A Novel, Quick, and Reliable Smartphone-Based Method for Serum PSA Quantification: Original Design of a Portable Microfluidic Immunosensor-Based System

ORTEGA, FRANCISCO GABRIEL; GÓMEZ, GERMÁN E.; GONZÁLEZ-MARTINEZ, CORAL; VALERO, TERESA; EXPÓSITO-HERNÁNDEZ, JOSÉ; PUCHE, IGNACIO; RODRIGUEZ-MARTINEZ, ALBA; SERRANO, MARÍA JOSÉ; LORENTE, JOSÉ ANTONIO; FERNÁNDEZ-BALDO, MARTÍN A.

Cancers

MDPI

Lugar: Basel; Año: 2022 vol. 14 p. 4483 - 4494

We describe a versatile, portable, and simple platform that includes a microfluidic electrochemical immunosensor for prostate-specific antigen (PSA) detection. It is based on the covalent immobi-lization of anti-PSA monoclonal antibody on magnetic microbeads retained in the central channel of a microfluidic device. Image flow cytometry and scanning electron microscopy were used to characterize the magnetic microbeads. A direct sandwich immunoassay (with horseradish pe-roxidase-conjugated PSA antibody) served to quantify the cancer biomarker in serum samples. The enzymatic product was detected at_100 mV by amperometry on sputtered thin-film electrodes. Electrochemical reaction produced a current proportional to the PSA level, with a linear range from 10 pg mL-1 to 1500 pg mL-1. The sensitivity was demonstrated by a detection limit of 2 pg mL-1 and the reproducibility by a coefficient of variation of 6.16 %. The clinical performance of this platform was tested in serum samples from patients with prostate cancer (PCa), observing high specificity and full correlation with gold standard determinations. In conclusion, this analytical platform is a promising tool for measuring PSA levels in patients with PCa, offering a high sen-sitivity and reduced variability. The small platform size and low cost of this quantitative meth-odology support its suitability for the fast and sensitive analysis of PSA and other circulating biomarkers in patients. Further research is warranted to verify these findings and explore its potential application at all healthcare levels.