AuNs-GO Nanocomposite Modified Paper-Based Amperometric Biosensor as an Alternative Approach for Early Investigation of Leptospirosis

Abstract

The gold nanoparticles-graphene oxide (AuNs-GO) nanocomposite customized screen-printed paper electrode (AuNs-GO/SPPE) immobilized the Lipl-41gene-specific 5’NH2 labeled single-stranded DNA probe for early diagnosis of leptospirosis using the electrochemical approach. GO nanoparticle was synthesized using the modified hummer’s method and reduced chloroauric tetra acid to form gold nanoparticles stabilized graphene oxide (AuNs-GO) nanocomposite. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measured the sensor response after hybridization with ssGDNA of L. interrogans. The sensitivity of the developed DNA sensor was calculated as 1487.4 µA/cm2/ng for ssGDNA of L. interrogans using CV studies with a limit of detection (LOD) of 0.002 ng/µl. The nanocomposite was characterized using UV-Vis spectroscopy, Fourier transforms infrared spectroscopy (FTIR), and, Transmission electron microscopy (TEM). The electrode surface modification was also monitored by EIS using potassium-ferricyanide (PBS buffer, 1 mM of pH7.2) as a redox indicator dye. The promising results show that the developed biosensor can become a point-of-need (PON) detection method for the early diagnosis of leptospirosis as it has better sensitivity and specificity, low cost, and rapid response time.