Abstract:
Magnetic biosensors have drawn significant research interest as a means to replace large optical instrumentation commonly found in centralized diagnostic laboratories. Ma...Show MoreMetadata
Abstract:
Magnetic biosensors have drawn significant research interest as a means to replace large optical instrumentation commonly found in centralized diagnostic laboratories. Magnetic biosensing is attractive since biological samples lack a magnetic background thus enabling high sensitivity measurements. Figure 11.4.1 shows a magnetic immunoassay where: 1) the surface of a magnetic sensor is coated with capture molecules (e.g., antibodies) specific to the biomarker (e.g., antigen) of interest, 2) the sample, detection molecules, and magnetic nanoparticles (MNPs) are added and self-assemble thus tethering the MNPs to the sensor, and 3) the sensor is read out by applying a magnetic field, HA, that magnetizes the superparamagnetic MNPs producing a stray field that perturbs the local magnetic field. The underlying magnetoresistive (MR) sensor detects this change in field as a miniscule ppm change in resistance, Rsig, that is directly proportional to the number of MNPs. Unfortunately, Rsig is superimposed on the baseline resistance, R0, resulting in a large baseline-to-signal ratio (R0/Rsig>10,000) that requires a very high dynamic range (DR>120dB) front-end for quantitative detection [1,2].
Date of Conference: 17-21 February 2019
Date Added to IEEE Xplore: 07 March 2019
ISBN Information: