Development of l-Lysine Based Biodegradable Polyurethanes and Their Dual-Responsive Amphiphilic Nanocarriers for Drug Delivery to Cancer Cells

The present investigation reports the development of new classes of l-lysine based polyurethanes by a solvent and isocyanate free melt transurethane polycondensation approach. New enzyme and thermo-dual responsive amphiphilic polyurethane nanocarriers were developed for the delivery of drugs both at the intracellular level and at cancer tissue temperature. Multifunctional l-lysine monomers were tailor-made by suitably converting the amine functionalities into urethanes (or carbamates) while masking the carboxylic acid functional unit as amide pendants. The l-lysine monomers underwent melt transurethane polymerization with diols at 150 °C in the presence of catalyst to produce high molecular weight linear polyurethanes. Further, a new amphiphilic l-lysine monomer was designed with a PEG-350 chain as a pendant, and this monomer upon polymerization yielded well-defined amphiphilic aliphatic polyurethanes (APUs). The APU was found to undergo core–shell type self-assembly in aqueous medium to produce nanoparti...