Stimuli-responsive electrospun nanofibers from poly(N-isopropylacrylamide)-co-poly(acrylic acid) copolymer and polyurethane.

A thermo- and pH-sensitive copolymer of poly(N-isopropylacrylamide)-co-poly(acrylic acid) (P(NIPAAm-co-AAc)) with an adjusted lower critical solution temperature (LCST)(at 37 °C) in an aqueous medium and pH of 7.4 was synthesized by a radical copolymerization, and was characterized by Fourier-transform infrared (FTIR) spectroscopy and H nuclear magnetic resonance (H-NMR) spectroscopy. Then, nanofibers composed of P(NIPAAm-co-AAc) and polyurethane (PU) were fabricated by the single-spinneret electrospinning technique and used as drug carriers by co-spinning with the water insoluble drug nifedipine (NIF).