MICROCHEMICAL JOURNAL
·
2020
·
IF 3.594
Wanying Fu,Hongying Wang,Yanwei Chen,Jinglei Ding,Guiye Shan
In this work, a gold nanocluster with lysine (Lys) as a ligand was fabricated, and a novel nanocomposite probe (AuNCs@Lys-MnO 2 ) was prepared based on fluorescence resonance energy transfer (FRET). AuNCs@Lys-MnO 2 was manufactured for sensitive and rapid sensing of glutathione (GSH) in human serum. Gold nanoclusters (AuNCs@Lys) and manganese dioxide nanosheets (MnO 2 nanosheets) are combined by electrostatic interaction. MnO 2 nanosheets can quickly quench the fluorescence of AuNCs@Lys through FRET. GSH has strong reducing ability, which can reduce MnO 2 and degrade AuNCs@Lys-MnO 2 FRET system. The presence of GSH subsequently releases AuNCs@Lys, which causes partial recovery of fluorescent signal. The nanocomposite probe is successfully applied to detect GSH in human serum. Detection range is near the normal value in human serum, and there is no need to dilute the serum during the detection process. This is a fast, simple, and cost-effective strategy. The method can detect GSH in the concentration range of 0.5 to 1000 μM, and has a very high sensitivity, the detection limit is as low as 5 nM.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2019
·Vol. 411
·期 10
·2189-2200
·
IF 3.286
Liu Lu,Du Jie,Liu Wen-e,Guo Yongliang,Wu Guofan,Qi Weinan,Lu Xiaoquan
Enzyme-mimicking (nanozyme)-based biosensors are attractive owing to their unique catalytic efficiency, multifunctionality, and tunable activity, but examples of oxidase-like nanozymes are quite rare. Herein, we demonstrated that histidine-capped gold nanoclusters (His@AuNCs) possessed intrinsic oxidase-like activity, which could directly oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) to blue colored ox-TMB without H 2 O 2 . The assembly of reduced graphene oxide (RGO) with His@AuNCs could further improve its oxidase-like activity and the His@AuNCs/RGO nanocomposites had a lower Michaelis constant ( K m ) and higher catalytic constant ( K cat ) for TMB oxidation. Furthermore, compared to other nanomaterials, the as-prepared His@AuNCs/RGO also exhibited enhanced electrocatalytic activity toward TMB. Interestingly, nitrite inhibited the catalytic (chromogenic) and electrocatalytic processes of His@AuNCs/RGO in the oxidation of TMB. The oxidase-like and electrocatalytic activity of His@AuNCs/RGO was evaluated with nitrite and TMB as substrates, and the results indicated that TMB and nitrite might share the same catalytic active sites. On the basis of these findings, a colorimetric and electrochemical sensor was developed with the His@AuNCs/RGO composite as an oxidase mimic for determination of nitrite with linear ranges of 10–500 μM and 2.5–5700 μM, respectively. The developed method was successfully applied to the detection of nitrites in real samples. The present work suggests that the oxidase-like nanozyme is not only suitable for colorimetric assay but also for development of electrochemical sensors in bioanalysis.
The colorimetric and electrochemical detection of nitrite using His@AuNCs/RGO.
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TALANTA
·
2024
·
IF 5.6
Dongxia Ren,Hua Wei,Na Li,Wenda Fu,Zhijun Huang,Longfei Yang,Shijie Mu
Breast cancer is the most common malignant tumor in women, which accounts for 6.9% of all cancer-related deaths. Early diagnosis is crucial for making the best clinical decision and improving the prognosis of patients. Circulating tumor cells (CTCs) have been regarded as significant tumor biomarkers. Herein, we designed a colorimetric biosensor for breast cancer CTCs quantification based on ladder-branch hybridization chain reaction (HCR) and DNA flowers/gold nanoclusters (DFs/AuNCs) nanozyme. With the assistance of complementary DNA labeled on magnetic beads (MBs), the cleavage products of RNA-cleaving DNAzymes (RCDs) could be rapidly captured, subsequently triggering ladder-branch HCR. In addition, the DFs/AuNCs nanozyme was applied for colorimetric analysis, which further improved the sensitivity for the detection of target CTCs. Benefiting from specific RCDs, ladder-branch HCR and DFs/AuNCs, we achieved a superior detection limit of 3 cells/mL as well as a broad linear range of 10 cells/mL to 10 4 cells/mL. Conclusively, this colorimetric biosensor achieved sensitively and selectively detection of breast cancer CTCs without the participation of enzymes at room temperature, which might provide new insight into the early detection of breast cancer.
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TALANTA
·
2025
·
IF 6.1
Pengyue Song,Doudou Lei,Lingling Li,Nan Long,Qingbin Xu,Ying Li,Lidong Zhou,Ruile Pan,Weijun Kong
Regarding the high incidence of residue and serious toxicity of acetochlor (ATC) pesticide, it is urgent to explore simple and low-cost methods for their sensitive detection in food. In this study, with zeolite-like imidazole frameworks (ZIFs) as the carriers for embedding glutathione-modified luminescent gold nanoclusters (GSH-AuNCs) exhibiting aggregation-induced emission (AIE) effect, a GSH-AuNCs@ZIF-8 probe driven strip-based lateral flow immunosensor (LFIS) was developed for visual qualitative and fluorescent quantitative dual-modal detection of ATC. The encapsulation of GSH-AuNCs into ZIF-8 with restriction effect not only significantly improved the stability and anti-interference ability of AuNCs, but also remarkably enhanced the fluorescence efficiency for signal amplification due to the enhanced AIE effect of GSH-AuNCs, endowing the LFIS platform with unique performance. Under optimal conditions, the LFIS platform could realize the point-of-care visualization and quantitation of ATC within 20 min with a detection limit of 8.3 pg/mL and a broad linear range of 0.01–10.0 ng/mL. High recoveries of 96.44%–106.8 % in the spiked ginger samples confirmed the outstanding accuracy and dependability of the new platform for ATC analysis of real samples. Compared with other immunoassays, the AuNCs@ZIF-8-based dual-modal LFIS exhibited the advantages of simple preparation, simple operation, short analytical time, and low cost, which could be expanded to monitor more pesticides and more trace contaminants in diverse food and agricultural products, and medicinal material matrices.
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Food Chemistry-X
·
2024
·
IF 6.5
Doudou Lei,Lingling Li,Pengyue Song,QingBin Xu,Lihua Huang,Xiao Ma,Lidong Zhou,Weijun Kong
Glyphosate (Gly) is a widely-used herbicide in food production, while, the residue of which due to the long-term and excessive overspray poses serious threats to public health. The development of reliable methods for its sensitive detection is of great urgency. In this study, a novel ratiometric fluorescent nanosensor by encapsulating N-doped carbon dots (N-CDs) and gold nanoclusters (AuNCs) in zeolitic imidazole framework-8 (ZIF-8) as the dual-emissive fluorescence probes at 410 and 650 nm, respectively, was constructed for Gly detection. Due to the adsorption property of ZIF-8, the N-CDs/AuNCs@ZIF-8 nanoprobes accumulated Cu 2+ to quench the red fluorescence of AuNCs, and the blue fluorescence of N-CDs was stable. While thiocholine, a product of acetylthiocholine, hydrolyzed by acetylcholinesterase could coordinate with Cu 2+ , resulting in significant fluorescence recovery of AuNCs. This phenomenon was utilized for the quantitation of Gly, due to its inhibitory effect on acetylcholinesterase activity. By calculating the fluorescence intensity ratio ( I 650 /I 410 ), Gly in real sample could be accurately determined in a concentration range of 2–100 ng/mL with a limit of detection of 1.92 ng/mL because of the anti-interference and the self-correction ability of the two fluorescence signals. The N-CDs/AuNCs@ZIF-8 nanoprobes-assisted ratiometric fluorescent nanosensor exhibited unique merits of rapid construction, simple operation, high specificity, and good accuracy for Gly in edible and medicinal malt samples with recoveries of 93.7–108.2 %. This study presents a multiple tool for the versatile sensing of trace pesticides in more food matrices, which can be extended to a full range of environmental and food safety applications.
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MICROCHEMICAL JOURNAL
·
2021
·
IF 4.821
Minting Li,Nengwu Zhu,Wen Zhu,Sihai Zhang,Fei Li,Pingxiao Wu,Xinyu Li
Tetracyclines, cheap and broad-spectrum antibiotics, are required to strictly monitor since they can lead to ecosystem disorders and the flood of resistance genes if overused. Although ovalbumin has been reported to synthesize metal nanoclusters for fluorescence detection, relatively low fluorescence intensity and quantum yield limited their application. In this study, ovalbumin-stabilized gold nanoclusters (OVA-AuNCs) modified by polyethyleneimine (PEI-OVA-AuNCs) with higher fluorescence intensity and quantum yield were successfully synthesized and applied to develop a sensitive fluorescent detection method for tetracycline antibiotics. The fluorescence intensity of the stable PEI-OVA-AuNCs modified with 10 μM PEI was 8.5 times stronger than unmodified OVA-AuNCs. The reason of the fluorescence intensity enhancement could be attributed to etching OVA-AuNCs from large particles to smaller ones by PEI and formation of a protective layer on the outside of the clusters to avoid non-radiative relaxation. The fluorescence quenching was linearly related to tetracycline (TC) in the concentration range 1–30 μM, and the detection limit was 0.563 μM. Meanwhile, the fluorescent probe could detect oxytetracycline and chlortetracycline with the linear correlations higher than 0.99. The quenching mechanism was inner filter effect caused by the overlap of the spectra of PEI-OVA-AuNCs and pollutants, and the aggregation-induced quenching caused by the binding of phenolic hydroxyl and ketone carbonyl groups on the pollutants to the probe as well. The method was successfully applied to the determination of TC in real samples. Therefore, PEI-OVA-AuNCs could be considered as a core material for tetracyclines fluorescence detection.
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FOOD CHEMISTRY
·
2023
·
IF 8.8
Xiaoyang Wang,Huajie Yu,Qiuhong Li,Yuhang Tian,Xiaolin Gao,Wanqi Zhang,Zhicong Sun,Yaoting Mou,Xia Sun,Yemin Guo,Falan Li
A novel dual-signal fluorescent sensor was developed for detecting organophosphorus pesticides (OPs). It relies on the catalytic activities of acetylcholinesterase (AChE) and choline oxidase (ChOx) to generate hydrogen peroxide (H 2 O 2 ) through the conversion of acetylcholine (ACh) to choline·H 2 O 2 then oxidizes ferrocene-modified tetraphenylethylene (TPE-Fc) to its oxidized state (TPE-Fc + ), resulting in enhanced cyan fluorescence due to aggregation. Simultaneously, ferrocene oxidation generates hydroxyl radicals (•OH), causing a decrease in orange fluorescence of glutathione-synthesized gold nanoclusters (GSH-AuNCs). The presence of OPs restricts AChE activity, reducing H 2 O 2 production. Increasing OPs concentration leads to decreased cyan fluorescence and increased orange fluorescence, enabling visual OPs detection. The sensor has a linear dynamic range of 10–2000 ng/mL with a detection limit of 2.05 ng/mL. Smartphone-based color identification and a WeChat mini program were utilized for rapid OPs analysis with successful outcomes.
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MICROCHIMICA ACTA
·
2024
·Vol. 191
·期 7
·1-13
·
IF 5.3
Li Ziqiang,Liang Shuang,Zhang Changsheng,Zhou Li,Luo Fengjian,Lou Zhengyun,Chen Zongmao,Zhang Xinzhong,Yang Mei
A ratiometric fluorescence sensing strategy has been developed for the determination of Cu 2+ and glyphosate with high sensitivity and specificity based on OPD (o-phenylenediamine) and glutathione-stabilized gold nanoclusters (GSH-AuNCs). Water-soluble 1.75-nm size GSH-AuNCs with strong red fluorescence and maximum emission wavelength at 682 nm were synthesized using GSH as the template. OPD was oxidized by Cu 2+ , which produced the bright yellow fluorescence oxidation product 2,3-diaminophenazine (DAP) with a maximum fluorescence emission peak at 570 nm. When glyphosate existed in the system, the chelation between glyphosate and Cu 2+ hindered the formation of DAP and reduced the fluorescence intensity of the system at the wavelength of 570 nm. Meanwhile, the fluorescence intensity at the wavelength of 682 nm remained basically stable. It exhibited a good linear relationship towards Cu 2+ and glyphosate in water in the range 1.0–10 µM and 0.050–3.0 µg/mL with a detection limit of 0.547 µM and 0.0028 µg/mL, respectively. The method was also used for the semi-quantitative determination of Cu 2+ and glyphosate in water by fluorescence color changes visually detected by the naked eyes in the range 1.0–10 µM and 0.30–3.0 µg/mL, respectively. The sensing strategy showed higher sensitivity, more obvious color changes, and better disturbance performance, satisfying with the detection demands of Cu 2+ and glyphosate in environmental water samples. The study provides a reliable detection strategy in the environment safety fields. Graphical abstract
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JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Xin-Yu Chang,Hong-Wei Li,Yuqing Wu
The composites of H 2 N-ZIF-8 supported gold nanoclusters (AuNCs@H 2 N-ZIF-8) were prepared by UV-induced photochemical reduction method in the methanol–water solution. The photochemical reaction was attributed to the generation of free radical as. CH 2 ·–OH, which reduced Au(III) to Au(0) and produced monodisperse AuNCs (<2.5 nm) in the mesoporous of H 2 N-ZIF-8. The generated AuNCs@H 2 N-ZIF-8 show oxidase-like properties to catalyze the oxidation of TMB, ABTS and OPD under mild conditions. Besides, the mechanism study by EPR shows that the composites can promote oxygen to generate singlet oxygen ( 1 O 2 ) and superoxide radicals ( ·O 2 - ), endowing it excellent catalytic activity of oxidation. Further studies revealed that the large number of exposed small AuNCs in the mesoporous pores of H 2 N-ZIF-8 and the highly active 211 crystalline facets formed at the edges contribute to the ROS generation intrinsically. Therefore, the present study demonstrates the significance of photochemical reduction method to prepare highly efficient oxidase-like materials, opening up a new avenue to construct noble metal materials as ultra-small nanozyme.
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ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Xiaoling Sun,Zhizhuo Gu,YiFan Gao,Maosheng Liang,Lian Xia,Fengli Qu
Luminescent thermometry affords remote measurement of temperature and shows huge potential in future technology beyond those possible with traditional methods. Strategies of temperature measurement aiming to increase thermal sensitivity in a wide temperature response window would represent a pivotal step forward, but most thermometers cannot do both of them. Herein, we propose a balancing strategy to achieve a trade-off between high Arrhenius activation energy (Ea), which could stretch the temperature response windows, and fluorescence quantum yields (QYs) in a manner that will increase thermal sensitivity in a wide response window. In particular, a luminescent thermometer composed of AuNCs-MOF is prepared via a facile impregnation process to enhance QYs and Ea, responsible for high relative sensitivity (Sr) (15.6% K–1) and ultrawide temperature linearity range (from 83 to 343 K), respectively. Taking fluorescence intensity and lifetime as multiple parameters, the maximum Sr can reach 22.4% K–1 by multiple linear regression. The maximum Sr and temperature response range of the proposed thermometer outperform those of the most recent luminescent thermometers. The strategy of balancing Sr and thermal response range by regulating Ea and QYs enables the construction of ultra-accurate thermal sensors in the age of artificial intelligence.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2026
·
IF 8.3
Xuan Zhou,Lei Yuan,Zongbao Sun,Wen Zhang
Residual organophosphorus pesticides (OPs) frequently contaminate farm products, such as vegetables, and consequently threaten food safety. Herein, we present an enzyme-regulated dual-emission probe, MIL-53-OPH@S-S-AuNCs, for synchronous OPs hydrolysis and fluorescence determination. The probe, containing NH 2 -MIL-53(Al), organophosphorus hydrolase (OPH), and disulfide-functionalized Au nanoclusters (S-S-AuNCs), thus provides two emissive outputs (F 427 and F 655 ). Specifically, an OPH-assisted hydrolysis route is designed, where OPs are converted into class-informative products, including p-nitrophenol (PNP) and thiol/thiolate species (R-SH/S - ). PNP induces pronounced quenching of the blue emission (F 427 ) via resonance energy transfer, while sulfur-containing products perturb the disulfide-crosslinked state of S-S-AuNCs and attenuate the red emission (F 655 ). Stepwise optimizations are performed to promote efficient catalytic conversion and stable dual-channel readout, where quenching time, pH, and temperature are tuned to achieve pleasurable sensing conditions. This method provides log-linear quantification for OPs in a wide range of 6.5 × 10 −6 ∼20 μg mL −1 , with an impressive limit of detection of 3.4 × 10 −6 μg mL −1 . The proposed method is further validated by natural sample analyses and recovery tests in real vegetables, giving relative errors of 4.2∼8.6% and recoveries of 96.2∼105.2%.
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TALANTA
·
2017
·
IF 4.162
Zhen Zhang,Nuanfei Zhu,Yanmin Zou,Xiangyang Wu,Guangbo Qu,Jianbo Shi
A novel, competitive, enzyme-linked immunosorbent assay (ELISA) was presented in this paper based on the inhibition of catalysis of AuNCs@BSA triggered by dissolved Ag + for the detection of dibutyl phthalate (DBP). In the immunoassay system, numerous Ag + was released from AgNPs (labelled on the second antibody, AgNPs@Ab 2 ) in the presence of H 2 O 2 after the competition step, preventing AuNCs@BSA from inducing a color change of 3,3′,5,5′-tetramethylbenzidine (TMB) to blue. Due to the signal amplification by the principle, the sensitivity of the modified ELISA was improved with the low limit of detection (LOD) of 4.017 μg/L for DBP, which was decreased 16 times relative to that using conventional ELISA with the same antibody. In addition, the established method showed satisfactory accuracy and reliability (recoveries, 85.75–117.73%; CV, 1.33–6.79%) in spike-recovery analysis. To the best of our knowledge, this is the first time that AuNCs@BSA has been used in ELISA as a peroxidase-like catalyst. Our method shows great potential for trace DBP detection from environmental and food samples.
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