Magnetic bead sensing platform for the detection of proteins.

Over the past 5 years, the on-chip detection and manipulation of magnetic beads via magnetoelectronics has emerged as a promising new biosensor platform. Magnetic bead sensing (MBS) provides a highly sensitive and specific technique, enabling these sensors to meet the diagnostic needs that are currently not met by existing technologies. Although many studies have proven the high physical sensitivity of magnetic sensors, the establishment of dose-response curves using MBS is unexplored and their capability to sensitively detect low concentrations of target molecules for diagnostic applications has remained unproven. In this study, we have exploited an alternative MBS concept based on the repositioning of the magnetic beads toward the most sensitive location on the spin valve sensors to allow for highly sensitive immunosensing over a wide range of target concentrations. Furthermore, we present the optimization of the magnetoimmuno assay, i.e., the surface chemistry, the blocking procedure, and the type of magnetic particle, for the highly sensitive and specific detection of S100betabeta, a diagnostic marker for stroke and minor head injury. Finally, a dose-response curve was established that illustrates that our MBS platform can specifically detect S100betabeta down to 27 pg/mL, while maintaining a broad dynamic detection range of approximately 2 decades.