A Microfluidic Chip-Based MRS Immunosensor for Biomarker Detection via Enzyme-Mediated Nanoparticle Assembly

Abstract

Conventional immunoassay methods have their common defects, such as tedious processing steps and inadequate sensitivity, in detecting whole blood. To overcome the above problems, we report a microfluidic chip–based magnetic relaxation switching (MRS) immunosensor via enzyme-mediated nanoparticles to simplify operation and amplify the signal in detecting whole blood samples. In the silver mirror reaction with catalase (CAT) as the catalyst, H2O2 can effectively control the production of Ag NPs. The amount of Ag NPs formed further affects the degree of aggregation of magnetic nanoparticles (MNPS), which gives rise to the changes of transverse relaxation time (T2). Both sample addition and reagent reaction are carried out in the microfluidic chip, thereby saving time and reagent consumption. We also successfully apply the sensor to detect alpha-fetoprotein (AFP) in real samples with a satisfied limit of detection (LOD = 0.56 ng/ml), which is superior to the conventional ELISA.

Emerging biotechnology applications in natural product and synthetic pharmaceutical analyses

“…The microfluidic chip or micro total analysis system (uTAS) is a new technology that integrates sampling, pretreatment, reagent addition, reaction, separation, and detection on a microchip. This technology has the advantages of small size, simple operation, low sample usage, fast analysis, and easy automation of operation 212 , and it can be used to perform chemical separation and enzyme and cell analyses 213 , 214 , 215 . The integration of microfluidic chip and enzymes or cells may improve the repeatability of bioassays.…”

Microfluidics-Based POCT for SARS-CoV-2 Diagnostics

“…Microfluidic chips' channels have cross-sectional dimensions in micrometers and fluid volumes in microliters [24,25]. On the one hand, the smaller volume significantly reduces reagent consumption and greatly saves costs.…”

Enzyme Method-Based Microfluidic Chip for the Rapid Detection of Copper Ions

“…As an emerging manufacturing technology, 3D printing has the characteristics of individuation and high precision. It has been widely used in miniaturized mechanical and electromechanical elements to efficiently manufacture microdevices in recent years [28,29]. We used a high-precision desktop 3D printer to make the molds of the microfluidic chip (Figure 1a).…”