Controlled Zn2+-Triggered Drug Release by Preferred Coordination of Open Active Sites within Functionalization Indium Metal Organic Frameworks

Drug delivery in target regions could make extraordinary progress in chemoselective therapies. A novel preferred coordination (PC) strategy referring to proactive interacting with open active sites to replace previous occupation by ion-exchange for controlling release of drug molecules is well-constructed. Two topological types of MOF-In1 (Schlafli symbol: (4,8)-connected of (4(10).6(15).8(3))(4(5).6)(2)) and MOF-In2 (Schlafli symbol: (4,4)-connected of (6(6))) show the specific way. Increasing node connectivity as well as the trapping of guest OH- anions, 5-fluorouracil (5-FU) is preferentially captured into the MOF-In1, which exhibits an outstanding loading capacity around 34.32 wt %. F-19 NMR spectroscopy was further employed to investigate host-guest interaction and reveal the binding constant (K-a = 3.84 X 10(2) M-1). Meanwhile, the controlled release of 5-FU in a simulated human body with liquid phosphate-buffered saline solution by biofriendly Zn2+-triggered is realized. With an elevated Zn2+ concentration, the drug release will be enhanced. This efficient strategy for MOFs as multifunctional drug carrier opens a new avenue for biological and medical applications.