Stimuli-responsive polymer vesicles

Li M-H, Keller P (2009) Stimuli-responsive polymer vesicles. Soft Matter 5 927-937... 

The era of biomimetic peptide- and sugar-based polymer vesicles has just begun and seems very promising. Bioinspired vesicles are mainly applied for drug deliv-ery/release and the fabrication of composite materials, but could readily be used for biomimetic materials science, biomineralization, and so on. Especially interesting are smart vesicles changing properties in response to an external stimulus (temperature, pH, ions). 

A sensor is a system that displays a readily detectable response in the presence of a specific analyte. Indeed, stimulus-responsive vesicles have been tailor-made to function as highly specific sensors. The overwhelming majority of vesicle-based sensors are based on a very simple type of amphiphile polydiacetylenes. These polymeric amphiphiles are easily formed from simple diacelylene amphiphiles by in situ photopolymerization of vesicles. If the vesicles are additionally equipped with ligand or receptor groups, the absorbance and fluorescence of the conjugated polymer backbone is highly sensitive to the presence of metal ions, anions, and small as well as large... 

Self-organization of amphiphilic (co)polymers has resulted in assemblies such as micelles, vesicles, fibers, helical superstructures, and macroscopic tubes [174, 175]. These nanoscale to macroscale morphologies are of interest in areas ranging from material science to biology [176]. Stimuli-responsive versions of these assemblies are likely to further enhance their scope as smart materials. Thermo- or pH-sensitive polymer micelles [177] and vesicles [178] have been reported in which the nature of the functionality at the corona changes in response to the stimulus. Some attention has been also paid to realize an environment-dependent switch from a micelle-type assembly with a hydrophilic corona to an inverted micelle-type assembly with a lipophilic corona [179]. 

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