Thermoresponsive thin hydrogel-grafted surfaces for biomedical applications

Thin poly(N-isopropylacrylamide) (PIPAAm) hydrogels were introduced onto biomaterials surfaces for accelerating the kinetics of the swelling and shrinking for PIPAAm hydrogels in response to temperature changes. Thin PIPAAm hydrogels on the biomaterials surfaces exhibit rapid and reversible phase transitions and act as switching sequences to regulate the interaction between the surfaces and biological materials by external temperature-induced changes. By utilizing the temperature-dependent changes of thin PIPAAm hydrogels grafted onto surfaces, our laboratory has pursued unique approaches for developing useful biomedical materials as new types of chromatographic matrices and cell culture surfaces. Aqueous thermoresponsive chromatography systems using PIPAAm-grafted stationary phases enable us to separate biomolecules with high biological activity. Additionally, thermoresponsive cell culture surfaces allow for the recovery of confluent cell monolayers, which have been clinically applied to ophthalmological treatments, dilated cardiomyopathy, esophageal ulcerations, periodontal disease, and cartilage injury. Furthermore, next-generation thermoresponsive cell culture surfaces for large-scale cell cultivation and the capture of specific cells have been considered a key technology for expanding small quantities of stem cells and isolating the resulting differentiated cells for therapeutic use. (C) 2013 Elsevier Ltd. All rights reserved.