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In this paper, a label-free fluorescent method for glutathione (GSH) detection based on a thioflavin T/G-quadruplex conformational switch is developed. The sensing assay is fabricated depending on the virtue of mercury ions to form a thymine–thymine mismatch, which collapses the distance between two ssDNA and directs the guanine-rich part to form an intra-strand asymmetric split G-quadruplex. The newly formed G-quadruplex efficiently reacts with thioflavin T and enhances the fluorescent intensity. In the presence of GSH, Hg2+ is absorbed, destroying the G-quadruplex formation with a significant decrease in fluorescence emission. The proposed fluorescent assay exhibits a linear range between 0.03–5 μM of GSH with a detection limit of 9.8 nM. Furthermore, the efficacy of this method is examined using human serum samples to detect GSH. Besides GSH, other amino acids are also investigated in standard samples, which display satisfactory sensitivity and selectivity. Above all, we develop a method with features including potentiality, facility, sensitivity, and selectivity for analyzing GSH for clinical diagnostics.
Xi Zhou; Doudou Zhang; Ying Yan; Hailun He; Yukui Zhou; Changbei Ma. A Label-Free Fluorometric Glutathione Assay Based on a Conformational Switch of G-quadruplex. Molecules 2021, 26, 2743 .
AMA StyleXi Zhou, Doudou Zhang, Ying Yan, Hailun He, Yukui Zhou, Changbei Ma. A Label-Free Fluorometric Glutathione Assay Based on a Conformational Switch of G-quadruplex. Molecules. 2021; 26 (9):2743.
Chicago/Turabian StyleXi Zhou; Doudou Zhang; Ying Yan; Hailun He; Yukui Zhou; Changbei Ma. 2021. "A Label-Free Fluorometric Glutathione Assay Based on a Conformational Switch of G-quadruplex." Molecules 26, no. 9: 2743.
As an important DNA 3′-phosphatase, alkaline phosphatase can repair damaged DNA caused by replication and recombination. It is essential to measure the level of alkaline phosphatase to indicate some potential diseases, such as cancer, related to alkaline phosphatase. Here, we designed a simple and fast method to detect alkaline phosphatase quantitively. When alkaline phosphatase is present, the resulting poly T-DNA with a 3′-hydroxyl end was cleaved by exonuclease I, prohibiting the formation of fluorescent copper nanoparticles. However, the fluorescent copper nanoparticles can be monitored with the absence of alkaline phosphatase. Hence, we can detect alkaline phosphatase with this turn-off strategy. The proposed method is able to quantify the concentration of alkaline phosphatase with the LOD of 0.0098 U/L. Furthermore, we utilized this method to measure the effects of inhibitor Na3VO4 on alkaline phosphatase. In addition, it was successfully applied to quantify the level of alkaline phosphatase in human serum. The proposed strategy is sensitive, selective, cost effective, and timesaving, having a great potential to detect alkaline phosphatase quantitatively in clinical diagnosis.
Yan Wang; Ying Yan; Xinfa Liu; Changbei Ma. An Exonuclease I-Aided Turn-Off Fluorescent Strategy for Alkaline Phosphatase Assay Based on Terminal Protection and Copper Nanoparticles. Biosensors 2021, 11, 139 .
AMA StyleYan Wang, Ying Yan, Xinfa Liu, Changbei Ma. An Exonuclease I-Aided Turn-Off Fluorescent Strategy for Alkaline Phosphatase Assay Based on Terminal Protection and Copper Nanoparticles. Biosensors. 2021; 11 (5):139.
Chicago/Turabian StyleYan Wang; Ying Yan; Xinfa Liu; Changbei Ma. 2021. "An Exonuclease I-Aided Turn-Off Fluorescent Strategy for Alkaline Phosphatase Assay Based on Terminal Protection and Copper Nanoparticles." Biosensors 11, no. 5: 139.
In this paper, a fast and simple strategy for sensitive detection of streptavidin (SA) was proposed based on terminal protection of small molecule-linked DNA and cationic conjugated polymer-mediated fluorescence resonance energy transfer (FRET). In principle, we designed a biotin-labelled DNA probe (P1) as the recognitive probe of SA, along with a complementary DNA probe (P2) to form double-stranded DNA (dsDNA) with P1. SYBR Green I (SG I) as a fluorescent dye was further used to specifically bind to dsDNA to emit stronger fluorescence. The cationic poly[(9,9-bis(6′-N,N,N-triethy-lammonium)hexyl) fluorenylene phenylene dibromide] (PFP) acted as the donor to participate in the FRET and transfer energy to the recipient SG I. In the absence of SA, P1 could not hybridize with P2 to form dsDNA and was digested by exonuclease I (Exo I); thus, only a weak FRET signal would be observed. In the presence of SA, biotin could specifically bind to SA, which protected P1 from Exo I cleavage. Then, P1 and P2 were hybridized into dsDNA. Therefore, the addition of SG I and PFP led to obvious FRET signal due to strong electrostatic interactions. Then, SA can be quantitatively detected by monitoring FRET changes. As the whole reagent reaction was carried out in 1.5 mL EP and detected in the colorimetric dish, the operation process of the detection system was relatively simple. The response time for each step was also relatively short. In this detection system, the linear equation was obtained for SA from 0.1 to 20 nM with a low detection limit of 0.068 nM (S/N = 3). In addition, this strategy has also achieved satisfactory results in the application of biological samples, which reveals the application prospect of this method in the future.
Tingting Hu; Ying Yan; Zhenwei Tang; Xinfa Liu; Changbei Ma. Detection of Streptavidin Based on Terminal Protection and Cationic Conjugated Polymer-Mediated Fluorescence Resonance Energy Transfer. Polymers 2021, 13, 725 .
AMA StyleTingting Hu, Ying Yan, Zhenwei Tang, Xinfa Liu, Changbei Ma. Detection of Streptavidin Based on Terminal Protection and Cationic Conjugated Polymer-Mediated Fluorescence Resonance Energy Transfer. Polymers. 2021; 13 (5):725.
Chicago/Turabian StyleTingting Hu; Ying Yan; Zhenwei Tang; Xinfa Liu; Changbei Ma. 2021. "Detection of Streptavidin Based on Terminal Protection and Cationic Conjugated Polymer-Mediated Fluorescence Resonance Energy Transfer." Polymers 13, no. 5: 725.
The authors describe a novel, facile, and sensitive fluorometric strategy based on a Cu2+-thiamine (Cu2+-TH) system for the detection of alkaline phosphatase (ALP) activity and inhibition. The principle of the method is as follows. Under a basic conditions, TH, which does not exhibit a fluorescence signal, is oxidized into fluorescent thiochrome (TC) by Cu2+. Ascorbic acid 2-phosphate (AAP), which is the enzyme substrate, is hydrolyzed to produce ascorbic acid (AA) by ALP. The newly formed AA then reduces Cu2+ to Cu+, which prevents the oxidation of TH by Cu2+; as a result, the fluorescent signal becomes weaker. On the contrary, in the absence of ALP, AAP cannot reduce Cu2+; additions of Cu2+ and TH result in a dramatic increase of the fluorescent signal. The sensing strategy displays brilliant sensitivity with a detection limit of 0.08 U/L, and the detection is linear in the concentration range of 0.1 to 100 U/L. This approach was successfully applied to ALP activity in human serum samples, indicating that it is reliable and may be applied to the clinical diagnosis of ALP-related diseases.
Han Zhao; Xinfa Liu; Changbei Ma. Sensitive Fluorescence Assay for the Detection of Alkaline Phosphatase Based on a Cu2+-Thiamine System. Sensors 2021, 21, 674 .
AMA StyleHan Zhao, Xinfa Liu, Changbei Ma. Sensitive Fluorescence Assay for the Detection of Alkaline Phosphatase Based on a Cu2+-Thiamine System. Sensors. 2021; 21 (3):674.
Chicago/Turabian StyleHan Zhao; Xinfa Liu; Changbei Ma. 2021. "Sensitive Fluorescence Assay for the Detection of Alkaline Phosphatase Based on a Cu2+-Thiamine System." Sensors 21, no. 3: 674.
In this study, we developed an aptamer-based fluorescent sensing platform for the detection of ochratoxin A (OTA) based on RecJf exonuclease-assisted signal amplification and interaction between graphene oxide (GO) and the OTA aptamer (OTA-apt). After optimizing the experimental conditions, the present aptamer-based sensing system can exhibit excellent fluorescent response in the OTA assay, with a limit of detection of 0.07 ng/mL. In addition to signal amplification, this strategy is also highly specific for other interfering toxins. Furthermore, this aptasensor can be reliably used for assessing red wine samples spiked with different OTA concentrations (2.4, 6 and 20 ng/mL). The proposed assay plays an important role in the field of food safety and can be transformed for detecting other toxins by replacing the sequence that recognizes the aptamer.
Han Zhao; Dehui Xiong; Ying Yan; Changbei Ma. Amplified Fluorescent Aptasensor for Ochratoxin A Assay Based on Graphene Oxide and RecJf Exonuclease. Toxins 2020, 12, 670 .
AMA StyleHan Zhao, Dehui Xiong, Ying Yan, Changbei Ma. Amplified Fluorescent Aptasensor for Ochratoxin A Assay Based on Graphene Oxide and RecJf Exonuclease. Toxins. 2020; 12 (11):670.
Chicago/Turabian StyleHan Zhao; Dehui Xiong; Ying Yan; Changbei Ma. 2020. "Amplified Fluorescent Aptasensor for Ochratoxin A Assay Based on Graphene Oxide and RecJf Exonuclease." Toxins 12, no. 11: 670.
With the development of oncology and bioanalytical chemistry, liquid biopsy emerges as their fruit and manages to bring perspective chance of healthcare. To date, several typical biomarkers (i.e circulating tumor cells, extracellular vesicles, circulating nuclei acids, etc) have been well-established as promising targets of liquid biopsy, and numerous methods, of which optical and electrochemical methods occupy in majority, have been proposed for the idealized detection of these targets. However, the advancements in this field are massive from cancer biology and analytical technology. Therefore, it is necessary to review these advancements from both medical and chemical sides. Here in this paper, our group, of which academic background from medicine and chemistry, aim to provide some comprehensive and in-depth summarization on contribution of optical and electrochemical methods to liquid biopsy, considering both the view of oncologist and analytical chemists. Besides, we will discuss the remaining challenges and future trend of this field in the end. We hope this review can be inspirational to researcher in this field and give helpful introduction to people from various research area.
Zhenwei Tang; Jin Huang; Hailun He; Changbei Ma; Kemin Wang. Contributing to liquid biopsy: Optical and electrochemical methods in cancer biomarker analysis. Coordination Chemistry Reviews 2020, 415, 213317 .
AMA StyleZhenwei Tang, Jin Huang, Hailun He, Changbei Ma, Kemin Wang. Contributing to liquid biopsy: Optical and electrochemical methods in cancer biomarker analysis. Coordination Chemistry Reviews. 2020; 415 ():213317.
Chicago/Turabian StyleZhenwei Tang; Jin Huang; Hailun He; Changbei Ma; Kemin Wang. 2020. "Contributing to liquid biopsy: Optical and electrochemical methods in cancer biomarker analysis." Coordination Chemistry Reviews 415, no. : 213317.
Prostate specific antigen (PSA) is one of the most common biomarkers for the management of prostate cancer. However, it still remains urgent to develop highly sensitive, cost-effective and selective strategies for PSA assay. In this paper, we developed a low-cost, highly sensitive and specific analytical strategy for the detection of PSA by using a fluorescence sensor based on Pb2+-dependent DNAzyme. We designed a DNA sequence called cmMB with a hairpin structure, containing PSA-specific aptamers and Pb2+-dependent DNAzyme chains. Also, a fluorophore-labelled DNA sequence called Sub-FAM, which contains a cleavage site of Pb2+-dependent DNAzyme and serves as substrate, is also designed for the signal generation. In the presence of PSA, interaction between aptamer and PSA blocks the hairpin structure of cmMB, resulting in the formation of Pb2+-dependent DNAzyme with Pb2+. Then, Pb2+-dependent DNAzyme can cleavage Sub-FAM and produce a high fluorescence. In the absence of PSA, since Sub-FAM remains to be ssDNA and can be absorbed by GO, only low fluorescence can be detected. Under optimal experimental conditions, a good linear relationship in the range of 1–100 pg mL−1 was exhibited, with a limit of detection (LOD) of 0.76 pg mL−1. In addition, the proposed method has potential value in the diagnosis and monitoring of prostate cancer because of its good selectivity and practical application in biological samples.
Ying Yan; Changbei Ma; Zhenwei Tang; Mingjian Chen; Han Zhao. A novel fluorescent assay based on DNAzyme-assisted detection of prostate specific antigen for signal amplification. Analytica Chimica Acta 2020, 1104, 172 -179.
AMA StyleYing Yan, Changbei Ma, Zhenwei Tang, Mingjian Chen, Han Zhao. A novel fluorescent assay based on DNAzyme-assisted detection of prostate specific antigen for signal amplification. Analytica Chimica Acta. 2020; 1104 ():172-179.
Chicago/Turabian StyleYing Yan; Changbei Ma; Zhenwei Tang; Mingjian Chen; Han Zhao. 2020. "A novel fluorescent assay based on DNAzyme-assisted detection of prostate specific antigen for signal amplification." Analytica Chimica Acta 1104, no. : 172-179.
Silver nanoclusters stabilized with DNA scaffolds, with excellent physical and chemical properties, have emerged as a versatile tool in biomedical systems. Silver nanoclusters as a late-model nanomaterial with a small size less than 2 nm shows good stability and strong fluorescence. By using DNA with diverse sequence and structures, soluble DNA-templated silver nanoclusters are facilely prepared. They possess tunable fluorescence emission and are suitable with multifunctional designs. Extensive efforts have been put into the application potential of this biocompatible material for biosensing, bioimaging and therapy. Here we are committed to outline the recent advances of DNA-templated silver nanoclusters in biomedical application. The future prospect and challenges are then discussed considering rising progress. Though there is still a long way for illuminating the mechanism behind traits and conducting further clinical trials, we believe DNA-templated silver nanoclusters’ unprecedented unique properties will finally benefit medical progress.
Jiaqi Xu; Xuanmeng Zhu; Xi Zhou; Farjana Yeasmin Khusbu; Changbei Ma. Recent advances in the bioanalytical and biomedical applications of DNA-templated silver nanoclusters. TrAC Trends in Analytical Chemistry 2019, 124, 115786 .
AMA StyleJiaqi Xu, Xuanmeng Zhu, Xi Zhou, Farjana Yeasmin Khusbu, Changbei Ma. Recent advances in the bioanalytical and biomedical applications of DNA-templated silver nanoclusters. TrAC Trends in Analytical Chemistry. 2019; 124 ():115786.
Chicago/Turabian StyleJiaqi Xu; Xuanmeng Zhu; Xi Zhou; Farjana Yeasmin Khusbu; Changbei Ma. 2019. "Recent advances in the bioanalytical and biomedical applications of DNA-templated silver nanoclusters." TrAC Trends in Analytical Chemistry 124, no. : 115786.
Endonucleases, one of the basic tool enzymes of modern molecular biology and medical genetics, have also been clarified as the potential targets for antimicrobial and antiviral drugs screening. However, traditional assays to monitor endonuclease activity can be expensive, time-consuming, or laborious. In order to provide new detective platform, we proposed a novel label-free one-step fluorescent method for the detection of endonuclease activity based on cleavage-induced G-quadruplex formation. In this detection system, a simple DNA probe can spontaneously form a duplex structure with recognition sites of EcoRI and prevent the generation of the G-quadruplex. Once EcoRI is present, the recognition sites in the duplex DNA are cleavage, producing a free guanine-rich sequence to form G-quadruplex. When thioflavin T (ThT) is added, a strong fluorescence signal is given by ThT/G-quadruplex, and therefore the EcoRI activity can be detected. After systematic investigation and optimization, this method has gained a sensitive limit of detection at 0.75 U/mL, and a wide detection range between 0.75 U/mL and 120 U/mL. Furthermore, the inhibitory effect of 5-fluorouracil on EcoRI activity was verified and IC50 was calculated. Taken together, these experimental results have proven that this turn-on fluorescent method has considerable analytical performances. As far as we are concerned, this method is the first reported EcoRI assay based on ThT/G-quadruplex, and only one kind of probe and one kind of dye are involved, providing one of the simplest detective strategies on EcoRI. More importantly, the convenience and cost make this one-step method quite attractive for application transformation. Therefore, we hope this method could be a hopeful option for EcoRI activity determination, and further to help monitoring the quality of tool enzymes and promote the development of high-through automatic drug screening system.
Zhenwei Tang; Haisheng Liu; Mingjian Chen; Changbei Ma. Label-free one-step fluorescent method for the detection of endonuclease activity based on thioflavin T/G-quadruplex. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2019, 228, 117823 .
AMA StyleZhenwei Tang, Haisheng Liu, Mingjian Chen, Changbei Ma. Label-free one-step fluorescent method for the detection of endonuclease activity based on thioflavin T/G-quadruplex. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 2019; 228 ():117823.
Chicago/Turabian StyleZhenwei Tang; Haisheng Liu; Mingjian Chen; Changbei Ma. 2019. "Label-free one-step fluorescent method for the detection of endonuclease activity based on thioflavin T/G-quadruplex." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 228, no. : 117823.
A facile fluorescent method has been developed for polynucleotide kinase detection based on copper nanoparticles and exonuclease III-assisted signal amplification.
Han Zhao; Ying Yan; Mingjian Chen; Tingting Hu; Kefeng Wu; Haisheng Liu; Changbei Ma. Exonuclease III-assisted signal amplification strategy for sensitive fluorescence detection of polynucleotide kinase based on poly(thymine)-templated copper nanoparticles. The Analyst 2019, 144, 6689 -6697.
AMA StyleHan Zhao, Ying Yan, Mingjian Chen, Tingting Hu, Kefeng Wu, Haisheng Liu, Changbei Ma. Exonuclease III-assisted signal amplification strategy for sensitive fluorescence detection of polynucleotide kinase based on poly(thymine)-templated copper nanoparticles. The Analyst. 2019; 144 (22):6689-6697.
Chicago/Turabian StyleHan Zhao; Ying Yan; Mingjian Chen; Tingting Hu; Kefeng Wu; Haisheng Liu; Changbei Ma. 2019. "Exonuclease III-assisted signal amplification strategy for sensitive fluorescence detection of polynucleotide kinase based on poly(thymine)-templated copper nanoparticles." The Analyst 144, no. 22: 6689-6697.
Herein, a turn-on fluorescence assay was introduced for alkaline phosphatase (ALP) detection based on ThT/G-quadruplex system. The basis of the method is that chelation of guanine bases at the binding sites by Ag+ blocks G-quadruplex formation and decreases the fluorescence intensity sharply. In the presence of ALP, ascorbic acid 2-phosphate (AAP) is hydrolyzed to form ascorbic acid (AA) which in turn reduces Ag+ to Ag0. As a result, the blockage ability of Ag+ is disrupted which augments the fluorescence intensity and relies on the concentration of ALP. Under the optimized parameters (500 nM DNA probe; 6 μM Ag+; 1 mM AAP; 30 min for Ag+ and DNA probe reaction time), fluorescence intensity correlates linear range between 1 and 100 U/L of ALP concentration with the detection limit of 0.503 U/L. In the inhibition assay, 50% of ALP inhibition is caused by Na3VO4 with a concentration of 0.254 mM. Furthermore, the assay was used to detect ALP activity in human serum samples in which the results were significant. Above all, the proposed strategy is potential, facile, and sensitive for analyzing ALP activity and screening ALP inhibitor.
Xi Zhou; Farjana Yeasmin Khusbu; Han-Chun Chen; Changbei Ma. A turn-on fluorescence assay of alkaline phosphatase activity based on an enzyme-triggered conformational switch of G-quadruplex. Talanta 2019, 208, 120453 .
AMA StyleXi Zhou, Farjana Yeasmin Khusbu, Han-Chun Chen, Changbei Ma. A turn-on fluorescence assay of alkaline phosphatase activity based on an enzyme-triggered conformational switch of G-quadruplex. Talanta. 2019; 208 ():120453.
Chicago/Turabian StyleXi Zhou; Farjana Yeasmin Khusbu; Han-Chun Chen; Changbei Ma. 2019. "A turn-on fluorescence assay of alkaline phosphatase activity based on an enzyme-triggered conformational switch of G-quadruplex." Talanta 208, no. : 120453.
Prostate specific antigen (PSA) is considered to be a well-established biomarker for prostate cancer, and the importance of PSA assay is increasing in order to improve the diagnosis and prognosis of prostate cancer. However, there are still some weaknesses with current methods of PSA detection including high-cost, heavy analyzer and complexed procedure, restricting the application of PSA assay in prevention of diseases. In this paper, we designed a novel fluorometric aptasensor for PSA assay. Inspired by the concept of enzyme-assisted target recycling (EATR), this novel aptasensor shows an excellent signal responsiveness by the exclusive recognition between aptamer and PSA, together with significant signal amplification through EATR. After systematic optimization, this method shows an excellent detective performance with a sensitive LOD at 0.043 pg mL−1(S/N = 3) and wide linear range of 0.05–150 pg mL−1. To verify the potential of practical application, a set of biomarkers that often co-exist in PSA samples and diluted human serum samples are used for selectivity and practical performances evaluation, and it turns out that this aptasensor exhibits selectivity and potential for clinical application. Specially, this method is easily performed under isothermal environment and needless of complexed preparation, making it more possible for wide application. In view of the superiority, a promising perspective can be provided by this method for practical PSA assay, further promoting the development of precise medicine and oncology.
Mingjian Chen; Zhenwei Tang; Changbei Ma; Ying Yan. A fluorometric aptamer based assay for prostate specific antigen based on enzyme-assisted target recycling. Sensors and Actuators B: Chemical 2019, 302, 127178 .
AMA StyleMingjian Chen, Zhenwei Tang, Changbei Ma, Ying Yan. A fluorometric aptamer based assay for prostate specific antigen based on enzyme-assisted target recycling. Sensors and Actuators B: Chemical. 2019; 302 ():127178.
Chicago/Turabian StyleMingjian Chen; Zhenwei Tang; Changbei Ma; Ying Yan. 2019. "A fluorometric aptamer based assay for prostate specific antigen based on enzyme-assisted target recycling." Sensors and Actuators B: Chemical 302, no. : 127178.
Polydeoxyadenosine (poly (dA)) has been extensively applied for detecting many drug molecules. Herein, we developed a sensitive method for detecting coralyne and heparin using a modified DNA probe with poly (dA) at one end. In the absence of coralyne, the DNA probe was digested by the Exonuclease I (Exo I), and therefore the SYBR Green I (SG I) emitted an extremely low fluorescent signal. While coralyne specifically binding to poly (dA) with strong propensity could remarkably restrain the disintegration of the DNA probe, through which as a template the second strand of DNA sequence was formed with the introduction of DNA polymerase. Therefore, the fluorescent signal of SG I was intensified to quantify coralyne. Based on this method, heparin can be determined due to its strong affinity towards coralyne. This method showed a linear range from 2 to 500 nM for coralyne with a low detection limit of 0.98 nM, and the linear range of heparin was from 1 to 100 nM when 1.25 nm was the detection limit. The proposed method was also implemented successfully in biological samples and showed a potential application for screening potential therapeutic molecules.
Changbei Ma; Miangjian Chen; Hailun He; Leilei Chen. Detection of coralyne and heparin by polymerase extension reaction using SYBR Green I. Molecular and Cellular Probes 2019, 46, 101423 .
AMA StyleChangbei Ma, Miangjian Chen, Hailun He, Leilei Chen. Detection of coralyne and heparin by polymerase extension reaction using SYBR Green I. Molecular and Cellular Probes. 2019; 46 ():101423.
Chicago/Turabian StyleChangbei Ma; Miangjian Chen; Hailun He; Leilei Chen. 2019. "Detection of coralyne and heparin by polymerase extension reaction using SYBR Green I." Molecular and Cellular Probes 46, no. : 101423.
A reliable fluorometric assay is described for the determination carcinoembryonic antigen (CEA) using exonuclease III (Exo III) and a 2-aminopurine binding aptamer. In the absence of CEA, dsDNA is degraded by Exo III, and free 2-AP (which has a blue fluorescence with excitation/emission maxima of 310/365 nm) is released. Strong fluorescence is generated after addition of graphene oxide (GO) to the solution. However, the 2-AP modified DNA (T2) cannot be degraded in the presence of CEA by Exo III due to the interaction between CEA and aptamer T1. Hence, only weak fluorescence can be detected after addition of GO. In this system, CEA can be quantified in the 0.05 - 2 ng·mL-1 concentration range with a detection limit of 30 pg·mL-1 (at S/N = 3). The method was successfully applied to analyze serum samples for CEA.
Mingjian Chen; Changbei Ma; Han Zhao; Ying Yan. Exonuclease III-assisted fluorometric aptasensor for the carcinoembryonic antigen using graphene oxide and 2-aminopurine. Microchimica Acta 2019, 186, 500 .
AMA StyleMingjian Chen, Changbei Ma, Han Zhao, Ying Yan. Exonuclease III-assisted fluorometric aptasensor for the carcinoembryonic antigen using graphene oxide and 2-aminopurine. Microchimica Acta. 2019; 186 (8):500.
Chicago/Turabian StyleMingjian Chen; Changbei Ma; Han Zhao; Ying Yan. 2019. "Exonuclease III-assisted fluorometric aptasensor for the carcinoembryonic antigen using graphene oxide and 2-aminopurine." Microchimica Acta 186, no. 8: 500.
Prostate-specific antigen (PSA) is the only biomarker for the diagnosis of prostate cancer. So the PSA screening test is very important due to the high occurrence of prostate cancer in men. In this work, a label-free fluorescent method was developed based on terminal deoxynucleotidyl transferase (TdT) and G–quadruplex–thioflavin T complex for detecting PSA. In the absence of PSA, the PSA aptamer can be used as the primer for TdT extension reactions, resulting in the formation of G-quadruplexes and generation of strong fluorescent signals. After the addition of PSA, the PSA–aptamer complex prevented the TdT extension reaction due to steric hindrance, thus resulting in a poor fluorescent signal. The assay showed a wide linear range (0.1 to 80 pg/mL) and a detection limit of 0.086 pg/mL (S/N = 3). It also has good specificity for PSA determination and gives satisfactory results when applied to biological samples. Conceivably, its merits such as good selectivity and high sensitivity indicate that the proposed method has a promising application potential in the clinical diagnosis and treatment of prostate cancer.
Mingjian Chen; Changbei Ma; Ying Yan; Han Zhao. A label-free fluorescence method based on terminal deoxynucleotidyl transferase and thioflavin T for detecting prostate-specific antigen. Analytical and Bioanalytical Chemistry 2019, 411, 5779 -5784.
AMA StyleMingjian Chen, Changbei Ma, Ying Yan, Han Zhao. A label-free fluorescence method based on terminal deoxynucleotidyl transferase and thioflavin T for detecting prostate-specific antigen. Analytical and Bioanalytical Chemistry. 2019; 411 (22):5779-5784.
Chicago/Turabian StyleMingjian Chen; Changbei Ma; Ying Yan; Han Zhao. 2019. "A label-free fluorescence method based on terminal deoxynucleotidyl transferase and thioflavin T for detecting prostate-specific antigen." Analytical and Bioanalytical Chemistry 411, no. 22: 5779-5784.
In this report, we propose a fast, reliable and convenient approach to determine the alkaline phosphatase (ALP) activity based on a label-free fluorescence strategy. Upon catalysis of ALP, dephosphorylated dsDNA hampers the λ exonuclease (λexo) cleavage, shows high affinity to SYBR Green I (SG I), resulting in a strong fluorescence emission peak at 520 nm. In the absence of ALP, the dsDNA with 5′-phosphoryl-termini could be employed as a substrate of λexo. After cleavage, a weak fluorescence emission peaks at 520 nm could be observed. The assay was both selective and sensitive, and the detection limit was found to be as low as 3 U/L. This method was utilized to evaluate Na3VO4 as ALP inhibitor. The method was successfully applied to the determination of the activity of ALP in spiked human serum samples.
Huiyu Wang; Changbei Ma; Zekun Li; Kefeng Wu. An exonuclease-assisted fluorescence sensor for assaying alkaline phosphatase based on SYBR Green I. Molecular and Cellular Probes 2019, 45, 26 -30.
AMA StyleHuiyu Wang, Changbei Ma, Zekun Li, Kefeng Wu. An exonuclease-assisted fluorescence sensor for assaying alkaline phosphatase based on SYBR Green I. Molecular and Cellular Probes. 2019; 45 ():26-30.
Chicago/Turabian StyleHuiyu Wang; Changbei Ma; Zekun Li; Kefeng Wu. 2019. "An exonuclease-assisted fluorescence sensor for assaying alkaline phosphatase based on SYBR Green I." Molecular and Cellular Probes 45, no. : 26-30.
In this work, a novel, simple, and time-saving fluorescence approach for the detection of biothiols (glutathione and cysteine) was developed by employing a DNA probe labeled with 2-aminopurine. As an adenine analogue, 2-aminopurine exhibits high fluorescence intensity that can be rapidly quenched in the presence of DNA. In the presence of Ag+, the fluorescence increased significantly, which was a result of the formation of cytosine–Ag+–cytosine base pairs and the release of 2-aminopurine. Upon addition of either glutathione or cysteine, the structure of cytosine–Ag+–cytosine was disrupted, a product of the stronger affinity between biothiols and Ag+. As a result, the 2-aminopurine-labeled DNA probe returned to its former structure, and the fluorescence signal was quenched accordingly. The detection limit for glutathione and cysteine was 3 nM and 5 nM, respectively. Furthermore, the determination of biothiols in human blood serum provided a potential application for the probe as a diagnostic tool in clinical practice.
Han Zhao; Mingjian Chen; Changbei Ma. Fluorescent Method for the Detection of Biothiols Using an Ag+-Mediated Conformational Switch. Sensors 2019, 19, 934 .
AMA StyleHan Zhao, Mingjian Chen, Changbei Ma. Fluorescent Method for the Detection of Biothiols Using an Ag+-Mediated Conformational Switch. Sensors. 2019; 19 (4):934.
Chicago/Turabian StyleHan Zhao; Mingjian Chen; Changbei Ma. 2019. "Fluorescent Method for the Detection of Biothiols Using an Ag+-Mediated Conformational Switch." Sensors 19, no. 4: 934.
Alkaline phosphatase (ALP) has become a representative enzyme of modern life industries. As a critical biomarker of numerous diseases and a major tool enzyme of experiments, classic methods for ALP assays fail to meet the emerging demand of sensitivity, precision, interference immunity and wide targeted types of sample. Therefore, numerous studies have been made to develop ALP detection strategies to solve these problems. In this view, we summarize and compare these studies with their working principals and major advantages or weakness. Also, the future prospective and trend are discussed on this topic, hoping to provide some inspirations for future work.
Zhenwei Tang; Haotian Chen; Hailun He; Changbei Ma. Assays for alkaline phosphatase activity: Progress and prospects. TrAC Trends in Analytical Chemistry 2019, 113, 32 -43.
AMA StyleZhenwei Tang, Haotian Chen, Hailun He, Changbei Ma. Assays for alkaline phosphatase activity: Progress and prospects. TrAC Trends in Analytical Chemistry. 2019; 113 ():32-43.
Chicago/Turabian StyleZhenwei Tang; Haotian Chen; Hailun He; Changbei Ma. 2019. "Assays for alkaline phosphatase activity: Progress and prospects." TrAC Trends in Analytical Chemistry 113, no. : 32-43.
This study describes a novel quencher-free fluorescent method for ochratoxin A (OTA) detection based on the photoinduced electron transfer (PIET) between guanine and fluorophore. In the absence of OTA, carboxyfluorescein (FAM)-labeled aptamer can partly hybridize with the complementary strand of OTA aptamer (OTA-cAPT), which contains four guanines at its 3′-end. As a result, the fluorescence of FAM is quenched due to PIET and stacked guanines. In the presence of OTA, FAM-labeled OTA aptamer can bind specifically to OTA, and thereby the high fluorescence intensity of the dye can be maintained. Under the optimal conditions, the method had a detection limit of 1.3 nM. In addition, the method we proposed is highly sensitive and specific for OTA. Furthermore, the method was proven to be reliable based on its successful application in the detection of OTA in red wine samples. Therefore, this promising, facile, and quencher-free method may be applied to detect other toxins by using other appropriate aptamers.
Han Zhao; Xinying Xiang; Mingjian Chen; Changbei Ma. Aptamer-Based Fluorometric Ochratoxin A Assay Based on Photoinduced Electron Transfer. Toxins 2019, 11, 65 .
AMA StyleHan Zhao, Xinying Xiang, Mingjian Chen, Changbei Ma. Aptamer-Based Fluorometric Ochratoxin A Assay Based on Photoinduced Electron Transfer. Toxins. 2019; 11 (2):65.
Chicago/Turabian StyleHan Zhao; Xinying Xiang; Mingjian Chen; Changbei Ma. 2019. "Aptamer-Based Fluorometric Ochratoxin A Assay Based on Photoinduced Electron Transfer." Toxins 11, no. 2: 65.
The base-excision repair enzyme uracil-DNA glycosylase (UDG) plays a crucial role in the maintenance of genome integrity. The authors describe a fluorometric method for the detection of the activity of UDG. It is making use of (a) a 3’-FAM-labeled hairpin DNA probe with two uracil deoxyribonucleotides in the self-complementary duplex region of its hairpin structure, (b) exonuclease I (Exo I) that catalyzes the release of FAM from the UDG-induced stretched ssDNA probe, and (c) graphene oxide that quenches the green FAM fluorescence of the intact hairpin DNA probe in the absence of UDG. If Exo I causes the release of FAM from the hairpin DNA probe, the fluorescence peaking at 517 nm is turned off in the absence of UDG but turned on in its presence. The resulting assay has a wide linear range (0.008 to 1 U·mL−1) and a detection limit as low as 0.005 U·mL−1. It has good specificity for UDG over potentially interfering enzymes and gave satisfactory results when applied to biological samples. Conceivably, the method may be used in a wide range of applications such as in diagnosis, drug screening, and in studying the repair of DNA lesions.
Mingjian Chen; Wenkai Li; Changbei Ma; Kefeng Wu; Hailun He; Kemin Wang. Fluorometric determination of the activity of uracil-DNA glycosylase by using graphene oxide and exonuclease I assisted signal amplification. Microchimica Acta 2019, 186, 110 .
AMA StyleMingjian Chen, Wenkai Li, Changbei Ma, Kefeng Wu, Hailun He, Kemin Wang. Fluorometric determination of the activity of uracil-DNA glycosylase by using graphene oxide and exonuclease I assisted signal amplification. Microchimica Acta. 2019; 186 (2):110.
Chicago/Turabian StyleMingjian Chen; Wenkai Li; Changbei Ma; Kefeng Wu; Hailun He; Kemin Wang. 2019. "Fluorometric determination of the activity of uracil-DNA glycosylase by using graphene oxide and exonuclease I assisted signal amplification." Microchimica Acta 186, no. 2: 110.