University News – Illinois Tech Today
College of Science Associate Professor of Chemistry Xiyun “Richard” Guan received a $422,500 three-year renewal award from the National Institutes of Health to continue his project entitled “Label-Free Nanopore Biosensor for Rapid, Ultrasensitive, and Multiplex Detection of Protease Activities.”
Guan’s group is working on the development of biosensors for detecting environmental toxins and biomolecules using nanopore sensing. A nanopore is a nanoscale cavity or channel, sometimes created by a pore-forming protein. When a nanopore resides in a membrane, only single molecules can pass through the pore, and as a result the pore acts as a single-molecule detector. Over the last 15-20 years, these nanoscale pores have been used not only to analyze the sequence of DNA, but also to study various types of chemical interactions. They also have been used to investigate biomolecular structure, for example the folding and unfolding (denatured) of proteins, and for other applications.
As an emerging new technique, nanopore sensing has many advantages, including real-time detection. It also does not require the use of fluorescent dyes or radioactive materials; therefore, it is known as a label-free technique. Nanopore sensing has the ability to detect ultra-low concentrations of analytes (targeted species), for example trace amounts of biomolecules as found in human blood samples. Nanopore sensors can detect the concentration and identity of an analyte based on the ionic current modulations in a salt solution. When the molecules of interest, such as peptides, proteins, or DNA (with diameters smaller than the nanopore) pass through a single nanopore, they will produce current modulations for analysis.
One aspect of Guan’s current nanopore research is centered on pioneering a new, highly selective and sensitive technique to measure the activities of proteases, enzymes that break down proteins and peptides (short amino acid chains). Proteases occur naturally in all living organisms and play key roles in diverse biological processes, from cell regeneration …