Green synthesis of carbon dots using the flowers of Osmanthus fragrans (Thunb.) Lour. as precursors: application in Fe3+ and ascorbic acid determination and cell imaging
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In this work, dried flowers of Osmanthus fragrans Lour. were applied as green precursors to synthesize carbon dots (CDs) by a green hydrothermal method for the first time. The CDs showed strong blue fluorescence at 410 nm under 340-nm excitation with a quantum yield of approximately 18.53%. Furthermore, the CDs were applied for the sensitive detection of Fe3+. The linear response of Fe3+ ranged from 10 nM to 50 μM with a limit of detection as low as 5 nM. In addition, other ions were used as competitive substances to explore the selectivity of CDs for Fe3+. The fluorescence quenching effect of Fe3+ was much stronger, which demonstrated that the CDs had high selectivity for Fe3+ and they can be employed for the selective detection of Fe3+. The potential fluorescence quenching mechanism between CDs and Fe3+ was identified as the inner filter effect. The CDs were then used as a fluorescent sensor for the detection of Fe3+ in water samples and human serum; the recovery range was 93.76–113.80% (relative standard deviation less than 0.79%). These results indicate that the CDs can be applied for the sensitive and selective detection of Fe3+ in real samples. Moreover, on the basis of the redox reaction between Fe3+ and ascorbic acid (AA), the CD–Fe3+ system can be used as a fluorescent “off–on” sensor for the detection of AA with a limit of detection of 5 μM. What is more, because of their low toxicity and biocompatibility, the CDs can also be used for cell imaging and acted as a fluorescent probe for fluorescence imaging of Fe3+ and AA in living cells. These results demonstrate that the CDs have great potential for application in the fields of sensing, bioimaging, and even disease diagnosis.
KeywordsCarbon dots Flowers of Osmanthus fragrans Lour. Fe3+ Inner filter effect Fluorescent “off–on” sensor Ascorbic acid
This work was supported by the university level fund of Southwest Medical University (no. 2017-ZRQN-032) and a joint program of Luzhou Government and Southwest Medical University [no. 2015LZCYD-S07(2/5)].
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interests.
Ethics approval and consent to participate
This study was approved by the Ethical Committee of Southwest Medical University. All blood samples were from healthy persons with their informed consent.
Human and animal rights
No violation of human or animal rights occurred during this investigation.
- 8.Liu YS, Li W, Wu P, Liu SX. Preparation and applications of carbon quantum dots prepared via hydrothermal carbonization method. Prog Chem. 2018;30:349–64.Google Scholar
- 12.Miao X, Qu D, Yang DX, Nie B, Zhao YK, Fan HY, et al. Synthesis of carbon dots with multiple color emission by controlled graphitization and surface functionalization. Adv Mater. 2018;30:1–8.Google Scholar