Synthesis of chitosan-based nanohydrogels for loading and release of 5-fluorouracil

•Several novel functionalized chitosan-based nanohydrogels were synthesized.•These nanohydrogels show different soluble property at a wide range of pH.•5-Fluorouracil (5-FU), a chemotherapy drug, was loaded into the nanohydrogels.•These nanohydrogels showed a consecutive release of 5-FU at different conditions.•Possible mechanisms of CS-based nanohydrogels and 5-FU loading were investigated.

Several functionalized copolymer nanohydrogels consisting of chitosan (CS) and the monomer acrylic acid (AA), methyl methacrylate (MMA) and N-isopropylacrylamide (NIPAM), which were used to adjust the limited solubility of CS under alkaline condition, have been synthesized by free radical polymerization method. They exhibited favorable solubility behavior in a broader pH range as well as thermal-sensitive properties at 37 °C. The nanohydrogels were analyzed by particle size, zeta potential, FT-IR and SEM. Results showed that the nanohydrogels possessed of a uniform spherical morphology with 140–190 nm in size and carried obvious positive surface charges. 5-Fluorouracil (5-FU) loaded nanohydrogels were prepared and the loading efficiencies of 5-FU with different concentrations of nanohydrogels were investigated. The maximal loading efficiency was 99.5%. And these nanohydrogels could provide a consecutive release of 5-FU at different conditions. Furthermore, the possible synthesis mechanisms of CS-based nanohydrogels and 5-FU loading were studied in this paper.

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