Photoinduced Luminescence Enhancement of Hydrophilic 'Caged' Carbons Dots

Over the last decade, carbon dots (CDs) have quickly emerged as outstanding 'green' nanoprobes for fluorescence imaging and microscopy techniques. In this context, the identification of a mechanism to tune the CD's optical properties (e.g., fluorescence) can translate into the development of photoactivatable probes with improved performance for super-resolution bioimaging. In relation to this, facile synthetic protocol was devised to photoactivate the luminescence of two types of hydrophilic carbon dots (-COOH and -N doped carbon dots) by 'caging' the nanostructures with photocleavable 2-nitrobenzyl groups. It was demonstrated that 2nitrobenzyl groups efficiently quench the emission intensity of both resulting nanoconstructs. Nonetheless, the luminescence of the 'caged' carbon dots can be partially recovered, upon ultraviolet illumination, in solution.