Disease detection often relies on spotting biomarkers in a body fluid sample, but they are usually rare and require expensive equipment to spot. A new method has been recently developed at MIT that utilizes the concept of synthetic biomarkers to amplify such signals, and it has just been paired with paper lateral flow assay technology to screen for cancer and other diseases.
The synthetic biomarkers are coated with special peptides to lure matrix metalloproteinases (MMPs), proteins involved in the spread of tumors, to stick to them. These MMPs then release the peptides to float away and to end up in the kidneys from where they are excreted for testing. Previously, the peptides were detected in urine using a mass spectrometer, but the team developed a paper assay capable of doing the same at a minimal cost. The technology has been tested for detecting colorectal cancer, and also adapted to detect thrombosis in lab mice.
From the study abstract in Proceedings of the National Academy of Sciences:
These synthetic biomarkers are composed of nanoparticles conjugated to ligand-encoded reporters via protease-sensitive peptide substrates. Upon delivery, the nanoparticles passively target diseased sites, such as solid tumors or blood clots, where up-regulated proteases cleave the peptide substrates and release reporters that are cleared into urine. The reporters are engineered for detection by sandwich immunoassays, and we demonstrate their quantification directly from unmodified urine; furthermore, capture antibody specificity allows the probes to be multiplexed in vivo and quantified simultaneously by ELISA or paper lateral flow assay (LFA).
Study in Proceedings of the National Academy of Sciences: Point-of-care diagnostics for noncommunicable diseases using synthetic urinary biomarkers and paper microfluidics
