High-yield synthesis of strong photoluminescent N-doped carbon nanodots derived from hydrosoluble chitosan for mercury ion sensing via smartphone APP

• Published in: Biosensors & bioelectronics 2016-05, Vol.79, p.1-8
• Main Authors: Wang, Lei, Li, Baoqiang, Xu, Feng, Shi, Xinyao, Feng, Demeng, Wei, Daqing, Li, Ying, Feng, Yujie, Wang, Yaming, Jia, Dechang, Zhou, Yu
• Format: Article
• Language: English
• Subjects: Biomass; Biosensing Techniques - instrumentation; Carbon; Carbon - chemistry; Cations, Divalent - analysis; Cell Line; Chitosan; Chitosan - chemistry; Heavy metals; High-yield synthesis; Humans; Imaging; Limit of Detection; Luminescent Agents - chemical synthesis; Luminescent Agents - chemistry; Mercury (metal); Mercury - analysis; Models, Molecular; Nanostructure; Nanostructures - chemistry; Nitrogen - chemistry; Nitrogen-containing biomass; Nitrogen-doped carbon nanodots; Optical Imaging; Photoluminescence; Smartphone - instrumentation; Smartphone-based mercury ion sensor
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2015.11.085

Photoluminescent carbon nanodots (CNDs) have offered considerable potential to be used in biomedical and environmental fields including live cell imaging and heavy metal ion detection due to their superior quantum emission efficiencies, ability to be functionalized using a variety of chemistries and apparent absence of toxicity. However, to date, synthetic yield of CNDs derived from biomass via hydrothermal carbonization is quite low. We report here the synthesis of nitrogen-doped carbon nanodots (N-doped CNDs) derived from hydrosoluble chitosan via hydrothermal carbonization. The synthetic yield could reach 38.4% which is 2.2–320 times increase compared with that from other biomass reported so far. These N-doped CNDs exhibited a high quantum yield (31.8%) as a consequence of nitrogen incorporation coincident with multiple types of functional groups (C=O, O–H, COOH, and NH2). We further demonstrate applications of N-doped CNDs as probes for live cell multicolor imaging and heavy metal ion detection. The N-doped CNDs offered potential as mercury ion sensors with detection limit of 80nM. A smartphone application (APP) based on N-doped CNDs was developed for the first time providing a portable and low cost detection platform for detection of Hg2+ and alert of heavy metal ions contamination. [Display omitted] •A high-yield synthesis (38.4%) of N-doped CNDs from hydrosoluble chitosan was developed.•The incorporation of nitrogen boosted fluorescence quantum yield of N-doped CNDs to 31.8%.•A portable Hg2+ detection platform based on smartphone combined with N-doped CNDs was developed for the first time providing an alert of heavy metal ions contamination.