Giant Magnetoresistance Sensor for Rapid and Simple Bovine Serum Albumin Assay with Ag-Functionalized Iron Oxide Nanoparticles Label

The demand for a rapid and simple device to monitor the albumin level in human blood and urine is urgent due to its importance as an early screening tool to predict human health status. This article proposes a new tool for albumin assay by using a giant magnetoresistance (GMR) chip that promises a simple method with real-time electrical read-out. The bovine serum albumin (BSA) was used as a human albumin model, while the Ag-functionalized iron oxide nanoparticles (Ag-IONPs) were used as a magnetic label. To realize the system with simplicity and speed in displaying measurement results, the chip was coupled with a microcontroller, which acts as a source-meter unit. The sensor system reveals a stable and high signal with good linearity to the concentration of interest of BSA. The signal can be acquired only in 30 s with a low biasing magnetic field. These results show that a couple of GMR chips and Ag-IONPs with a microcontroller promise a simple system of BSA assay with a fast report.