Pure nanodiamonds with quantum technology set to predict disease with unprecedented accuracy

One of the biggest headaches when it comes to the application of microscopic physics, noise, has now enabled the most promising development in precision and preventive medicine: quantum sensors. Any interaction alters the state of a particle and this instability is one of the biggest computational limits in relation to this science, and must be controlled or corrected. But recently, University of Murcia physicist Javier Prior, a specialist in biology, thermodynamics and quantum sensors, has turned this challenge into an enormous opportunity for opening up an unprecedented field through the identification of any alteration at the most basic cellular level, at its very beginning. Pure nanometric diamonds can house particles that react to any anomaly in the development of these miniscule biological units and allow the identification of dysfunction in their initial stage or in a body’s microfluid. It is a microscopic beacon that puts out signals when it detects the first physicochemical sign of an incipient cellular storm.

Prior heads a group whose members he met during his time at universities like Oxford, Imperial College and Germany’s Universität Ulm. They include Fedor Jelezko, a pioneer in nitrogen-vacancy (NV) centers in diamonds, and Alex Retzker, an expert on sensors. Their work, coupled with a patent for microfluid based in quantum sensors (that allows one to optically read responses in minimal liquid or gaseous substances) opened a door that has led to the creation of Qlab, an initiative that combines research with business and is working on getting support from Spain’s Ministry of Digital Transformation. Its investigations are currently carried out with funding from the country’s State Research Agency.

This is complicated stuff, but Prior makes an effort to simplify years of research: “We have a device that is very sensitive to a certain external action. We generate a quantum system. I take an electron and, using ultrafast pulses, put it in a superposition where it’s spinning to one side, although it’s not really a spin, and the other way around at the same time. Since any quantum state is very sensitive to the action of any electric or magnetic field or other physical parameter, we use it as a compass. If you bring a magnet close to it, the needle moves and aligns with the magnetic field. My sensor detects the smallest magnetic fields and it works at room temperature.”

The vehicle of this sensor capable of detecting the slightest signal is a diamond with an atomic particle at nine nanometers — a nanometer is one billionth of a meter (10⁻⁹) — from the surface. “We make the diamonds synthetically because natural diamonds have many impurities [that can affect the quantum system] and we want them to be very pure, because we are only interested in having atoms of carbon 12. We build it by chemical vapor deposition: a plasma is generated that is deposited layer by layer.” To insert the quantum particle, it is accelerated and precipitated against the diamond. “Depending on the speed and how you throw it, it will go in, say, at a certain distance,” he says, taking pains to summarize a complex process.

The next step is bringing the nanodiamond, which is absolutely biocompatible, to a cell in a petri dish using optic tweezers, two lasers that trap the device. “In this way, it can be introduced in a part of the cell and detect if it is generating a protein that is related to inflammation. It’s like introducing a camera that constantly monitors the molecules.” He offers an example: “Free radicals don’t have the same number of electrons as protons and they are triggers for aging and many diseases, such as degenerative processes, because they steal particles from their neighbors.”

The sensor’s application in an organism can be carried out through implantation, injection or simply, in the case of the brain, with a helmet that covers and measures the electric fields of the neurons.

Qlab, the business that has come out of this research, is developing another quantum sensor concept known as Lab-in-chip, mini-devices with laboratory functions that are able to analyze a sample of bodily microfluid using these same quantum principles, that could some day be a household device. In that case, the diamond would have a kind of 100-nanometer channel for micro-samples and could yield an accurate result similar to a blood test or biopsy.

With the necessary funding, about which conversations regarding public and private investment are already taking place, Prior is convinced that semi-commercial prototypes of the quantum sensors could be developed within five years. In addition to these beacons of precision and preventive medicine, the same quantum technology could be applied to create a nuclear magnetic resonator that would emit a specific signal by matching the frequency to that of the thing being analyzed.

The quantum field is vast and Prior thinks that Spain, in collaboration with other institutions, has a possibility of developing a strategic specialty that is already seen as crucial, though it does have competition in neighboring countries. The devices and technology already exist and have been proven to work; the next step is institutional and private involvement in a technology whose growth forecasts exceed double digits.

Other advances

Though Spain has a good starting position, there are many laboratories in the race for the control and use of these quantum states. A group of researchers led by Professor Nobuhiro Yanai, from Kyushu University, has achieved quantum coherence (the maintenance of a quantum state) for more than 100 nanoseconds at room temperature, according to a study published in Science Advances. The finding was made possible by a chromophore, a molecule that absorbs light and emits color, in a metal-organic framework (MOF).

“The MOF that has been developed is a unique system that can accumulate dense chromophores. Additionally, the nanopores within the crystal allow the chromophore to turn, but at a very restricted angle,” explains Yanai. This discovery is also relevant for sensor technologies. “This can open the door to room-temperature molecular quantum computing, as well as quantum sensing of various target compounds,” he says.

Kaden Hazzard, a physics and astronomy professor at Rice University and co-author of a study published in Nature Physics took a different path. Hazzard’s experiment has proven capable of prolonged quantum behavior by nearly 30 times (1.5 seconds) through the use of ultracold temperatures and laser wavelengths to generate a “trick” that delays the onset of decoherence.

“If you want to make new materials, new sensors or other quantum technologies, you need to understand what is happening at the quantum level, and that research is a step towards the achievement of new learning,” Hazzard explains.

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