Er3+ Sensitized 1530nm to 1180 nm Second Near-Infrared Window Upconversion Nanocrystals for InVivo Biosensing

Fluorescent bioimaging in the second near-infrared window (NIR-II) can probe deep tissue with minimum auto-fluorescence and tissue scattering. However, current NIR-II fluorophore-related biodetection invivo is only focused on direct disease lesion or organ bioimaging, it is still a challenge to realize NIR-II real-time dynamic biosensing. A new type of Er3+ sensitized upconversion nanoparticles are presented with both excitation (1530 nm) and emission (1180 nm) located in the NIR-II window for invivo biosensing. The microneedle patch sensor for invivo inflammation dynamic detection is developed based on the ratiometric fluorescence by combining the effective NIR-II upconversion emission and H2O2 sensing organic probes under the Fenton catalysis of Fe2+. Owing to the large anti-Stokes shifting, low auto-fluorescence, and tissue scattering of the NIR-II upconversion luminescence, inflammation can be dynamically evaluated invivo at very high resolution (200 x 200 mu m).