Merging lateral flow immunoassay with electroanalysis as a novel sensing platform: Prostate specific antigen detection as case of study

COVID-19 pandemic highlighted lateral flow immunoassay (LFIA) strips as the most known point-of-care (POC) devices enabling rapid and easy detection of relevant biomarker by non-specialists. However, these diagnostic tests are usually as-sociated with qualitative detection of the biomarker of interest. Alternatively, electrochemical-based diagnostics, especially known for diabetes care, enables quantitative determination of biomarkers. From an analytical point perspective, the com-bination of the two approaches might be representing a step forward for the POC world: in fact, electrochemical transduc-tion is attractive to be integrated into LFIA strips due to its simplicity, high sensitivity, fast signal generation, and cost-effectiveness. In this work, LFIA strip has been empowered by the combination with an electrochemical transduction, yield-ing an electrochemical LFIA (eLFIA). As proof-of-concept, the detection of prostate-specific antigen (PSA) has been carried out by combining printed-electrochemical strip with the traditional LFIA tests. The electrochemical detection has been based on the measurement of the Au ions produced from the dissolution of the gold nanoparticles previously captured on the test line. After having optimized both gold nanoparticles dissolution and the electrochemical parameters, the analytical perfor-mance obtained at LFIA and eLFIA were compared, highlighting how the use of differential pulse voltammetry allowed for a lower detection limit, respectively 0.38 and 0.15 ng/mL, but with the necessity of longer time of analysis. Although the cor-relation between the two architectures confirmed the satisfactory agreement of outputs, this technical note has been thought to provide the reader a fair statement with regards the strength and drawbacks about combining the two (apparently) com-petitor devices in diagnostics field, namely LFIA and electrochemical strips