Cargo delivery on demand from photodegradable MOF nano-cages

Abstract

We report the photo-induced degradation of and cargo release from a nanoscale metal–organic framework (nMOF) incorporating photo-isomerizable 4,4′-azobenzenedicarboxylate (AZB) linkers. The structure matches a UiO-type framework where 12 4,4′-azobenzenedicarboxylate moieties are connected to a Zr₆O₄(OH)₄ cluster, referred to as UiO-AZB. Due to the incorporation of photo-isomerizable struts, the degradation of UiO-AZB is accelerated by irradiation with white light (1.3 ± 0.1% h⁻¹ under dark conditions vs. 8.4 ± 0.4% h⁻¹ when irradiated). Additionally, we show slow release of Nile Red (NR) which is triggered by irradiation (0.04 ± 0.01% h⁻¹ under dark conditions vs. 0.36 ± 0.02% h⁻¹ when irradiated).