A quantum sensor that uses tiny diamonds implanted inside a living animal could be used to study cellular processes in minute detail or eventually detect diseases such as cancer.
The most common ways to image cells involve adding fluorescent dyes or nanoparticles and using the light these give off to measure and map cellular processes. But these methods can falter if the markers damage the cells or change cellular conditions, such as the acidity or thickness of cellular fluid.
Quantum sensors use the properties of quantum mechanics to detect features like motion, electric fields and magnetic fields, but their precision can be limited when they work far away from their target.
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at the University of Cambridge and her colleagues have developed a quantum biosensing chip called Q-BiC that uses nanodiamonds to detect properties within living organisms. The nanodiamonds, which are about 100 nanometres wide, are injected into the cells being studied and the chip is placed nearby to detect the state of the diamonds.
The team used Q-BiC to measure the temperature and magnetic resonance inside live cancer cells and nematode worms, and found that the process caused no damage.
鈥淭he challenge was realising the diamond quantum sensing system on a chip that is both small enough to fit it into a microscope and provides a stable environment for the living sample we鈥檙e imaging, so the sample can remain unperturbed by the quantum measurement,鈥� says Knowles.
The chip measures diamonds that have had some carbon atoms removed and others replaced with nitrogen, which changes the quantum states that the atoms鈥� electrons can have. After the electrons are excited with microwave radiation, they relax to quantum states that are affected by their environment, such as temperature or the local magnetic field, which can then be used to map the cell.
Knowles and her team hope that the ability to measure multiple properties at the same time will eventually be useful for characterising damaged or diseased cells, such as for cancer, or for monitoring cells over long periods of time.
It is a remarkable accomplishment, says at Heriot-Watt University in Edinburgh, UK, and could offer significant advantages over current bioimaging techniques. 鈥淣anodiamonds can be much smaller than the wavelength of visible light, so they offer information on a much shorter length scale than purely optical techniques,鈥� he says. 鈥淭hat enables you to image properties which are different and complementary to what you might see with fluorescent markers, but also with a higher spatial resolution.鈥�
Last month, at the University of Science and Technology of China and his colleagues used a quantum sensor to monitor magnetic heart signals inside a living rat, but this used diamonds outside the body, which meant it was relatively imprecise.
arXiv
