Fluorescent N-doped carbon dots for both cellular imaging and highly-sensitive catechol detection

N-doped carbon dots (NCDs) obtained by one-step reflux treatment of C3N4 with ethane diamine possess good water dispersibility, strong visible fluorescence, low toxicity, proton adsorption capacity, and photo-induced electron-accepting/donating abilities. Based on these unique properties, we demonstrate that the obtained NCDs can be used as a good fluorescent probe for cellar imaging without any further functionalization. Further, the NCDs are combined with laccase (LAC) to form NCDs-laccase (NCD-LAC) hybrids, which are sensitive, stable, and of low cost for the precise detection of catechol and catechol derivatives.