Facile Synthesis of N, B-Doped Carbon Dots and Their Application for Multisensor and Cellular Imaging

In this work, multifunctional B,N codoped carbon dots (B/N–C-dots) were synthesized from a facile hydrothermal treatment of branched polyethylenimine and 4-formylphenylboronic acid. The obtained B/N–C-dots had a very narrow size distribution and showed excitation-wavelength-dependent photoluminescence properties with a high fluorescence quantum yield (QY) of 15.85%. The B/N–C-dots showed temperature and pH (3–13) dual responses. Additionally, the B/N–C-dots showed a good sensitivity and selectivity to Fe3+ with a detection limit of 1.62 μM. What is more, the as-prepared B/N–C-dots exhibited low toxicity and good biocompatibility and could be used for cell imaging. Considering these good properties, the obtained B/N–C-dots have good potential for temperature, pH, and ion sensors and cellular imaging.