Microfluidic Quantitative Analysis of Cellular Secretions Via Droplet Based Fluorescence Polarization Immunoassay with On-Chip Preconcentration.

[摘要] A droplet-based microfluidic preconcentration and quantitative immunoassay for protein and peptide analysis was demonstrated in model systems of insulin measurements for use in microdialysis sampling of neuropeptides.First, glucose stimulated insulin release was quantified with a droplet-based microfluidic immunoassay; specifically, on-chip generated chemical gradient stimulus of cultured Islets of Langerhans with perfusion sampling and a droplet-based fluorescence polarization immunoassay improved temporal resolution over existing techniques by an order of magnitude such that sub-minute oscillations in insulin secretion were directly measured.Second, an on-chip preconcentrator compatible with the highly ionic microdialysis sampling media was developed to store concentrated bands of peptides sequestered in droplets generated on-demand.Enrichment factors of charged species as high as 50,000-fold in an hour were achieved by applying a voltage across a fluidic channel with a bipolar (or floating) electrode such that ion concentration polarization resulted from the charge exclusion zone created near the electrode.Both sampling efficiency and droplet capture efficiency were mathematically analyzed.These systems demonstrate a proof-of-principle for a robust preconcentration and quantification system for any charged analyte with a commercially available antibody/labeled-antigen.

[发布机构] University of Michigan

[效力级别] FPIA

[关键词] Microfluidic;FPIA;Preconcentration;Bipolar Electrode;Insulin;Chemistry;Science;Chemistry