Data in Support of Online Affinity Micro Free-Flow Electrophoresis for the Continuous Monitoring of Insulin via a Competitive Immunoassay

An online, micro free-flow electrophoresis (µFFE) assay was developed for the real-time measurement of insulin in a continuous, competitive immunoassay. In the manuscript corresponding to this dataset, fluorescently labeled insulin and anti-insulin monoclonal antibody were mixed with the sample stream online and flowed through an incubation capillary into the µFFE device. Under an electric field, the bound antibody:insulin-FITC complex was separated from free insulin-FITC. When unlabeled insulin was introduced, labeled and unlabeled insulin competed for binding sites on the antibody, and the separated peaks of the bound complex and free insulin-FITC changed in real-time. Temporal resolution of 30 seconds was achieved following injections of unlabeled insulin, with a limit of detection of 63 nM and a linear response over the tested range of 50 nM to 1 µM insulin. To approximate an online cellular response, glucose-stimulated insulin secretion was collected offline from human islets and injected into the affinity µFFE instrument. A measurable change in insulin secretion was observed between samples exposed to low and high glucose, demonstrating sufficient limit of detection, linearity, the compatibility of the instrument with a complex biological matrix.