Towards an asynchronous magnetic bead rotation method for immunological assays

摘要

This paper presents proof of principle of a new type of biosensor, based on label-acquired magnetorotation, called the asynchronous magnetic bead rotation (AMBR) assay. This assay is modeled after a traditional sandwich assay, but with a 6.7 urn nonmagnetic sphere as the solid phase and a 1.05 μm superparamagnetic bead as the label. The analyte (a 40 nm biotin-coated particle) is sandwiched between the solid phase and the label, forming a "sandwich complex," and the presence of the analyte is indicated by this binding. The sandwich complex is placed inside a rotating magnetic field, and the rotational frequency of the sandwich complex is a function of the concentration of bound analyte. The AMBR assay is demonstrated to be sensitive over two orders of magnitude in physiologically relevant concentrations.