title: Homogeneous agglutination assay based on micro-chip sheathless flow cytometry.
abstract: Homogeneous assays possess important advantages that no washing or physical separation is required, contributing to robust protocols and easy implementation which ensures potential point-of-care applications. Optimizing the detection strategy to reduce the number of reagents used and simplify the detection device is desirable. A method of homogeneous bead-agglutination assay based on micro-chip sheathless flow cytometry has been developed. The detection processes include mixing the capture-probe conjugated beads with an analyte containing sample, followed by flowing the reaction mixtures through the micro-chip sheathless flow cytometric device. The analyte concentrations were detected by counting the proportion of monomers in the reaction mixtures. Streptavidin-coated magnetic beads and biotinylated bovine serum albumin (bBSA) were used as a model system to verify the method, and detection limits of 0.15 pM and 1.5 pM for bBSA were achieved, using commercial Calibur and the developed micro-chip sheathless flow cytometric device, respectively. The setup of the micro-chip sheathless flow cytometric device is significantly simple; meanwhile, the system maintains relatively high sensitivity, which mainly benefits from the application of forward scattering to distinguish aggregates from monomers. The micro-chip sheathless flow cytometric device for bead agglutination detection provides us with a promising method for versatile immunoassays on microfluidic platforms.
authors.affiliation: State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University , Beijing, China.
authors.forename: Zengshuai
authors.initials: Z
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University , Beijing, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University , Beijing, China.
authors.forename: Yinuo
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University , Beijing, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Xie
authors.affiliation: State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University , Beijing, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University , Beijing, China.
authors.forename: Xiongying
authors.initials: X
authors.lastname: Ye