Drug self-assembly for synthesis of highly-loaded antimicrobial drug-silica particles

Antimicrobial drug release from biomaterials for orthopedic repair and dental restorations can prevent biofilm growth and caries formation. Carriers for drug incorporation would benefit from long-term drug storage, controlled release, and structural stability. Mesoporous silica, synthesized through a co-assembly of silica and surfactant template, is an ideal drug encapsulation scaffold that maintains structural integrity upon release. However, conventional loading of drug within meso-silica pores via concentration-gradient diffusion limits the overall payload, concentration uniformity, and drug release control. Herein we demonstrate the co-assembly of an antimicrobial drug (octenidine dihydrochloride, OCT), and silica, to form highly-loaded (35% wt.) OCT-silica nanocomposite spheres of 500 nm diameter. Drug release significantly outlasted conventional OCT-loaded mesoporous silica, closely fit Higuchi models of diffusive release, and was visualized via electron microscopy. Extension of this concept to the broad collection of self-assembling drugs grants biomedical community a powerful tool for synthesizing drug-loaded inorganic nanomaterials from the bottom-up.