A SERS nano-tag-based magnetic-separation strategy for highly sensitive immunoassay in unprocessed whole blood

Assay technologies capable of detecting biomarker concentrations in unprocessed whole blood samples are fundamental for applications in medical diagnostics. SERS nano-tags integrated magnetic-separation biosensor (MSB) was realized for the first time for immunoassay in whole blood. The reliability and sensitivity of this method rely, in a large extent, on the quality and properties of the SERS nano-tags. The constructed silicacoated Ag SERS nano-tags as labels were used in a rapid and specific MSB immune sensor to detect Matrix Metalloproteinases 9 (MMP-9) in unprocessed blood samples. With fast screening ability and outstanding sensitivity, we anticipate that this method would greatly promote practical application of stroke-based early-stage cancer diagnosis.