Photodynamic Therapy Metal Organic Frameworks (PDT-MOFs)

Nicole Azbill and Randy W. Larsen

University of South Florida

The versatility of metal organic frameworks (MOFs) for drug delivery applications can be expanded by including a stimuli-response element for drug release. Of the various stimuli available (i.e., pH, temperature, bio-stimulation), light induced release is particularly attractive due to precise control of drug release. Although a variety of photo-releasable drug systems have now been developed, one that is particularly appealing for MOF applications involves [Ru(2,2-bipyriidne)₂(Drug)₂]²⁺ and related complexes. These molecules are thermally stable in the dark while illumination with visible light results in photo-release of the Drug ligands with reasonable quantum yields. In addition, the quantum yields can be tuned, using a wide variety of substituted bipyridine, phenanthroline, and pyrazine ligands. Our laboratory has now demonstrated the successful encapsulation of several types of Ru(II) complexes within the cavities of various MOFs, including Ru complexes with photoreleasable ligands. Here we report the structural and photophysical characterization of several prototype solid state photodynamic therapy MOFs (PDT-MOFs) containing Ru(2,2’-bipyridine)(2,2’,2”-terpyridine)Drug, (Drug= MeCN, NO, CO) type complexes encapsulated within a Zn-trimesic acid based MOF, USF2.