生物安全性发光碳点纳米材料的制备及其在Hg^2+检测中的应用

Preparation of Eco-Friendly Luminescent Carbon Dots Nanomaterial and Application of Hg ^2+ Detection

环境及食品污染物种类广、含量低,因此相应的分析监测方法须具备灵敏、准确、快速、无二次污染等特点。发光碳点纳米材料是一种新型发光纳米材料,以碳为基本骨架,毒性较低、生物相容性好,能解决传统发光纳米材料的缺陷,并具有更高的发光性能及光稳定性。以盐酸多巴胺为碳源,邻苯二胺为修饰剂,通过简单水热法制备了一批低成本环保发光碳点纳米材料,发射波长在596 nm(λex=532 nm)。经紫外可见光谱、荧光光谱、红外光谱及透射电镜等表征的结果表明,该发光碳点纳米材料具有很好的发光性能,尺寸均一(~3 nm),分散性好。对该材料应用于重金属污染物检测进行了探索。水中汞元素主要以Hg^2+的形式存在,含Hg^2+的水体可以通过土壤渗透污染地下水环境,而Hg^2+在生物体内富集,会使水体中的生物群受到危害,甚至可以通过生活用水及水产品进一步间接地危害到人类的健康。Hg^2+对人体神经细胞产生不可逆转、不可修复的伤害。Hg^2+检测是重金属检测的重中之重。通过金属选择性检测实验进行筛选,结果表明,在一定条件下,发光碳点纳米材料可对Hg^2+实现专一高灵敏快速检测,检出限为0.0006μg·mL^-1(S/N=3,n=6),满足生活用水(<0.001 mg·L^-1)及工业废水(<0.005 mg·L-1)中Hg^2+检测国家标准的要求。在0.001~10μg·mL^-1浓度范围内符合Stern-Volmer方程,且在范围为0~0.04μg·mL^-1(y=190x+0.498,R 2=0.9924),以及0.6~10μg·mL^-1(y=3.2x+18.7,R 2=0.9932),均有良好的线性响应,实际水样中Hg^2+检测的加标回收率在91%~106%(RSD=0.5~1.5)之间。进一步考察了发光碳点纳米材料的生物安全性,细胞毒性MTT分析实验,结果表明随着发光碳点纳米材料浓度的升高,细胞活性并没有出现明显的下降,说明该近红外发光碳点材纳米料毒性较小且具有良好的生物相容性,可在环保监测、示踪传感、生物医学等领域广泛应用。

As the requirement limitation of toxic contaminants such as heavy metals in food and environmental samples is lower and lower,the detection methods developed should be simpler,sensitive and less contaminated.Luminescent carbon dots nanomaterials are a new type of nanomaterials with carbon as a basic skeleton which have been shown low toxicity and excellent fluorescence performance.In our work,low-cost,eco-friendly carbon dots nanomaterial was prepared by simple hydrothermal method using dopamine hydrochloride as carbon source and o-phenylenediamine as a modifier.The carbon dotsemission wavelength was 596 nm(λex=532 nm).The UV-Vis spectra,fluorescence spectra,infrared spectrum and TEM characterization showed that the carbon dots had good optical performance,good dispersion and uniform size(~3 nm).Under the same conditions,the synthesized carbon dots were found selected detection of Hg^2+.The detection of mercury is very important,because it is very poisonous and usually presents in the water sample as a form of Hg^2+ions,and has even irreversible effect on the human being from the contaminated of bio-products in the water.The Stern-Volmer plot with an upward curvature indicates a bindinginduced quenchingof carbon dots at the presence of Hg^2+ions,andthe range of 0~0.04μg·mL^-1(R 2=0.9924)and 0.6~10μg·mL^-1(R 2=0.9932)showed good linear correlation.The detection limit was achieved as 0.0006μg·mL^-1(S/N=3,n=6)which meet the Chinese guidelines for both drinking water and industrial sewage.The spiked recovery of Hg^2+detection in domestic water samples ranged from 91%to 106%(RSD=0.5 to 1.5).In addition,the biosafety of the prepared carbon dots nanomaterial was further investigated,the results of the MTT for cytotoxicity testing in liver cells showed no significant decrease in cell viability by increasingthe concentration of carbon dotsto 40μg·mL^-1,indicating that the carbon dots nanomaterial were low toxic and eco-friendly.The high-performance near-infrared carbon dots nanomaterial have good potential in the application of environmental monitoring and biosensor.