Abstract:

We report on a facile and efficient construction of electrochemical biosensors by modifying the screen printed carbon electrodes (SPCE) with multifunctional polymeric nanoparticles. An amphiphilic random copolymer, poly(St-co-AA-co-VCz-co-DMAEMA) (PSACD), was first synthesized using styrene (St), acrylic acid (AA), N-vinylcarbazole (VCz) and dimethylaminoethyl methacrylate (DMAEMA) as hydrophobic, hydrophilic, electroactive and enzymatic compatible monomers, respectively. The polymeric nanoparticles (PSACD NPs) were then prepared through self-assembly of polymers in a selective solvent mixture of DMF/H₂O. The obtained PSACD NPs were characterized by particle size analyzer and scanning electron microscope (SEM), and were used to fabricate the hydrogen peroxide (H₂O₂) biosensor with the functions of improving the specific surface areas, providing a suitable microenvironment for keeping the enzyme activity, and accelerating the electron transfer between enzymes and the electrodes. Specifically, the SPCE was successively modified by PSACD NPs suspensions, horseradish peroxidase (HRP) solution and perfluorosulfonic acid-PTFE copolymer (Nafion) solution. The properties of the proposed electrochemical biosensor were studied via an amperometric detection method. The results show that the biosensor has a short response time (less than 2 s) and a linear increasing response current with the concentration of H₂O₂ increasing from 0.02 to 7.48 mmol/L. The biosensor also has nice stability, good selectivity and excellent anti-interference performance.

Key words: polymeric nanoparticles, self-assembly, screen-printed carbon electrode, horseradish peroxidase, biosensor