A low-cost, disposable GO-CS screen printed carbon electrode for electrochemical detection of tyrosine

A low-cost, sustainable and sensitive method for the continuous detection and quantification of Tyrosine (Tyr), a valuable metabolic biomarker, in biological fluids would present a valuable platform to aid patients and medical personnel in dietary management and the diagnosis and monitoring of metabolic and neurodegenerative disease. This work, therefore, presents a facile approach for the development of a graphene oxide (GO) - chitosan (CS) screen-printed carbon electrode (SPCE) (GO-CS/SPCE) on a flexible polyvinyl chloride (PVC) substrate, for the electrochemical detection of Tyr. The low-cost, disposable sensor was achieved by successfully immobilizing a homogenous GO-CS film at the surface of the SPCE via a simple ultrasound-assisted chemical reaction strategy. GO-CS was chosen as the sensitive nanocomposite film due to excellent electrochemical sensing properties, as well as the cost-effective, disposable and biocompatible nature of these nanomaterials. The GO-CS/SPCE demonstrated a wide linear range of 30-500 $\mu M$ with a sensitivity of 0.03 $\mu A\mu M^{-1}$ and good reproducibility, highlighting the potential of GO-CS/SPCE as a low-cost, disposable and practical sensor for Tyr point of care (POC) testing.