Thermoresponsive synthetic polymers

Thermoresponsive Synthetic Polymers that Support hPSC Culture... 

Classic examples of synthetic polymers exhibiting an aqueous LCST include poly-diethyl acrylamide), poly(dimethylaminoethyl methacrylate), poly(A -acryloylpyrrolidine), poly(2-isopropyl-2-oxazoline), elastin-like artificial polypeptides, poly(vinyl methyl ether) and poly(7V-isopropylacrylamide) (PNIPAM, Scheme 1). The latter has been by far the most studied and applied thermoresponsive polymer and therefore can be considered as the gold standard in this field of research. During the last decades, several thousands of research articles and patents described the synthesis, the properties and the applications of this fascinating macromolecule. 

Although chemical ligations on mammalian cell surfaces have been performed using unnatural functional groups delivered to carbohydrates [37], the number of studies of mammalian cell surface modifications with synthetic polymers remains limited [31]. In order to control biointerfacial aspects with environmental stimuli, thermoresponsive polymers were immobilized on mammalian cell surfaces. 

In addition to the commonly used synthetic polymers such as pNIPAM and poly(N-vinylcaprolactam) (PVCL), elastin-like polymers were introduced as thermoresponsive polymers for affinity precipitation (Shimazu et al., 2003). An elastin-like polymer consists of the repeating penta-peptide, Val-Pro-Gly-Xaa-Gly (Xaa being any amino acid except proline). It undergoes reversible phase transition under temperature or salt concentration changes similar to pNIPAM (Shimazu et a/., 2003). An elastin-like polymer was used as a terminal tag for the facilitation of recombinant protein purification as attaching it to the hydrolase enzyme improves its purification. Purification, in excess of 1300-fold was achieved after two cycles of reversible changes of elastin-like polypeptide conformation precipitation induced by environmental changes (Shimazu et al., 2003). 

Thermoresponsive synthetic glycopolymers were reported by Chen and coworkers via thiol-ene click addition [121]. The facile conjugation of glucose onto polymer scaffolds afforded self-assembled particles having specific... 

Synthesis of various functionalized 2008 [30] iV-isopropylacrylamide- and vinylether-based polymers grafting onto various substrates detailed review of thermoresponsive polymers, block and graft copolymers synthesis of PiPAAm of various shapes ionic and neutral block copolymers self-assembly stimuli-responsive polymers new initiating systems and synthetic methodologies... 

Most interesting, however, are thermoresponsive polymer phase transitions in aqueous solutions since this phenomenon provides high potential for biomedical applications, such as drug dehvery and switchable synthetic cell culture surfaces (de las Heras Alarcon et al, 2005 Schmaljohann, 2006 Ward and Theoni, 2011). The remainder of this chapter will focus on such temperature-responsive polymers in aqueous solution, by discussing basic principles (Section 2.2) and key types of temperature-responsive polymers (Section 2.3) as well as selected applications (Section 2.4). 

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