A novel high pH-sensitive nitrogen-doped yellow fluorescent carbon dots based one-step synthesis and detection application in living cells
Monitoring the pH in living cells is of great significance for deeper understanding cellular functions as well diseases diagnosis. Herein, a rare example of N-doped carbon dots (N-CDs) that emit bright-yellow ﬂuorescence is reported using o-phenylenediamine as carbon precursor by a simple one-pot hydrothermal method. The prepared N-CDs exhibit not only highly optical stabilities and good biocompatibility but also pH sensitivity. A good linear relationship between the fluorescence intensity and the pH value could be obtained in the range of 4.2 to 7.0 (R2 = 0.9983). In addition, the N-CDs also possess superior selectivity of hydrogen ions over common metal ions and some bioactive molecules. On this basis, the N-CDs are successfully applied to cellular imaging and monitor pH fluctuations in living cells.