Enzyme decorated dendritic bimetallic nanocomposite biosensor for detection of HCHO

In recent times, bi- and tri-metallic nanocomposites are being extensively studied to improve the catalytic surface and sensitivity of detection. In this study, we designed a formaldehyde dehydrogenase decorated Cys-AuPd-ErGO nanocomposite with fern like AuPd dendrites deposited on reduced graphene oxide (ErGO) on screen printed electrode (SPE) for determination of NADH and successfully demonstrated its application for detection of HCHO. This biosensor exhibited direct electron transfer by lowering the oxidation potential of NADH from +0.63 V to 0.32 V vs Ag/AgCl, avoiding usage of electron mediators. The sensor LOD was 0.3 mu M HCHO with excellent sensitivity of 70 mu A/mu M/cm(2) and linear detection range between 1 mu M and 100 mu M during chronoamperometric studies at applied over potential of +0.35 V vs Ag/AgCl. The sensor was tested for its performance in simulated HCHO adulterated samples of fish and milk, and appreciable recoveries (88-104%) at tested concentrations indicated good sensor performance. It was also validated against conventional method of HPLC with highly acceptable correlation coefficient of 0.99, indicating successful fabrication of a simple, on site disposable sensor for HCHO detection. The developed biosensor can also find wide application in quantitative measurement of NADH and analytes involved in reactions with the co-enzyme.

Automated summary

Recent studies have focused on bi- and tri-metallic nanocomposites to enhance catalytic surface and detection sensitivity. A biosensor based on formaldehyde dehydrogenase decorated Cys-AuPd-ErGO nanocomposite was successfully developed for NADH and HCHO detection, showing direct electron transfer and high sensitivity. The sensor demonstrated excellent performance in detecting HCHO in adulterated samples of fish and milk, with recoveries of 88-104%, and was validated against HPLC method with a correlation coefficient of 0.99.