Gold-nanoparticles antibody conjugates optimization in a lateral flow immunoassay for multivariants SARS-CoV-2 biosensor

Introduction: The optimization of multivariate detection systems in lateral flow assays using gold nanoparticles (AuNPs) conjugates represents a pivotal advancement in the field of point-of-care diagnostics. Lateral flow immunoassays (LFIA) are widely employed due to their simplicity, rapidity, and cost-effectiveness; however, enhancing their sensitivity and specificity remains a challenge. The research involves the investigation of key parameters influencing the performance of antibody conjugation through physical adsorption methods, such as pH value of AuNPs, concentration of antibody (Ab) as well as incubation time. Materials and Methods: S1 Delta and Omicron antibody of SARS-CoV-2 were used as the recognition element. The LFIA platform was developed through a series of optimization steps, including the selection and conjugation of appropriate pH for AuNPs, optimal concentration specific S1 Antibody (Ab-S1) and optimal incubation time for AuNPs conjugates. The performance of the LFIA was evaluated using specific S1 Delta and Omicron antigens. Results: The findings underscore the significance of optimum pH value which are pH 8.0 and concentration of Ab which are 8 µg/mL as well as 1 hour of specific incubation time to be optimal in multivariate lateral flow detection that able to maximize conjugation efficiency providing valuable insights for diagnostic assays. Conclusion: The results from this project highlight the complexity and sensitivity of LFIA creation as well as the significance of thorough validation and optimization methods respectively.