Synthesis of polyurethane-derived nitrogen-doped carbon dots for a high-performance fluorescence bioimaging probe

Abstract

Carbon quantum dots, as a new type of fluorescent material, possess many advantages with adjustable fluorescence performance and low toxicity. In this work, a universal and robust strategy using polyurethane (PU) sponge as precursor was developed to synthesize highly-soluble nitrogen-doped carbon quantum dots (NCDs) via a solvothermal method. The decomposition and polymerization process of PU sponge result in the formation of NCDs-1 with oxygen and nitrogen-containing functional groups. Specifically, the as-prepared NCDs-1 showed high photostability and tunable photoluminescence properties. Most importantly, this strategy enables us to fabricate other NCDs using various polyurethane sponges. Cytotoxicity studies indicated that these highly-soluble NCDs-1 show low cytotoxicity for HeLa and MC3T3-E1 cells, and can be used as good probes for cellular imaging. This work not only develops an eco-friendly strategy to utilize polyurethane material, but also provides a simple method to fabricate fluorescence carbon dots for cellular imaging and other therapeutic applications.