Abstract: Various embodiments are drawn to systems and methods for detecting an analyte of interest in a solution that also contains a plurality of magnetic particles. The system may include a first magnet configured to generate a first magnetic field that forces the magnetic particles in the solution toward an optical sensor with a capture probe. A detector may be included to detect a change in an optical property of the optical sensor, the change in the optical property resulting from the binding of at least the analyte, a magnetic particle, and the capture probe at the optical sensor.