We present a resistive network model, protein assay data, and outlook of the giant magnetoresistive (GMR) spin-valve magneto-nanosensor platform ideal for multiplexed detection of protein biomarkers in solutions. The magneto-nanosensors are designed to have optimal performance considering several factors such as sensor dimension, shape anisotropy, and magnetic nanoparticle tags. The resistive network model indicates that thinner spin-valve sensors with narrower width lead to higher signals from magnetic nanoparticle tags. Standard curves and real-time measurements showed a sensitivity of ~10 pM for phosphorylated-structural maintenance of chromosome 1 (phosphor-SMC1), ~53 fM for granulocyte colony stimulation factor (GCSF), and ~460 fM for interleukin-6 (IL6), which are among the representative biomarkers for radiation exposure and cancer.
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Acknowledgments The authors thank Dr. Richard G. Ivey at Fred Hutchinson Cancer Research Center in Seattle for his generous support of phosphor-SMC1 antibodies and standard. This work was supported, in part, by the United States National Institute of Health (grants U54CA143907, U54CA151459, R21AI085566, and R33CA138330), the United States National Science Foundation (grant ECCS-0801385-000), a Gates Foundation Grand Challenge Exploration Award, and Stanford Bio-X Program. Correspondence and requests for materials should be addressed to S.X.W.
- Cancer biomarker
- Magnetic nanoparticles
- Radiation biomarker