Fluidics for a multi-anlyte detector based on intermolecular binding forces

摘要

We are developing a novel biosensor--the Bead Array Counter (BARC)--which has the potential to simultaneously detect thousands of analytes. BARC is an adpatation of atomic force microscope (AFM) experiments in which the interaction forces that bind DNA-DNA, antibody-antigen, or ligand-receptor pairs together are measured. Using magnetic microbeads to exert force and numerous magnetoresitive sensors to detect the microbeads, it is possible to perform thousands of such experiments simultaneously. Thus, with BARC, it is possible to detect individual molecular bonds and test their strength. For our preliminary investigation, we are developing BARC as a hybridization assay in which DNA probes are covalently attached to the sensors by inkjet patterning techniques. We are also developing miniature fluidic devices through modeling and testing of prototype designs that will assure the delivery of microliter volumes of fluid and the even dispersion of microbeads at the site of detection. Operational idiosyncrasies of BRAC require special consideraitons in the construction and actuation of the miniaturized pumps and valves, such as non-magnetic components and attention to particulate matter. Other objectives include thermoplastic replication of the fluidic channels, modularity of the fluidic and electronic components, ease of sample delivery and assay preparation, reduction of contamination between assays, and materials compatibility with the assay chemistry.