoporous silica nanoparticles (MSNs@pSBMA) with the property of enhanced lubrication and sustained drug release were successfully synthesized via photopolymerization of 3-[dimethyl-[2-(2-methylprop-2-enoyloxy) ethyl] azaniumyl] propane-1-sulfonate polymer (pSBMA) on the surface of MSNs. The tribiological test showed that the lubrication performance of MSNs@pSBMA was remarkably improved, with a reduction of 80% in friction coefficient compared with MSNs. It was attributed to hydration lubrication mechanism by which a tenacious hydration layer was formed surrounding the N+(CH2)(2)(CH3)(2) and SO3- headgroups in the pSBMA polyelectrolyte polymer. Additionally, the surface morphology analysis of the tribopairs demonstrated that MSNs@pSBMA were endowed with excellent anti-wear performance. Importantly, the drug release test illustrated that, compared with MSNs, MSNs@pSBMA achieved good sustained drug release behavior. In summary, the MSNs@pSBMA nanoparticles developed herein, as an injectable lubricant with enhanced lubrication and drug delivery, may represent a promising approach for the treatment of osteoarthritis.