1
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Yan Y, Cai S, Zhao Y, Zhang Y, Wang X, Zhou N. Development of a Fluorescent Biosensor Based on DNAzyme for Tracing the Release of Zinc in Maize Leaves. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:7131-7139. [PMID: 37125744 DOI: 10.1021/acs.jafc.3c00508] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A fluorescent biosensor for real-time monitoring the release of Zn2+ in plants was constructed through immobilization of DNAzyme-containing hairpin DNA on nanofertilizer ZnO@Au nanoparticles (ZnO@Au NPs). A specially designed hairpin DNA containing both DNAzyme and its substrate sequence, which was also labeled with 5'-FAM and 3'-SH groups, was modified on ZnO@Au NPs through the Au-S bond. The fluorescent signal of FAM was initially quenched by AuNPs. When Zn2+ was released from ZnO@Au NPs, DNAzyme was activated and the substrate sequence in hairpin DNA was cleaved. The restored fluorescent signal in Tris-HCl buffer (pH 6.5) was correlated with the concentration of the released Zn2+. The performance of the biosensor was first demonstrated in the solution. The linear detection range was from 50 nM to 1.5 μM, with a detection limit of 30 nM. The biosensor system can penetrate into maize leaves with ZnO@Au NPs. With the release of Zn2+ in leaves, the restored fluorescence can be imaged by a confocal laser scanning microscope and used for monitoring the release and distribution of Zn2+. This work may provide a novel strategy for tracing and understanding the mechanism of nanofertilizers in organisms.
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Affiliation(s)
- Yilin Yan
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Shixin Cai
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Yi Zhao
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Yuting Zhang
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Xiaoli Wang
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Nandi Zhou
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
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2
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Chen L, Lyu Y, Zhang X, Zheng L, Li Q, Ding D, Chen F, Liu Y, Li W, Zhang Y, Huang Q, Wang Z, Xie T, Zhang Q, Sima Y, Li K, Xu S, Ren T, Xiong M, Wu Y, Song J, Yuan L, Yang H, Zhang XB, Tan W. Molecular imaging: design mechanism and bioapplications. Sci China Chem 2023. [DOI: 10.1007/s11426-022-1461-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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3
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Zhang Y, Ji Z, Wang X, Cao Y, Pan H. Single-Molecule Study of DNAzyme Reveals Its Intrinsic Conformational Dynamics. Int J Mol Sci 2023; 24:ijms24021212. [PMID: 36674728 PMCID: PMC9864658 DOI: 10.3390/ijms24021212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 01/11/2023] Open
Abstract
DNAzyme is a class of DNA molecules that can perform catalytic functions with high selectivity towards specific metal ions. Due to its potential applications for biosensors and medical therapeutics, DNAzyme has been extensively studied to characterize the relationships between its biochemical properties and functions. Similar to protein enzymes and ribozymes, DNAzymes have been found to undergo conformational changes in a metal-ion-dependent manner for catalysis. Despite the important role the conformation plays in the catalysis process, such structural and dynamic information might not be revealed by conventional approaches. Here, by using the single-molecule fluorescence resonance energy transfer (smFRET) technique, we were able to investigate the detailed conformational dynamics of a uranyl-specific DNAzyme 39E. We observed conformation switches of 39E to a folded state with the addition of Mg2+ and to an extended state with the addition of UO22+. Furthermore, 39E can switch to a more compact configuration with or without divalent metal ions. Our findings reveal that 39E can undergo conformational changes spontaneously between different configurations.
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Affiliation(s)
- Yiming Zhang
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325001, China
- Wenzhou–Kean University, Wenzhou 325060, China
| | - Zongzhou Ji
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325001, China
- Northeastern University, Shenyang 110819, China
| | - Xin Wang
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325001, China
| | - Yi Cao
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325001, China
- Jinan Microecological Biomedicine Shandong Laboratory, Shounuo City Light West Block, Qingdao Road 3716#, Huaiyin District, Jinan 250117, China
- National Laboratory of Solid–State Microstructure, Department of Physics, Nanjing University, Nanjing 210093, China
| | - Hai Pan
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325001, China
- Correspondence:
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4
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Yi Z, Zhou Y, Ren Y, Hu W, Long F, Zhu A. A novel sensitive DNAzyme-based optical fiber evanescent wave biosensor for rapid detection of Pb 2+ in human serum. Analyst 2022; 147:1467-1477. [PMID: 35266947 DOI: 10.1039/d2an00043a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe here a portable DNAzyme-based optical fiber evanescent wave biosensor (OFEWB) for the rapid and sensitive detection of Pb2+ in human serum. Unlike other biosensors, the OFEWB dispensed with the complicated process of attaching biometric elements to the optical fiber, and the optical fiber directly acted as a transducer to transmit the excitation light and simultaneously collected the fluorescence, which could simplify the detection process, avoid the susceptibility to interference from complex environments and strengthen the reusability of the biosensor. The fluorescence (Cy3) labelled substrate sequence (GR-5S-Cy3) could be cleaved under the catalysis of the GR-5 DNAzyme sequence (GR-5E-BHQ2) in the presence of Pb2+; then the released fluorescence labelled fragments could be directly excited and detected by the OFEWB due to the high transmission efficiency of the excitation light and fluorescence in the OFEWB. Several key factors affecting Pb2+ detection were investigated in detail and optimized. Under the optimal conditions, the LOD of Pb2+ in human serum was 9.34 nM (equivalent to 93.4 nM in whole serum) with a detection range of 0-120 nM. The possible matrix interference was evaluated with different spiked human serum samples, and the recovery of Pb2+ ranged from 74.4% to 112.5% with RSD < 14.8%, implying this method had excellent practicability and could be potentially used in analyzing some biomedical samples.
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Affiliation(s)
- Zhihao Yi
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China.
| | - Yue Zhou
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China.
| | - Yashuang Ren
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China.
| | - Wei Hu
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China.
| | - Feng Long
- School of Environment and Natural Resource, Renmin University of China, Beijing, 100872, China.
| | - Anna Zhu
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China.
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5
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Heaton I, Platt M. DNAzyme Sensor for the Detection of Ca 2+ Using Resistive Pulse Sensing. SENSORS 2020; 20:s20205877. [PMID: 33080851 PMCID: PMC7589696 DOI: 10.3390/s20205877] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/07/2020] [Accepted: 10/10/2020] [Indexed: 12/26/2022]
Abstract
DNAzymes are DNA oligonucleotides that can undergo a specific chemical reaction in the presence of a cofactor. Ribonucleases are a specific form of DNAzymes where a tertiary structure undergoes cleavage at a single ribonuclease site. The cleavage is highly specificity to co-factors, which makes them excellent sensor recognition elements. Monitoring the change in structure upon cleavage has given rise to many sensing strategies; here we present a simple and rapid method of following the reaction using resistive pulse sensors, RPS. To demonstrate this methodology, we present a sensor for Ca2+ ions in solution. A nanoparticle was functionalised with a Ca2+ DNAzyme, and it was possible to follow the cleavage and rearrangement of the DNA as the particles translocate the RPS. The binding of Ca2+ caused a conformation change in the DNAzyme, which was monitored as a change in translocation speed. A 30 min assay produced a linear response for Ca2+ between 1–9 μm, and extending the incubation time to 60 min allowed for a concentration as low as 0.3 μm. We demonstrate that the signal is specific to Ca2+ in the presence of other metal ions, and we can quantify Ca2+ in tap and pond water samples.
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6
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Meir R, Zverzhinetsky M, Harpak N, Borberg E, Burstein L, Zeiri O, Krivitsky V, Patolsky F. Direct Detection of Uranyl in Urine by Dissociation from Aptamer-Modified Nanosensor Arrays. Anal Chem 2020; 92:12528-12537. [PMID: 32842739 DOI: 10.1021/acs.analchem.0c02387] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
An ever-growing demand for uranium in various industries raises concern for human health of both occupationally exposed personnel and the general population. Toxicological effects related to uranium (natural, enriched, or depleted uranium) intake involve renal, pulmonary, neurological, skeletal, and hepatic damage. Absorbed uranium is filtered by the kidneys and excreted in the urine, thus making uranium detection in urine a primary indication for exposure and body burden assessment. Therefore, the detection of uranium contamination in bio-samples (urine, blood, saliva, etc.,) is of crucial importance in the field of occupational exposure and human health-related applications, as well as in nuclear forensics. However, the direct determination of uranium in bio-samples is challenging because of "ultra-low" concentrations of uranium, inherent matrix complexity, and sample diversity, which pose a great analytical challenge to existing detection methods. Here, we report on the direct, real-time, sensitive, and selective detection of uranyl ions in unprocessed and undiluted urine samples using a uranyl-binding aptamer-modified silicon nanowire-based field-effect transistor (SiNW-FET) biosensor, with a detection limit in the picomolar concentration range. The aptamer-modified SiNW-FET presented in this work enables the simple and sensitive detection of uranyl in urine samples. The experimental approach has a straight-forward implementation to other metals and toxic elements, given the availability of target-specific aptamers. Combining the high surface-to-volume ratio of SiNWs, the high affinity and selectivity of the uranyl-binding aptamer, and the distinctive sensing methodology gives rise to a practical platform, offering simple and straightforward sensing of uranyl levels in urine, suitable for field deployment and point-of-care applications.
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Affiliation(s)
- Reut Meir
- School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel.,Department of Analytical Chemistry, Nuclear Research Center, Negev, Beer-Sheva 84190, Israel
| | - Marina Zverzhinetsky
- School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Nimrod Harpak
- School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ella Borberg
- School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Larisa Burstein
- Wolfson Applied Materials Research Center, Tel Aviv University, Tel Aviv 69978, Israel
| | - Offer Zeiri
- Department of Analytical Chemistry, Nuclear Research Center, Negev, Beer-Sheva 84190, Israel
| | - Vadim Krivitsky
- School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Fernando Patolsky
- School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel.,Department of Materials Science and Engineering, the Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
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7
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Lee S, Kim KY, Lim NY, Jung JH, Lee JH, Choi MY, Jung JH. Terpyridine-based complex nanofibers with Eu 3+ as a highly selective chemical probes for UO 22. JOURNAL OF HAZARDOUS MATERIALS 2019; 378:120713. [PMID: 31306904 DOI: 10.1016/j.jhazmat.2019.05.106] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 05/22/2019] [Accepted: 05/30/2019] [Indexed: 06/10/2023]
Abstract
Uranyl is a radioactive, toxic pollutant commonly found in the waste remaining after nuclear fuel reprocessing, and it poses several types of risks to human health; therefore, developing absorbents and chemical probes for this compound is crucial to overcoming these issues. This study examined the sensing abilities of terpyridine-appended benzenetricarboxyamide (T-BTA) as a chromogenic probe for detecting uranyl ions (UO22+). The complex with Eu3+ (1-Eu) spontaneously formed nanostructured fibers in H2O owing to the triamide groups of T-BTA, which induced intermolecular hydrogen-bonding interactions. The strong blue emission of these nanofibers in H2O was quenched upon adding UO22+ but not upon adding any other metal ion. This high selectivity was probably because of the interactions between the nitrigen atoms of the terpyridine moieties of 1 and UO22+. Furthermore, the 1-Eu nanofibers assumed spherical morphologies when UO22+ was added. To develop a convenient UO22+ sensor, an electrospun film incorporating 1-Eu (ESF-1-Eu) was manufactured, and it exhibited high selectivity for UO22+ over a variety of rival metal ions. The plot for luminescence change of ESF-1-Eu vs UO22+ concentrations in seawater samples showed a good linearty. Thus, the ESF-1-Eu shows potential as a useful sensor for detecting and removing UO22+ in H2O.
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Affiliation(s)
- Seonae Lee
- Department of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Ka Young Kim
- Department of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Na Young Lim
- Department of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Jin Hwan Jung
- Department of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Ji Ha Lee
- Department of Chemistry and Biochemistry, The University of Kitakyushu, Hibikino, Kitakyushu, 808-0135, Japan.
| | - Myong Yong Choi
- Department of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju, 52828, Republic of Korea.
| | - Jong Hwa Jung
- Department of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju, 52828, Republic of Korea.
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8
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He Y, Chen D, Huang PJJ, Zhou Y, Ma L, Xu K, Yang R, Liu J. Misfolding of a DNAzyme for ultrahigh sodium selectivity over potassium. Nucleic Acids Res 2019; 46:10262-10271. [PMID: 30215808 PMCID: PMC6212836 DOI: 10.1093/nar/gky807] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 09/08/2018] [Indexed: 02/07/2023] Open
Abstract
Herein, the excellent Na+ selectivity of a few RNA-cleaving DNAzymes was exploited, where Na+ can be around 3000-fold more effective than K+ for promoting catalysis. By using a double mutant based on the Ce13d DNAzyme, and by lowering the temperature, increased 2-aminopurine (2AP) fluorescence was observed with addition of both Na+ and K+. The fluorescence increase was similar for these two metals at below 10 mM, after which K+ took a different pathway. Since 2AP probes its local base stacking environment, K+ can be considered to induce misfolding. Binding of both Na+ and K+ was specific, since single base mutations could fully inhibit 2AP fluorescence for both metals. The binding thermodynamics was measured by temperature-dependent experiments revealing enthalpy-driven binding for both metals and less coordination sites compared to G-quadruplex DNA. Cleavage activity assays indicated a moderate cleavage activity with 10 mM K+, while further increase of K+ inhibited the activity, also supporting its misfolding of the DNAzyme. For comparison, a G-quadruplex DNA was also studied using the same system, where Na+ and K+ led to the same final state with only around 8-fold difference in Kd. This study provides interesting insights into strategies for discriminating Na+ and K+.
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Affiliation(s)
- Yanping He
- State Key Laboratory of Precision Measurement Technology and Instruments, University of Tianjin, Tianjin 300072, China.,Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Da Chen
- State Key Laboratory of Precision Measurement Technology and Instruments, University of Tianjin, Tianjin 300072, China
| | - Po-Jung Jimmy Huang
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Yibo Zhou
- School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114, P. R. China
| | - Lingzi Ma
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Kexin Xu
- State Key Laboratory of Precision Measurement Technology and Instruments, University of Tianjin, Tianjin 300072, China
| | - Ronghua Yang
- School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114, P. R. China
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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9
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Gu L, Yan W, Wu H, Fan S, Ren W, Wang S, Lyu M, Liu J. Selection of DNAzymes for Sensing Aquatic Bacteria: Vibrio Anguillarum. Anal Chem 2019; 91:7887-7893. [DOI: 10.1021/acs.analchem.9b01707] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
| | | | | | | | - Wei Ren
- Key Laboratory of Marine Biology, Nanjing Agricultural University, Nanjing, Jiangsu 210000, P. R. China
| | | | | | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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10
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Feng M, Gu C, Sun Y, Zhang S, Tong A, Xiang Y. Enhancing Catalytic Activity of Uranyl-Dependent DNAzyme by Flexible Linker Insertion for More Sensitive Detection of Uranyl Ion. Anal Chem 2019; 91:6608-6615. [PMID: 31016961 DOI: 10.1021/acs.analchem.9b00490] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The uranyl-dependent DNAzyme 39E cleaves its nucleic acid substrate in the presence of uranyl ion (UO22+). It has been widely utilized in many sensor designs for selective and sensitive detection of UO22+ in the environment and inside live cells. In this work, by inserting a flexible linker (C3 Spacer) into one critical site (A20) of the 39E catalytic core, we successfully enhanced the original catalytic activity of 39E up to 8.1-fold at low UO22+ concentrations. Applying such a modified DNAzyme (39E-A20-C3) in a label-free fluorescent sensor for UO22+ detection achieved more than 1 order of magnitude sensitivity enhancement over using native 39E, with the UO22+ detection limit improved from 2.6 nM (0.63 ppb) to 0.19 nM (0.047 ppb), while the high selectivity to UO22+ over other metal ions was fully preserved. The method was also successfully applied for the detection of UO22+-spiked environmental water samples to demonstrate its practical usefulness.
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Affiliation(s)
- Mengli Feng
- Department of Chemistry, Beijing Key Laboratory for Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education) , Tsinghua University , Beijing 100084 , People's Republic of China
| | - Chunmei Gu
- Department of Chemistry, Beijing Key Laboratory for Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education) , Tsinghua University , Beijing 100084 , People's Republic of China
| | - Yanping Sun
- School of Chemistry and Biological Engineering , University of Science and Technology Beijing , Beijing 100083 , People's Republic of China
| | - Shuyuan Zhang
- School of Chemistry and Biological Engineering , University of Science and Technology Beijing , Beijing 100083 , People's Republic of China
| | - Aijun Tong
- Department of Chemistry, Beijing Key Laboratory for Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education) , Tsinghua University , Beijing 100084 , People's Republic of China
| | - Yu Xiang
- Department of Chemistry, Beijing Key Laboratory for Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education) , Tsinghua University , Beijing 100084 , People's Republic of China
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11
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He Y, Lopez A, Zhang Z, Chen D, Yang R, Liu J. Nucleotide and DNA coordinated lanthanides: From fundamentals to applications. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2019.02.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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12
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He Y, Zhou Y, Chen D, Liu J. Global Folding of a Na
+
‐Specific DNAzyme Studied by FRET. Chembiochem 2018; 20:385-393. [DOI: 10.1002/cbic.201800548] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Indexed: 12/24/2022]
Affiliation(s)
- Yanping He
- State Key Laboratory of Precision Measurement Technology and InstrumentsUniversity of Tianjin Tianjin 300072 P.R. China
- Department of Chemistry, Waterloo Institute for NanotechnologyUniversity of Waterloo Waterloo Ontario N2L 3G1 Canada
| | - Yibo Zhou
- School of Chemistry and Biological EngineeringChangsha University of Science and Technology Changsha 410114 P.R. China
| | - Da Chen
- State Key Laboratory of Precision Measurement Technology and InstrumentsUniversity of Tianjin Tianjin 300072 P.R. China
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for NanotechnologyUniversity of Waterloo Waterloo Ontario N2L 3G1 Canada
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13
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Manochehry S, McConnell EM, Tram KQ, Macri J, Li Y. Colorimetric Detection of Uranyl Using a Litmus Test. Front Chem 2018; 6:332. [PMID: 30140672 PMCID: PMC6095041 DOI: 10.3389/fchem.2018.00332] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 07/16/2018] [Indexed: 01/10/2023] Open
Abstract
Ingestion of water containing toxic contaminants above levels deemed safe for human consumption can occur unknowingly since numerous common contaminants in drinking water are colorless and odorless. Uranyl is particularly problematic as it has been found at dangerous levels in sources of drinking water. Detection of this heavy metal-ion species in drinking water currently requires sending a sample to a laboratory where trained personnel use equipment to perform the analysis and turn-around times can be long. A pH-responsive colorimetric biosensor was developed to enable detection of uranyl in water which coupled the uranyl-specific 39E DNAzyme as a recognition element, and an enzyme capable of producing a pH change as the reporter element. The rapid colorimetric assay presented herein can detect uranyl in lake and well water at concentrations relevant for environmental monitoring, as demonstrated by the detection of uranyl at levels below the limits set for drinking water by major regulatory agencies including the World Health Organization (30 μg/L). This simple and inexpensive DNAzyme-based assay enabled equipment-free visual detection of 15 μg/L uranyl, using both solution-based and paper-based pH-dependent visualization strategies.
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Affiliation(s)
- Sepehr Manochehry
- Department of Biochemistry and Biomedical Sciences, McMaster UniversityHamilton, ON, Canada
| | - Erin M. McConnell
- Department of Biochemistry and Biomedical Sciences, McMaster UniversityHamilton, ON, Canada
| | - Kha Q. Tram
- Department of Chemistry and Chemical Biology, McMaster UniversityHamilton, ON, Canada
| | - Joseph Macri
- Department of Pathology and Molecular Medicine, McMaster UniversityHamilton, ON, Canada
- Hamilton Regional Laboratory Medicine ProgramHamilton, ON, Canada
| | - Yingfu Li
- Department of Biochemistry and Biomedical Sciences, McMaster UniversityHamilton, ON, Canada
- Department of Chemistry and Chemical Biology, McMaster UniversityHamilton, ON, Canada
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14
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Zhou W, Ding J, Liu J. Splitting a DNAzyme enables a Na +-dependent FRET signal from the embedded aptamer. Org Biomol Chem 2018; 15:6959-6966. [PMID: 28792040 DOI: 10.1039/c7ob01709j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Recently, a few Na+-specific RNA-cleaving DNAzymes have been reported, and a Na+ aptamer was identified from the NaA43 and Ce13d DNAzymes. These DNAzymes and the embedded aptamer have been used for Na+ detection. In this work, we studied the Na+-dependent folding of the Ce13d DNAzyme using fluorescence resonance energy transfer (FRET). When a FRET donor and an acceptor were respectively labeled at the ends of the DNAzyme, Na+ failed to induce an obvious end-to-end distance change, suggesting a rigid global structure. To relax this rigidity, the Ce13d DNAzyme was systematically split at various sites on both the enzyme and the substrate strands. The Na+ binding activity of the split structures was characterized by 2-aminopurine fluorescence, enzymatic activity, Tb3+-sensitized luminescence, and DMS footprinting. Among the various constructs, the only one that retained Na+ binding was the split at the cleavage site, and this construct was further labeled with two dyes near the split site. This FRET result showed Na+-dependent folding with a Kd of 26 mM Na+. This study provides important structural information related to Na+ binding to this new aptamer, which might also be useful for future work in biosensor design.
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Affiliation(s)
- Wenhu Zhou
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, Hunan 410013, China
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15
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Folding of the silver aptamer in a DNAzyme probed by 2-aminopurine fluorescence. Biochimie 2017; 145:145-150. [PMID: 28711684 DOI: 10.1016/j.biochi.2017.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Accepted: 07/04/2017] [Indexed: 12/28/2022]
Abstract
The RNA-cleaving Ag10c DNAzyme was recently isolated via in vitro selection and it can bind two Ag+ ions for activity. The Ag10c contains a well-defined Ag+ binding aptamer as indicated by DMS footprinting. Since aptamer binding is often accompanied with conformational changes, we herein used 2-aminopurine (2AP) to probe its folding in the presence of Ag+. The Ag10c was respectively labeled with 2AP at three different positions, both in the substrate strand and in the enzyme strand, one at a time. Ag+-induced folding was observed at the substrate cleavage junction and the A9 position of the enzyme strand, consistent with aptamer binding. The measured Kd at the A9 position was 18 μM Ag+ with a Hill coefficient of 2.17, similar to those obtained from the previous cleavage activity based assays. However, labeling a 2AP at the A2 position inhibited the activity and folding. Compared to other metal ions, Ag+ has a unique sigmoidal folding profile indicative of multiple silver binding cooperatively. This suggests that Ag+ can induce a local folding in the enzyme loop and this folding is important for activity. This study provides important biophysical insights into this new DNAzyme, suggesting the possibility of designing folding-based biosensors for Ag+.
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16
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Affiliation(s)
- Wenhu Zhou
- Xiangya
School of Pharmaceutical Sciences, Central South University, Changsha, Hunan 410013, China
- Department
of Chemistry, Water Institute, and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Runjhun Saran
- Department
of Chemistry, Water Institute, and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Juewen Liu
- Department
of Chemistry, Water Institute, and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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17
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Wang XY, Niu CG, Guo LJ, Hu LY, Wu SQ, Zeng GM, Li F. A Fluorescence Sensor for Lead (II) Ions Determination Based on Label-Free Gold Nanoparticles (GNPs)-DNAzyme Using Time-Gated Mode in Aqueous Solution. J Fluoresc 2016; 27:643-649. [DOI: 10.1007/s10895-016-1993-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/25/2016] [Indexed: 10/20/2022]
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18
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Huang Y, Fang L, Zhu Z, Ma Y, Zhou L, Chen X, Xu D, Yang C. Design and synthesis of target-responsive hydrogel for portable visual quantitative detection of uranium with a microfluidic distance-based readout device. Biosens Bioelectron 2016; 85:496-502. [DOI: 10.1016/j.bios.2016.05.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 04/16/2016] [Accepted: 05/02/2016] [Indexed: 11/26/2022]
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19
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Zhou W, Ding J, Liu J. A highly specific sodium aptamer probed by 2-aminopurine for robust Na+ sensing. Nucleic Acids Res 2016; 44:10377-10385. [PMID: 27655630 PMCID: PMC5137442 DOI: 10.1093/nar/gkw845] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 09/10/2016] [Accepted: 09/13/2016] [Indexed: 12/12/2022] Open
Abstract
Sodium is one of the most abundant metals in the environment and in biology, playing critical ecological and physiological roles. Na+ is also the most common buffer salt for nucleic acids research, while its specific interaction with DNA has yet to be fully studied. Herein, we probe a highly selective and robust Na+ aptamer using 2-aminopurine (2AP), a fluorescent adenine analog. This aptamer has two DNA strands derived from the Ce13d DNAzyme. By introducing a 2AP at the cleavage site of the substrate strand, Na+ induces ∼40% fluorescence increase. The signaling is improved by a series of rational mutations, reaching >600% with the C10A20 double mutant. This fluorescence enhancement suggests relaxed base stacking near the 2AP label upon Na+ binding. By replacing a non-conserved adenine in the enzyme strand by 2AP, Na+-dependent fluorescence quenching is observed, suggesting that the enzyme loop folds into a more compact structure upon Na+ binding. The fluorescence changes allow for Na+ detection. With an optimized sequence, a detection limit of 0.4 mM Na+ is achieved, reaching saturated signal in less than 10 s. The sensor response is insensitive to ionic strength, which is critical for Na+ detection.
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Affiliation(s)
- Wenhu Zhou
- School of Pharmaceutical Sciences, Central South University, Changsha, Hunan 410013, China.,Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Jinsong Ding
- School of Pharmaceutical Sciences, Central South University, Changsha, Hunan 410013, China
| | - Juewen Liu
- School of Pharmaceutical Sciences, Central South University, Changsha, Hunan 410013, China .,Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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20
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Zhang J, Cheng F, Li J, Zhu JJ, Lu Y. Fluorescent nanoprobes for sensing and imaging of metal ions: recent advances and future perspectives. NANO TODAY 2016; 11:309-329. [PMID: 27818705 PMCID: PMC5089816 DOI: 10.1016/j.nantod.2016.05.010] [Citation(s) in RCA: 156] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Recent advances in nanoscale science and technology have generated nanomaterials with unique optical properties. Over the past decade, numerous fluorescent nanoprobes have been developed for highly sensitive and selective sensing and imaging of metal ions, both in vitro and in vivo. In this review, we provide an overview of the recent development of the design and optical properties of the different classes of fluorescent nanoprobes based on noble metal nanomaterials, upconversion nanoparticles, semiconductor quantum dots, and carbon-based nanomaterials. We further detail their application in the detection and quantification of metal ions for environmental monitoring, food safety, medical diagnostics, as well as their use in biomedical imaging in living cells and animals.
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Affiliation(s)
- JingJing Zhang
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - FangFang Cheng
- College of Chemistry, Nanjing University, Nanjing, P. R. China
| | - JingJing Li
- College of Chemistry, Nanjing University, Nanjing, P. R. China
| | - Jun-Jie Zhu
- College of Chemistry, Nanjing University, Nanjing, P. R. China
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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21
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Gwak R, Kim H, Yoo SM, Lee SY, Lee GJ, Lee MK, Rhee CK, Kang T, Kim B. Precisely Determining Ultralow level UO2(2+) in Natural Water with Plasmonic Nanowire Interstice Sensor. Sci Rep 2016; 6:19646. [PMID: 26791784 PMCID: PMC4726367 DOI: 10.1038/srep19646] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/15/2015] [Indexed: 01/01/2023] Open
Abstract
Uranium is an essential raw material in nuclear energy generation; however, its use raises concerns about the possibility of severe damage to human health and the natural environment. In this work, we report an ultrasensitive uranyl ion (UO22+) detection method in natural water that uses a plasmonic nanowire interstice (PNI) sensor combined with a DNAzyme-cleaved reaction. UO22+ induces the cleavage of DNAzymes into enzyme strands and released strands, which include Raman-active molecules. A PNI sensor can capture the released strands, providing strong surface-enhanced Raman scattering signal. The combination of a PNI sensor and a DNAzyme-cleaved reaction significantly improves the UO22+ detection performance, resulting in a detection limit of 1 pM and high selectivity. More importantly, the PNI sensor operates perfectly, even in UO22+-contaminated natural water samples. This suggests the potential usefulness of a PNI sensor in practical UO22+-sensing applications. We anticipate that diverse toxic metal ions can be detected by applying various ion-specific DNA-based ligands to PNI sensors.
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Affiliation(s)
- Raekeun Gwak
- KAIST, Department of Chemistry, Daejeon 34141, Korea
| | - Hongki Kim
- KAIST, Department of Chemistry, Daejeon 34141, Korea
| | - Seung Min Yoo
- KAIST, Department of Chemical and Biomolecular Engineering, Daejeon 34141, Korea
| | - Sang Yup Lee
- KAIST, Department of Chemical and Biomolecular Engineering, Daejeon 34141, Korea
| | - Gyoung-Ja Lee
- KAERI, Nuclear Materials Development Division, Daejeon 34057, Korea
| | - Min-Ku Lee
- KAERI, Nuclear Materials Development Division, Daejeon 34057, Korea
| | - Chang-Kyu Rhee
- KAERI, Nuclear Materials Development Division, Daejeon 34057, Korea
| | - Taejoon Kang
- KRIBB, BioNanotechnology Research Center and BioNano Health Guard Research Center, Daejeon 34141, Korea.,UST, Major of Nanobiotechnology and Bioinformatics, Daejeon 34113, Korea
| | - Bongsoo Kim
- KAIST, Department of Chemistry, Daejeon 34141, Korea
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22
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Zhu G, Zhang CY. Functional nucleic acid-based sensors for heavy metal ion assays. Analyst 2015; 139:6326-42. [PMID: 25356810 DOI: 10.1039/c4an01069h] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Heavy metal contaminants such as lead ions (Pb(2+)), mercury ions (Hg(2+)) and silver ions (Ag(+)) can cause significant harm to humans and generate enduring bioaccumulation in ecological systems. Even though a variety of methods have been developed for Pb(2+), Hg(2+) and Ag(+) assays, most of them are usually laborious and time-consuming with poor sensitivity. Due to their unique advantages of excellent catalytic properties and high affinity for heavy metal ions, functional nucleic acids such as DNAzymes and aptamers show great promise in the development of novel sensors for heavy metal ion assays. In this review, we summarize the development of functional nucleic acid-based sensors for the detection of Pb(2+), Hg(2+) and Ag(+), and especially focus on two categories including the direct assay and the amplification-based assay. We highlight the emerging trends in the development of sensitive and selective sensors for heavy metal ion assays as well.
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Affiliation(s)
- Guichi Zhu
- Single-Molecule Detection and Imaging Laboratory, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Guangdong 518055, China.
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23
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Zhang J, Tang Y, Teng L, Lu M, Tang D. Low-cost and highly efficient DNA biosensor for heavy metal ion using specific DNAzyme-modified microplate and portable glucometer-based detection mode. Biosens Bioelectron 2015; 68:232-238. [DOI: 10.1016/j.bios.2015.01.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 12/03/2014] [Accepted: 01/01/2015] [Indexed: 11/28/2022]
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24
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Wu P, Yu Y, McGhee CE, Tan LH, Lu Y. Applications of synchrotron-based spectroscopic techniques in studying nucleic acids and nucleic acid-functionalized nanomaterials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:7849-72. [PMID: 25205057 PMCID: PMC4275547 DOI: 10.1002/adma.201304891] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 06/02/2014] [Indexed: 05/22/2023]
Abstract
In this review, we summarize recent progress in the application of synchrotron-based spectroscopic techniques for nucleic acid research that takes advantage of high-flux and high-brilliance electromagnetic radiation from synchrotron sources. The first section of the review focuses on the characterization of the structure and folding processes of nucleic acids using different types of synchrotron-based spectroscopies, such as X-ray absorption spectroscopy, X-ray emission spectroscopy, X-ray photoelectron spectroscopy, synchrotron radiation circular dichroism, X-ray footprinting and small-angle X-ray scattering. In the second section, the characterization of nucleic acid-based nanostructures, nucleic acid-functionalized nanomaterials and nucleic acid-lipid interactions using these spectroscopic techniques is summarized. Insights gained from these studies are described and future directions of this field are also discussed.
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Affiliation(s)
- Peiwen Wu
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yang Yu
- Center of Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Claire E. McGhee
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Li Huey Tan
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yi Lu
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Center of Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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25
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Abstract
Increasing interest in detecting metal ions in many chemical and biomedical fields has created demands for developing sensors and imaging agents for metal ions with high sensitivity and selectivity. This review covers recent progress in DNA-based sensors and imaging agents for metal ions. Through both combinatorial selection and rational design, a number of metal-ion-dependent DNAzymes and metal-ion-binding DNA structures that can selectively recognize specific metal ions have been obtained. By attachment of these DNA molecules with signal reporters such as fluorophores, chromophores, electrochemical tags, and Raman tags, a number of DNA-based sensors for both diamagnetic and paramagnetic metal ions have been developed for fluorescent, colorimetric, electrochemical, and surface Raman detection. These sensors are highly sensitive (with a detection limit down to 11 ppt) and selective (with selectivity up to millions-fold) toward specific metal ions. In addition, through further development to simplify the operation, such as the use of "dipstick tests", portable fluorometers, computer-readable disks, and widely available glucose meters, these sensors have been applied for on-site and real-time environmental monitoring and point-of-care medical diagnostics. The use of these sensors for in situ cellular imaging has also been reported. The generality of the combinatorial selection to obtain DNAzymes for almost any metal ion in any oxidation state and the ease of modification of the DNA with different signal reporters make DNA an emerging and promising class of molecules for metal-ion sensing and imaging in many fields of applications.
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Affiliation(s)
- Yu Xiang
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Fax: 217-244-3186; Tel: 217-333-2619
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Fax: 217-244-3186; Tel: 217-333-2619
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26
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Cepeda-Plaza M, Null EL, Lu Y. Metal ion as both a cofactor and a probe of metal-binding sites in a uranyl-specific DNAzyme: a uranyl photocleavage study. Nucleic Acids Res 2013; 41:9361-70. [PMID: 23939617 PMCID: PMC3814387 DOI: 10.1093/nar/gkt694] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
DNAzymes are known to bind metal ions specifically to carry out catalytic functions. Despite many studies since DNAzymes were discovered nearly two decades ago, the metal-binding sites in DNAzymes are not fully understood. Herein, we adopt uranyl photocleavage to probe specific uranyl-binding sites in the 39E DNAzyme with catalytically relevant concentrations of uranyl. The results indicate that uranyl binds between T23 and C25 in the bulge loop, G11 and T12 in the stem loop of the enzyme strand, as well as between T2.4 and G3 close to the cleavage site in the substrate strand. Control experiments using two 39E DNAzyme mutants revealed a different cleavage pattern of the mutated region. Another DNAzyme, the 8–17 DNAzyme, which has a similar secondary structure but shows no activity in the presence of uranyl, indicated a different uranyl-dependent photocleavage as well. In addition, a close correlation between the concentration-dependent photocleavage and enzymatic activities is also demonstrated. Together, these experiments suggest that uranyl photocleavage has been successfully used to probe catalytically relevant uranyl-binding sites in the 39E DNAzyme. As uranyl is the cofactor of the 39E DNAzyme as well as the probe, specific uranyl binding has now been identified without disruption of the structure.
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Affiliation(s)
- Marjorie Cepeda-Plaza
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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27
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Chiral Ar-BINMOL-derived salan as fluorescent sensor for recognition of CuCl and cascade discrimination of α-amino acids. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.01.047] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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28
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Nakayama S, Sintim HO. Investigating the interactions between cations, peroxidation substrates and G-quadruplex topology in DNAzyme peroxidation reactions using statistical testing. Anal Chim Acta 2012; 747:1-6. [PMID: 22986129 DOI: 10.1016/j.aca.2012.08.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 07/28/2012] [Accepted: 08/08/2012] [Indexed: 12/11/2022]
Abstract
Cations affect the topology and enzymatic proficiency of most macromolecular catalysts but the role of cations in DNAzyme peroxidation reactions remains unresolved. Herein, we use statistical methods (ANOVA, t-test and Wilcoxon Mann-Whitney non-parametric test) to demonstrate that there are strong associations between cations, DNAzyme topology, peroxidation substrate and peroxidation rates of G-quadruplex peroxidises. Ammonium cation was found to be superior to all tested cations, including potassium. A t-test indicated that NH(4)(+) was better than K(+) with a p-value=0.05. Interestingly, the nature of the peroxidation substrate employed affected the dependence of peroxidation rate on the cation present and of the three substrates tested, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), tyramine and 3,3',5,5'-tetramethylbenzidine (TMB), ABTS was the most sensitive to the nature of cation present.
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Affiliation(s)
- Shizuka Nakayama
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
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