1
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Zheng H, Munusamy S, Arora P, Jahani R, Guan X. A highly sensitive nanopore platform for measuring RNase A activity. Talanta 2024; 276:126276. [PMID: 38796995 PMCID: PMC11187776 DOI: 10.1016/j.talanta.2024.126276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/11/2024] [Accepted: 05/16/2024] [Indexed: 05/29/2024]
Abstract
Ribonuclease A (RNase A) plays significant roles in several physiological and pathological conditions and can be used as a valuable diagnostic biomarker for human diseases such as myocardial infarction and cancer. Hence, it is of great importance to develop a rapid and cost-effective method for the highly sensitive detection of RNase A. The significance of RNase A assay is further enhanced by the growing attention from the biotechnology and pharmaceutical industries to develop RNA-based vaccines and drugs in large part as a result of the successful development of mRNA vaccines in the COVID-19 pandemic. Herein, we report a label-free method for the detection of RNase A by monitoring its proteolytic cleavage of an RNA substrate in a nanopore. The method is ultra-sensitive with the limit of detection reaching as low as 30 fg per milliliter. Furthermore, sensor selectivity and the effects of temperature, incubation time, metal ion, salt concentration on sensor sensitivity were also investigated.
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Affiliation(s)
- Haiyan Zheng
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA
| | | | - Pearl Arora
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Rana Jahani
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA
| | - Xiyun Guan
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
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2
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Kang X, Wu C, Alibakhshi MA, Liu X, Yu L, Walt DR, Wanunu M. Nanopore-Based Fingerprint Immunoassay Based on Rolling Circle Amplification and DNA Fragmentation. ACS NANO 2023; 17:5412-5420. [PMID: 36877993 PMCID: PMC10629239 DOI: 10.1021/acsnano.2c09889] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
In recent years, nanopore-based sequencers have become robust tools with unique advantages for genomics applications. However, progress toward applying nanopores as highly sensitive, quantitative diagnostic tools has been impeded by several challenges. One major limitation is the insufficient sensitivity of nanopores in detecting disease biomarkers, which are typically present at pM or lower concentrations in biological fluids, while a second limitation is the general absence of unique nanopore signals for different analytes. To bridge this gap, we have developed a strategy for nanopore-based biomarker detection that utilizes immunocapture, isothermal rolling circle amplification, and sequence-specific fragmentation of the product to release multiple DNA reporter molecules for nanopore detection. These DNA fragment reporters produce sets of nanopore signals that form distinctive fingerprints, or clusters. This fingerprint signature therefore allows the identification and quantification of biomarker analytes. As a proof of concept, we quantify human epididymis protein 4 (HE4) at low pM levels in a few hours. Future improvement of this method by integration with a nanopore array and microfluidics-based chemistry can further reduce the limit of detection, allow multiplexed biomarker detection, and further reduce the footprint and cost of existing laboratory and point-of-care devices.
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Affiliation(s)
- Xinqi Kang
- Departments
of Bioengineering, Physics, and Chemistry and Chemical Biology, Northeastern
University, Boston, Massachusetts 02115, United States
| | - Connie Wu
- Department
of Pathology, Brigham and Women’s Hospital, Harvard Medical School and Wyss Institute for Biologically Inspired
Engineering at Harvard University, Boston, Massachusetts 02115, United States
| | - Mohammad Amin Alibakhshi
- Departments
of Bioengineering, Physics, and Chemistry and Chemical Biology, Northeastern
University, Boston, Massachusetts 02115, United States
| | - Xingyan Liu
- Departments
of Bioengineering, Physics, and Chemistry and Chemical Biology, Northeastern
University, Boston, Massachusetts 02115, United States
| | - Luning Yu
- Departments
of Bioengineering, Physics, and Chemistry and Chemical Biology, Northeastern
University, Boston, Massachusetts 02115, United States
| | - David R. Walt
- Department
of Pathology, Brigham and Women’s Hospital, Harvard Medical School and Wyss Institute for Biologically Inspired
Engineering at Harvard University, Boston, Massachusetts 02115, United States
| | - Meni Wanunu
- Departments
of Bioengineering, Physics, and Chemistry and Chemical Biology, Northeastern
University, Boston, Massachusetts 02115, United States
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3
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Wang L, Wang H, Chen X, Zhou S, Wang Y, Guan X. Chemistry solutions to facilitate nanopore detection and analysis. Biosens Bioelectron 2022; 213:114448. [PMID: 35716643 DOI: 10.1016/j.bios.2022.114448] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/24/2022] [Accepted: 05/30/2022] [Indexed: 11/29/2022]
Abstract
Characteristic ionic current modulations will be produced in a single molecule manner during the communication of individual molecules with a nanopore. Hence, the information regarding the length, composition, and structure of a molecule can be extracted from deciphering the electrical message. However, until now, achieving a satisfactory resolution for observation and quantification of a target analyte in a complex system remains a nontrivial task. In this review, we summarize the progress and especially the recent advance in utilizing chemistry solutions to facilitate nanopore detection and analysis. The discussed chemistry solutions are classified into several major categories, including covalent/non-covalent chemistry, redox chemistry, displacement chemistry, back titration chemistry, chelation chemistry, hydrolysis-chemistry, and click chemistry. Considering the significant success of using chemical reaction-assisted nanopore sensing strategies to improve sensor sensitivity & selectivity and to study various topics, other non-chemistry based methodologies can undoubtedly be employed by nanopore sensors to explore new applications in the interdisciplinary area of chemistry, biology, materials, and nanotechnology.
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Affiliation(s)
- Liang Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing, 400714, China
| | - Han Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing, 400714, China
| | - Xiaohan Chen
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing, 400714, China
| | - Shuo Zhou
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing, 400714, China
| | - Yunjiao Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing, 400714, China.
| | - Xiyun Guan
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, 60616, USA.
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4
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Denuga S, Whelan DE, O'Neill SP, Johnson RP. Capture and analysis of double‐stranded DNA with the α‐hemolysin nanopore: Fundamentals and applications. ELECTROCHEMICAL SCIENCE ADVANCES 2022. [DOI: 10.1002/elsa.202200001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
| | | | | | - Robert P. Johnson
- School of Chemistry University College Dublin Ireland
- UCD‐Centre for Food Safety University College Dublin Dublin Ireland
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5
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Ohnishi S, Kamiya K. Formation of Giant Lipid Vesicle Containing Dual Functions Facilitates Outer Membrane Phospholipase. ACS Synth Biol 2021; 10:1837-1846. [PMID: 34258991 DOI: 10.1021/acssynbio.0c00468] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Giant lipid vesicles are used to study artificial cell models, as well as the encapsulation of biomolecules, and the reconstitution of membrane proteins on these vesicles. Recently, complex reactions in giant vesicles have been controlled by reconstituting numerous kinds of biomolecules. However, it is challenging to generate giant lipid vesicles containing a diverse set of proteins at concentrations sufficient to ensure proper functioning. Here, we describe an artificial cell model showing dual functions of small molecule transportation and small vesicle budding, using a dual functional membrane protein (transportation and phosphatase activity) called the outer membrane phospholipase (OmpLA). To the best of our knowledge, we have revealed for the first time the transportation of ions or small molecules through OmpLA on the charged lipid bilayer. The lipid composition controlled the orientation of OmpLA through proteinase K digestion. Finally, OmpLA enzyme activity of phospholipid hydrolysis caused the budding of small vesicles.
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Affiliation(s)
- Seren Ohnishi
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Koki Kamiya
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
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6
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Li X, Song G, Dou L, Yan S, Zhang M, Yuan W, Lai S, Jiang X, Li K, Sun K, Zhao C, Geng J. The structure and unzipping behavior of dumbbell and hairpin DNA revealed by real-time nanopore sensing. NANOSCALE 2021; 13:11827-11835. [PMID: 34152351 DOI: 10.1039/d0nr08729g] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Hairpin structures play an essential role in DNA replication, transcription, and recombination. Single-molecule studies enable the real-time measurement and observation of the energetics and dynamics of hairpin structures, including folding and DNA-protein interactions. Nanopore sensing is emerging as a powerful tool for DNA sensing and sequencing, and previous research into hairpins using an α-hemolysin (α-HL) nanopore suggested that hairpin DNA enters from its stem side. In this work, the translocation and interaction of hairpin and dumbbell DNA samples with varying stems, loops, and toeholds were investigated systematically using a Mycobacterium smegmatis porin A (MspA) nanopore. It was found that these DNA constructs could translocate through the pore under a bias voltage above +80 mV, and blockage events with two conductance states could be observed. The events of the lower blockage were correlated with the loop size of the hairpin or dumbbell DNA (7 nt to 25 nt), which could be attributed to non-specific collisions with the pore, whereas the dwell time of events with the higher blockage were correlated with the stem length, thus indicating effective translocation. Furthermore, dumbbell DNA with and without a stem opening generated different dwell times when driven through the MspA nanopore. Finally, a new strategy based on the dwell time difference was developed to detect single nucleotide polymorphisms (SNPs). These results demonstrated that the unzipping behaviors and DNA-protein interactions of hairpin and dumbbell DNA could be revealed using nanopore technology, and this could be further developed to create sensors for the secondary structures of nucleic acids.
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Affiliation(s)
- Xinqiong Li
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu 610041, China.
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7
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Wang Y, Zhang Y, Chen X, Guan X, Wang L. Analysis with biological nanopore: On-pore, off-pore strategies and application in biological fluids. Talanta 2020; 223:121684. [PMID: 33303138 DOI: 10.1016/j.talanta.2020.121684] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 09/14/2020] [Accepted: 09/16/2020] [Indexed: 10/23/2022]
Abstract
Inspired from ion channels in biology, nanopores have been developed as promising analytical tools. In principle, nanopores provide crucial information from the observation and analysis of ionic current modulations caused by the interaction between target analytes and fluidic pores. In this respect, the biological, chemical and physical parameters of the nanopore regime need to be well-understood and regulated for intermolecular interaction. Because of well-defined molecular structures, biological nanopores consequently are of a focal point, allowing precise interaction analysis at single-molecule level. In this overview, two analytical strategies are summarized and discussed accordingly, upon the challenges arising in case-dependent analysis using biological nanopores. One kind of strategies relies on modification, functionalization and engineering on nanopore confined interface to improve molecular recognition sites (on-pore strategies); The other kind of highlighted strategies concerns to measurement of various chemistry/biochemistry based interactions triggered by employed molecular agents or probes (off-pore strategies). In particularly, a few recent paradigms using these strategies for practical application of accurate analysis of biomarkers in biological fluids are illustrated. To end, the challenging and future outlook of using analytical tools by means of biological nanopores are depicted.
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Affiliation(s)
- Yunjiao Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing, 400714, China
| | - Youwen Zhang
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Xiaohan Chen
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Xiyun Guan
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, 60616, USA.
| | - Liang Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China; Chongqing School, University of Chinese Academy of Sciences, Chongqing, 400714, China.
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8
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Zhou S, Wang H, Chen X, Wang Y, Zhou D, Liang L, Wang L, Wang D, Guan X. Single-molecule Study on the Interactions between Cyclic Nonribosomal Peptides and Protein Nanopore. ACS APPLIED BIO MATERIALS 2019; 3:554-560. [PMID: 34169233 DOI: 10.1021/acsabm.9b00961] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nonribosomal peptides (NRPs) are a type of secondary metabolites mostly originated from microorganisms such as bacteria and fungi. Their proteolytic stability, highly selective bioactivity, and microorganism-specificity have made them an attractive source of drugs for the pharmaceutical industry. Herein, with microcystins (MCs) as a NRP model, we, for the first time, proposed a sensitive method to study the interactions between NRPs and the protein nanopore. Due to the large molecular size (~3 nm diameter) of MCs and their net negative charges, MCs failed to translocate through the α-hemolysin (α-HL) protein channel. Our results demonstrated that the biomolecular interaction of MC-α-HL protein was significantly affected by the applied potential bias. The constant blockage amplitude in the voltage-dependent studies indicated that the current modulation events were dominantly contributed to the bumping interaction between MCs and the α-HL protein under the electrophoretic force. The mean residence time of the bumping events exhibited a two-stage decrease (from 1.90 ms to 1.02 ms, and from 1.02 ms to 0.69 ms) at the threshold voltages of -70 mV and -100 mV, respectively. Using our strategy (i.e., based on their electrophoretic driven interaction with the α-HL protein pore), discrimination of different MC molecules (MC-LR, MC-RR, MC-YR and linear analog) with varied branched residues could be accomplished. This work should provide an insight in developing a rapid and effective method for the identification of cyclic NRPs as valuable biomarkers for fungal infections.
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Affiliation(s)
- Shuo Zhou
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Han Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaohan Chen
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Yunjiao Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Daming Zhou
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Liyuan Liang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liang Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Deqiang Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiyun Guan
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL 60616, USA
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9
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Wang L, Chen X, Zhou S, Roozbahani GM, Zhang Y, Wang D, Guan X. Displacement chemistry-based nanopore analysis of nucleic acids in complicated matrices. Chem Commun (Camb) 2018; 54:13977-13980. [PMID: 30480311 PMCID: PMC6800042 DOI: 10.1039/c8cc07944g] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
To overcome the effect of other components of complicated biological samples on nanopore stochastic sensing, displacement chemical reaction was utilized to selectively extract the target nucleic acid from whole blood. Given its simplicity and high sensitivity for detecting nucleic acids, our developed displacement chemistry-based nanopore sensing strategy offers the potential for fieldable/point-of-care diagnostic applications.
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Affiliation(s)
- Liang Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, P. R. China.
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10
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Röder K, Wales DJ. Mutational Basin-Hopping: Combined Structure and Sequence Optimization for Biomolecules. J Phys Chem Lett 2018; 9:6169-6173. [PMID: 30299103 DOI: 10.1021/acs.jpclett.8b02839] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The study of energy landscapes has led to a good understanding of how and why proteins and nucleic acids adopt their native structure. Through evolution, sequences have adapted until they exhibit a strongly funneled energy landscape, stabilizing the native fold. Design of artificial biomolecules faces the challenge of creating similar stable, minimally frustrated, and functional sequences. Here we present a biminimization approach, mutational basin-hopping, in which we simultaneously use global optimization to optimize the energy and a target function describing a desired property of the system. This optimization of structure and sequence is a generalized basin-hopping method and produces an efficient design process, which can target properties such as binding affinity or solubility.
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Affiliation(s)
- Konstantin Röder
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , U.K
| | - David J Wales
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , U.K
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11
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Roozbahani GM, Chen X, Zhang Y, Juarez O, Li D, Guan X. Computation-Assisted Nanopore Detection of Thorium Ions. Anal Chem 2018; 90:5938-5944. [PMID: 29648804 DOI: 10.1021/acs.analchem.8b00848] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Thorium is a well-known radioactive and chemically toxic contaminant in the environment. The continuous exposure to thorium may cause an increased risk of developing lung and liver diseases as well as lung, pancreas, and bone cancer. Due to its use in nuclear industry and other industrial applications, thorium may be accidentally released to the environment from its mining and processing plants. In this work, we developed a rapid, real-time, and label-free nanopore sensor for Th4+ detection by using an aspartic acid containing peptide as a chelating agent and tuning the electrolyte solution pH to control the net charges of the peptide ligand and its metal ion complex. The method is highly sensitive with a detection limit of 0.45 nM. Furthermore, the sensor is selective: other metal ions (e.g., UO22+, Pb2+, Cu2+, Ni2+, Hg2+, Zn2+, As3+, Mg2+, and Ca2+) with concentrations of up to 3 orders of magnitude greater than that of Th4+ would not interfere with Th4+detection. In addition, simulated water samples were successfully analyzed. Our developed computation-assisted sensing strategy should find useful applications in the development of nanopore sensors for other metal ions.
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Affiliation(s)
- Golbarg M Roozbahani
- Department of Chemistry , Illinois Institute of Technology , Chicago , Illinois 60616 , United States
| | - Xiaohan Chen
- Department of Chemistry , Illinois Institute of Technology , Chicago , Illinois 60616 , United States
| | - Youwen Zhang
- Department of Chemistry , Illinois Institute of Technology , Chicago , Illinois 60616 , United States
| | - Oscar Juarez
- Department of Biology , Illinois Institute of Technology , Chicago , Illinois 60616 , United States
| | - Dien Li
- Environmental Sciences and Biotechnology , Savannah River National Laboratory , Aiken , South Carolina 29808 , United States
| | - Xiyun Guan
- Department of Chemistry , Illinois Institute of Technology , Chicago , Illinois 60616 , United States
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12
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Chen X, Roozbahani GM, Ye Z, Zhang Y, Ma R, Xiang J, Guan X. Label-Free Detection of DNA Mutations by Nanopore Analysis. ACS APPLIED MATERIALS & INTERFACES 2018; 10:11519-11528. [PMID: 29537824 PMCID: PMC6760912 DOI: 10.1021/acsami.7b19774] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Cancers are caused by mutations to genes that regulate cell normal functions. The capability to rapid and reliable detection of specific target gene variations can facilitate early disease detection and diagnosis and also enables personalized treatment of cancer. Most of the currently available methods for DNA mutation detection are time-consuming and/or require the use of labels or sophisticated instruments. In this work, we reported a label-free enzymatic reaction-based nanopore sensing strategy to detect DNA mutations, including base substitution, deletion, and insertion. The method was rapid and highly sensitive with a detection limit of 4.8 nM in a 10 min electrical recording. Furthermore, the nanopore assay could differentiate among perfect match, one mismatch, and two mismatches. In addition, simulated serum samples were successfully analyzed. Our developed nanopore-based DNA mutation detection strategy should find useful application in genetic diagnosis.
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Affiliation(s)
- Xiaohan Chen
- Department of Chemistry, Illinois Institute of Technology, 3101 S Dearborn St, Chicago, IL 60616, USA
| | - Golbarg M Roozbahani
- Department of Chemistry, Illinois Institute of Technology, 3101 S Dearborn St, Chicago, IL 60616, USA
| | - Zijing Ye
- Department of Biology, Illinois Institute of Technology, 3101 S Dearborn St, Chicago, IL 60616, USA
| | - Youwen Zhang
- Department of Chemistry, Illinois Institute of Technology, 3101 S Dearborn St, Chicago, IL 60616, USA
| | - Rui Ma
- Department of Chemistry, Illinois Institute of Technology, 3101 S Dearborn St, Chicago, IL 60616, USA
| | - Jialing Xiang
- Department of Biology, Illinois Institute of Technology, 3101 S Dearborn St, Chicago, IL 60616, USA
| | - Xiyun Guan
- Department of Chemistry, Illinois Institute of Technology, 3101 S Dearborn St, Chicago, IL 60616, USA
- Corresponding author: Tel: 312-567-8922. Fax: 312-567-3494.
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13
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DUAN J, ZHUO S, YAO FJ, ZHANG YN, KANG XF. A Single-molecule Mycobacterium Smegmatis Porin A Protein Nanopore Sensor for Host-Guest Chemistry. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2016. [DOI: 10.1016/s1872-2040(16)60976-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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14
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Perera RT, Fleming AM, Peterson AM, Heemstra JM, Burrows CJ, White HS. Unzipping of A-Form DNA-RNA, A-Form DNA-PNA, and B-Form DNA-DNA in the α-Hemolysin Nanopore. Biophys J 2016; 110:306-314. [PMID: 26789754 DOI: 10.1016/j.bpj.2015.11.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/03/2015] [Accepted: 11/16/2015] [Indexed: 01/04/2023] Open
Abstract
Unzipping of double-stranded nucleic acids by an electric field applied across a wild-type α-hemolysin (αHL) nanopore provides structural information about different duplex forms. In this work, comparative studies on A-form DNA-RNA duplexes and B-form DNA-DNA duplexes with a single-stranded tail identified significant differences in the blockage current and the unzipping duration between the two helical forms. We observed that the B-form duplex blocks the channel 1.9 ± 0.2 pA more and unzips ∼15-fold more slowly than an A-form duplex at 120 mV. We developed a model to describe the dependence of duplex unzipping on structure. We demonstrate that the wider A-form duplex (d = 2.4 nm) is unable to enter the vestibule opening of αHL on the cis side, leading to unzipping outside of the nanopore with higher residual current and faster unzipping times. In contrast, the smaller B-form duplexes (d = 2.0 nm) enter the vestibule of αHL, resulting in decreased current blockages and slower unzipping. We investigated the effects of varying the length of the single-stranded overhang, and studied A-form DNA-PNA duplexes to provide additional support for the proposed model. This study identifies key differences between A- and B-form duplex unzipping that will be important in the design of future probe-based methods for detecting DNA or RNA.
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Affiliation(s)
- Rukshan T Perera
- Department of Chemistry, University of Utah, Salt Lake City, Utah
| | - Aaron M Fleming
- Department of Chemistry, University of Utah, Salt Lake City, Utah
| | | | | | | | - Henry S White
- Department of Chemistry, University of Utah, Salt Lake City, Utah.
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15
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Lella M, Mahalakshmi R. Engineering a Transmembrane Nanopore Ion Channel from a Membrane Breaker Peptide. J Phys Chem Lett 2016; 7:2298-2303. [PMID: 27257735 DOI: 10.1021/acs.jpclett.6b00987] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Re-engineering nature's molecules is an ideal strategy to obtain explicit functionality such as synthetic molecular machines, yet novel strategies for producing engineered molecular channels are few. Here we report a peptide engineering strategy through sequence reversal, which we applied on the first transmembrane peptide of the mycobacteriophage membranoporin protein holin. We have successfully redesigned the membrane rupture property of this peptide to form specific nanopore ion channels. We report the structural characterization and electrophysiology measurements of a library of 28-residue engineered membrane peptides, with remarkable ion channel behavior. We further identify that key residues at the peptide terminus, the central proline, charge distribution, and hydropathy index of the peptide together contribute to the channel properties that we measure. Our sequence reversal strategy for peptide engineering to successfully obtain nanopore channels can pave the way for better biobased design of controlled nanopores, using only natural amino acids.
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Affiliation(s)
- Muralikrishna Lella
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research , ITI Building, Govindpura, Bhopal - 462023, India
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research , ITI Building, Govindpura, Bhopal - 462023, India
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16
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Johnson RP, Fleming AM, Beuth LR, Burrows CJ, White HS. Base Flipping within the α-Hemolysin Latch Allows Single-Molecule Identification of Mismatches in DNA. J Am Chem Soc 2016; 138:594-603. [PMID: 26704521 PMCID: PMC4828915 DOI: 10.1021/jacs.5b10710] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A method for identifying and differentiating DNA duplexes containing the mismatched base pairs CC and CA at single molecule resolution with the protein pore α-hemolysin (αHL) is presented. Unique modulating current signatures are observed for duplexes containing the CC and CA mismatches when the mismatch site in the duplex is situated in proximity to the latch constriction of αHL during DNA residence inside the pore. The frequency and current amplitude of the modulation states are dependent on the mismatch type (CC or CA) permitting easy discrimination of these mismatches from one another, and from a fully complementary duplex that exhibits no modulation. We attribute the modulating current signatures to base flipping and subsequent interaction with positively charged lysine residues at the latch constriction of αHL. Our hypothesis is supported by the extended residence times of DNA duplexes within the pore when a mismatch is in proximity to the latch constriction, and by the loss of the two-state current signature in low pH buffers (<6.3), where the protonation of one of the cytosine bases increases the stability of the intrahelical state.
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Affiliation(s)
- Robert P Johnson
- Department of Chemistry, University of Utah , 315 S. 1400 East, Salt Lake City, Utah 84112-0850, United States
| | - Aaron M Fleming
- Department of Chemistry, University of Utah , 315 S. 1400 East, Salt Lake City, Utah 84112-0850, United States
| | - Laura R Beuth
- Department of Chemistry, University of Utah , 315 S. 1400 East, Salt Lake City, Utah 84112-0850, United States
| | - Cynthia J Burrows
- Department of Chemistry, University of Utah , 315 S. 1400 East, Salt Lake City, Utah 84112-0850, United States
| | - Henry S White
- Department of Chemistry, University of Utah , 315 S. 1400 East, Salt Lake City, Utah 84112-0850, United States
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17
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Johnson RP, Fleming AM, Jin Q, Burrows CJ, White HS. Temperature and electrolyte optimization of the α-hemolysin latch sensing zone for detection of base modification in double-stranded DNA. Biophys J 2015; 107:924-31. [PMID: 25140427 DOI: 10.1016/j.bpj.2014.07.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 06/16/2014] [Accepted: 07/03/2014] [Indexed: 01/24/2023] Open
Abstract
The latch region of the wild-type protein pore α-hemolysin (α-HL) constitutes a sensing zone for individual abasic sites (and furan analogs) in double-stranded DNA (dsDNA). The presence of an abasic site or furan within a DNA duplex, electrophoretically captured in the α-HL vestibule and positioned at the latch region, can be detected based on the current blockage prior to duplex unzipping. We investigated variations in blockage current as a function of temperature (12-35°C) and KCl concentration (0.15-1.0 M) to understand the origin of the current signature and to optimize conditions for identifying the base modification. In 1 M KCl solution, substitution of a furan for a cytosine base in the latch region results in an ∼ 8 kJ mol(-1) decrease in the activation energy for ion transport through the protein pore. This corresponds to a readily measured ∼ 2 pA increase in current at room temperature. Optimal resolution for detecting the presence of a furan in the latch region is achieved at lower KCl concentrations, where the noise in the measured blockage current is significantly lower. The noise associated with the blockage current also depends on the stability of the duplex (as measured from the melting temperature), where a greater noise in the measured blockage current is observed for less stable duplexes.
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Affiliation(s)
- Robert P Johnson
- Department of Chemistry, University of Utah, Salt Lake City, Utah
| | - Aaron M Fleming
- Department of Chemistry, University of Utah, Salt Lake City, Utah
| | - Qian Jin
- Department of Chemistry, University of Utah, Salt Lake City, Utah
| | | | - Henry S White
- Department of Chemistry, University of Utah, Salt Lake City, Utah.
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18
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Wang X, Ma S, Su Y, Zhang Y, Bi H, Zhang L, Han X. High Impedance Droplet–Solid Interface Lipid Bilayer Membranes. Anal Chem 2015; 87:2094-9. [PMID: 25600185 DOI: 10.1021/ac502953v] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Xuejing Wang
- State
Key Laboratory of Urban Water Resource and Environment, School of
Chemical Engineering and Technology, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, China
| | - Shenghua Ma
- State
Key Laboratory of Urban Water Resource and Environment, School of
Chemical Engineering and Technology, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, China
| | - Yingchun Su
- State
Key Laboratory of Urban Water Resource and Environment, School of
Chemical Engineering and Technology, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, China
| | - Ying Zhang
- State
Key Laboratory of Urban Water Resource and Environment, School of
Chemical Engineering and Technology, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, China
| | - Hongmei Bi
- State
Key Laboratory of Urban Water Resource and Environment, School of
Chemical Engineering and Technology, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, China
| | - Lixue Zhang
- Qingdao
Key Lab of Solar Energy Utilization and Energy Storage Technology,
Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China
| | - Xiaojun Han
- State
Key Laboratory of Urban Water Resource and Environment, School of
Chemical Engineering and Technology, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, China
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19
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Ding Y, Fleming AM, White HS, Burrows CJ. Internal vs fishhook hairpin DNA: unzipping locations and mechanisms in the α-hemolysin nanopore. J Phys Chem B 2014; 118:12873-82. [PMID: 25333648 PMCID: PMC4234443 DOI: 10.1021/jp5101413] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
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Studies
on the interaction of hairpin DNA with the α-hemolysin
(α-HL) nanopore have determined hairpin unzipping kinetics,
thermodynamics, and sequence-dependent DNA/protein interactions. Missing
from these results is a systematic study comparing the unzipping process
for fishhook (one-tail) vs internal (two-tail) hairpins when they
are electrophoretically driven from the cis to the trans side of α-HL via a 30-mer single-stranded tail.
In the current studies, fishhook hairpins showed long unzipping times
with one deep blockage current level. In contrast, the internal hairpins
demonstrated relatively fast unzipping and a characteristic pulse-like
current pattern. These differences were further explored with respect
to stem length and sequence context. Further, a series of internal
hairpins with asymmetric tails were studied, for which it was determined
that a second tail longer than 12 nucleotides results in internal
hairpin unzipping behavior, while tail lengths of 6 nucleotides behaved
like fishhook hairpins. Interestingly, these studies were able to
resolve a current difference of ∼6% between hairpin DNA immobilized
in the nanopore waiting to unzip vs the translocating unzipped DNA,
with the latter showing a deeper current blockage level. This demonstration
of different currents for immobilized and translocating DNA has not
been described previously. These results were interpreted as fishhook
hairpins unzipping inside the vestibule, while the internal hairpins
unzip outside the vestibule of α-HL. Lastly, we used this knowledge
to study the unzipping of a long double-stranded DNA (>50 base
pairs)
outside the vestibule of α-HL. The conclusions drawn from these
studies are anticipated to be beneficial in future application of
nanopore analysis of nucleic acids.
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Affiliation(s)
- Yun Ding
- Department of Chemistry, University of Utah , 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States
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20
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Wang Y, Tian K, Hunter LL, Ritzo B, Gu LQ. Probing molecular pathways for DNA orientational trapping, unzipping and translocation in nanopores by using a tunable overhang sensor. NANOSCALE 2014; 6:11372-9. [PMID: 25144935 PMCID: PMC6201287 DOI: 10.1039/c4nr03195d] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Nanopores provide a unique single-molecule platform for genetic and epigenetic detection. The target nucleic acids can be accurately analyzed by characterizing their specific electric fingerprints or signatures in the nanopore. Here we report a series of novel nanopore signatures generated by target nucleic acids that are hybridized with a probe. A length-tunable overhang appended to the probe functions as a sensor to specifically modulate the nanopore current profile. The resulting signatures can reveal multiple mechanisms for the orientational trapping, unzipping, escaping and translocation of nucleic acids in the nanopore. This universal approach can be used to program various molecular movement pathways, elucidate their kinetics, and enhance the sensitivity and specificity of the nanopore sensor for nucleic acid detection.
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Affiliation(s)
- Yong Wang
- Department of Bioengineering and Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA.
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21
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Real-time label-free measurement of HIV-1 protease activity by nanopore analysis. Biosens Bioelectron 2014; 62:158-62. [PMID: 24997370 DOI: 10.1016/j.bios.2014.06.041] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 06/19/2014] [Accepted: 06/19/2014] [Indexed: 11/22/2022]
Abstract
A label-free method for the measurement of the activity of HIV-1 protease is developed by real-time monitoring of the cleavage of a peptide substrate by HIV-1 protease in a nanopore. The method is rapid and sensitive: picomolar concentrations of HIV-1 protease could be detected in ~10 min. Simulated clinical samples are analyzed, and the activity of HIV-1 protease could be accurately detected. Our developed nanopore sensor design strategy should find useful applications in the development of stochastic sensors for other proteases of medical, pharmaceutical, and biological importance.
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22
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Wang L, Han Y, Zhou S, Wang G, Guan X. Nanopore biosensor for label-free and real-time detection of anthrax lethal factor. ACS APPLIED MATERIALS & INTERFACES 2014; 6:7334-7339. [PMID: 24806593 PMCID: PMC4039345 DOI: 10.1021/am500749p] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 05/07/2014] [Indexed: 05/29/2023]
Abstract
We report a label-free real-time nanopore sensing method for the detection of anthrax lethal factor, a component of the anthrax toxin, by using a complementary single-stranded DNA as a molecular probe. The method is rapid and sensitive: sub-nanomolar concentrations of the target anthrax lethal factor DNA could be detected in ∼1 min. Further, our method is selective, which can differentiate the target DNA from other single-stranded DNA molecules at the single-base resolution. This sequence-specific detection approach should find useful application in the development of nanopore sensors for the detection of other pathogens.
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Affiliation(s)
| | | | | | | | - Xiyun Guan
- Tel: 01-312-567-8922. Fax: 01-312-567-3494. E-mail:
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23
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Wang G, Wang L, Han Y, Zhou S, Guan X. Nanopore stochastic detection: diversity, sensitivity, and beyond. Acc Chem Res 2013; 46:2867-77. [PMID: 23614724 DOI: 10.1021/ar400031x] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nanopore sensors have emerged as a label-free and amplification-free technique for measuring single molecules. First proposed in the mid-1990s, nanopore detection takes advantage of the ionic current modulations produced by the passage of target analytes through a single nanopore at a fixed applied potential. Over the last 15 years, these nanoscale pores have been used to sequence DNA, to study covalent and non-covalent bonding interactions, to investigate biomolecular folding and unfolding, and for other applications. A major issue in the application of nanopore sensors is the rapid transport of target analyte molecules through the nanopore. Current recording techniques do not always accurately detect these rapid events. Therefore, researchers have looked for methods that slow molecular and ionic transport. Thus far, several strategies can improve the resolution and sensitivity of nanopore sensors including variation of the experimental conditions, use of a host compound, and modification of the analyte molecule and the nanopore sensor. In this Account, we highlight our recent research efforts that have focused on applications of nanopore sensors including the differentiation of chiral molecules, the study of enzyme kinetics, and the determination of sample purity and composition. Then we summarize our efforts to regulate molecular transport. We show that the introduction of various surface functional groups such as hydrophobic, aromatic, positively charged, and negatively charged residues in the nanopore interior, an increase in the ionic strength of the electrolyte solution, and the use of ionic liquid solutions as the electrolyte instead of inorganic salts may improve the resolution and sensitivity of nanopore stochastic sensors. Our experiments also demonstrate that the introduction of multiple functional groups into a single nanopore and the development of a pattern-recognition nanopore sensor array could further enhance sensor resolution. Although we have demonstrated the feasibility of nanopore sensors for various applications, challenges remain before nanopore sensing is deployed for routine use in applications such as medical diagnosis, homeland security, pharmaceutical screening, and environmental monitoring.
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Affiliation(s)
- Guihua Wang
- Department of Biological and Chemical Sciences, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Liang Wang
- Department of Biological and Chemical Sciences, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Yujing Han
- Department of Biological and Chemical Sciences, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Shuo Zhou
- Department of Biological and Chemical Sciences, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Xiyun Guan
- Department of Biological and Chemical Sciences, Illinois Institute of Technology, Chicago, Illinois 60616, United States
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24
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Wolna AH, Fleming AM, An N, He L, White HS, Burrows CJ. Electrical Current Signatures of DNA Base Modifications in Single Molecules Immobilized in the α-Hemolysin Ion Channel. Isr J Chem 2013; 53:417-430. [PMID: 24052667 PMCID: PMC3773884 DOI: 10.1002/ijch.201300022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Nanopore technology holds high potential for next-generation DNA sequencing. This method operates by drawing an individual single-stranded DNA molecule through a nanoscale pore while monitoring the current deflections that occur as the DNA passes through. Individual current levels for the four DNA nucleotides have been established by immobilization of an end biotinylated strand in the pore in which the nucleotide of interest is suspended at the most sensitive region of the ion channel. Due to the inherent reactivity of the DNA bases, many modified nucleotides in the genome exist resulting from oxidative and UV insults, among others. Herein, the current levels for the common DNA damages 8-oxo-7,8-dihydroguanine (OG), spiroiminodihydantoin (Sp), guanidinohydantoin (Gh), uridine (U), abasic sites (AP), thymine dimers (T=T), thymine glycol (Tg) and 5-iodocytosine (5-I-C) were assessed via immobilization experiments. In some cases, the current difference between the damaged and canonical nucleotides was not well resolved; therefore, we took advantage of the chemical reactivity of the new functional groups present to make amine adducts that shifted the current levels outside the range of the native nucleotides. Among adducts studied, only the 2-aminomethyl-18-crown-6 adduct was able to give a large current shift in the immobilization experiment, as well as to be observed in a translocation experiment. The results show potential in providing current level modulators for identification of some types of DNA damage. In principle, any DNA base modification that can be converted chemically or enzymatically to an abasic site could be identified in this way.
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Affiliation(s)
- Anna H. Wolna
- Department of Chemistry University of Utah 315 S 1400 East Salt Lake City, UT 84112-0850
| | - Aaron M. Fleming
- Department of Chemistry University of Utah 315 S 1400 East Salt Lake City, UT 84112-0850
| | - Na An
- Department of Chemistry University of Utah 315 S 1400 East Salt Lake City, UT 84112-0850
| | - Lidong He
- Department of Chemistry University of Utah 315 S 1400 East Salt Lake City, UT 84112-0850
| | - Henry S. White
- Department of Chemistry University of Utah 315 S 1400 East Salt Lake City, UT 84112-0850
| | - Cynthia J. Burrows
- Department of Chemistry University of Utah 315 S 1400 East Salt Lake City, UT 84112-0850
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25
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An N, Fleming AM, Burrows CJ. Interactions of the human telomere sequence with the nanocavity of the α-hemolysin ion channel reveal structure-dependent electrical signatures for hybrid folds. J Am Chem Soc 2013; 135:8562-70. [PMID: 23682802 DOI: 10.1021/ja400973m] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Human telomeric DNA consists of tandem repeats of the sequence 5'-TTAGGG-3', including a 3' terminal single-stranded overhang of 100-200 nucleotides that can fold into quadruplex structures in the presence of suitable metal ions. In the presence of an applied voltage, the α-hemolysin (α-HL) protein ion channel can produce unique current patterns that are found to be characteristic for various interactions between G-quadruplexes and the protein nanocavity. In this study, the human telomere in a complete sequence context, 5'-TAGGG(TTAGGG)3TT-3', was evaluated with respect to its multiple folding topologies. Notably, the coexistence of two interchangeable conformations of the K(+)-induced folds, hybrid-1 and hybrid-2, were readily resolved at a single-molecule level along with triplex folding intermediates, whose characterization has been challenging in experiments that measure the bulk solution. These results enabled us to profile the thermal denaturation process of these structures to elucidate the relative distributions of hybrid-1, hybrid-2, and folding intermediates such as triplexes. For example, at 37 °C, pH 7.9, in 50 mM aqueous KCl, the ratio of hybrid-1:hybrid-2:triplex is approximately 11:5:1 in dilute solution. The results obtained lay the foundation for utilizing the α-HL ion channel as a simple tool for monitoring how small molecules and physical context shift the equilibrium between the many G-quadruplex folds of the human telomere sequence.
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Affiliation(s)
- Na An
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, USA
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26
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Wang G, Zhao Q, Kang X, Guan X. Probing mercury(II)-DNA interactions by nanopore stochastic sensing. J Phys Chem B 2013; 117:4763-9. [PMID: 23565989 DOI: 10.1021/jp309541h] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In this work, DNA-Hg(II) interactions were investigated by monitoring the translocation of DNA hairpins in a protein ion channel in the absence and presence of metal ions. Our experiments demonstrate that target-specific hairpin structures could be stabilized much more significantly by mercuric ions than by the stem length and the loop size of the hairpin due to the formation of Thymine-Hg(II)-Thymine complexes. In addition, the designed DNA probe allows the development of a highly sensitive nanopore sensor for Hg(2+) with a detection limit of 25 nM. Further, the sensor is specific, and other tested metal ions including Pb(2+), Cu(2+), Cd(2+), and so on with concentrations of up to 2 orders of magnitude greater than that of Hg(2+) would not interfere with the mercury detection.
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Affiliation(s)
- Guihua Wang
- Department of Biological and Chemical Sciences, Illinois Institute of Technology, 3101 South Dearborn Street, Chicago, Illinois 60616, United States
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27
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Zhu ZW, Wang Y, Zhang X, Sun CF, Li MG, Yan JW, Mao BW. Electrochemical impedance spectroscopy and atomic force microscopic studies of electrical and mechanical properties of nano-black lipid membranes and size dependence. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:14739-14746. [PMID: 22985346 DOI: 10.1021/la303047v] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present electrochemical impedance spectroscopic (EIS) and two-chamber AFM investigations of the electrical and mechanical properties of solvent-containing nano-BLMs suspended on chip-based nanopores of diameter of 200, 400, and 700 nm. The chips containing nanoporous silicon nitride membranes are fabricated based on low-cost colloidal lithography with low aspect ratio of the nanopores. BLMs of DPhPC lipid molecules are constructed across the nanopores by the painting method. Two equivalent circuits are compared in view of their adequacy in description of the EIS performances of the nano-BLMs and more importantly the structures associated with the nano-BLMs systems. The BLM resistance and capacitance as well as their size and time dependence are studied by EIS. The breakthrough forces, elasticity in terms of apparent spring constant, and lateral tension of the solvent-containing nano-BLMs are investigated by AFM force measurements. The exact relationship of the breakthrough force of the nano-BLM as a function of pore size is revealed. Both EIS and AFM studies show increasing lifetime and mechanical stability of the nano-BLMs with decreasing pore size. Finally, the robust 200 nm diameter nanopores are used to accommodate functional BLMs containing DPhPC lipid molecules and gramicidins by using a painting method with drop of mixture solutions of DPhPC and gramicidins. EIS investigation of the functional nano-BLMs is also performed.
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Affiliation(s)
- Zai-Wen Zhu
- State Key Laboratory of Physical Chemistry of the Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China
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28
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Schibel AEP, Fleming AM, Jin Q, An N, Liu J, Blakemore CP, White HS, Burrows CJ. Sequence-specific single-molecule analysis of 8-oxo-7,8-dihydroguanine lesions in DNA based on unzipping kinetics of complementary probes in ion channel recordings. J Am Chem Soc 2011; 133:14778-84. [PMID: 21875081 PMCID: PMC3173567 DOI: 10.1021/ja205653v] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Translocation measurements of intact DNA strands with the ion channel α-hemolysin (α-HL) are limited to single-stranded DNA (ssDNA) experiments as the dimensions of the channel prevent double-stranded DNA (dsDNA) translocation; however, if a short oligodeoxynucleotide is used to interrogate a longer ssDNA strand, it is possible to unzip the duplex region when it is captured in the α-HL vestibule, allowing the longer strand to translocate through the α-HL channel. This unzipping process has a characteristic duration based on the stability of the duplex. Here, ion channel recordings are used to detect the presence and relative location of the oxidized damage site 8-oxo-7,8-dihydroguanine (OG) in a sequence-specific manner. OG engages in base pairing to C or A with unique stabilities relative to native base Watson-Crick pairings, and this phenomenon is used here to engineer probe sequences (10-15mers) that, when base-paired with a 65mer sequence of interest, containing either G or OG at a single site, produce characteristic unzipping times that correspond well with the duplex melting temperature (T(m)). Unzipping times also depend on the direction from which the duplex enters the vestibule if the stabilities of leading base pairs at the ends of the duplex are significantly different. It is shown here that the presence of a single DNA lesion can be distinguished from an undamaged sequence and that the relative location of the damage site can be determined based on the duration of duplex unzipping.
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Affiliation(s)
- Anna E. P. Schibel
- Department of Chemistry, University of Utah, 315 S. 1400 East, RM 2020, Salt Lake City, UT 84112-0850, USA
| | - Aaron M. Fleming
- Department of Chemistry, University of Utah, 315 S. 1400 East, RM 2020, Salt Lake City, UT 84112-0850, USA
| | - Qian Jin
- Department of Chemistry, University of Utah, 315 S. 1400 East, RM 2020, Salt Lake City, UT 84112-0850, USA
| | - Na An
- Department of Chemistry, University of Utah, 315 S. 1400 East, RM 2020, Salt Lake City, UT 84112-0850, USA
| | - Jin Liu
- Department of Chemistry, University of Utah, 315 S. 1400 East, RM 2020, Salt Lake City, UT 84112-0850, USA
| | - Charles P. Blakemore
- Department of Chemistry, University of Utah, 315 S. 1400 East, RM 2020, Salt Lake City, UT 84112-0850, USA
| | - Henry S. White
- Department of Chemistry, University of Utah, 315 S. 1400 East, RM 2020, Salt Lake City, UT 84112-0850, USA
| | - Cynthia J. Burrows
- Department of Chemistry, University of Utah, 315 S. 1400 East, RM 2020, Salt Lake City, UT 84112-0850, USA
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