Rapid Multianalyte Microfluidic Homogeneous Immunoassay on Electrokinetically Driven Beads

Abstract

The simplicity of homogeneous immunoassays makes them suitable for diagnostics of acute conditions. Indeed, the absence of washing steps reduces the binding reaction duration and favors a rapid and compact device, a critical asset for patients experiencing life-threatening diseases. In order to maximize analytical performance, standard systems employed in clinical laboratories rely largely on the use of high surface-to-volume ratio suspended moieties, such as microbeads, which provide at the same time a fast and efficient collection of analytes from the sample and controlled aggregation of collected material for improved readout. Here, we introduce an integrated microfluidic system that can perform analyte detection on antibody-decorated beads and their accumulation in confined regions within 15 min. We employed the system to the concomitant analysis of clinical concentrations of Neutrophil Gelatinase-Associated Lipocalin (NGAL) and Cystatin C in serum, two acute kidney injury (AKI) biomarkers. To this end, high-aspect-ratio, three-dimensional electrodes were integrated within a microfluidic channel to impart a controlled trajectory to antibody-decorated microbeads through the application of dielectrophoretic (DEP) forces. Beads were efficiently retained against the fluid flow of reagents, granting an efficient on-chip analyte-to-bead binding. Electrokinetic forces specific to the beads’ size were generated in the same channel, leading differently decorated beads to different readout regions of the chip. Therefore, this microfluidic multianalyte immunoassay was demonstrated as a powerful tool for the rapid detection of acute life-threatening conditions.

NR4A2 may be a potential diagnostic biomarker for myocardial infarction: A comprehensive bioinformatics analysis and experimental validation

“…However, cardiac troponin, the biomarker of choice, is associated with a significant lag time before increasing after MI. With the advancement of modern research, genetic tests can nowadays be performed in less than 15 minutes ( 6 ), reducing the time to clinical diagnosis of MI, but this first requires us to identify the most specific gene. Accordingly, this study sought to identify a diagnostic gene with high specificity.…”

Microfluidic Bio-Sensors and Their Applications

“…One of the research articles presents integrated microfluidic sensors for rapid analyte detection on antibody-decorated beads for two acute kidney injury biomarkers [ 5 ]. A novel silicon-based lab-on-chip sensor to perform low-density and high-resolution multi-assay analysis for DNA amplification and hybridization is also presented to complement this Special Issue [ 6 ].…”