Biocompatible, crystalline and amorphous bismuth-based metal-organic frameworks for drug delivery.

The synthetic flexibility of metal-organic frameworks (MOFs) with high loading capacities and biocompat-ibility makes them ideal candidates for drug delivery system (DDS). Here, we report the use of CAU-7, a biocompatible bismuth-based MOF, for the delivery of two cancer drugs, sodium dichloroacetate (DCA) and α-cyano-4-hy-droxycinnamic acid (α-CHC). We achieved loadings of 33 and 9 wt.% for DCA and α-CHC, respectively. Interestingly, CAU-7 showed a gradual release of the drugs, achieving time release up to 17 days for DCA and 31 days for α-CHC. We then performed mechanical and thermal amorphization processes to attempt to delay even more the delivery of guest molecules. With the thermal-treatment, we were able to achieve an outstanding 32% slower release of α-CHC from the thermal treated CAU-7. Using in vitro studies and endocytosis inhibitors, confocal microscopy and fluorescence-acti-vated cell sorting (FACS), we also demonstrated that CAU-7 was successfully internalized by cancer cells, partially avoid-ing lysosome degradation. Finally, we showed that CAU-7 loaded either with DCA or α-CHC had a higher therapeutic efficiency compared with the free drug approach, making CAU-7 a great option for biomedical applications.