基于铜离子修饰金纳米簇“关-开”型荧光探针检测多巴胺

doi:10.7503/cjcu20170251

摘要/Abstract

摘要：

以11-巯基十一烷酸(11-MUA)为还原剂和保护剂, 通过一步水热法合成了具有强烈荧光的水溶性金纳米簇(AuNCs), 基于Cu²⁺修饰的AuNCs@11-MUA构建了“关-开”型荧光探针用于多巴胺(DA) 的选择性、高灵敏检测. 向AuNCs@11-MUA溶液中加入Cu²⁺离子后, AuNCs@11-MUA的荧光发生猝灭, 体系的荧光信号处于“关闭”状态. 在DA存在下, 由于DA与Cu²⁺具有更强的结合力, 形成比Cu²⁺/AuNCs@11-MUA复合体更稳定的络合物, 可将Cu²⁺从AuNCs@11-MUA表面移除下来, 从而使其荧光得以恢复, 体系的荧光信号呈“打开”状态. AuNCs@11-MUA探针的荧光恢复程度与DA的浓度在2.0×10^-7~5.0×10^-5 mol/L范围呈良好的线性关系, 检出限为8.0×10^-8 mol/L(S/N=3). 将该探针应用于人血清和尿液中DA的检测, 回收率为93.2%~97.3%, 相对标准偏差RSD<4.08%, 表明该方法可应用于人体内多巴胺的检测.

关键词: 金纳米簇, 荧光, 铜离子, 多巴胺

Abstract:

One-step hydrothermal method was used for the preparation of water-soluble gold nanoclusters(AuNCs) with strong fluorescence using 11-mercaptoundecanoic acid(11-MUA) as reducing agent and protective agent. A turn-on fluorescent probe based on Cu²⁺ modified AuNCs@11-MUA was developed for the detection of DA with high sensitivity and selectivity. After Cu²⁺ ions were added into AuNCs@11-MUA solution, the fluorescence of AuNCs@11-MUA was quenched, and the fluorescence signal of the system was in the “off” state. In the presence of DA, a more stable complex than the AuNCs@11-MUA-Cu²⁺ complex was formed due to DA and Cu²⁺ have a stronger binding force, which resulted in the departure of Cu²⁺ from the surface of the AuNCs@11-MUA, and the fluorescence signal of the system was “open”. The fluorescence recovery degree of the AuNCs@11-MUA probe showed a good linear relationship with the concentration of DA from 2.0×10^-7 mol/L to 5.0×10^-5 mol/L. The limit of detection was estimated to be 8.0×10^-8 mol/L(S/N=3). The present method was applied for the detection of DA in human serum and urine. Recoveries were found to be in the range of 93.2%—97.3%, and the result of statistical calculation shows that relative standard deviations(RSDs) were lower than 4.08%. The results indicate that present method can be applied for the detection of DA in the human body.

Key words: Gold nanoclusters, Fluorescence, Copper ion, Dopamine

TrendMD:

于锡娟, 韩璐璐, 混旭. 基于铜离子修饰金纳米簇“关-开”型荧光探针检测多巴胺. 高等学校化学学报, 2017, 38(12): 2169.

YU Xijuan, HAN Lulu, HUN Xu. Cu²⁺ Modified Gold Nanoclusters for Fluorescence Turn-on Detection of Dopamine^†. Chem. J. Chinese Universities, 2017, 38(12): 2169.

图/表 15

Fig.1 UV-Vis absorption spectrum of the as-prepared AuNCs@11-MUA

Fig.2 Fluorescence excitation(a) and emission(b) spectra of the AuNCs@11-MUA Inset shows photographs of the AuNCs@11-MUA under 365 nm UV light illumination(left) and sunlight(right).

Fig.3 TEM image of AuNCs@11-MUA

Fig.4 DLS histogram of the AuNCs@11-MUA

Fig.5 Fluorescence emission spectra under UV light of the AuNCs@11-MUA(a), AuNCs@11-MUA+Cu2++DA(b) and AuNCs@11-MUA+Cu2+(c)

Fig.6 Emisson spectra of AuNCs@11-MUA in the presence of varying concentrations of Cu2+

Fig.7 Plot of the fluorescent intensity of AuNCs@11-MUA recorded at 611 nm vs. the concen-tration of Cu2+

Fig.8 Relative fluorescence intensity at 611 nm of the AuNCs@11-MUA in the HEPES buffer at different pH values from 3 to 12

Fig.9 Real-time variation of relative fluorescence intensity(I/I0 at 611 nm) of the AuNCs@11-MUA with Cu2+(A) and Cu2+/AuNCs@11-MUA with DA(B)

Fig.10 Fluorescence emission spectra of AuNCs@11-MUA with the addition of varying concentrations of dopamine

Scheme 1 Scheme 1 Schematic illustration of the Cu2+/AuNCs@11-MUA for dopamine detection

Table 1 Analytical performance of this method compared with other methods

Method	Liner range/(μmol·L^-1)	LOD/(μmol·L^-1)	Ref.
ECL	0.1—50.0	0.040	[10]
ECL	0.2—70.0	0.067	[11]
GC/MS	1.41—2.74	0.004	[12]
DPV	0.05—10.0	0.033	[13]
DPV	0.2—30.0	0.080	[14]
FL	0.1—20.0	0.029	[15]
FL	0.05—8.0	0.018	[16]
FL	0.20—50.0	0.080	This work

Fig.11 Corresponding calibration curve for dopamine detection

Fig.12 Selectivity of the assay for DAa. Ascorbic acid; b. uric acid; c. glycine; d. valine; e. methionine;f. tyrosine; g. tryptophan; h. L-lysine; i. L-cysteine; j. glutathione;k. Ca2+; l. K+; m. Na+; n. Cl-; o. NO3-; p. DA.

Table 2 Determination of dopamine in serum or urine samples(n=5)

Sample	Spiked DA/(μmol·L^-1)	Found/(μmol·L^-1)	Recovery(%)	RSD(%)
Human serum 1	10.0	9.71	97.1	4.08
Human serum 2	20.0	18.64	93.2	1.75
Human serum 3	30.0	28.95	96.5	2.76
Human urine 1	10.0	9.73	97.3	2.6
Human urine 2	20.0	18.96	94.8	3.9
Human urine 3	30.0	28.68	95.6	2.7

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