Reviewed by Lexie CornerJan 3 2025
Researchers at the University of California, Riverside, have developed a nanopore-based diagnostic tool capable of detecting illnesses more quickly and accurately by analyzing signals from individual molecules. The study was published in Nature Nanotechnology.
The sensor, a glass tube that is melted at the tip to form a sharp needle-like structure, is dipped into a fluid containing molecules. Image Credit: Kevin Freedman/ImageFX/UCR.
The molecules targeted by the tool, such as specific DNA or proteins, are extremely small—about one-billionth of a meter—producing faint electrical signals that require specialized detection.
Right now, you need millions of molecules to detect diseases. We are showing that it is possible to get useful data from just a single molecule. This level of sensitivity could make a real difference in disease diagnostics.
Kevin Freedman, Assistant Professor and Study Lead Author, University of California, Riverside
Freedman’s lab focuses on developing electronic detectors that mimic the behavior of neurons, including the ability to "remember" molecules previously detected by the sensor. To achieve this, the researchers designed a new circuit model that accounts for subtle variations in sensor behavior.
At the core of this system is a nanopore, a microscopic hole through which molecules pass one at a time. The circuit is loaded with salts that dissociate into ions along with biological samples. When DNA or protein molecules pass through the nanopore, they reduce the flow of ions, generating a measurable electrical signal.
Our detector measures the reduction in flow caused by a protein or bit of DNA passing through and blocking the passage of ions.
Kevin Freedman, Assistant Professor and Study Lead Author, University of California, Riverside
Freedman explained that the system must account for the possibility of some molecules going undetected as they pass through the nanopore. The nanopore also acts as a filter, reducing background noise from unrelated molecules that could obscure important signals.
Unlike conventional sensors, which require external filters that may inadvertently remove critical data, Freedman’s approach preserves the signal from each molecule, increasing diagnostic accuracy.
Freedman envisions the device as the foundation for a compact, portable diagnostic tool—potentially the size of a USB drive—capable of detecting infections within 24 to 48 hours, compared to the days current tests often require. Such rapid detection could enable earlier intervention for fast-spreading diseases.
Nanopores offer a way to catch infections sooner before symptoms appear and before the disease spreads. This kind of tool could make early diagnosis much more practical for both viral infections and chronic conditions.
Kevin Freedman, Assistant Professor and Study Lead Author, University of California, Riverside
Beyond diagnostics, the tool has applications in protein research. Proteins are key cellular components; even minor structural changes can affect health. Current diagnostic tools struggle to differentiate between similar proteins, but the nanopore’s ability to detect small differences may support the development of more targeted treatments.
The technology also advances the goal of single-molecule protein sequencing, which provides insights into real-time genetic expression and changes. This could lead to earlier disease detection and personalized treatments tailored to individual patients.
“There is a lot of momentum toward developing protein sequencing because it will give us insights we cannot get from DNA alone. Nanopores allow us to study proteins in ways that were not possible before,” Freedman said.
Nanopores are the focus of a research grant awarded to Freedman by the National Human Genome Research Institute, supporting his team's work on sequencing individual proteins. This study builds on Freedman’s earlier research into enhancing nanopore technology for detecting molecules, viruses, and other nanoscale entities. He views these developments as a potential catalyst for advancements in biological research and molecular diagnostics.
Freedman said, “There is still a lot to learn about the molecules driving health and disease. This tool moves us one step closer to personalized medicine.”
Freedman anticipates that nanopore technology will become a standard feature in medical and research tools. As these devices become more accessible and affordable, they could be integrated into routine diagnostic kits for clinics or home use.
He said, “I am confident that nanopores will become part of everyday life. This discovery could change how we will use them moving forward.”
Journal Reference:
Farajpour, N., et al. (2025) Negative memory capacitance and ionic filtering effects in asymmetric nanopores. Nature Nanotechnology. doi.org/10.1038/s41565-024-01829-5.