Nanodiamonds can detect viruses at the single molecule level. The


  sensitivity is 5 orders of magnitude higher than that of gold nanoparticles.

  Science and Technology Daily News (Reporter Feng Weidong) According to the latest issue of "Nature" magazine, a new study by University College London found that the quantum sensing capability of low-cost nanodiamonds can improve the sensitivity of paper-based diagnostic tests with a wide range of sensitivity Tests using gold nanoparticles are five orders of magnitude higher, and are expected to detect viral diseases such as HIV earlier.

  The paper lateral flow test works in the same way as the pregnancy test. A piece of paper is immersed in a liquid sample, and the color (or fluorescence signal) changes indicate a positive result and the detection of viral proteins or DNA. It is widely used to detect HIV to COVID-19 Viruses and other viruses can be diagnosed quickly without having to process the results in the laboratory.

  Nanodiamonds have higher sensitivity and can detect a lower viral load, which means that diseases can be detected at an earlier stage, which is expected to reduce the risk of virus transmission and take timely and effective treatment.

  Diamond has a highly regular structure, and some have a defect called "nitrogen vacancy (NV) center".

The NV Center has many potential applications, from fluorescent biomarkers for ultra-sensitive imaging to information processing qubits in quantum computing.

Researchers are taking advantage of this characteristic of nanodiamonds.

  The NV center can emit bright fluorescence to indicate the presence of antigen or other target molecule signals.

In the past, fluorescent labeling was limited by background fluorescence from samples or test strips, making it difficult to detect low concentrations of viral proteins or DNA.

However, the quantum nature of fluorescent nanodiamonds allows for selective adjustment of its luminescence, so the microwave field can be used to fix the signal at a set frequency, and it can be effectively separated from the background fluorescence, thus solving this limitation.

  The optical results show that the sensitivity of nanodiamonds is increased by 5 orders of magnitude (100,000 times) compared with gold nanoparticles, that is, the number of nanoparticles required to generate a detectable signal is much smaller.

Through a short 10-minute constant temperature amplification step, researchers can detect HIV RNA at a single molecule level in the model sample.

  This work has been demonstrated in a laboratory environment, but the research team hopes to develop new test methods so that the results can be read using a smartphone or a portable fluorescence reader, making it easier for users to test.