In a study published in Advanced Science, researchers from the Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences developed a novel application of lanthanide-doped nanoparticles (LnNPs) to improve both biomedical imaging and information encryption. These nanoparticles use second near-infrared (NIR-II) emissions to enable high-resolution fluorescence imaging and offer advanced data security solutions through optical coding. The use of NIR-II light is crucial for reducing background noise in imaging while allowing for deeper tissue penetration. Researchers synthesized orthogonal NIR-IIb/c emitting nanoparticles by doping Tm3+ and Er3+ into a multi-layer core-shell structure. The nanoparticles emitted two distinct wavelengths, 1530 nm and 1825 nm, under different NIR excitations (808 and 980 nm), effectively separating the emissions spatially. Using a coprecipitation method, researchers controlled the nanoparticle layers, optimizing their photoluminescence properties and preventing energy crosstalk between Tm3+ and Er3+. These properties were confirmed through transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS), which verified the nanoparticle's composition and structure.
These orthogonal luminescent nanoparticles have the unique design which allows for deeper tissue imaging than traditional fluorescence imaging techniques. How this could be applied to real-time blood vessel depth detection was demonstrated by using the different optical properties of NIR-II light. Furthermore, these nanoparticles were used to encrypt data, creating binary matrices and quick-response (QR) codes that could only be decoded with specific NIR excitations. The optical signals from these nanoparticles ensure high security for data encryption as only those with the proper decoding tools could access the hidden information.
These lanthanide-doped nanoparticles represent advancements in both biomedical fields and data encryption technologies. Their ability to penetrate deep into tissues while minimizing background noise makes them ideal for non-invasive medical imaging, particularly for detecting vascular diseases. In addition, their application in data encryption offers robust protection against counterfeiting and unauthorized access with potential use in secure data transmission and storage.
