The Application of Green-Synthesis-Derived Carbon Quantum Dots to Bioimaging and the Analysis of Mercury(II).

Qianchun Zhang,Yuan Wang,Xiaolan Zhang,Yuguo Zheng,Li Jiang,Linchun Bao,Yun Wu,Yafei Chen

doi:10.1155/2019/8183134

Abstract

Ginkgo leaves were used as precursors for the hydrothermal synthesis of carbon quantum dots (CQDs), which were subsequently characterized by transmission electron microscopy as well as Fourier-transform infrared, X-ray powder diffraction, and X-ray photoelectron spectroscopy. The prepared CQDs exhibited a fluorescence quantum yield of 11% and superior water solubility and fluorescence stability, as well as low cytotoxicities and excellent biocompatibilities with A549 and HeLa cells; these CQDs were also used to bioimage HeLa cells. Moreover, owing to the experimental observation that Hg2+ quenches the fluorescence of the CQDs in a specific and sensitive manner, we developed a method for the detection of Hg2+ using this fluorescence sensor. The sensor exhibited a linear range for Hg2+ of 0.50–20 μM, with an excellent coefficient of determination (R2 = 0.9966) and limit of detection (12.4 nM). In practice, the proposed method was shown to be highly selective and sensitive for the monitoring of Hg2+ in lake water and serum samples.

Highlights

Carbon quantum dots (CQDs) are receiving significant attention because of their stable photoluminescence properties, lack of bleaching, low toxicity, and biocompatibility [1,2,3]. ese superior qualities are promising for bioimaging applications [4, 5], metal-ion detection [6, 7], fluorescence labelling [8], sensing [9], catalysis [10], and optics [11], with analysis techniques based on CQDs expected to be cost effective, highly sensitive, and easy to use
Considering the operating security of para-polyphenyl equipped stainless-steel autoclave, the temperature of 220°C was used. e effect of reaction time was investigated at a concentration of 0.420 g/mL, from 4 h to 14 h at a constant temperature of 220°C, and the results indicated more CQD particles were obtained and suggested reaction time of 10 h was adopted (Figure 1(c))
Characterizing the Carbon Quantum Dots. e morphology, fine structure, and particle size of the as-prepared CQDs were characterized by High-resolution transmission electron microscopy (HRTEM), as shown in Figure 2(a), which reveals that the CQDs are nearly spherical and monodispersed

Summary

Introduction

Carbon quantum dots (CQDs) are receiving significant attention because of their stable photoluminescence properties, lack of bleaching, low toxicity, and biocompatibility [1,2,3]. ese superior qualities are promising for bioimaging applications [4, 5], metal-ion detection [6, 7], fluorescence labelling [8], sensing [9], catalysis [10], and optics [11], with analysis techniques based on CQDs expected to be cost effective, highly sensitive, and easy to use. Carbon quantum dots (CQDs) are receiving significant attention because of their stable photoluminescence properties, lack of bleaching, low toxicity, and biocompatibility [1,2,3]. E fluorescence method is more widely applied, and it has avoidably complicated sample preparation, using expensive instrumentations and professional skills. In this regard, some works have been reported for mercury (II) detection [14,15,16,17], such as Yue et al [16] who used apple juice as the carbon source.

Methods

Results

Conclusion