Characterization of PSHU-PNIPAAm systems. (A) FTIR of PSHU-PNIPAAm-lysine
(green), PSHU-PNIPAAm-laminin (red), and PSHU-PNIPAAm (blue). (*)
Amide III (C–H stretching) vibrations, which are characteristic
of proteins, were observed at 1230–1280 cm–1 in both PSHU-PNIPAAm-lysine and PSHU-PNIPAAm-laminin, while no amide
III vibrations were observed in plain PSHU-PNIPAAm. (B) TGA of PSHU-PNIPAAm-lysine
(green), PSHU-PNIPAAm-laminin (red), and PSHU-PNIPAAm (blue). The
chemical incorporation of proteins makes the polymeric system more
thermally stable. (C) From left to right, SEM of PSHU-PNIPAAm-lysine
1% (w/w) gel, PSHU-PNIPAAm-laminin 1% (w/w) gel, and PSHU-PNIPAAm
1% (w/w) gel. The chemical incorporation of proteins enlarged the
pore size of the polymeric gels, facilitating nutrients and waste
transportation. Scale bar: 20 μm.