Mechanically robust enzymatically degradable shape memory polyurethane urea with a rapid recovery response induced by NIR

NIR-light triggered shape memory process involving PU/gold-nanorod composites is shown.

A Facile Strategy to Prepare an Enzyme-Responsive Mussel Mimetic Coating for Drug Delivery Based on Mesoporous Silica Nanoparticles

Surface functional mesoporous silica nanoparticles (MSNs) have been widely used as promosing materials for drug delivery. Herein, we reported a facile strategy to construct MSNs coated by enzyme-resposive polylysine-dopamine (PLDA) films through self-polymerization of dopamine derivative lysine-dopamine, in which the drug could be loaded and delivered efficiently. In detail, RhB or DOX was used as a drug model and loaded in functional MSNs via a one-pot procedure among MSNs, drug, and lysine-dopamine (LDA) under basic conditions. Owing to the fact that the peptide bonds between lysine and dopamine can be cleaved under triggering by pepsin, the resulting RhB/DOX@PLDA-MSNs exibit enzyme-responsive characterization. After the DOX@PLDA-MSNs enter into the cancer cells, the drug can be released effectively through degradation of peptide bonds under the influence of enzyme in cancer cells, which shows marked anticancer activity in vitro. This facile strategy may provide a new platform to construct enzyme-responsive controlled drug delivery systems.

Trypsin-inspired poly(urethane-urea)s based on poly-lysine oligomer segment

A new kind of biodegradable poly(urethane-urea)s based on poly-lysine oligomer used as the soft segment was synthesized and characterized. In vitro degradation behavior of poly (urethane-urea)s was investigated, and was assessed by (1)H NMR and mass loss. The results indicated that the peptide bonds in poly(urethane-urea)s were effectively cleaved in simulated pancreatic juice containing trypsin, while those in buffer solution without trypsin remained unaffected. The degradability was obviously improved by introducing poly-lysine oligomer into the main chain of poly(urethane-urea)s. The results of cells viability test indicated that the poly (urethane-urea)s showed a good biocompatibility on endothelial cells. The thermostability and hydrophilicity of poly(urethane-urea)s increased with increase in poly-lysine oligomer content.