Fully dispersible spherical gold nanoparticles (AuNPs) and stable graphene oxide nanosheets (GO) were prepared, characterized and used as nano-labeling for the Lateral Flow Immunoassays (LFIA) based Point-of-Care (POC) monitoring of Covid-19 nucleocapsid (N) protein in clinical samples. The Covid-19 N-protein was immobilized onto the test line of the strip, and IgG protein was conjugated with nanolabels to form the detectable intensity. The results are achieved within 15 min. The effect of different sizes and concentra t ions of nanolabels in test line intensity were also evaluat ed. As-prepared LFIA based AuNPs and GO labels revealed visual LOD of 3.0 and 0.1 mg mL-1 for Covid-19 N-protein, respectively. The LFIA test was performed on ten positive and negative serum samples including patients, healthy and carrier people to demonstrate the clinical feasibility of our proposed assay for Covid-19 identification. This work pre sented a simple, low cost, and fast method for the diagnosis of Covid-19 in the clinical samples.

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