Towards One-Step Quantitation of Prostate-Specific Antigen (PSA) in Microfluidic Devices: Feasibility of Optical Detection with Nanoparticle Labels

Abstract

Rapid and quantitative prostate-specific antigen (PSA) biomarker detection would be beneficial to cancer diagnostics, improving early detection and therefore increasing chances of survival. Nanoparticle-based detection is routinely used in one-step nitrocellulose-based lateral flow (LF) immunoassays; however, it is well established within the scientific diagnostic community that LF technology lacks sensitivity for measuring biomarkers, such as prostate-specific antigen (PSA). A trend in point-of-care (POC) protein biomarker quantitation is the miniaturization of immunoassays in microfluidic devices. This work aimed at testing the feasibility of carbon and gold nanoparticles as immunoassay labels for PSA detection with cost-effective optical detection in a novel microfluidic POC platform called microcapillary film (MCF), consisting of a parallel array of fluoropolymer microcapillaries with 200-μm internal diameter. With neutravidin-coated carbon, nanoparticles were able to quantify an immobilized biotinylated monoclonal antibody (coating solution from 10 to 40 μg/ml) and PSA was successfully quantified in a sandwich assay using silver-enhanced gold nanoparticles and a flatbed scanner; yet, the dynamic range was limited to 10–100 ng/ml. Although direct optical detection of PSA without enzymatic amplification or fluorophores is possible and technically appealing for the simplified fluidics and signal scanning setups involved, ultimately, the binding of a thin layer of nanoparticles onto the wall of transparent microcapillaries is not sufficient to cause a significant drop on the optical colorimetric signal. Future studies will explore the use of fluorescence nanoparticles.

A Point-of-Care Measurement of NT-proBNP for Heart Failure Patients

“…The results show a close trend, with the accuracy of each measurement system of a similar order: the average coefficient of variation (CV) of results (triplicate sets of LFIA tested at each concentration for the biomarker analyser is 7.8% versus 7.3% for ImageJ. Some of the heterogeneity in measurement derives from defects in the optical quality of the test line (for example, variation caused by unequal fluid flow [44]). It should be also noted that our conjugate antibody was the '24E11' antibody which recognises a.a. 61-76 of NT-proBNP and the test line ab was the 15F11 which recognises a.a. 13-27 of NT-proBNP.…”

Finding the perfect match between nanoparticles and microfluidics to respond to cancer challenges

“…Nuno M. Reis evaluated two different procedures for optical detection of PSA on a transparent plastic microcapillary film (MCF). 89 One was based on carbon nanoparticles, while the other was based on AuNPs. In the case of carbon nanoparticles, MCF was coated with a biotinylated antibody, which then reacted with the neutravidin conjugated carbon nanoparticle, resulting in an optical colorimetric signal.…”

Current nanotechnology advances in diagnostic biosensors

“…These nanomaterials can be applied in different manners, like NPs, nanocrystal, QDs, among others, depending on the biosensor detection mode and biochemical assay involved. Nevertheless, in general, nanomaterials enhance the efficiency of probe immobilization, due to their high surface area and chemistry (Barbosa et al, 2017, 2019), providing signal amplification, improving analyte‐transducer contact and promoting efficient catalysis in case of electrochemical sensors. The combination of these effects enables the quantification of low analyte concentrations in assays with improved performance, which is highly desirable in diagnostics.…”