Semiconductor Nanoplatelets as Ultra-Bright Fluorophores for Two-Photon Absorption Cell Imaging

The development of new two-photon fluorescent probes is desirable for imaging in biosystems. Semiconductor CdSe nanoplatelets are promising candidates for this purpose due to their large absorption cross sections, extremely narrow photoluminescence emission, and high spectral brightness. Herein, we obtained water dispersible nanoplatelets (poly-NPLs) and explored their potential for intracellular imaging using commercially available Qdot 655 CdSe-based quantum dots as a control. Comparison was carried out for one- and two-photon imaging. The emission of poly-NPLs was found to be consistently higher than the one of Qdot 655 at equal particle concentrations as well as at equal cadmium concentrations for both one-photon and two-photon excitations. In particular, poly-NPLs can show up to 3 orders of magnitude higher fluorescence brightness compared to Qdot 655 when excited with two-photons, which makes them interesting candidates for multiphoton imaging and single molecule detection applications.