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

Abstract

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 immobilization of the 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 peroxidase-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 sensitivity and reduced variability. The small platform size and low cost of this quantitative methodology 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.

Microfluidic Platform Integrated with Carbon Nanofibers-Decorated Gold Nanoporous Sensing Device for Serum PSA Quantification

“…In comparison with a previous work [ 32 ], our microfluidic immunosensor based on the CNF/GNP nanocomposite platform for antibody monoclonal immobilization presents relevant advantages, such as its high surface and biocompatibility, miniaturization and easy handling, low-cost production, and short time analysis. In another recently published work [ 33 ], we developed an amperometric microfluidic immunosensor for claudin7 cancer biomarker determination in circulating extracellular vesicles (EVs) in colorectal cancer patient’s samples.…”

Point-of-Care Prostate Specific Antigen Testing: Examining Translational Progress toward Clinical Implementation

“…However, Dou et al and Ortega et al performed measurements using a higher number of patient serum samples (n = 46 and n = 60, respectively). Ortega et al validated their results against gold standard ELISA and radioimmune assays with excellent correlation (95% confidence interval) . The patient samples used by Dou et al were previously measured with ELISA and their results demonstrated significant differences between PCa negative and positive samples using one-way analysis of variance (*** p < 0.001).…”

“…Most tests use antibodies as recognition elements as they exhibit high sensitivity/specificity toward PSA. For example, Ortega et al immobilized antibodies to Au/Pt-coated electrodes to detect PSA using a smartphone-based sensor, which exhibited a favorable LoD (0.002 ng/mL), reasonable measurement times (30 min), and low sample volume requirements (10 μL) . However, antibodies are laborious and expensive to produce, frequently exhibit high batch-to-batch variation, and have poor environmental stability. , Due to these issues, several next-generation recognition elements have become more common within emerging PSA sensors.…”

“…Ortega et al validated their results against gold standard ELISA and radioimmune assays with excellent correlation (95% confidence interval). 64 The patient samples used by Dou et al were previously measured with ELISA and their results demonstrated significant differences between PCa negative and positive samples using one-way analysis of variance (*** p < 0.001). These clinical measurements, coupled with low-cost electrodes, rapid assay times, and favorable detection, further affirm the PoC potential of this emerging PSA sensor.…”