The protein-detection assays that are currently in use rely on a variety of mechanisms, such as measuring electrical charge, fluorescent signals or pH, all of which are prone to interference from the biological matrix in which the desired proteins reside. While a particular assay may be fine for assessing a protein's concentration in urine, for example, it may perform poorly when applied to a blood sample, as differences in the composition of the matrix affect properties such as pH or electrical charge.
"Our sensors are shown to be rather insensitive to matrix, so that is another key element from a scientific point of view," said Wang. As an example, he said, "We know that in saliva and blood, they have totally different pH values and different chemistry, but they are all nonmagnetic. Magnetically they are just like air. So it does not interfere with our mechanism [of detection]."
Most of the assays currently in use are only able to detect proteins over a narrow range of concentrations before interference of some kind degrades the sensitivity of the assay. That can require a series of assays to be performed on a sample diluted to different strengths, in order to assemble a complete picture of a protein's concentration in the matrix. But again, by using magnetic detection, Wang and his colleagues are able to sidestep such signal degradation.
"With the high sensitivity and the broad range we can look at a big panel of proteins over a wide range of concentrations, and with the matrix insensitivity, we can look at them in different fluids," said Richard Gaster, MD/PhD candidate in bioengineering and medicine, and first author on the Nature Medicin
|Contact: Louis Bergeron|