Smart Approach for InSitu One-Step Encapsulation and Controlled Delivery of a Chemotherapeutic Drug using Metal-Organic Framework-Drug Composites in Aqueous Media

Controlled release of an anticancer drug, doxorubicin (dox), from metal-organic framework (MOF)-drug composites is demonstrated under different external stimuli. 1,3,5-Benzenetricarboxylic acid (H3BTC) is used as an organic ligand, and iron acetate and zinc nitrate are used as metal sources to synthesize Fe-BTC and Zn-BTC MOFs, which are known to be biocompatible. The insitu formation of MOF-drug composites demonstrates high drug loading capacity compared to conventional methods. The present methodology is devoid of any extra steps for loading the drug after synthesis. Moreover, the drug loading is also independent of pore size of the MOF as the drug molecules are embedded inside the MOF during their insitu formation. The drug release was monitored under external stimuli including change to acidic pH and the presence of biocompatible liposomes for a period of more than 72h. Steady-state fluorescence spectroscopy is used to monitor the drug release as a function of time and confocal laser scanning microscopy is used to unravel the post-release fate of doxorubicin in the presence of liposomes. It is found that drug release rate is higher for the Zn-BTC-dox composite than for the Fe-BTC-dox composite. This is attributed to the stronger binding between dox and Fe-BTC than that between dox and Zn-BTC. This study highlights a novel approach for the preparation of MOF-drug composites in an aqueous medium for future biomedical applications.