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

Binfeng Yin; Changcheng Qian; Songbai Wang; Xinhua Wan; Teng Zhou

doi:10.3389/fchem.2021.688442

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

Front Chem. 2021 May 28:9:688442. doi: 10.3389/fchem.2021.688442. eCollection 2021.

Authors

Binfeng Yin¹, Changcheng Qian¹, Songbai Wang², Xinhua Wan¹, Teng Zhou³

Affiliations

¹ School of Mechanical Engineering, Yangzhou University, Yangzhou, China.
² School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan, China.
³ Mechanical and Electrical Engineering College, Hainan University, Haikou, China.

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 (MNP_S), 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.

Keywords: alpha-fetoprotein; immunosensor; magnetic relaxation switching; microfluidic chip; nanoprobe.