On-chip immuno-agglutination assay based on a dynamic magnetic bead clump and a sheath-less flow cytometry

Abstract

Immunoagglutination assay is a promising approach for the detection of waterborne analytes like virus, cells, proteins with its advantages such as a smaller amount of reagents and easier operation. This paper presents a microfluidic agglutination assay on which all the assay processes including analyte capture, agglutination, and detection are performed. The chip integrates an on-chip pump for sample loading, a dynamic magnetic bead (MB) clump for analyte capture and agglutination, and a sheath-less flow cytometry for particle detection, sizing, and counting. The chip is tested with streptavidin-coated MBs and biotinylated bovine serum albumin as a model assay, which realizes a limit of detection (LOD) of 1 pM. Then, an antigen/antibody assay using rabbit IgG and goat anti-rabbit IgG coated MBs is tested and a LOD of 5.5 pM is achieved. At last, human ferritin in 10% fetal bovine serum is tested with Ab-functionalized MBs and the detection achieves a LOD of 8.5 pM. The whole procedure takes only 10 min in total.

Vibration Induced Flow Facilitating Immunoagglutination for Rapid Detection and Quantification of Nanoparticles

“…To do this, it is necessary to increase the chance of collision between the capture MP and NPs during stirring. It is conceivable that using smaller capture MPs 54,55 with a higher surface volume ratio may promote the aggregate formation, but this may require larger magni cation for imaging.…”

High‐performance enrichment of casein and ovalbumin in wall painting with immunomagnetic beads

“…The antigens can be captured by IMBs, and the purpose of concentration and separation through magnetic separation is achieved (Huang et al, 2021; Yatsomboon et al, 2021; Zhang et al, 2020). The immobilization of antibodies to magnetic beads (MBs) is occasionally performed using different methods, such as covalent binding between the amino group of antibodies and carboxyl group of magnetic beads (Song et al, 2018; Zhai et al, 2021), biotin and a streptavidin system (Lv et al, 2021; Zhang et al, 2019), and the specific adsorption of protein A/G to antibodies (Chen et al, 2019). In covalent binding method, carboxyl groups of MBs can be activated by addition of EDC/NHS, and then amino group of antibodies conjugated with it.…”