Amino acid-derived stimuli-responsive polymers and their applications

Natural biopolymers such as proteins and nucleic acids in living organisms possess an inherent ability to respond to local environmental stimuli, which motivated researchers to make biomolecule-derived non-biological macromolecules with a biomimetic structure having stimuli-responsive properties. This review mainly focuses on stimuli-responsive polymers having natural amino acid units either in the main-chain or in the side-chain, their self-assembled nanostructures and hydrogel networks. Recent advances in the design and synthesis of amino acid-derived polymers that are responsive to various physical, chemical, or biochemical stimuli such as temperature, light, pH, redox-, metal ions, gas, glucose, enzyme, proteins, DNA or a combination of these are illustrated. Their potential for use as stimuli-responsive "smart" nanomaterials in biomedical and biotechnological applications such as in controlled drug delivery, gene delivery, non-fouling materials, etc . is also highlighted. The primary aim of this review article is to motivate researchers towards the design and synthesis of novel stimuli-responsive biohybrid materials for making next generation smart materials. The recent advances achieved in the study of various stimuli-responsive polymers derived from natural amino acids have been reviewed.