In-situ Electrochemical Synthesis Of Prussian Blue Composite With Gold Nanoparticles And Its Application In Hydrogen Peroxide Biosensor

Abstract

This manuscript presents in-situ electrochemical synthesis of Prussian Blue-gold nanoparticles (PB-AuNPs) composite for application in hydrogen peroxide (H 2 O 2) biosensor. The SEM image clearly showed the presence of AuNPs of size in range of 50 to 200 nm spread on PB matrix. UV-Visible spectra showed absorbance peak at 530 nm corresponding to AuNPs and a hump in 690-740 nm region for PB, confirming the synthesis of composite. The cyclic voltammetry (CV) showed the surface coverage of 3.65 x 10-9 mol/cm 2 for pure PB film and 4.33 x 10-9 mol/cm 2 for PB-AuNPs film, with diffusion coefficient of 1.19 x 10-9 cm 2 /s, and 5.64 x 10-9 cm 2 /s respectively. The film thickness is found to be 2.4 x 10-12 cm for PB and 2.9 x 10-12 cm for PB-AuNPs composite. The concentration of redox active centers (Fe +3/+2) is 3.5 moles/cm 3 for ITO/PB and 4.1 moles/cm 3 for ITO/PB-AuNPs respectively. The CV of ITO/PB showed one redox couple at 0.118 V and 0.215 V, whereas with ITO/PB-AuNPs electrode, two sets of well-defined redox peaks; (i) 0.095 V & 0.135 V and (ii) 0.74 V & 0.78 V were obtained. The faradic current obtained with ITO/PB was 3.6 x 10-3 A and 7.3 x 10-3 A for ITO/PB-AuNPs composite film, respectively. The faradic current was almost double in presence of gold nanoparticles, as compared to pure PB. For H 2 O 2 biosensor, the horse radish peroxidase (HRP) was immobilized on composite film and was used for H 2 O 2 detection. The linearity was obtained from 10 to 90 nM, with sensitivity of 0.73µA/nM and the apparent K m value was 45 nM. The response time of reported biosensor is 20 sec and is stable for about three months.