If humans could use x-ray vision to watch the earliest cellular processes of Alzheimer’s disease, they would see a strand of protein somewhere in the brain tie itself into a misshapen knot.
This microscopic macramé, known as protein misfolding, is normal in human biology. However, when the body’s mechanism for sifting out these misfolded proteins fails, the result can lead to neurodegenerative diseases like Alzheimer’s, Parkinson’s, and Huntington’s.
Why exactly proteins misfold and why the body sometimes fails to eliminate them is unknown, and it’s one reason why researchers at the University of Chicago’s Pritzker School of Molecular Engineering (PME) are developing some of the world’s most advanced biological sensors.
Peter Maurer, assistant professor of molecular engineering, creates next-generation quantum sensors that will unlock new doors in biological and medical research.
Built from diamonds and powered by quantum physics, Maurer’s nanosensors will be able to measure magnetic and electric fields, time, temperature, and pressure inside a living cell. And while his research is still in an early phase, it has far-reaching potential in medicine and beyond.
Quantum sensors can perform measurements of biological processes that are not accessible by current technologies or detect diseases before they manifest clinically. This technology has the potential to expand biophysics and molecular biology research,” Maurer said. “It will help us understand processes that we cannot see with conventional methods. Then, when it is adapted in the clinical setting, you will see new, incredibly effective screening processes for diseases—tests for diseases that we cannot currently test for.”
Getting a sense of things
To understand this work, it helps to know a bit about quantum mechanics, Maurer explains.
“Quantum mechanics is this great theory that explains the world in almost its entirety as far as we know,” Maurer said. “It explains how atoms hold together and what drives chemical reactions, which can explain biology and how cells work. In some sense, quantum mechanics is the most fundamental theory of the world we have now.”
Quantum mechanics also contains some of science’s most counterintuitive principles, like superposition and quantum tunneling. Over the years, engineers like Maurer have discovered ways to apply those principles to the development of industry-transforming technology.
Atomic clocks, which can accurately keep time within 100ms over 15 billion years, are considered an early form of quantum sensing. Since their creation, they have become the backbone of several sophisticated technologies, like GPS and modern satellite communication. In much the same way that atomic clocks transformed time measurement, engineers like Maurer hope to transform the measurement of many other phenomena.
A diamond in the rough
One application Maurer has pursued since his postdoctoral years is the study of temperature in cells. Quantum systems are extremely sensitive to temperature changes. Quantum computers, for example, need to be stored at near absolute zero to function, requiring refrigerators the size of a person. That sensitivity, a hindrance in quantum computing, can provide highly detailed information when applied to sensing.
Working from that understanding, Maurer has developed sensors that are small enough to be inserted into living biology. To do this, he uses lab-grown diamonds designed with a specific flaw in their center: what’s called a nitrogen-vacancy (NV) center. This flaw, because of its structure, has a quantum property called spin. Researchers can use electromagnetic radiation to change the spin inside of the diamond, like moving a compass needle with a magnet. Pairing that with other tools, researchers can sense various forces, such as magnetic and electrical fields, pressure, and temperature.
The advantage of Maurer’s approach is that he can “feed” one of these nanosensors to a living cell through a process called endocytosis. Once inside the cell, Maurer’s sensor can monitor temperature without disrupting the cell’s normal functions, warm parts, and measure the response.
Understanding temperature in cells is crucial because many chemical reactions are triggered by heat, and on occasion, those reactions can lead to undesirable results like denatured or misfolded proteins.
A leap for sensing
Currently, Maurer is working with David Pincus, assistant professor in the Department of Molecular Genetics and Cell Biology at the University of Chicago, as part of the National Science Foundation’s Quantum Leap Challenge Institute for Quantum Sensing for Biophysics and Bioengineering (QuBBE). Together, they’re investigating heat shock response, which is the body’s mechanism for sifting out misfolded proteins. Their research could potentially unlock new methods for addressing protein misfolding and lead to new tests or treatments for neurodegenerative disease. For Maurer, it’s the opportunity to apply his work in quantum engineering to an issue affecting many.
“Quantum sensors are particularly appealing because they allow us to probe molecular and biological processes that we wouldn’t be able to access with conventional technologies,” Maurer said. “By this, we can learn something about the inner workings of human health, and that’s something that our society can draw very direct benefit from quantum technology. It’s the ability to use this technology to do something meaningful.”
Quantum biosensors like those Maurer is developing are still in the early proof-of-concept stage, meaning it may be some time before they make an appearance in the commercial space. However, he predicts that medical researchers will begin to see their benefits within the next 5-10 years.
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