Three-dimensional network polyamidoamine dendrimer-Au nanocomposite for the construction of a mediator-free horseradish peroxidase biosensor

Abstract

A three-dimensional network PAMAM-Au nanocomposite (3D-PAMAM-Au NC) was prepared by using the first generation polyamidoamine dendrimer (G1 PAMAM) as the dispersant agent. The resultant 3D-PAMAM-Au NC was successfully used as an immobilization matrix for the construction of a reagentless mediator-free horseradish peroxidase (HRP)-based H₂O₂ biosensor on a multi-walled carbon nanotubes (MWCNTs) modified glassy carbon electrode. With the advantages of the three-dimensional network, the organic–inorganic hybrid materials dramatically facilitate the direct electron transfer of HRP, and good bioelectrocatalytic activity towards H₂O₂ was demonstrated. Under optimum conditions, the current response of the enzyme modified electrode at −0.30 V was detected. The current response is linearly correlated to H₂O₂ concentration within the range of 18.00 μM to 20.80 mM with a correlation coefficient of 0.9992 and a sensitivity of 377.78 μA mM⁻¹ cm⁻². The detection limit was down to 6.72 μM (S/N = 3). Furthermore, the biosensor exhibits some other excellent characteristics, such as high selectivity, short response time, and long-term stability. The 3D-PAMAM-Au NC has proved to be a promising biosensing platform for the construction of mediator-free biosensors, and may find wide potential applications in biosensors, biocatalysis, bioelectronics and biofuel cells.