Cr4+ activated NIR-NIR multi-mode luminescent nanothermometer for double biological windows

Abstract

Remote temperature sensing in biological media is used to monitor intracellular evolutionary process reliably, and is potentially applied in the field of diagnostics and therapeutics. Ideally, such nanothermometers should be functional in biological optical transparency windows across a wide range of broad absorption and emission bands, strong luminescence and larger Stokes shift. Here, this is achieved via using NIR-to-NIR transition metal (Cr4+)-doped aluminosilicate nanoparticles as multiparametric thermal sensing probes. They can be excited in first biological window and emitted in second biological window, allowing for large optical penetration into tissues while maintaining high-spatial resolution. We also demonstrate that the phenomena of temperature-induced population redistribution and temperature-induced spectral red-shift (maximum thermal sensitivity is 0.61% °C−1, superior to the most of the current materials), essentially allow for a multi-mode thermal sensing within a single probe towards to a very different optical response. We believe that these findings can be expanded a wide range of promising applications using transition metal-activated luminescent nanoparticles as nanothermometers in deep tissue temperature measurements of biological and biochemical.