These are nanopore-based sensors that can, by capturing signals from individual molecules, make it possible to diagnose diseases much more quickly and with greater precision than current tests. Because the molecules scientists want to detect – usually certain DNA or protein molecules – are about a billionth of a meter wide, the electrical signals they produce are infinitesimally small and require specialized detection instruments.
Lead author Kevin Freedman, professor of bioengineering at UCR, comments on the state of the science: “Right now, it takes millions of molecules to detect disease. We show that it is possible to obtain useful or even sufficient data from a single molecule.”
1 molecule and a sufficient level of sensitivity for diagnosis
The Californian team is developing electronic detectors that behave like neurons in the brain and can retain memories: more precisely, memories of molecules that have previously passed through the sensor. To do this, UCR scientists developed a new circuit model that accounts for small changes in the sensor’s behavior. At the heart of the circuit is a nanopore, a tiny opening through which molecules pass one by one. Biological samples are loaded into the circuit with salts, which dissociate into ions. If protein or DNA molecules from the sample pass through the pore, this reduces the flow of ions that can pass through. “Our detector measures the reduction in flux caused by a protein or DNA fragment passing through and blocking the passage of ions.”
So the nanopore is not just a sensorbut itself acts as a filter, reducing background noise from other molecules in a sample that might mask critical signals.
Traditional sensors require external filters to remove unwanted signals, and these filters can accidentally remove valuable information from samples. The new approach ensures that the signal from each molecule is preserved, increasing the accuracy of diagnostic applications.
Soon small portable diagnostic kits? This is the ultimate objective of these scientists who are working on a device on this principle, no bigger than a USB key, which could detect infections at an early stage.
While current tests may not detect infections for several days after exposure, nanopore sensors are able to detect infections within 24 to 48 hours.
A significant advantage for rapidly spreading diseases,
allowing for earlier intervention and treatment.
“Nanopores offer a way to detect infections earlier, before symptoms appear and before the disease spreads. This type of tool could make early diagnosis much more practical for viral infections but also for chronic diseases.”
The research also marks a step towards single-molecule protein sequencing (or at the level of a single cell), a long-sought goal in biology. While DNA sequencing reveals genetic instructions, protein sequencing provides insight into how these instructions are expressed and modified in real time. In short, an emerging technology that allows earlier detection of diseases and more precise and better personalized therapies.
“We are convinced that nanopores will soon become part of everyday life.”
Health
