Monday, November 9, 2015: 2:10 PM
151D/E (Salt Palace Convention Center)
Metal-Organic Frameworks (MOFs) are promising functional materials for encapsulation of medicinal drugs by adsorption and the subsequent controlled drug delivery. It is important to learn about molecular-level detail of chemical bonding between biologically active adsorbates and major structural units in the MOF encapsulation sorbents. 5-fluorouracil (5-FU) is a major anti-cancer drug that features a quick metabolism and hence needs to be encapsulated for a controlled drug delivery. We report mechanistic studies of encapsulation of 5-FU by adsorption on non-toxic F300 MOF, chemical bonding between 5-FU and adsorption sites in F300, and kinetics of controlled drug release to bodily fluid. Adsorption of 5-FU from non-toxic solvent DMSO yields an adsorption complex with F300, with encapsulated amount of 5-FU up to 45 wt. %. To learn about adsorbed state of 5-FU, we have used, for the first time, the front face 3-dimensional photoluminescence spectra at 77 K, the FF-Cryo-3D PL spectra. The FF-Cryo-3D PL spectra of F300 MOF at λexc>390 nm show vibronically resolved emission from the BTC linker connected to the Fe(III) coordinatively unsaturated site (CUS). Upon encapsulation of 5-FU, vibronically resolved FF-Cryo-3D PL spectra of F300 undergo a drastic change with quenching of vibrations of the BTC linker, due to the formation of molecular complex with 5-FU. These findings were complemented by the near-UV-Visible and Near InfraRed Diffuse Reflectance Spectra (UV-Vis-NIR DRS), ATR-FTIR, Raman spectra and DFT calculations. Release of encapsulated 5-FU to simulated intestinal fluid (SIF) at 37 ºC was studied by the in-situ FF-PL spectroscopy in suspension; controlled drug release occurs on time scale of >24 h. Non-toxic mesoporous MOF F300 is a promising novel encapsulation platform for the synthesis of the new biologically active composite functional materials and for targeted drug delivery of anti-cancer drugs and other small molecule heterocyclic drugs. Acknowledgments: A.S. thanks Rutgers University for his Research Council Award.