In the present work, a new and facile strategy for the synthesis of light‐responsive polyurethanes (LrPUs) based on serinol with o‐nitrobenzyl pendent groups is developed. Stable monodisperse nanoparticles from these LrPUs can be formulated reproducibly in a simple manner, which is shown by dynamic light scattering (DLS) measurements. Upon irradiation with UV light, both polymers and nanoparticles undergo rapid degradation, which is investigated by DLS, scanning electron microscopy, size exclusion chromatography, and UV–vis spectroscopy. The nanoparticles are also employed for the encapsulation of the model drug Nile Red, and by exposure to UV light, a burst release of the payload is detected via fluorescence spectroscopy. This strategy can be easily applied to the straightforward synthesis of various new serinol‐based monomers with different stimuli‐responsive properties and therefore expand the family of biodegradable polymers.

To overcome the high relapse rate of multiple myeloma (MM), a drug delivery coating for functionalization of bone substitution materials (BSM) is reported based on adhesive, catechol-containing and stimuli-responsive polyelectrolyte complexes (PECs). This system is designed to deliver the MM drug bortezomib (BZM) directly to the anatomical site of action. To establish a gradual BZM release, the naturally occurring caffeic acid (CA) is coupled oxidatively to form poly(caffeic acid) (PCA), which is used as a polyanion for complexation. The catechol functionalities within the PCA are particularly suitable to form esters with the boronic acid group of the BZM, which are then cleaved in the body fluid to administer the drug. To achieve a more thorough control of the release, the thermoresponsive poly(N-isoproplyacrylamide-co-dimethylaminoethylmethacrylate) (P(NIPAM-co-DMAEMA)) was used as a polycation. Using turbidity measurements, it was proven that the lower critical solution temperature (LCST) character of this polymer was transferred to the PECs. Further special temperature dependent attenuated total reflection infrared spectroscopy (ATR-FTIR) showed that coatings formed by PEC immobilization exhibit a similar thermoresponsive performance. By loading the coatings with BZM and studying the release in a model system, via UV/Vis it was observed, that both aims, the retardation and the stimuli control of the release, were achieved.

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.

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Stimuli-degradable polymers are regarded as interesting materials for various applications like patterning or drug delivery. In particular, light as a trigger received a lot of attention due to the possibility...

The controlled delivery of active pharmaceutical ingredients to the site of disease represents a major challenge in drug therapy. Particularly when drugs have to be transported across biological barriers, suitable drug delivery systems are of importance. In recent years responsive delivery systems have been developed which enable a controlled drug release depending on internal or external stimuli such as changes in pH, redox environment or light and temperature. In some studies delivery systems with reactivity against two different stimuli were established either to enhance the response by synergies of the stimuli or to broaden the window of possible trigger events. In the present review numerous exciting developments of pH‐, light‐ and redox‐cleavable polymers suitable for the preparation of smart delivery systems are described. The review discusses the different stimuli that can be used for a controlled drug release of polymer‐based delivery systems. It puts a focus on the different polymers described for the preparation of stimuli‐sensitive systems, their preparation techniques as well as their stimuli‐responsive degradation. © 2022 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.