New reductant-free synthesis of gold nanoparticles-doped chitosan-based semi-IPN nanogel: A robust nanoreactor for exclusively sensitive 5-fluorouracil sensor

Abstract We report a novel class of chitosan (CS)-based hybrid semi-interpenetrating nanogel catalyst by the reductant-free green synthesis of gold nanoparticles (Au NPs) within the CS-poly(methacrylic acid) (Au@CS-PMAA) polymer network. The covalently cross-linked Au@CS-PMAA nanogel with CS chains semi-interpenetrating (semi-IPN) in the PMAA cross-linked network show superior colloidal stability and improved catalytic activity. The synthesized Au@CS-PMAA semi-IPN nanogel was applied as a superior modifier to create a new and sorely selective electrochemical sensing platform for the determination of antileukemic drug 5-fluorouracil (5-FU). The existence of –OH and –COOH groups in the CS and PMAA offers numerous binding sites for 5-FU. This assures the incorporation of Au NPs which affords a larger surface area and ameliorate electrical conductivity. Besides, the synergic effect amid both compounds improves the detection of 5-FU. Under optimal conditions, the constructed sensor offered a good performance in determination of 5-FU with a wide linear range from 0.1–497 μM and low detection limits of 0.03 μM, respectively. Further, this study proved that the fabricated sensor could be useful for analysis of 5-FU in actual human blood serum samples.