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Ahmadi-Sangachin E, Mohammadnejad J, Hosseini M. Fluorescence self-assembled DNA hydrogel for the determination of prostate specific antigen by aggregation induced emission. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 303:123234. [PMID: 37582316 DOI: 10.1016/j.saa.2023.123234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/17/2023]
Abstract
In this study, an aptamer-based, functionalized-DNA hydrogel system is developed for prostate-specific antigen (PSA) detection. A pure DNA hydrogel is constructed using specific DNA building blocks and an aptamer as a cross-linker. Firstly, silver nanoclusters (AgNCs) are constructed on the Y-shaped DNA (Y-DNA) building blocks. Then, the DNA hydrogel was formed via the addition of the cross-linker to the Y-DNA solution. In this case, the fluorescence emission of silver nanoclusters that have accumulated in the hydrogel increases due to aggregation-induced emission (AIE). The presence of PSA and its subsequent interaction with its specific aptamer dissolve the hydrogel structures, which leads to a low emission intensity. A great linear relationship was attained in this assay in the range of 0.05 to 8 ng mL-1 with a detection limit of 4.4 pg mL-1 for the detection of PSA. Additionally, the proposed aptasensor was successfully used to detect PSA in human serum samples. The recovery for different concentrations of PSA was in the range of 96.1% to 99.3%, and the RSD range was from 2.3% to 4.5%. Comparing our method to current ones in the field of PSA detection proves that our platform benefits from a simpler procedure, lower cost, and better efficiency, providing high potential for future clinical applications.
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Affiliation(s)
- Elnaz Ahmadi-Sangachin
- Department of Life Science Engineering, Faculty of New Sciences & Technologies, University of Tehran, Tehran 1439817435, Iran
| | - Javad Mohammadnejad
- Department of Life Science Engineering, Faculty of New Sciences & Technologies, University of Tehran, Tehran 1439817435, Iran.
| | - Morteza Hosseini
- Department of Life Science Engineering, Faculty of New Sciences & Technologies, University of Tehran, Tehran 1439817435, Iran; Department of Pharmaceutical Biomaterials, Medical Biomaterials Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
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2
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Ji C, Wei J, Zhang L, Hou X, Tan J, Yuan Q, Tan W. Aptamer-Protein Interactions: From Regulation to Biomolecular Detection. Chem Rev 2023; 123:12471-12506. [PMID: 37931070 DOI: 10.1021/acs.chemrev.3c00377] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
Serving as the basis of cell life, interactions between nucleic acids and proteins play essential roles in fundamental cellular processes. Aptamers are unique single-stranded oligonucleotides generated by in vitro evolution methods, possessing the ability to interact with proteins specifically. Altering the structure of aptamers will largely modulate their interactions with proteins and further affect related cellular behaviors. Recently, with the in-depth research of aptamer-protein interactions, the analytical assays based on their interactions have been widely developed and become a powerful tool for biomolecular detection. There are some insightful reviews on aptamers applied in protein detection, while few systematic discussions are from the perspective of regulating aptamer-protein interactions. Herein, we comprehensively introduce the methods for regulating aptamer-protein interactions and elaborate on the detection techniques for analyzing aptamer-protein interactions. Additionally, this review provides a broad summary of analytical assays based on the regulation of aptamer-protein interactions for detecting biomolecules. Finally, we present our perspectives regarding the opportunities and challenges of analytical assays for biological analysis, aiming to provide guidance for disease mechanism research and drug discovery.
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Affiliation(s)
- Cailing Ji
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Junyuan Wei
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Lei Zhang
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Xinru Hou
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Jie Tan
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Quan Yuan
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Weihong Tan
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
- The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
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3
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Ji D, Feng H, Liew SW, Kwok CK. Modified nucleic acid aptamers: development, characterization, and biological applications. Trends Biotechnol 2023; 41:1360-1384. [PMID: 37302912 DOI: 10.1016/j.tibtech.2023.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 04/30/2023] [Accepted: 05/18/2023] [Indexed: 06/13/2023]
Abstract
Aptamers are single-stranded oligonucleotides that bind to their targets via specific structural interactions. To improve the properties and performance of aptamers, modified nucleotides are incorporated during or after a selection process such as systematic evolution of ligands by exponential enrichment (SELEX). We summarize the latest modified nucleotides and strategies used in modified (mod)-SELEX and post-SELEX to develop modified aptamers, highlight the methods used to characterize aptamer-target interactions, and present recent progress in modified aptamers that recognize different targets. We discuss the challenges and perspectives in further advancing the methodologies and toolsets to accelerate the discovery of modified aptamers, improve the throughput of aptamer-target characterization, and expand the functional diversity and complexity of modified aptamers.
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Affiliation(s)
- Danyang Ji
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong, SAR, China
| | - Hengxin Feng
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong, SAR, China
| | - Shiau Wei Liew
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong, SAR, China
| | - Chun Kit Kwok
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong, SAR, China; Shenzhen Research Institute of City University of Hong Kong, Shenzhen, China.
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4
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Lee M, Shin S, Kim S, Park N. Recent Advances in Biological Applications of Aptamer-Based Fluorescent Biosensors. Molecules 2023; 28:7327. [PMID: 37959747 PMCID: PMC10647268 DOI: 10.3390/molecules28217327] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/24/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
Aptamers have been spotlighted as promising bio-recognition elements because they can be tailored to specific target molecules, bind to targets with a high affinity and specificity, and are easy to chemically synthesize and introduce functional groups to. In particular, fluorescent aptasensors are widely used in biological applications to diagnose diseases as well as prevent diseases by detecting cancer cells, viruses, and various biomarkers including nucleic acids and proteins as well as biotoxins and bacteria from food because they have the advantages of a high sensitivity, selectivity, rapidity, a simple detection process, and a low price. We introduce screening methods for isolating aptamers with q high specificity and summarize the sequences and affinities of the aptamers in a table. This review focuses on aptamer-based fluorescence detection sensors for biological applications, from fluorescent probes to mechanisms of action and signal amplification strategies.
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Affiliation(s)
- Minhyuk Lee
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea; (M.L.); (S.K.)
| | - Seonhye Shin
- Department of Chemistry, The Natural Science Research Institute, Myongji University, 116 Myongji-ro, Yongin-si 17058, Republic of Korea;
| | - Sungjee Kim
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea; (M.L.); (S.K.)
| | - Nokyoung Park
- Department of Chemistry, The Natural Science Research Institute, Myongji University, 116 Myongji-ro, Yongin-si 17058, Republic of Korea;
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Minagawa H, Sawa H, Fujita T, Kato S, Inaguma A, Hirose M, Orba Y, Sasaki M, Tabata K, Nomura N, Shingai M, Suzuki Y, Horii K. A high-affinity aptamer with base-appended base-modified DNA bound to isolated authentic SARS-CoV-2 strains wild-type and B.1.617.2 (delta variant). Biochem Biophys Res Commun 2022; 614:207-212. [PMID: 35617879 PMCID: PMC9060713 DOI: 10.1016/j.bbrc.2022.04.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 04/15/2022] [Indexed: 11/02/2022]
Abstract
Simple, highly sensitive detection technologies for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are crucial for the effective implementation of public health policies. We used the systematic evolution of ligands by exponential enrichment with a modified DNA library, including a base-appended base (uracil with a guanine base at its fifth position), to create an aptamer with a high affinity for the receptor-binding domain (RBD) of the SARS-CoV-2 spike glycoprotein. The aptamer had a dissociation constant of 1.2 and < 1 nM for the RBD and spike trimer, respectively. Furthermore, enzyme-linked aptamer assays confirmed that the aptamer binds to isolated authentic SARS-CoV-2 wild-type and B.1.617.2 (delta variant). The binding signal was larger that of commercially available anti-SARS-CoV-2 RBD antibody. Thus, this aptamer as a sensing element will enable the highly sensitive detection of SARS-CoV-2.
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Affiliation(s)
- Hirotaka Minagawa
- NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-ku, Tokyo, 136-8627, Japan.
| | - Hirofumi Sawa
- Division of Molecular Pathobiology, International Institute for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan; International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan; One Health Research Center, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan.
| | - Tomoko Fujita
- NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-ku, Tokyo, 136-8627, Japan.
| | - Shintaro Kato
- NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-ku, Tokyo, 136-8627, Japan.
| | - Asumi Inaguma
- NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-ku, Tokyo, 136-8627, Japan.
| | - Miwako Hirose
- NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-ku, Tokyo, 136-8627, Japan.
| | - Yasuko Orba
- Division of Molecular Pathobiology, International Institute for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan; International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan.
| | - Michihito Sasaki
- Division of Molecular Pathobiology, International Institute for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan.
| | - Koshiro Tabata
- Division of Molecular Pathobiology, International Institute for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan.
| | - Naoki Nomura
- Laboratory for Biologics Development, International Institute for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan.
| | - Masashi Shingai
- International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan; Laboratory for Biologics Development, International Institute for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan.
| | - Yasuhiko Suzuki
- Division of Bioresource, International Institute for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo, 001-0020, Japan.
| | - Katsunori Horii
- NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-ku, Tokyo, 136-8627, Japan.
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Pundir M, Papagerakis S, De Rosa MC, Chronis N, Kurabayashi K, Abdulmawjood S, Prince MEP, Lobanova L, Chen X, Papagerakis P. Emerging biotechnologies for evaluating disruption of stress, sleep, and circadian rhythm mechanism using aptamer-based detection of salivary biomarkers. Biotechnol Adv 2022; 59:107961. [DOI: 10.1016/j.biotechadv.2022.107961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/30/2022] [Accepted: 04/09/2022] [Indexed: 12/26/2022]
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Ondruš M, Sýkorová V, Bednárová L, Pohl R, Hocek M. Enzymatic synthesis of hypermodified DNA polymers for sequence-specific display of four different hydrophobic groups. Nucleic Acids Res 2020; 48:11982-11993. [PMID: 33152081 PMCID: PMC7708046 DOI: 10.1093/nar/gkaa999] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 10/08/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022] Open
Abstract
A set of modified 2′-deoxyribonucleoside triphosphates (dNTPs) bearing a linear or branched alkane, indole or phenyl group linked through ethynyl or alkyl spacer were synthesized and used as substrates for polymerase synthesis of hypermodified DNA by primer extension (PEX). Using the alkyl-linked dNTPs, the polymerase synthesized up to 22-mer fully modified oligonucleotide (ON), whereas using the ethynyl-linked dNTPs, the enzyme was able to synthesize even long sequences of >100 modified nucleotides in a row. In PCR, the combinations of all four modified dNTPs showed only linear amplification. Asymmetric PCR or PEX with separation or digestion of the template strand can be used for synthesis of hypermodified single-stranded ONs, which are monodispersed polymers displaying four different substituents on DNA backbone in sequence-specific manner. The fully modified ONs hybridized with complementary strands and modified DNA duplexes were found to exist in B-type conformation (B- or C-DNA) according to CD spectral analysis. The modified DNA can be replicated with high fidelity to natural DNA through PCR and sequenced. Therefore, this approach has a promising potential in generation and selection of hypermodified aptamers and other functional polymers.
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Affiliation(s)
- Marek Ondruš
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, CZ-16000 Prague 6, Czech Republic.,Department of Organic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, CZ-12843 Prague 2, Czech Republic
| | - Veronika Sýkorová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, CZ-16000 Prague 6, Czech Republic
| | - Lucie Bednárová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, CZ-16000 Prague 6, Czech Republic
| | - Radek Pohl
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, CZ-16000 Prague 6, Czech Republic
| | - Michal Hocek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, CZ-16000 Prague 6, Czech Republic.,Department of Organic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, CZ-12843 Prague 2, Czech Republic
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8
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Modified aptamers as reagents to characterize recombinant human erythropoietin products. Sci Rep 2020; 10:18593. [PMID: 33122796 PMCID: PMC7596557 DOI: 10.1038/s41598-020-75713-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 10/14/2020] [Indexed: 11/08/2022] Open
Abstract
Reliable and reproducible monitoring of the conformational state of therapeutic protein products remains an unmet technological need. This need is amplified by the increasing number of biosimilars entering the drug development pipeline as many branded biologics are reaching the end of their market exclusivity period. Availability of methods to better characterize protein conformation may improve detection of counterfit and unlicensed therapeutic proteins. In this study, we report the use of a set of modified DNA aptamers with enhanced chemical diversity to probe the conformational state of 12 recombinant human erythropoietin (rHuEPO) therapeutic protein products; one FDA-licensed rHuEPO originator biological product, three rHuEPO products that are approved for marketing in the US or EU as biosimilars, and eight rHuEPO products that are not approved for marketing in the US or EU. We show that several of these modified aptamers are able to distinguish rHuEPO reference products or approved biosimilars from non-licensed rHuEPO products on the basis of differences in binding kinetics and equilibrium affinity constants. These reagents exhibit sensitivity to the conformational integrity of various forms of rHuEPO and as such represent powerful, simple-to-use analytical tools to monitor the conformational integrity of therapeutic-proteins during manufacture and to screen for and identify both substandard and counterfeit products.
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Bognár Z, Gyurcsányi RE. Aptamers against Immunoglobulins: Design, Selection and Bioanalytical Applications. Int J Mol Sci 2020; 21:E5748. [PMID: 32796581 PMCID: PMC7461046 DOI: 10.3390/ijms21165748] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/26/2020] [Accepted: 08/06/2020] [Indexed: 12/11/2022] Open
Abstract
Nucleic acid aptamers show clear promise as diagnostic reagents, as highly specific strands were reported against a large variety of biomarkers. They have appealing benefits in terms of reproducible generation by chemical synthesis, controlled modification with labels and functionalities providing versatile means for detection and oriented immobilization, as along with high biochemical and temperature resistance. Aptamers against immunoglobulin targets-IgA, IgM, IgG and IgE-have a clear niche for diagnostic applications, therefore numerous aptamers have been selected and used in combination with a variety of detection techniques. The aim of this review is to overview and evaluate aptamers selected for the recognition of antibodies, in terms of their design, analytical properties and diagnostic applications. Aptamer candidates showed convincing performance among others to identify stress and upper respiratory tract infection through SIgA detection, for cancer cell recognition using membrane bound IgM, to detect and treat hemolytic transfusion reactions, autoimmune diseases with IgG and detection of IgE for allergy diseases. However, in general, their use still lags significantly behind what their claimed benefits and the plethora of application opportunities would forecast.
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Affiliation(s)
| | - Róbert E. Gyurcsányi
- BME “Lendület” Chemical Nanosensors Research Group, Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, H-1111 Budapest, Hungary;
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Aptamer binding assays and molecular interaction studies using fluorescence anisotropy - A review. Anal Chim Acta 2020; 1125:267-278. [PMID: 32674773 DOI: 10.1016/j.aca.2020.05.061] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/16/2020] [Accepted: 05/23/2020] [Indexed: 12/26/2022]
Abstract
Binding of nucleic acid aptamers to specific targets and detection with fluorescence anisotropy (FA) or fluorescence polarization (FP) take advantage of the complementary features of aptamers and the fluorescence techniques. We review recent advances in affinity binding assays using aptamers and FA/FP, with an emphasis on studies of molecular interactions and identification of binding sites. Aptamers provide several benefits, including the ease of labelling fluorophores on specific sites, binding-induced changes in aptamer structures, hybridization of the aptamers to complementary sequences, changes in molecular volume upon binding of the aptamer to its target, and adsorption of aptamers onto nanomaterials. Some of these benefits have been utilized for FA/FP assays. Once the aptamer binds to its target, the resulting changes in molecular volume (size), structure, local rotation of the fluorophore, and/or the fluorescence lifetime influence changes to the FA/FP values. Measurements of these fluorescence anisotropy/polarization changes have provided insights into the molecular interactions, such as the binding affinity and the site of binding. Studies of molecular interactions conducted in homogeneous solutions, as well as those with separations, e.g., capillary electrophoresis, have been summarized in this review. Studies on mapping the position of binding in aptamers at the single nucleotide level have demonstrated a unique benefit of the FA/FP techniques and pointed to an exciting direction for future research.
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Modified DNA Aptamers for C-Reactive Protein and Lactate Dehydrogenase-5 with Sub-Nanomolar Affinities. Int J Mol Sci 2020; 21:ijms21082683. [PMID: 32294882 PMCID: PMC7215426 DOI: 10.3390/ijms21082683] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/03/2020] [Accepted: 04/08/2020] [Indexed: 12/14/2022] Open
Abstract
Human C-reactive protein (CRP) and lactate dehydrogenase are important markers in clinical laboratory testing-the former is used to detect in vivo inflammation, and the latter is used to detect cell necrosis and tissue destruction. We developed aptamers that bind to human CRP and human lactate dehydrogenase-5 (LDH-5) with high affinities (dissociation constants of 6.2 pM and 235 pM, respectively), applying the systematic evolution of ligands by exponential enrichment (SELEX) method, and by using a modified DNA library containing the following base-appended base modifications: analog adenine derivative at the fifth position of uracil (Uad), analog guanine derivative at the fifth position of uracil (Ugu), and analog adenine derivative at the seventh position of adenine (Aad). A potential application of these aptamers as sensor elements includes high-sensitivity target detection in point-of-care testing.
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A high affinity modified DNA aptamer containing base-appended bases for human β-defensin. Anal Biochem 2020; 594:113627. [PMID: 32067984 DOI: 10.1016/j.ab.2020.113627] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 12/31/2022]
Abstract
We used base-appended base modification to develop a new adenine analog, which incorporates an adenine derivative at position 7 of adenine. Using the systematic evolution of ligands by exponential enrichment method with a modified DNA library including this analog, we obtained Aad1, an aptamer that binds strongly to human β-defensin 2, a biomarker of physical stress found in saliva. The dissociation constant of Aad1 with respect to human β-defensin 2 was found to be low (6.8 nM), and was found to bind specifically to human β-defensin 2 in saliva spiked with the protein, as confirmed using pull-down with magnetic beads. To our knowledge, there are no prior reports of nucleic-acid aptamers that bind specifically to human β-defensin 2. However, our results indicated that such adenine analog-containing DNA libraries are extremely effective in the acquisition of high-affinity aptamers.
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