Synthesis, characterization, pH‐sensitive swelling and antimicrobial activities of chitosan–graft‐poly(hydroxyethyl methacrylate) hydrogel composites for biomedical applications

Abstract In this paper, 2‐hydroxyethyl methacrylate (HEMA) was graft copolymerized onto chitosan (CHI) at different ratios using a radical initiator. The grafted hydrogel composites were then characterized by attenuated total reflection Fourier transform ınfrared spectroscopy (ATR‐FTIR) and thermo‐gravimetric analysis (TGA). Swelling behavior of the hydrogels was investigated at different pH and different times. The antimicrobial activity of the chitosan‐graft‐HEMA (CHI‐HEMA) against gram‐negative bacteria and gram‐positive bacteria was studied by the standard agar well diffusion assay method. The CHI‐HEMA 1:1 and CHI‐HEMA 1:2 showed an obvious antimicrobial effect against six test strains. The CHI‐HEMA 1:1 and CHI‐HEMA 1:2 exhibited a highly significant increase ( p < 0.01) in diameter of the inhibition zones compared with the standard antibiotics. Furthermore, CHI‐HEMA 1:1 presented the highest antimicrobial activity against all test strains with a significant difference ( p < 0.01) compared with CHI‐HEMA 1:2. Meanwhile, the decreasing order of the average sensitivity to CHI‐HEMA 1:1 and CHI‐HEMA 1:2 was observed to be S. marcescens > E. coli > S. aureus subsp. aureus > S. enteritidis > E. faecalis > E. aerogenes . These results indicate potential application of CHI‐HEMA 1:1 and CHI‐HEMA 1:2 graft hydrogels as a novel and efficient antimicrobial agent in biomedical fields.