Design of silk–vaterite microsphere systems as drug carriers with pH-responsive release behavior

Abstract

Improving the therapeutic efficacy of chemotherapy remains a key goal for cancer therapy. Various passive and active targeting strategies have been developed to facilitate drug release targeted to cancer lesions, but actively designing tunable drug release behavior for this need remains a challenge. As a step towards this need, silk–vaterite microspheres were fabricated and utilized as carriers to tune drug release. Doxorubicin (DOX) was loaded onto the microspheres with high efficiency and the release behavior was regulated by tuning the microspheres via thermal processing. In vitro cell inhibition results showed that the drug-loaded microspheres had different cytotoxic efficiencies depending on the DOX release rates. Better efficacy at lower drug doses suggests options to optimize anticancer effects while minimizing toxic side effects. The tunable drug release capacity combined with the inherent passive targeting properties of vaterite-based carriers based on pH sensitivity suggest a promising system for enhanced efficacy of chemotherapy.