The scientists obtained highly doped up-conversion nanoparticles

Recently, led by Australia’s Macquarie university professor da-yong jin advanced cell instrument laboratory and engineering college of Beijing university department of biomedical engineering XiPeng research joint research, found the new nano photonics light-emitting mechanism, and implements the high concentration of doping on the conversion of nanoparticles (Upconversionnanocrystals) technology, which shows the most sensitive nano fluorescent material yet. The paper was published in Nature Nanotechnology by Nature publishing group.

Up-conversion nanoparticles, a new type of fluorescent material, are promising for a wide range of applications, especially in biomedical imaging, immune analysis, solar cells, 3d display and other fields, because of their unique optical properties. It is usually composed of inorganic matrix and rare earth doped ions embedded in it. Because it is excited in the near infrared, it can obtain a deeper penetration than visible light. However, it is well known in the industry that the material has a relatively low conversion efficiency and dark fluorescence intensity, which hinders the further application of up-conversion particles. Although increasing the doping concentration can increase the luminous efficiency intuitively, due to the serious fluorescence quenching caused by high concentration doping, the up-conversion nanoparticles prepared traditionally are mostly limited to low doping concentration.

In view of this bottleneck problem, it is found for the first time that the limitation of fluorescence quenching can be solved by high excitation light energy density, and the up-conversion nanoparticles with high concentration doping can be realized. By combining high doping with high excitation power, the fluorescence signal strength was significantly enhanced compared with the traditional low-doping nanoparticles, which made the remote detection of individual nanoparticles assisted by optical fiber become a reality for the first time. The new nanoparticles are three orders of magnitude more sensitive than the traditional quantum dot. The nanoparticle was named SuperDotTM because the high-doping up-conversion nanotechnology provided an ultra-sensitive means of optical inspection. This achievement has greatly promoted the application of up-conversion nanotechnology in infrared detection, biological identification, medical imaging, high-throughput single-cell detection, anti-counterfeiting technology and other fields.

For many years, the research group of Prof. Dayong Kim from Australia has been committed to realize new technologies such as flow cytometry detection without background, high speed and high quantum yield, slide cell detection and high speed detection of massive samples of rare events by combining optical detection with up-conversion nanoparticles. The research areas of xi peng’s team at Peking University include ultra-diffraction extreme resolution microscopy, laser confocal scanning microscopy, multi-photon microscopy, and optical coherence tomography. The collaboration between the two research groups dates back to 2010 and seven articles have been published in internationally renowned journals. (source: China innovation net. Editor in charge: li hao)