Poly(N-isopropylacrylamide)-based semi-interpenetrating polymer networks for tissue engineering applications. Effects of linear poly(acrylic acid) chains on rheology.
Semi-interpenetrating polymer networks (semi-IPNs), comprised of poly(N-isopropylacrylamide-co-acrylic acid) (p(NIPAAm-co-AAc)) hydrogels and linear p(AAc) chains, were synthesized, and the effects of the p(AAc) chains on semi-IPN rheology were examined. Oscillatory shear rheometry studies were performed and the rheological data were analyzed as a function of temperature, frequency, and p(AAc) chain amount (weight average molecular weight (Mw) 4.5 x 10(5) g/mol). At 22 degrees C, the semi-IPNs, as well as control p(NIPAAm-co-AAc) hydrogels, demonstrated rheological data that were representative of soft, loosely cross-linked solids. Furthermore, only the highest p(AAc) chain amount tested affected the rigidity of the p(NIPAAm-co-AAc)-based semi-IPNs, as compared to the p(NIPAAm-co-AAc) hydrogels. At 37 degrees C, the complex shear moduli (G*) demonstrated by the p(NIPAAm-co-AAc)-based semi-IPNs were significantly greater than G* exhibited by the p(NIPAAm-co-AAc) hydrogels, and the semi-IPN G* values significantly increased with increasing p(AAc) chain amount. These results can be used to develop p(NIPAAm)-based semi-IPNs with tailored mechanical properties that may function as scaffolds in tissue engineering initiatives.
Department of Biomedical Engineering, Robert R. McCormick School of Engineering and Applied Sciences, Northwestern University, Evanston, IL 60208, USA.
Ranee A
RA
Stile
Eugene
E
Chung
Wesley R
WR
Burghardt
Kevin E
KE
Healy
D000179:Acrylates; D000180:Acrylic Resins / Q000737:chemistry*; D000704:Analysis of Variance; D003094:Collagen / Q000737:chemistry; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D008956:Models, Chemical; D009991:Oscillometry; D011108:Polymers / Q000737:chemistry*; D012212:Rheology / Q000379:methods; D013696:Temperature; D023822:Tissue Engineering / Q000379:methods*
D000179:Acrylates; D000180:Acrylic Resins; D011108:Polymers; C052970:poly-N-isopropylacrylamide; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; C006903:carbopol 940; D003094:Collagen; C036658:acrylic acid