Heat-triggered drug release systems based on mesoporous silica nanoparticles filled with a maghemite core and phase-change molecules as gatekeepers

Core-shell nanoparticles made of a maghemite core and a mesoporous silica shell were developed as drug delivery systems (DDS). Doxorubicin® (DOX, DNA intercalating drug) was loaded within the mesoporous cavities, while phase-change molecules (PCMs), e.g. 1-tetradecanol (TD) with a melting temperature (Tm) of 39 °C, were introduced as gatekeepers to regulate the release behaviours. An overall loading amount of ca. 20 wt% (TD/DOX ca. 50/50 wt/wt) was confirmed. Heat-triggered release of DOX evidenced a "zero premature release" (95% viability after 72 h incubation). However, continuous cell apoptosis was detected at cell culture temperature above Tm of TD, due to the heat-triggered release of DOX (