Thermoresponsive hydrogels based on poly(N-isopropylacrylamide)/chondroitin sulfate

Department of Biomedical Engineering, Hanyang University, Seoul 133-791, Republic of Korea
Sensors and Actuators B Chemical (Impact Factor: 4.1). 12/2008; 135(1):336-341. DOI: 10.1016/j.snb.2008.09.001


A fast, thermoresponsive hydrogel composed of poly(N-isopropylacrylamide) (PNIPAm) and chondroitin sulfate (ChS) was synthesized using precipitation polymerization. ChS was introduced to increase the water absorption of the PNIPAm hydrogel, and the precipitation polymerization method was used to induce a porous network morphology to enhance the thermal response of the hydrogel. PNIPAm/ChS hydrogels (15:7.5 wt.%) underwent a very fast deswelling, within a period of approximately 2 min, due to the presence of a large free water content (∼90–94%), which was associated with the interconnected filamentous morphology within the hydrogel. The swelling ratio was greatly enhanced by the addition of ChS. The hydrogels exhibited stable thermoactuation behavior, following a volume change of 75% while cycling the temperature between 20 and 45 °C.

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