Analytical Methods
·
2019
·Vol. 12
·期 1
·63-72
·
IF 2.378
Nasibeh Saeedzadeh Amiri,Mohammad-Reza Milani Hosseini
Molecularly imprinted polymer-coated quantum dots (MIP@QDs) as fluorescent sensors modified with ratiometric fluorescence techniques and mesoporous structured epitope-imprinted silica materials (QDs@SiO2@EMSiO2) were fabricated and applied for the detection of tyrosine phosphopeptide (pTyr) for the first time. The probe exhibited dual-emission peaks at 520 and 625 nm under the single excitation wavelength of 400 nm. The pTyr molecules could selectively quench the QDs, which had red emission, but the intensity of the QDs with green emission did not change; thus, it was considered as an internal reference. These phenomena caused a discernible change in the fluorescence color from orange to green under a UV lamp. In this work, phenylphosphonic acid and 1-tetradecyl-3-methylimidazolium chloride were utilized as the template molecule and template for mesoporous silica, respectively. 1-Propyltrimethoxysilane-3-methylimidazolium chloride was applied as the functional monomer and 3-aminopropyltriethoxysilane was employed as the cross-linker. Meanwhile, the conventional heating technique, namely, hydrothermal synthesis was substituted with the microwave heating method, resulting in fast, uniform and controllable nucleation and growth of the nanoparticles. The suggested epitope-imprinted polymer-coated mesoporous structured fluorescence composite compared with the non-mesoporous structured composite and single-emission MIP biosensor demonstrated excellent efficiency. Under the optimum conditions, the linear range and the detection limit obtained were 0.07–230 μM and 34 nM, respectively. Besides, the suggested nano-biosensor depicted highly reproducible results in the probing of real samples, with recoveries between 95.85% and 103.23%.
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DYES AND PIGMENTS
·
2018
·
IF 3.767
Shenghong Yang,Wenjing Guo,Xiaohan Sun
A ratiometric fluorescence probe for robust and rapid Cu 2+ detection was established based on an electrostatic association complex of polyallylamine capped CdTe(S) quantum dots (CdTe(S)@PAI QDs) and a small molecule dye 5-oxo-3,5-dihydro-2H-thiazolo[3,2-a]pyridine-7-carboxylic acid (TPCA). Both of the components are easy to make. Strongly fluorescent CdTe(S)@PAI QDs could be simply prepared through a one-step UV irradiation while TPCA could be obtained directly through the hydrothermal method . The ratiometric probe was built through mixing of both components, neither organic solvent nor other harsh conditions is involved. The as-prepared probe shows dual-emission at 525 nm and 420 nm under excitation wavelength of 350 nm. The fluorescence ratio ( I 525nm /I 420nm ) remains constant with concentration changes of the complex up to ± 20% and a temperature variation from 20 to 50 °C, but shows significant change in the presence of Cu 2+ . The proposed probe exhibits excellent selectivity and sensitivity for Cu 2+ . The fluorescence ratio ( I 525nm /I 420nm ) show good linear relationship with the Cu 2+ concentration range from 0.05 to 1.6 μM and the limit of detection (S/N = 3) can reach 24 nM . Its applicability was demonstrated by detecting Cu 2+ ions in certified reference materials and real samples with recoveries in a range of 91.0–107.3%.
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MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Xintian Wang,Hengye Chen,Yao Fan,Wei Lan,Juan He,Haiyan Fu,Xiaolong Yang
The economic and medicinal value of Atractylodis Rhizoma (AR) is intricately tied to its geographical origin and mainly depends on the atractylodin (IUPAC Name: 2-[(1E,7E)-nona-1,7-dien-3,5-diynyl]furan) content in it. In this study, a green fluorescent sensor using N-acetyl-L-cysteine (NAC, IUPAC Name: (2R)-2-acetamido-3-sulfanylpropanoic acid)-capped CdTe quantum dots (QDs) was developed for the detection of AR origin discrimination. Both electron transfer and internal filtration effects was introduced into sensor to improve the sensitivity and selectivity. The sensors can achieve visual quantitative analysis of atractylodin using the partial least squares regression (PLSR) model. This model with a detection limit of 0.321 µg /mL and the quantification range of 0.002–0.030 mg /mL. Furthermore, the visual sensor also could be applied to the quantification of atractylodin in the actual AR samples with recoveries as high as 95.36 % to 105 %. Their sensor was also able to identify different origin of AR with an accuracy of 100 % for the training set and 95.29 % for the prediction set using the Partial Least Squares Discriminant Analysis (PLSDA) model. The method offers direction for verifying the authenticity of traditional Chinese medicine and precise analysis of intended constituents in complex systems.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2022
·
IF 9.221
Wenqi Zhang,Jiang Ling,Di Wen,Zijia Cheng,Suiping Wang,Yanjun Ding
The early diagnosis of acute myocardial infarction (AMI) was a tough nut in both clinical medicine and forensic science since the occurrence of gross changes needed at least 12 h. Compared to other diagnostic methods, microRNA was reported as an earlier cardiac biomarker with higher sensitive. In this work, we designed a novel fluorescent analytical strategy using a dual-emission probe based on T7 Exo-assisted target recycling amplification for simultaneous detection of AMI-related miR-199a and miR-499, which could indicate myocardial ischemia or damage in AMI. The dual-emission probe was conducted by yellow-emission and red-emission CdTe quantum dots capped with beta-cyclodextrin. The florescence of probe was firstly quenched by graphene oxide (GO) and then recovered in the presence of target miR-199a and miR-499. Under the optimized conditions, the limit of detection as low as 0.1 pM was obtained and the overall test could be performed within 50 min. Besides, the simultaneous detections of microRNAs in spiked serum samples were achieved with the recovery of 81.3–109.6%, which suggested the potential method for diagnosis in practical. The advantages of this method include easy operation, high accuracy and low labor cost, which makes point-of-care test possible both in hospital and forensic application.
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MICROCHEMICAL JOURNAL
·
2023
·
IF 4.8
Hui Cao,Xiner Ding,Zixin Chen,Jialuo Mao,Xiuna Ma,Ziqi Wei,Tai Ye,Min Yuan,Jinsong Yu,Xiuxiu Wu,Fengqin Yin,Fei Xu
EDTA-etched CdTe@CdS QDs were used as the specific recognition element and signal probe of a fluorescence sensor or paper chip for the highly sensitive detection of Cd(II) with an electronic eye device as readout. The results showed that the CdTe@CdS QDs were successfully synthesized with a typical core–shell structure. Under the optimum conditions, the EDTA-etched CdTe@CdS QDs sensor achieved the sensitive detection of Cd(II) with a detection limit of 0.092 μM and a concentration range of 0.44–6.67 μM. The paper chips based on the EDTA-etched CdTe@CdS QDs sensor had a visual cut-off value of 0.44 μM with a short detection time (<15 min). The proposed method also exhibited excellent stability, high specificity, and good recovery for Cd(II) in real rice samples. These results suggested that the EDTA-etched CdTe@CdS QDs provide a promising platform for on-site and visual detection of Cd(II) in rice samples.
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JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
·
2020
·Vol. 101
·期 6
·2552-2560
·
IF 2.614
Hengye Chen,Liuna Wei,Xiaoming Guo,Chengying Hai,Lu Xu,Lei Zhang,Wei Lan,Chunsong Zhou,Yuanbin She,Haiyan Fu
BACKGROUND The quality of tea is influenced by numerous factors, especially l- theanine, which is one of the important markers used to evaluate the sweetness and freshness of tea. Sensitive, rapid, and accurate detection of l -theanine is therefore useful to identify the grade and quality of tea. RESULTS A high-sensitivity, paper-based fluorescent sensor combined with chemometrics was established to detect l- theanine in tea water based on CdTe quantum dots / corn carbon dots and nano tetra pyridel-porphine zinc (ZnTPyP). To verify the reliability of this method, fluorescence spectra and fluorescence-visualized paper-based sensors were compared. The fluorescence spectrum method demonstrated a linear range of 1 to 10 000 nmol L −1 and a limit of detection (LOD) of 0.19 nmol L −1 . In the fluorescence-visualized paper-based sensors there was a linear range of 10–1000 nmol L −1 , and the LOD was 10 nmol L −1 . Partial least squares discriminant analysis (PLSDA) and partial least squares regression analysis (PLSR) were used successfully to determine l -theanine accurately in tea water with this approach. The accuracy of the PLSDA model was 100% both in the training set and the predicting set, and the correlation coefficient between the actual concentration and the predicted concentration was greater than 0.9997 in the PLSR model. CONCLUSION This fluorescence-visualized paper-based sensor, combined with chemometrics, could be applied efficiently to the practical analysis of tea water samples, which provides a new idea to ensure the flavor and quality of tea. © 2020 Society of Chemical Industry
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ANALYTICAL LETTERS
·
2021
·
IF 2.329
Penghui Jin,Daoqing Ma,Yabiao Gao,Libin Wang,Zhihong Gao,Yating Zhang,Mingxin Liu,Jingying Xu,Jidong Wang
A highly sensitive and dual-directional fluorescent sensing system was developed to detect both cisplatin prodrug cross-linked hyaluronic acid (CPHA) hydrogel (quencher) and DNA (receptor) based on mercaptopropionic acid (MPA) capped CdTe quantum dots (QDs). Different from the previous work for this platinum compound, a multifunctional delivery system, CPHA hydrogel, which was used to address the challenges in drug resistance and severe side effects, was prepared and accurately detected based on the synthesis of the cisplatin prodrug and fluorescence quenching of CdTe QDs resulting from photo-induced electron transfer. When DNA was conjugated with Pt ions in a system composed of CdTe QDs and CPHA hydrogel, the fluorescence of the system was recovered for the determination of DNA. This reversible “turn off–on” strategy presented a high sensitivity and low detection for CPHA hydrogel from 10 to 50 nM with a detection limit of 1.50 nM and DNA from 0 to 75 nM with a detection limit of 0.60 nM. This approach provides a novel direction for further study of the Pt based drug-load with reduced side effects and improved therapy efficacy, effective screening of anticancer drugs, and accurate determination of DNA at low concentrations.
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Toxins
·
2013
·Vol. 5
·期 5
·865-883
·
IF 2.129
Ning Gan,Jing Zhou,Ping Xiong,Futao Hu,Yuting Cao,Tianhua Li,Qianli Jiang
An ultrasensitive electrochemiluminescent immunoassay (ECLIA) for aflatoxins M1 (ATM1) in milk using magnetic Fe3O4-graphene oxides (Fe-GO) as the absorbent and antibody-labeled cadmium telluride quantum dots (CdTe QDs) as the signal tag is presented. Firstly, Fe3O4nanoparticles were immobilized on GO to fabricate the magnetic nanocomposites, which were used as absorbent to ATM1. Secondly, aflatoxin M1 antibody (primary antibody, ATM1 Ab1), was attached to the surface of the CdTe QDs-carbon nanotubes nanocomposite to form the signal tag (ATM1 Ab1/CdTe-CNT). The above materials were characterized. The optimal experimental conditions were obtained. Thirdly, Fe-GO was employed for extraction of ATM1 in milk. Results indicated that it can adsorb ATM1 efficiently and selectively within a large extent of pH from 3.0 to 8.0. Adsorption processes reached 95% of the equilibrium within 10 min. Lastly, the ATM1 with a serial of concentrations absorbed on Fe-GO was conjugated with ATM1 Ab1/CdTe-CNT signal tag based on sandwich immunoassay. The immunocomplex can emit a strong ECL signal whose intensity depended linearly on the logarithm of ATM1 concentration from 1.0 to 1.0 × 105pg/mL, with the detection limit (LOD) of 0.3 pg/mL (S/N= 3). The method was more sensitive for ATM1 detection compared to the ELISA method. Finally, ten samples of milk were tested based on the immunoassay. The method is fast and requires very little sample preparation, which was suitable for high-throughput screening of mycotoxins in food.Keywords:aflatoxin M1;Fe3O4-graphene nanocomposite;cadmium telluride-quantumn dots;milk;electrochemiluminescence immunoassay;mycotoxins
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Journal of Materials Chemistry C
·
2016
·Vol. 4
·期 41
·9856-9863
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IF 5.066
Jun Yao,Xin Gou
In this paper, we report a green, ultrafast and facile aqueous preparation of highly luminescent core–shell CdTe/CdS with significant stability under atmospheric pressure. The surface topography, size, physical shape as well as crystalline structures were studied fully and in depth by adopting a variety of analytical methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). The possible mechanism involved in the core growth was proposed and the relevant processes were conjectured too. In this study, we presented a convenient label-free fluorescence nanosensor for the rapid determination of trace mercury, which exhibited many advantages, such as a high sensitivity, excellent selectivity, a rapid response time, a wide linear range and a low limit of detection (LOD). The LOD is down to 1.7 × 10−9 mol L−1, which is lower than that of most other detection methods for mercury.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Jing Wang,Daquan Li,Yu Qiu,Xinyue Liu,Xin Zhang,Liang Huang,Huimin Wen,Jun Hu
Developing a reliable fluorescent nanosensor for cyanide anions (CN − ), with the potential to enable visual discrimination by naked eye, is highly sought after yet is limited by low sensitivity and selectivity. Herein based on the synergistic effect of fluorescence recovery and enhancement, a specific dual-emission nano-system was designed for ultrasensitive detection of CN − , by employing carbon dots (peaking at 443 nm) as a reference and N-acetyl-L-cysteine (NALC)-capped CdTe quantum dots (QDs, peaking at 611 nm) as a reporter. The red fluorescence of CdTe QDs is first quenched by Cu 2+ primarily with electron transfer. Upon addition of CN − , CN − coordinates with Cu 2+ to form [Cu(CN) n ] (n−1)− complex, causing the Cu 2+ to detach from the QDs, and consequently fluorescence recovery. More importantly, the CN − can undergo a nucleophilic addition reaction with the carbonyl group of NALC ligands, inducing 1.3-fold fluorescence enhancement towards the original QDs while the blue fluorescence of carbon dots remains constant. This results the fluorescence intensity ratios ( I 611 / I 443 ) are proportional to the concentrations of CN − in the ranges of 0.02―10 and 15―80 μM, and an ultra-low detection limit down to 10.35 nM is achieved. By using both Cu 2+ -promoted complexation and addition reaction as recognition units, the present method also showed excellent selectivity for CN − over other coexisting anions. Especially, we have already demonstrated, by spiked tests, the practicability of monitoring the concentration changes of CN − in both environmental water and cassava samples, and further realized visual monitoring of CN − changes in aqueous solution and test paper.
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ANALYST
·
2014
·Vol. 139
·期 22
·5858-5867
·
IF 3.906
Yizhong Shen,Shaopu Liu,Ling Kong,Xuanping Tan,Youqiu He,Jidong Yang
Although various strategies have been reported for double-stranded DNA (DNA) detection, development of a time-saving, specific, and regeneratable fluorescence sensing platform still remains a desired goal. In this study, we proposed a new DNA detection method that relies on an “off-on” switch of a regenerated fluorescence biosensor based on an electron transfer mechanism from glutathione (GSH)-capped CdTe quantum dots (QDs) to nile blue (NB). Initially, the high fluorescence of GSH-capped CdTe QDs could be effectively quenched by NB due to the binding of NB to the GSH on the surface of the QDs and the electron transfer from the photoexcited GSH-capped CdTe QDs to NB. Then, the high affinity of DNA to NB enabled the NB to be dissociated from the surface of GSH-capped CdTe QDs to form a more stable complex with DNA and suppress the electron transfer process between GSH-capped CdTe QDs and NB, thereby restoring the fluorescence of NB surface modified GSH-capped CdTe QDs (QDs–NB). In addition, we have testified the regenerability of the proposed DNA senor. The corresponding result shows that this DNA sensor is stable for two reuses. This fluorescence “off-on” signal was sensitive to the concentration of DNA in the range from 0.0092 to 25.0 μg mL−1 with a good correlation coefficient of 0.9989, and the detection limit (3σ/S) was 2.78 ng mL−1. To further investigate for perfect analysis performance, the developed biosensor was applied for the determination of DNA in human fresh serum samples with satisfactory results.
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MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 12
·4637-4646
·
IF 4.58
Hu Jie,Guo Feng,Wang Li
The authors describe an electrostatic self-assembly strategy for the modification of a glassy carbon electrode (GCE) with CdTe quantum dots (QDs), cetyltrimethylammonium bromide, chitosan, and multiwalled carbon nanotubes (MWCNTs). The nanocomposite was characterized by scanning electron microscopy revealing the distribution of spherically shaped CdTe QDs on the tubular networks of the MWCNTs. The modified GCE is shown to enable improved voltammetric sensing of nitrite, best at a working potential of 0.78 V (vs. SCE). The synergetic effect of the four components leads to rapid electron transfer and in an increased active area. Hence, excellent electrocatalytic activity towards the oxidation of nitrite is observed. Square wave voltammetry was applied to quantify nitrite, and the two linear ranges cover the 1 to 100 μmol L −1 and 100 to 600 μmol L −1 nitrite concentration ranges. The detection limit is 0.30 μmol L −1 . The method was applied to the determination of nitrite in pickled vegetables and the results were compared to a UV-Vis method. The method is found to be sensitive, accurate, rapid, and well repeatable.
Schematic illustration of the procedure of the modification of a glassy carbon electrode (GCE) with CdTe quantum dots (QDs), cetyltrimethylammonium bromide (CTAB); chitosan (Chit) and multiwalled carbon nanotubes (MWCNTs).
研究领域:
分析化学
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纳米技术
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环境科学
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