The magnetonanosensor has 64 sensors capable of detecting up to 64 different proteins. In the center of the chip is the well that holds the fluid of interest. The reader that measures the magnetic fields of the sensors is in the background. Thumb and fingers are courtesy of Richard Gaster, M.D./Ph.D. candidate in both bioengineering and the school of medicine. (Image: Linda Cicero, Stanford News Service)
Matrix-insensitive protein assays push the limits of biosensors in medicine
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.
Searching for biomarkers that can warn of diseases such as cancer while they are still in their earliest stage is likely to become far easier thanks to an innovative biosensor chip developed by Stanford University researchers.
The sensor is up to 1,000 times more sensitive than any technology now in clinical use, is accurate regardless of which bodily fluid is being analyzed and can detect biomarker proteins over a range of concentrations three times broader than any existing method, the researchers say.
The nanosensor chip also can search for up to 64 different proteins simultaneously and has been shown to be effective in early detection of tumors in mice, suggesting that it may open the door to significantly earlier detection of even the most elusive cancers in humans. The sensor also can be used to detect markers of diseases other than cancer.
“In the early stage [of a cancer], the protein biomarker level in blood is very, very low, so you need ultra-sensitive technology to detect it,” said Shan Wang, professor of materials science and engineering and of electrical engineering.