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Wang X, Jing S, Wang W, Wang J. Direct and noninvasive fluorescence analysis of an RNA-protein interaction based on a CRISPR/Cas12a-powered assay. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 299:122884. [PMID: 37210856 DOI: 10.1016/j.saa.2023.122884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/25/2023] [Accepted: 05/12/2023] [Indexed: 05/23/2023]
Abstract
RNA-protein interactions (RPIs) play critical roles in gene transcription and protein expression, but current analytical methods for RPIs are mainly performed in an invasive manner, involving special RNA/protein labeling, hampering access to intact and precise information on RPIs. In this work, we present the first CRISPR/Cas12a-based fluorescence assay for the direct analysis of RPIs without RNA/protein labeling steps. Select vascular endothelial growth factor 165 (VEGF165)/its RNA aptamer interaction as a model, the RNA sequence simultaneously serves as both the aptamer of VEGF165 and crRNA of CRISPR/Cas12a system, and the presence of VEGF165 facilitates VEGF165/its RNA aptamer interaction, thus prohibiting the formation of Cas12a-crRNA-DNA ternary complex along with low fluorescence signal. The assay showed a detection limit of 0.23 pg mL-1, and good performance in serum-spiked samples with an RSD of 0.4 %-13.1 %. This simple and selective strategy opens the door for establishing CRISPR/Cas-based biosensors for gaining intact information on RPIs, and shows widespread potential for other RPIs analysis.
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Affiliation(s)
- Xueliang Wang
- Xi'an Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Medical Research, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, Shaanxi 710072, China; Collaborative Innovation Center of NPU, Shanghai 201100, P.R. China; Research & Development Institute of Northwestern Polytechnical University in Shenzhen, 45 South Gaoxin Road, Shenzhen 518057, China; Northwestern Polytechnical University Chongqing Technology Innovation Center, Chongqing 400000, PR China
| | - Shaozhen Jing
- Xi'an Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Medical Research, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, Shaanxi 710072, China; Collaborative Innovation Center of NPU, Shanghai 201100, P.R. China; Research & Development Institute of Northwestern Polytechnical University in Shenzhen, 45 South Gaoxin Road, Shenzhen 518057, China; Northwestern Polytechnical University Chongqing Technology Innovation Center, Chongqing 400000, PR China
| | - Wanhe Wang
- Xi'an Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Medical Research, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, Shaanxi 710072, China; Collaborative Innovation Center of NPU, Shanghai 201100, P.R. China; Research & Development Institute of Northwestern Polytechnical University in Shenzhen, 45 South Gaoxin Road, Shenzhen 518057, China; Northwestern Polytechnical University Chongqing Technology Innovation Center, Chongqing 400000, PR China.
| | - Jing Wang
- Xi'an Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Medical Research, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, Shaanxi 710072, China; Collaborative Innovation Center of NPU, Shanghai 201100, P.R. China; Research & Development Institute of Northwestern Polytechnical University in Shenzhen, 45 South Gaoxin Road, Shenzhen 518057, China; Northwestern Polytechnical University Chongqing Technology Innovation Center, Chongqing 400000, PR China.
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Zhang HL, Lv C, Li ZH, Jiang S, Cai D, Liu SS, Wang T, Zhang KH. Analysis of aptamer-target binding and molecular mechanisms by thermofluorimetric analysis and molecular dynamics simulation. Front Chem 2023; 11:1144347. [PMID: 37228865 PMCID: PMC10204870 DOI: 10.3389/fchem.2023.1144347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 04/26/2023] [Indexed: 05/27/2023] Open
Abstract
Introduction: Aptamers are valuable for bioassays, but aptamer-target binding is susceptible to reaction conditions. In this study, we combined thermofluorimetric analysis (TFA) and molecular dynamics (MD) simulations to optimize aptamer-target binding, explore underlying mechanisms and select preferred aptamer. Methods: Alpha-fetoprotein (AFP) aptamer AP273 (as the model) was incubated with AFP under various experimental conditions, and melting curves were measured in a real-time PCR system to select the optimal binding conditions. The intermolecular interactions of AP273-AFP were analysed by MD simulations with these conditions to reveal the underlying mechanisms. A comparative study between AP273 and control aptamer AP-L3-4 was performed to validate the value of combined TFA and MD simulation in selecting preferred aptamers. Results: The optimal aptamer concentration and buffer system were easily determined from the dF/dT peak characteristics and the melting temperature (Tm) values on the melting curves of related TFA experiments, respectively. A high Tm value was found in TFA experiments performed in buffer systems with low metal ion strength. The molecular docking and MD simulation analyses revealed the underlying mechanisms of the TFA results, i.e., the binding force and stability of AP273 to AFP were affected by the number of binding sites, frequency and distance of hydrogen bonds, and binding free energies; these factors varied in different buffer and metal ion conditions. The comparative study showed that AP273 was superior to the homologous aptamer AP-L3-4. Conclusion: Combining TFA and MD simulation is efficient for optimizing the reaction conditions, exploring underlying mechanisms, and selecting aptamers in aptamer-target bioassays.
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Affiliation(s)
| | | | | | | | | | | | - Ting Wang
- *Correspondence: Ting Wang, ; Kun-He Zhang,
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Li J, Liu Y, Wang C, Jia Q, Zhang G, Huang X, Zhou N, Zhang Z. Determination of VEGF 165 using impedimetric aptasensor based on cyclohexanehexone-melem covalent-organic framework. Mikrochim Acta 2021; 188:211. [PMID: 34050442 DOI: 10.1007/s00604-021-04843-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 05/03/2021] [Indexed: 11/29/2022]
Abstract
A porous nanostructured covalent-organic framework (COF) has been prepared via condensation polymerization between the two building blocks of melem and hexaketocyclohexane octahydrate (represented as M-HO-COF). Basic characterizations revealed that the M-HO-COF network was composed of C=N and highly conjugated aromatic moieties, along with a high surface area, large pore size, remarkable electrochemical activity, and strong bioaffinity toward aptamer strands. Given that the vascular endothelial growth factor 165 (VEGF165)-targeted aptamer was stably anchored over M-HO-COF via weak intermolecular forces, the prepared M-HO-COF network exhibited great potential as a sensitive and selective platform for the impedimetric VEGF165 aptasensor. Consequently, the M-HO-COF-based aptasensor displayed an ultralow limit of detection of 0.18 fg mL-1 within a wide range of VEGF165 concentrations from 1 fg mL-1 to 10 ng mL-1. Considering its strong fluorescence performance, excellent biocompatibility, and small nanosheet-like structure, the obtained COF-based aptasensor showed a superior sensing performance and regeneration capability after 7 regeneration cycles for the detection of osteosarcoma cells (K7M2 cells), which overexpressed with VEGF165, with a low limit of detection of 49 cells mL-1. For real f human serum samples, the obtained COF-based aptasensor exhibits acceptable mean apparent recoveries of 97.41% with a relative standard deviation of 4.60%. Furthermore, the proposed bifunctional aptasensor for the detection VEGF165 and K7M2 cells exhibited good stability, appropriate selectivity toward other biomarkers or normal cells, acceptable reproducibility, and applicability. A bifunctional sensing system was constructed for detecting osteosarcoma cells (K7M2 cells) and VEGF165 based on the a porous nanostructured covalent-organic framework (M-HO-COF) via condensation polymerization between melem and hexaketocyclohexane octahydrate. The M-HO-COF-based aptasensor displayed ultralow detection limit of 0.18 fg mL-1 toward VEGF165 and 49 cell mL-1 for K7M2 cells with high selectivity, acceptable reproducibility, and good stability.
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Affiliation(s)
- Jiangnan Li
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, No. 1, Jianshe East Road, Zhengzhou, 450052, People's Republic of China
| | - Yang Liu
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, No. 1, Jianshe East Road, Zhengzhou, 450052, People's Republic of China
| | - Changbao Wang
- School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, No. 136, Science Avenue, Zhengzhou, 450001, People's Republic of China
| | - Qiaojuan Jia
- School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, No. 136, Science Avenue, Zhengzhou, 450001, People's Republic of China
| | - Geyi Zhang
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, No. 1, Jianshe East Road, Zhengzhou, 450052, People's Republic of China
| | - Xiaoyu Huang
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, No. 1, Jianshe East Road, Zhengzhou, 450052, People's Republic of China
| | - Nan Zhou
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, No. 1, Jianshe East Road, Zhengzhou, 450052, People's Republic of China.
| | - Zhihong Zhang
- School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, No. 136, Science Avenue, Zhengzhou, 450001, People's Republic of China.
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Zheng Y, Geng X, Yang X, Li S, Liu Y, Liu X, Wang Q, Wang K, Jia R, Xu Y. Exploring Interactions of Aptamers with Aβ 40 Amyloid Aggregates and Its Application: Detection of Amyloid Aggregates. Anal Chem 2020; 92:2853-2858. [PMID: 31916749 DOI: 10.1021/acs.analchem.9b05493] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The exhaustive investigating interactions between recognition probes and amyloid aggregates, especially simultaneous recognition events, are challenging and crucial for the design of biosensing probes and further diagnosis of amyloid diseases. In the present work, the interactions of aptamers (Apts) with β-amyloid (Aβ) aggregates were explored thoroughly by single-molecule force spectroscopy (SMFS). Indeed, it was found that the interaction of aptamer1 (Apt1)-amyloid aggregates was different from that of aptamer2 (Apt2)-Aβ40 aggregates at the single-molecule level. Especially, the interaction force of Apt1-Aβ40 fibril showed a double distinguishing Gaussian fitting. The only unimodal distribution of the force histogram was displayed for the interactions of Apt2-Aβ40 oligomer, Apt2-Aβ40 fibril, and Apt1-Aβ40 oligomer. More intriguingly, two Apts could bind to amyloid aggregates simultaneously. With the assistance of two Apts recognition, a novel sensitive dual Apt-based surface plasmon resonance (SPR) sensor using Au nanoparticles (AuNPs) was developed for quantifying Aβ40 aggregates. The dual Apt-based SPR sensor not only avoided the limitation of steric hindrance and epitope but also employed simple operation as well as inexpensive recognition probes. A detection limit as low as 0.2 pM for Aβ40 oligomer and 0.05 pM for Aβ40 fibril could be achieved. Moreover, the established sensor could be successfully applied to detect Aβ40 aggregates in artificial cerebrospinal fluid (CSF) and undiluted real CSF. This work could provide a strategy to monitor a simultaneous recognition event using SMFS and broaden the application of Apts in the diagnosis of neurodegenerative diseases.
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Affiliation(s)
- Yan Zheng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province , Hunan University , Changsha 410082 , P. R. China
| | - Xiuhua Geng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province , Hunan University , Changsha 410082 , P. R. China
| | - Xiaohai Yang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province , Hunan University , Changsha 410082 , P. R. China
| | - Shaoyuan Li
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province , Hunan University , Changsha 410082 , P. R. China
| | - Yaqin Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province , Hunan University , Changsha 410082 , P. R. China
| | - Xiaofeng Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province , Hunan University , Changsha 410082 , P. R. China
| | - Qing Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province , Hunan University , Changsha 410082 , P. R. China
| | - Kemin Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province , Hunan University , Changsha 410082 , P. R. China
| | - Ruichen Jia
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province , Hunan University , Changsha 410082 , P. R. China
| | - Yao Xu
- Huaihe Hospital of Henan University , Henan University , Kaifeng 475001 , P. R. China
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Li S, Zheng Y, Liu Y, Geng X, Liu X, Zou L, Wang Q, Yang X, Wang K. Investigation of the interaction between split aptamer and vascular endothelial growth factor 165 using single molecule force spectroscopy. J Mol Recognit 2019; 33:e2829. [PMID: 31816660 DOI: 10.1002/jmr.2829] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 11/17/2019] [Accepted: 11/28/2019] [Indexed: 01/06/2023]
Abstract
Understanding the binding of split aptamer/its target could become a breakthrough in the application of split aptamer. Herein, vascular endothelial growth factor (VEGF), a major biomarker of human diseases, was used as a model, and its interaction with split aptamer was explored with single molecule force spectroscopy (SMFS). SMFS demonstrated that the interaction force of split aptamer/VEGF165 was 169.44 ± 6.59 pN at the loading rate of 35.2 nN/s, and the binding probability of split aptamer/VEGF165 was dependent on the concentration of VEGF165 . On the basis of dynamic force spectroscopy results, one activation barrier in the dissociation process of split aptamer/VEGF165 complexes was revealed, which was similar to that of the intact aptamer/VEGF165 . Besides, the dissociation rate constant (koff ) of split aptamer/VEGF165 was close to that of intact aptamer/VEGF165 , and the interaction force of split aptamer/VEGF165 was higher than the force of intact aptamer/VEGF165 . It indicated that split aptamer also possessed high affinity with VEGF165 . The work can provide a new method for exploring the interaction of split aptamer/its targets at single-molecule level.
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Affiliation(s)
- Shaoyuan Li
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Yan Zheng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Yaqin Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Xiuhua Geng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Xiaofeng Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Liyuan Zou
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Qing Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Xiaohai Yang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Kemin Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
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Hoare D, Bussooa A, Neale S, Mirzai N, Mercer J. The Future of Cardiovascular Stents: Bioresorbable and Integrated Biosensor Technology. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1900856. [PMID: 31637160 PMCID: PMC6794628 DOI: 10.1002/advs.201900856] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/26/2019] [Indexed: 05/15/2023]
Abstract
Cardiovascular disease is the greatest cause of death worldwide. Atherosclerosis is the underlying pathology responsible for two thirds of these deaths. It is the age-dependent process of "furring of the arteries." In many scenarios the disease is caused by poor diet, high blood pressure, and genetic risk factors, and is exacerbated by obesity, diabetes, and sedentary lifestyle. Current pharmacological anti-atherosclerotic modalities still fail to control the disease and improvements in clinical interventions are urgently required. Blocked atherosclerotic arteries are routinely treated in hospitals with an expandable metal stent. However, stented vessels are often silently re-blocked by developing "in-stent restenosis," a wound response, in which the vessel's lumen renarrows by excess proliferation of vascular smooth muscle cells, termed hyperplasia. Herein, the current stent technology and the future of biosensing devices to overcome in-stent restenosis are reviewed. Second, with advances in nanofabrication, new sensing methods and how researchers are investigating ways to integrate biosensors within stents are highlighted. The future of implantable medical devices in the context of the emerging "Internet of Things" and how this will significantly influence future biosensor technology for future generations are also discussed.
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Affiliation(s)
- Daniel Hoare
- BHF Cardiovascular Research CentreUniversity of GlasgowG12 8TAGlasgowScotland
| | - Anubhav Bussooa
- BHF Cardiovascular Research CentreUniversity of GlasgowG12 8TAGlasgowScotland
| | - Steven Neale
- James Watt South BuildingSchool of EngineeringUniversity of GlasgowG12 8QQGlasgowScotland
| | - Nosrat Mirzai
- Bioelectronics UnitCollege of Medical, Veterinary & Life Sciences (MVLS)University of GlasgowG12 8QQGlasgowScotland
| | - John Mercer
- BHF Cardiovascular Research CentreUniversity of GlasgowG12 8TAGlasgowScotland
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Zheng Y, Wang Q, Yang X, Li Z, Gao L, Zhang H, Nie W, Geng X, Wang K. Investigation of the interactions between aptamer and misfolded proteins: From monomer and oligomer to fibril by single-molecule force spectroscopy. J Mol Recognit 2017; 31. [PMID: 29143447 DOI: 10.1002/jmr.2686] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 10/10/2017] [Accepted: 10/19/2017] [Indexed: 12/13/2022]
Abstract
Increasing knowledge on the understanding interactions of aptamer with misfolded proteins (including monomer, oligomer, and amyloid fibril) is crucial for development of aggregation inhibitors and diagnosis of amyloid diseases. Herein, the interactions of lysozyme monomer-, oligomer-, and amyloid fibril-aptamer were investigated using single-molecule force spectroscopy. The results revealed that the aptamer screened against lysozyme monomer could also bind to oligomer and amyloid fibril, in spite of the recognition at a lower binding probability. It may be attributed to the inherent structural differences of misfolded proteins and the flexible conformation of aptamer. In addition, dynamic force spectra showed that there were similar dissociation paths in the dissociation process of lysozyme monomer-, oligomer-, and amyloid fibril-aptamer complexes. It showed that the dissociation only passed 1 energy barrier from the binding state to the detachment. However, the dynamic parameters suggested that the oligomer- and amyloid fibril-aptamer were more stable than lysozyme monomer-aptamer. The phenomena may result from the exposure of aptamer-recognized sequences on the surface and the electrostatic interactions. This work demonstrated that single-molecule force spectroscopy could be a powerful tool to study the binding behavior of the aptamer with misfolded proteins at single-molecule level, providing abundant information for researches and comprehensive applications of aptamer probes in diagnosis of amyloid diseases.
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Affiliation(s)
- Yan Zheng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Qing Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Xiaohai Yang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Zhiping Li
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Lei Gao
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Hua Zhang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Wenyan Nie
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Xiuhua Geng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
| | - Kemin Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, China
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Schön P. Atomic force microscopy of RNA: State of the art and recent advancements. Semin Cell Dev Biol 2017; 73:209-219. [PMID: 28843977 DOI: 10.1016/j.semcdb.2017.08.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/17/2017] [Accepted: 08/18/2017] [Indexed: 12/26/2022]
Abstract
The atomic force microscope (AFM) has become a powerful tool for the visualization, probing and manipulation of RNA at the single molecule level. AFM measurements can be carried out in buffer solution in a physiological medium, which is crucial to study the structure and function of biomolecules, also allowing studying them at work. Imaging the specimen in its native state is a great advantage compared to other high resolution methods such as electron microscopy and X-ray diffraction. There is no need to stain, freeze or crystallize biological samples. Moreover, compared to NMR spectroscopy for instance, for AFM studies the size of the biomolecules is not limiting. Consequently the AFM allows one also to investigate larger RNA molecules. In particular, structural studies of nucleic acids and assemblies thereof, have been carried out by AFM routinely including ssRNA, dsRNA and nucleoprotein complexes thereof, as well as RNA aggregates and 2D RNA assemblies. These are becoming increasingly important as novel unique building blocks in the emerging field of RNA nanotechnology. In particular by AFM unique information can be obtained on these RNA based assemblies. Moreover, the AFM is of fundamental relevance to study biological relevant RNA interactions and dynamics. In this short review a brief overview will be given on structural studies that have been done related to AFM topographic imaging of RNA, RNA assemblies and aggregates. Finally, an overview on AFM beyond imaging will be provided. This includes force spectroscopy of RNA under physiological conditions in aqueous buffer to probe RNA interaction with proteins and ligands as well as other AFM tip based RNA probing. Important applications include the detection and quantification of RNA in biological samples. A selection of recent highlights and breakthroughs will be provided related to structural and functional studies by AFM. The main intention of this short review to provide the reader with a flavor of what AFM is able to contribute to RNA research and engineering.
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Affiliation(s)
- Peter Schön
- NanoBioInterface Research Group, Research Center Design and Technology, Saxion University of Applied Sciences, 7500 KB Enschede, The Netherlands; Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
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9
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Schön P. Imaging and force probing RNA by atomic force microscopy. Methods 2016; 103:25-33. [PMID: 27222101 DOI: 10.1016/j.ymeth.2016.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/19/2016] [Accepted: 05/20/2016] [Indexed: 12/12/2022] Open
Abstract
In the past 30years, the atomic force microscope (AFM) has become a true enabling platform in the life sciences opening entire novel avenues for structural and dynamic studies of biological systems. It enables visualization, probing and manipulation across the length scales, from single molecules to living cells in buffer solution under physiological conditions without the need for labeling or staining of the specimen. In particular, for structural studies of nucleic acids and assemblies thereof, the AFM has matured into a routinely used tool providing nanometer spatial resolution. This includes ssRNA, dsRNA and nucleoprotein complexes thereof, as well as RNA aggregates and 2D RNA assemblies. By AFM unique information can be obtained on RNA based assemblies which are becoming increasingly important as novel unique building blocks in the emerging field of RNA nanotechnology. In addition, the AFM is of fundamental relevance to study biological relevant RNA interactions and dynamics. In this short review first the basic functioning principles of commonly used AFM modes including AFM based force spectroscopy will be briefly described. Next a brief overview will be given on structural studies that have been done related to AFM topographic imaging of RNA, RNA assemblies and aggregates. Finally, an overview on AFM beyond imaging will be provided. This includes force spectroscopy of RNA under physiological conditions in aqueous buffer to probe RNA interaction with proteins and ligands as well as other AFM tip based RNA probing. The main intention of this short review to give the reader a flavor of what AFM contributes to RNA research and engineering.
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Affiliation(s)
- Peter Schön
- NanoBioInterface Chair, Research Center Design and Technology, Saxion University of Applied Sciences, 7500 KB Enschede, The Netherlands; Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
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10
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Wang C, Jin Y, Desai UR, Yadavalli VK. Investigation of the heparin-thrombin interaction by dynamic force spectroscopy. Biochim Biophys Acta Gen Subj 2015; 1850:1099-106. [PMID: 25647100 DOI: 10.1016/j.bbagen.2015.01.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 01/08/2015] [Accepted: 01/25/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND The interaction between heparin and thrombin is a vital step in the blood (anti)coagulation process. Unraveling the molecular basis of the interactions is therefore extremely important in understanding the mechanisms of this complex biological process. METHODS In this study, we use a combination of an efficient thiolation chemistry of heparin, a self-assembled monolayer-based single molecule platform, and a dynamic force spectroscopy to provide new insights into the heparin-thrombin interaction from an energy viewpoint at the molecular scale. RESULTS Well-separated single molecules of heparin covalently attached to mixed self-assembled monolayers are demonstrated, whereby interaction forces with thrombin can be measured via atomic force microscopy-based spectroscopy. Further these interactions are studied at different loading rates and salt concentrations to directly obtain kinetic parameters. CONCLUSIONS An increase in the loading rate shows a higher interaction force between the heparin and thrombin, which can be directly linked to the kinetic dissociation rate constant (koff). The stability of the heparin/thrombin complex decreased with increasing NaCl concentration such that the off-rate was found to be driven primarily by non-ionic forces. GENERAL SIGNIFICANCE These results contribute to understanding the role of specific and nonspecific forces that drive heparin-thrombin interactions under applied force or flow conditions.
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Affiliation(s)
- Congzhou Wang
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond VA 23284, United States
| | - Yingzi Jin
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298, United States
| | - Umesh R Desai
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298, United States
| | - Vamsi K Yadavalli
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond VA 23284, United States.
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Wang C, Yadavalli VK. Spatial recognition and mapping of proteins using DNA aptamers. NANOTECHNOLOGY 2014; 25:455101. [PMID: 25338629 DOI: 10.1088/0957-4484/25/45/455101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Atomic force microscopy-based adhesion force measurements have emerged as a powerful tool for the biophysical analyses of biological systems. Such measurements can now be extended to detection and mapping of biomolecules on surfaces via integrated imaging and force spectroscopy techniques. Critical to these experiments is the choice of the biomolecular recognition probe. In this study, we demonstrate how oligonucleotide aptamers can be used as versatile probes to simultaneously image and spatially locate targets on surfaces. We focus on two structurally distinct proteins relevant to the clotting cascade - human α-thrombin and vascular endothelial growth factor. Via AFM-recognition mapping using specific DNA aptamers on a commercially available instrument, we show a clear consistency between height and force measurements obtained simultaneously. Importantly, we are able to observe changes in binding due to changes in the external microenvironment, which demonstrate the ability to study fluctuating biological systems in real time. The aptamer specificity and the ability to distinguish their targets are shown through positive and negative controls. It is therefore possible to generate high resolution maps to spatially and temporally identify proteins at the molecular level on complex surfaces.
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Huang X, Li X, Wang Q, Dai J, Hou J, Chen L. Single-molecule level binding force between collagen and collagen binding domain-growth factor conjugates. Biomaterials 2013; 34:6139-46. [PMID: 23706541 DOI: 10.1016/j.biomaterials.2013.04.057] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 04/27/2013] [Indexed: 11/19/2022]
Abstract
Biological studies have shown that collagen/collagen binding domain (CBD)-growth factor composites are effective biomaterials systems for tissue engineering and regeneration. Here we present atomic force spectroscopy (AFM)-based investigations at the single molecule level to address fundamental biophysical questions such as CBD binding sites distribution and the mechanism for controlled release of growth factors from the collagen scaffold. Non-uniformly distributed CBD binding sites on collagen membrane are directly visualized with a quantum dot-based bimodal imaging method. AFM force spectroscopy unbinding experiments reveal that modest unbinding force and dissociation constant of the CBD/collagen interaction could be the key for its successful application in controlled release systems.
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Affiliation(s)
- Xun Huang
- i-LAB, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
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Selecting Molecular Recognition. What Can Existing Aptamers Tell Us about Their Inherent Recognition Capabilities and Modes of Interaction? Pharmaceuticals (Basel) 2012; 5:493-513. [PMID: 24281560 PMCID: PMC3763653 DOI: 10.3390/ph5050493] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 04/19/2012] [Accepted: 05/10/2012] [Indexed: 01/02/2023] Open
Abstract
The use of nucleic acid derived aptamers has rapidly expanded since the introduction of SELEX in 1990. Nucleic acid aptamers have demonstrated their ability to target a broad range of molecules in ways that rival antibodies, but advances have been very uneven for different biochemical classes of targets, and clinical applications have been slow to emerge. What sets different aptamers apart from each other and from rivaling molecular recognition platforms, specifically proteins? What advantages do aptamers as a reagent class offer, and how do the chemical properties and selection procedures of aptamers influence their function? Do the building blocks of nucleic acid aptamers dictate inherent limitations in the nature of molecular targets, and do existing aptamers give us insight in how these challenges might be overcome? This review is written as an introduction for potential endusers of aptamer technology who are evaluating the advantages of aptamers as a versatile, affordable, yet highly expandable platform to target a broad range of biological processes or interactions.
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Zhang X, Yadavalli VK. Functional self-assembled DNA nanostructures for molecular recognition. NANOSCALE 2012; 4:2439-2446. [PMID: 22399156 DOI: 10.1039/c2nr11711h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Nucleic acids present a wonderful toolkit of structural motifs for nanoconstruction. Functional DNA nanostructures can enable protein recognition by the use of aptamers attached to a basic core shape formed by DNA self-assembly. Here, we present a facile, programmable strategy for the assembly of discrete aptamer-tagged DNA shapes and nanostructures that can function for molecular recognition and binding in an aqueous environment. These nanostructures, presented here to bind two different protein targets, are easily synthesized in large numbers, and are portable and stable over long periods of time. This construction modality can facilitate on-demand production of libraries of diverse shapes to recognize and bind proteins or catalyze reactions via functional nucleic acid tags.
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Affiliation(s)
- Xiaojuan Zhang
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
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O'Donoghue MB, Shi X, Fang X, Tan W. Single-molecule atomic force microscopy on live cells compares aptamer and antibody rupture forces. Anal Bioanal Chem 2012; 402:3205-9. [PMID: 22278072 DOI: 10.1007/s00216-011-5667-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 12/12/2011] [Accepted: 12/15/2011] [Indexed: 11/24/2022]
Abstract
Some researchers have questioned whether synthetic aptamers bind as robustly as natural antibodies. To address this issue, we used single-molecule atomic force microscopy to measure the rupture force between a protein and both its aptamer and its antibody. The rupture force on live cell membranes between the aptamer and protein was 46 ± 26 pN; the force with the antibody was 68 ± 33 pN, we conclude that the binding forces are about equal.
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Affiliation(s)
- Meghan B O'Donoghue
- Department of Chemistry, Center for Research at the Bio/Nano Interface, UF Genetics Institute, University of Florida, Gainesville, FL 32611-7200, USA
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Neundlinger I, Poturnayova A, Karpisova I, Rankl C, Hinterdorfer P, Snejdarkova M, Hianik T, Ebner A. Characterization of enhanced monovalent and bivalent thrombin DNA aptamer binding using single molecule force spectroscopy. Biophys J 2012; 101:1781-7. [PMID: 21961605 DOI: 10.1016/j.bpj.2011.07.054] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 07/27/2011] [Accepted: 07/28/2011] [Indexed: 11/15/2022] Open
Abstract
Thrombin aptamer binding strength and stability is dependent on sterical parameters when used for atomic force microscopy sensing applications. Sterical improvements on the linker chemistry were developed for high-affinity binding. For this we applied single molecule force spectroscopy using two enhanced biotinylated thrombin aptamers, BFF and BFA immobilized on the atomic force microscopy tip via streptavidin. BFF is a dimer composed of two single-stranded aptamers (aptabody) connected to each other by a complementary sequence close to the biotinylated end. In contrast, BFA consists of a single DNA strand and a complementary strand in the supporting biotinylated part. By varying the pulling velocity in force-distance cycles the formed thrombin-aptamer complexes were ruptured at different force loadings allowing determination of the energy landscape. As a result, BFA aptamer showed a higher binding force at the investigated loading rates and a significantly lower dissociation rate constant, k(off), compared to BFF. Moreover, the potential of the aptabody BFF to form a bivalent complex could clearly be demonstrated.
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Surface immobilization of DNA aptamers for biosensing and protein interaction analysis. Biosens Bioelectron 2010; 26:3142-7. [PMID: 21227676 DOI: 10.1016/j.bios.2010.12.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 11/06/2010] [Accepted: 12/08/2010] [Indexed: 11/23/2022]
Abstract
To utilize aptamers as molecular recognition agents in biosensors and biodiagnostics, it is important to develop strategies for reliable immobilization of aptamers so that they retain their biophysical characteristics and binding abilities. Here we report on quartz crystal microbalance (QCM) measurements and atomic force microscope (AFM)-based force spectroscopy studies to evaluate aptasensors fabricated by different modification strategies. Gold surfaces were modified with mixed self assembled monolayers (SAMs) of aptamer and oligoethylene glycol (OEG) thiols (HS-C(11)-(EG)(n)OH, n=3 or 6) to impart resistance to nonspecific protein adsorption. By affinity analysis, we show that short OEG thiols have less impact on aptamer accessibility than longer chain thiols. Backfilling with OEG as a step subsequent to aptamer immobilization provides greater surface coverage than using aptamer and OEG thiol to form a mixed SAM in one-step. Immunoglobulin E and vascular endothelial growth factor (VEGF) were studied as target proteins in these experiments. Binding forces obtained by these strategies are similar, demonstrating that the biophysical properties of the aptamer on the sensors are independent from the immobilization strategy. The results present mixed SAMs with aptamers and co-adsorbents as a versatile strategy for aptamer sensor platforms including ultrasensitive biosensor design.
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