Global first: Scientists program living cells to create biological qubits

Biology and quantum physics often seem like they belong to separate worlds. Living cells function in warm, noisy environments, full of constant motion, while quantum technologies usually need near-absolute zero temperatures and isolation from outside disturbances.

Yet, in a surprising breakthrough, scientists at the University of Chicago Pritzker School of Molecular Engineering have brought these two realms together. They turned a fluorescent protein, the same type that makes jellyfish glow, into a functioning quantum bit, or qubit.

Qubits are the building blocks of quantum computers and quantum sensors. Unlike the ordinary bits in your laptop that are either 0 or 1, qubits can hold multiple states at the same time. This unique ability allows them to sense and process information with incredible sensitivity.

Until now, most qubits came from solid materials such as diamonds or carefully designed molecules, which are difficult to put inside living systems. By transforming a naturally occurring protein into a qubit, researchers may have found a way to blend quantum tools directly with life itself.

The team focused on an enhanced yellow fluorescent protein, a molecule just three nanometers across. These glowing proteins are already widely used by biologists as cellular tags because cells can make them naturally once given the right genetic instructions. What the researchers realized is that these proteins carry a “triplet state”—a hidden energy configuration that had never been tapped for quantum sensing.

By firing a near-infrared laser pulse, the scientists managed to read the protein’s triplet state and achieved up to 20 percent spin contrast. That means they could tell the difference between quantum spin states clearly enough to use the protein as a qubit.

Microwave pulses were then used to control the spin states, but because quantum behavior is fragile, this part of the experiment required cooling the proteins to liquid nitrogen temperatures. Under those conditions, the protein qubits held their coherence for about 16 microseconds with the help of a technique called CPMG decoupling.

To test real-world usefulness, the team placed the protein qubits inside mammalian cells. Surprisingly, the same quantum properties held up, even in the complex, messy environment of a living cell. They also tried bacteria at room temperature and detected magnetic resonance signals, recording up to 8 percent contrast. These results demonstrated that fluorescent proteins can act as optically addressable spin qubits even inside life itself.

This discovery matters because it shifts how researchers might study biology at the smallest scales. Current quantum sensors are extremely sensitive, but getting them inside living cells is nearly impossible. With protein-based qubits, the sensors are grown by the cells themselves. That opens the door to tagging proteins, then directly measuring magnetic or electric fields in their immediate surroundings in real time.

David Awschalom, co-principal investigator of the study and director of the Chicago Quantum Exchange, explained the thinking behind the project: “Rather than taking a conventional quantum sensor and trying to camouflage it to enter a biological system, we wanted to explore the idea of using a biological system itself and developing it into a qubit.”

That approach not only bridges physics and biology but also introduces a new philosophy in designing quantum materials. As Peter Maurer, assistant professor of molecular engineering and another leader of the project, put it, “We can now start using nature’s own tools of evolution and self-assembly to overcome some of the roadblocks faced by current spin-based quantum technology.”

For decades, fluorescent proteins have been biologists’ go-to method for tracking cellular events. You might have seen images of glowing green or yellow cells under a microscope. Those glowing spots are proteins helping scientists follow processes such as cell division or signaling. Turning those same proteins into qubits adds a new layer of information. Instead of only seeing where something happens, researchers could now measure what happens on the quantum level.

Co-first author Benjamin Soloway, a quantum PhD candidate at UChicago, described the excitement: “Through fluorescence microscopy, scientists can see biological processes but must infer what’s happening on the nanoscale. Now, for the first time, we can directly measure quantum properties inside living systems.”

The project took years and was far from straightforward. Early experiments often looked discouraging, but students in the lab pushed through setbacks. Jacob Feder, a co-first author who completed his PhD during the project, emphasized how persistence was essential. Awschalom credited that determination, saying, “This work was only possible because our students had the courage to take risks and push forward even when the results looked discouraging for quite some time.”

Right now, protein qubits don’t match the sensitivity of diamond-based sensors, which remain the gold standard. But their strength lies elsewhere. Because they can be genetically encoded, scientists can place them exactly where they’re needed, produced naturally by cells in specific amounts. That precision means they could one day watch proteins fold, track enzyme activity, or even detect the earliest signs of disease from inside a cell.

The findings, published in Nature, highlight what happens when different disciplines collaborate. Maurer credited the environment at UChicago PME, where quantum engineers and molecular biologists could work side by side, for making the project possible. As Soloway noted, “We’re entering an era where the boundary between quantum physics and biology begins to dissolve. That’s where the really transformative science will happen.”

If further developed, protein-based qubits could change how you study health and disease. Scientists might create nanoscale MRI-like tools capable of mapping the atomic structures inside cells with unmatched precision. Medical researchers could track disease progression or drug effects in real time at the quantum level.

Beyond medicine, this approach might guide the design of new quantum materials inspired by biology’s self-assembling proteins.

While the road ahead involves improving sensitivity and stability, the promise is clear: the ability to look at life not just through a microscope, but through the lens of quantum mechanics.

Note: The article above provided above by The Brighter Side of News.

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