One-pot synthesis of boron and nitrogen co-doped silicon-carbon dots for fluorescence enhancement and on-site colorimetric detection of dopamine with high selectivity

The boron and nitrogen co-doped silicon-carbon dots (BN-SiCDs) were synthesized by one-pot method. The introduction of boron in BN-SiCDs played a significant role to selectively respond to dopamine (DA) based on fluorescence enhancement, while almost no respond to structural analogues, i.e. norepinephrine and epinephrine. The hydrogen bonds and π-π conjugation between BN-SiCDs and DA oligomers, and the polymerization nature of DA could be contributing factors to this phenomenon. BN-SiCDs were employed as the fluorescent nanoprobe to determine DA with the linearity of 0.005–10 μg mL−1, and limit of detection of 1.58 ng mL−1. For on-site detection, the fluorescence colorimetric probe was constructed based on BN-SiCDs and bovine serum albumin-stabilized gold nanoclusters. The sensitive color change from red to blue-green was visually observed by naked eyes corresponding to DA concentration of 0–9 μg mL−1. Further combined with the APP by the smartphone, the colorimetric probe was used for the quantitative detection. The proposed BN-SiCDs probe, colorimetric system or APP method were applied to determine DA in hydrochloride dopamine injection and human urine samples, and results agreed well with each other. The present study provided an effective strategy to adjust properties of fluorescent nanoprobes from synthetic sources to realize high selective detection.