Sustained Release of Antibacterial Therapeutic Elements from Functionalized Mesoporous Silica-Coated Silver Nanoparticles for Bone Tissue Engineering

Applying therapeutic elements to prevent injury from potential infections is a promising avenue in the development of novel bone substitutes; however, achieving controllable delivery of therapeutic ions is crucial to realizing their expected functions. In this study, a Ag nanoparticle core wrapped in an MSN shell was successfully synthesized using a one-pot sol–gel process. Subsequently, the produced Ag@MSN was functionalized with amino and carboxylic groups. The experimental results indicated that these core–shell-structured Ag@MSN spheres had a uniform size of ~60 nm and a specific area of 904.6 m2/g. Their release profiles, influenced by different surface charges, were investigated, with the aim of achieving sustainable release of Ag ions. The concentration-dependent biological effects of Ag@MSNs, including their anti-infection properties and biocompatibility, were comprehensively characterized in vitro, considering their potential for use as bioactive bone substitutes. Functionalized mesoporous silica nanoparticles significantly enhanced the sustained release profile of silver ions, achieving a cumulative release efficiency greater than 50% within 24 h. These nanoparticles also demonstrated exceptional antibacterial efficacy, with an inhibition rate surpassing 98% at a concentration of 30 μg/mL, while concurrently maintaining cell viability above 88%, indicating high biocompatibility. We achieved our goal of effectively decreasing the burst release of Ag to satisfy the intrinsic need for long-term resistance to bacteria in bone substitutes and stimulate osteoblast proliferation.