Structuring hydrophobic domains in Poly(N-isopropylacrylamide-co-Methacrylic acid) hydrogels

Abstract Poly(N-isopropylacrylamide-co-methacrylic acid) hydrogels were structured with hydrophobic compartments. To achieve that, N-isopropylacrylamide was copolymerized with methacrylic acid and a small percentage (~0.4 %mol) of (3,4-dihydroxy-5-nitrophenyl)methacrylamide (nitrocatechol monomer) in the presence of sodium dodecyl sulphate at a concentration below its CMC value. All the results support the structuring of poly(N-isopropylacrylamide-co-methacrylic acid) hydrogels with hydrophobic domains in water. These compartments were found to be rich in methacrylic acid and nitrocatechol units. Moreover, the structuring disappeared when hydrogels were swollen at pH 7.4. The structured hydrogel was capable of loading hydrophobic molecules (methyl-2-naphthoate and methyl-9-anthracenecarboxylate) as well as charged drugs (doxorubicin hydrochloride). This hydrogel permitted cell adhesion and growth as well as its detachment when the temperature fell below the LCST.