Photostimulable near-infrared persistent luminescent nanoprobes for ultrasensitive and longitudinal deep-tissue bioimaging
MetadataShow full item record
Cancer imaging is very important in cancer diagnosis, prognosis, and therapy effectiveness monitoring. Among all the imaging techniques, fluorescence imaging is becoming an important set of tools in biomarker-guided diagnosis, staging, typing, and prognosis of cancer. However, in vivo fluorescence imaging suffers from suboptimal signal-to-noise ratio and shallow detection depth, caused by the strong tissue autofluorescence under external excitation and by the scattering and absorption of short-wavelength light in tissues. In this dissertation, we tackle these limitations by using a new, novel type of optical nanoprobes, LiGa5O8:Cr3+ (LGO:Cr) nanoparticles with very-long-lasting near-infrared (NIR) persistent luminescence and unique NIR photostimulated persistent luminescence (PSPL) capability. This allows optical imaging to be performed in an excitation-free and hence autofluorescence-free manner. The LGO:Cr nanoparticles were fabricated by a sol-gel method, followed by calcination at high temperature. LGO:Cr nanoparticles pre-charged by ultraviolet light can be repeatedly (>20 times) stimulated in vivo, even from deep tissues, by short-exposure (~15 seconds) to a white light-emitting-diode flashlight, giving rise to multiple NIR PSPL that expands the tracking window from hours to 10 days. Our studies reveal promising potential of these nanoprobes in cell tracking and tumor targeting, exhibiting exceptional sensitivity (~5 cells) and penetration (see through a mouse body) that far exceed those afforded by conventional fluorescence imaging.