Multiphoton tools for hydrogen peroxide imaging in vivo with subcellular resolution

Improving Three-Photon Fluorescence of Near-Infrared Quantum Dots for Deep Brain Imaging by Suppressing Biexciton Decay

“…Besides the excitation light, the wavelength of fluorescent dyes also determines the loss and attenuation of fluorescent signals and influences the quality of imaging. Owing to the rigorous requirement of the 3P process, only limited materials have been developed for 3PFM, including endogenous fluorescent proteins, organic molecules, aggregation-induced emission (AIE) luminogens, and carbon nanomaterials. − Moreover, the emission wavelengths of most 3P materials concentrate in the visible region (400–700 nm). − Considering the effective attenuation length of light with longer wavelength, the exploration of 3P materials emitting in the NIR region would be a promising direction of 3PFM. Attributed to the quantum confinement effect, quantum dots (QDs) exhibit favorable features for 3PFM, including broad excitation range, emission tunability, and enhanced optical nonlinearity. ,− It is possible to prepare QD-based three-photon fluorescent (3PF) probes emitting in the NIR region, which could be excited by an NIR-II light source.…”