2.1. Materials
K3[Fe(CN)6]•3H2O was brought from Fuchen Chemical Reagent Factory (China). Poly (N-vinylpyrrolidone) (PVP) was obtained from Zhanyun Chemical Co., Ltd. (China). Ofloxacin, Haluronic acid and Polyacrylic acid were obtained from Macklin Biotechnology Co., Ltd (China). 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) were purchased from Sigma Aldrich. All other chemicals and solvents were of reagent grade.