Poly(methyl methacrylate) (core)–biosurfactant (shell) nanoparticles: Size controlled sub-100 nm synthesis, characterization, antibacterial activity, cytotoxicity and sustained drug release behavior

Abstract

A facile oil/water (O/W) modified atomized microemulsion process for the synthesis of novel poly(methyl methacrylate) (nPMMA) (core)–biosurfactant (shell) particles designed for drug delivery applications is reported. The amount of biosurfactant required was 1/35 of the monomer amount by weight and the surfactant/water ratio could be as low as 1/210. These surfactant levels are much lower in comparison with those used in a conventional microemulsion polymerization system. The particles were spherical and 20–50nm in diameter with an average molecular weight of (0.9–1.5)×105gmol−1 (polydispersity index 1.64–2.65). These nanoparticles were non-toxic, biocompatible and exhibited strong antibacterial activity against Bacillus subtilis and Pseudomonas aeruginosa. Glutathione depletion with a concomitant increase in malondialdehyde levels (increasing reactive oxygen species) and lactate dehydrogenase activity demonstrates that nPMMAs induce oxidative stress leading to genotoxicity and cytotoxicity in B. subtilis. The release of ibuprofen, anthraquinone and curcumin from the particles was sustained and strongly dependent on the initial drug loading content and medium pH. The system showed sustained drug release through three stages; although the release in stage I followed non-Fickian diffusion, Fickian diffusion was proven to be the release mechanism of stages II and III. The unique biosurfactant coated nPMMA enables it not only to be a pH-responsive nanocarrier, but also to possess a tailored release profile. Thus, this work manifests the potential of biosurfactant–polymer hybrids as next generation delivery vehicles for biomedical applications.