Category: Assay Development and Screening
Rapid and accurate biosensing with low concentrations of the analytes is usually challenged by the diffusion limited reaction kinetics. Thus, long incubation times or excess amounts of the reagents are employed in biosensor and diagnostic platforms to ensure the reactions to go to completion. Here we propose a technology that provides electromixing of the reagents in solutions where the incubation times, or in other words, the time required for the desired molecules to meet in stationary solutions, can be reduced substantially. This technology has been applied to an immunoassay based diagnostic kit for diabetes (glycated hemoglobin (HbA1c) test) and a FRET based quenching bioplatform consists of a molecular beacon DNA and gold nanoparticles in electode-enabled microwell plates as called as iPlates. When electromixing was employed, the incubation times were reduced by approximately a factor 5 and 4 for the diabetes diagnostic kit and FRET based quenching bioplatform, respectively. Furthermore, if the quantity of the reagents was further reduced by half, where almost no distinguishable signals could be obtained with conventional immunoassay, electromixing still facilitated acquisition of signals while varying the concentration of the glycated hemoglobin (HbA1c).
Thus, this technique has a potential to vastly improve the efficiency of immunoassay based diagnostic platforms so that within a very short time and with just sufficient reagents, high throughput analysis of clinical samples may be achieved. It may also open new avenues in point of care diagnostic devices and biosensor platforms, where kinetics and sampling size/volume play a critical role.
Emir Yasun– Specialist Research Scientist, University of California, Santa Barbara, Department of Mechanical Engineering and Biological Nanostructures Laboratory, California NanoSystems Institute (CNSI), Santa Barbara, CA