Matrix-insensitive protein assays push the limits of biosensors in medicine

Abstract

Despite progress in the biosensor field, a platform that allows the sensitive detection of disease-specific proteins in a diverse range of clinical samples such as saliva, serum and urine has proved elusive. Here, Richard Gaster and his colleagues introduce a magnetic nanosensing protein detection platform that offers quantitative multiplex protein detection at attomolar concentrations over a large linear dynamic range and in a range of biological fluids. Advances in biosensor technologies for in vitro diagnostics have the potential to transform the practice of medicine. Despite considerable work in the biosensor field, there is still no general sensing platform that can be ubiquitously applied to detect the constellation of biomolecules in diverse clinical samples (for example, serum, urine, cell lysates or saliva) with high sensitivity and large linear dynamic range. A major limitation confounding other technologies is signal distortion that occurs in various matrices due to heterogeneity in ionic strength, pH, temperature and autofluorescence. Here we present a magnetic nanosensor technology that is matrix insensitive yet still capable of rapid, multiplex protein detection with resolution down to attomolar concentrations and extensive linear dynamic range. The matrix insensitivity of our platform to various media demonstrates that our magnetic nanosensor technology can be directly applied to a variety of settings such as molecular biology, clinical diagnostics and biodefense.