| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 867380 | Biosensors and Bioelectronics | 2012 | 7 Pages |
The combination of magnetoresistive sensors and magnetic labeling of bioanalytes, which are selectively captured by their complementary antibody in the proximity of the sensor is a powerful method in order to attain truly quantitative immunological assays. In this paper we present a technical solution to exploit the existing spin valve technology to readout magnetic signals of bio-functionalized magnetic nanoparticles. The method is simple and reliable, and it is based on a discrete scan of lateral flow strips with a precise control of the contact force between sensor and sample. It is shown that the signal of the sensor is proportional to the local magnetization produced by the nanoparticles in a wide range of concentrations, and the sensitivity thresholds in both calibration samples and real immunorecognition assays of human chorionic gonadotropin hormone are well below the visual inspection limit (5.5 ng/ml). Furthermore the sample scanning approach and the reduced dimensions of the sensors provide unprecedented spatial resolution of the nanoparticle distribution across the supporting nitrocellulose strip, therefore enabling on-stick control references and multi-analyte capability.
► GMR based magnetoresistive biosensor with sensibility below the visual limit in lateral flow assays and quantitative response in four signal decades. ► Large spatial resolution of the test line enabling multianalyte test and reference test lines. ► Proved sensibility to model human chorionic gonadotropin hormone down to 5 ng/ml. ► Versatile, unexpensive and quick performance, featuring controlled contact pressure between sensor array and nitrocellulose strip sample surface.
