Backbone-Degradable (Co-)Polymers for Light-Triggered Drug Delivery

In modern therapy, cutting side effects caused by the administration of drugs is one of the core challenges. One possible strategy is the delivery of a drug to the disease site by encapsulation into a polymeric matrix. Especially, light-responsive polymers are regarded as promising materials due to, e.g., the capability of tailored on-demand release in illuminated areas. In this work, a series of light-responsive backbone-degradable (co-)­polymers were synthesized by polycondensation and polyaddition. All obtained polymers showed rapid degradation in solution upon exposure to ultraviolet (UV) light as observed by size-exclusion chromatography (SEC) and ultraviolet-visible (UV–vis) spectroscopy. Light-induced decomposition of films prepared from the polycarbonate was confirmed by UV–vis, surface plasmon resonance (SPR), and profilometry measurements. Depending on the incorporated comonomers, the functional co-polyurethanes exhibited either enhanced hydrophilicity or dual-responsiveness to light and redox environments, which was detected by SEC after treatment with a reducing agent. The formulation of nanoparticles from light-responsive polyurethanes proved the processability of the synthesized polymers, and dynamic light scattering (DLS) measurements confirmed the photo-induced degradation of the prepared particles. Water-soluble tetrazolium salt (WST-1) assays were carried out to evaluate the cytotoxic potential before and after irradiation.