Thermal-responsive polymeric hydrogels

Hatakeyama H, Kikuchi A, Yamato M et al (2007) Patterned biofunctional designs of thermo-responsive surfaces for spatiotemporally controlled cell adhesion, growth, and thermally induced detachment. Biomaterials 28 3632-3643 Hem DL, Hubbell JA (1998) Incorporation of adhesion peptides into nonadhesive hydrogels useful for tissue resurfacing. J Biomed Mater Res 39 266-276 Huang J, Wang XL, Chen XZ et al (2003) Temperature-sensitive membranes prepared by the plasma-induced graft polymerization of N-isopropylacrylamide into porous polyethylene membranes. J Appl Polym Sci 89 3180-3187... 

This chapter covers the preparation, characterization, and biomedical application of thermally sensitive particles. Thermosensitive hydrogel is prepared by precipitation polymerization of A-alkylacrylamide or A-alkylmethacrylamide as a principal water-soluble monomer, a water-soluble cross-linker (for instance, A-methylenebisacrylamide), and an initiator (such as Azobis-amidinopropane derivatives, potassium persulfate, or basically any charged initiator). The core-shell latexes are produced by a combination of emulsion and precipitation polymerization, such as the preparation of polystyrene core and poly(A-isopropylacrylamide) shell or encapsulation of coUoidal seed using alkylacrylamide derivatives. During the elaboration of such stimuli-responsive particles, various aspects should be considered (1) a water-soluble cross-linker is needed, (2) the polymerization temperature should be higher than the LCST of the corresponding linear polymer, and (3) the production of water-soluble polymer (which can be controlled by monitoring the polymerization conditions). The polymerization mechanism has been clearly discussed and well illustrated, but the nucleation step remains questionable and requires further work. 

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