Article

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

ABSTRACT

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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Available from: Yahya Ismail, Jan 27, 2016
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    • "This dehydration of the polymer chains could potentially result in cellular exclusion from the matrix and excessive volume loss. However, the fixed negative charges on chondroitin sulfate (–COO -and –SO 3 -) at neutral pH have been shown to enhance osmotic pressure of highly crosslinked PNIPAAm networks[50]. Water loss data for our in situ forming system at 37 °C, shown in Fig. 1, is consistent with these prior findings. The PNIPAAm homopolymer gel exhibited an approximate 83.0 ± 3.6 % water loss over the 14 day period. "
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    • "), hyaluronic acid (Ha et al., 2006; H.P. Tan et al., 2009), chondroitin sulfate (Varghese et al., 2008) or other polymers to adjust its gelling temperature and mechanical properties. This is to preserve the viability and phenotypic morphology, as well as improve proliferation, differentiation and extracellular matrix secretion of the cells entrapped within the hydrogel. "
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