Design of poly-l-glutamic acid embedded mesoporous bioactive glass nanospheres for pH-stimulated chemotherapeutic drug delivery and antibacterial susceptibility.

Abstract In this research, a core-shell type pH-responsive poly- l -glutamic acid embedded mesoporous bioactive glass nanospheres (MBAG/PLGA) was designed via aminosilane functionalization of MBAG using 3-aminopropyltriethoxysilane (APTES). The formation of MBAG/PLGA was well dispersed in an aqueous medium and demonstrated high drug loading efficacy and enhanced drug delivery rate. Daunomycin (DAN) was considered as a model chemotherapeutic drug for loading and release study. The cumulative in vitro release of DAN from DAN loaded MBAG/PLGA (MBAG/PLGA@DAN) was observed to be pH-dependent and, the DAN release rate was much higher at pH ∼ 5.5 compared to pH at 7.4. The modified Kirby-Bauer microbial assay results showed that the MBAG is a potential antimicrobial agent and susceptibility for Gram-negative bacteria is observed to be much higher than Gram-positive ones. Advanced characterization studies such as SEM coupled with EDX, HRTEM, FTIR, XPS, TGA, XRD, and BET analysis were performed to support the findings of this research. Overall, these results demonstrated that MBAG/PLGA is a promising candidate for a pH-responsive localized drug delivery system in bioconjugate science.