Label-free chlorine and nitrogen-doped fluorescent carbon dots for target imaging of lysosomes in living cells.

Abstract

Lysosomes with a single-layered membrane structure are mainly involved in the scavenging of foreign substances and play an important role in maintaining normal physiological functions of living cells. In this work, near-neutrally charged fluorescent carbon dots (CDs) were preparedwith lipophilicity through a facile one-pot hydrothermal carbonization of chloranil and triethylenetetramine at 160°C for 3h. The as-obtained CDs are proved to have good photostability, low cost, and excellent biocompatibility. Importantly, the as-prepared CDs with high quantum yield of 30.8% show excitation-dependent emission with great stability, and thus, they can be well used for the long-term target imaging of lysosomes in living cells without further modification. Meanwhile, the CDs can quickly enter into the lysosomes within 30min, and the green fluorescence (FL) of CDs reaches the plateau when incubated for 60min. By comparing the fluorescent intensity, the information aboutdistribution and amount of lysosomes in different cells can be obtained. Theproposed CD-based strategy demonstrates great promise for label-free target imaging of lysosomes in living cells. Graphical abstract The near-neutral carbon dots (CDs) with lipophilicity are used as label-free fluorescent nanoprobes for the long-term imaging of lysosomes in living cells.