An enzyme-free layer-by-layer glutathione sensor using Cu nanoparticles electrodeposited onto graphene oxide

An electrochemical glutathione sensor incorporating graphene oxide film and electrodeposited copper nanoparticles layer was investigated. The copper nanoparticles were electrodeposited onto the graphene oxide film to build an ultrasensitive sensing interface with excellent electrocatalytic activity. The electrode materials were characterized using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The electrocatalytic activity of the sensor was studied using cyclic voltammetry. The analytical performance of the fabricated sensor scheme with and without graphene oxide and/or copper nanoparticles was determined from direct glutathione injections during an amperometry analysis. The increased electroactive area and the synergistic effect of both graphene oxide and copper nanoparticles resulted in excellent sensitivity ( \(10.52 \mu A.{mM}^{-1}\) $10.52\mu A.{\mathit{mM}}^{-1}$ ), lower detection limit ( \(1.82 \mu M\) $1.82\mu M$ ), wide linear responses over physiologically relevant concentrations, and fast response times ( \(<5 s\) $<5s$ ).