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Liu M, Tan Y, Zhou C, Fu Z, Huang R, Li J, Li L. Fluorogenic Aptamer-Based Hybridization Chain Reaction for Signal-Amplified Imaging of Apurinic/Apyrimidinic Endonuclease 1 in Living Cells. BIOSENSORS 2024; 14:274. [PMID: 38920578 PMCID: PMC11202136 DOI: 10.3390/bios14060274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 04/28/2024] [Accepted: 05/01/2024] [Indexed: 06/27/2024]
Abstract
A fluorogenic aptamer (FA)-based hybridization chain reaction (HCR) could provide a sensitive and label-free signal amplification method for imaging molecules in living cells. However, existing FA-HCR methods usually face some problems, such as a complicated design and significant background leakage, which greatly limit their application. Herein, we developed an FA-centered HCR (FAC-HCR) method based on a remote toehold-mediated strand displacement reaction. Compared to traditional HCRs mediated by four hairpin probes (HPs) and two HPs, the FAC-HCR displayed significantly decreased background leakage and improved sensitivity. Furthermore, the FAC-HCR was used to test a non-nucleic acid target, apurinic/apyrimidinic endonuclease 1 (APE1), an important BER-involved endonuclease. The fluorescence analysis results confirmed that FAC-HCR can reach a detection limit of 0.1174 U/mL. By using the two HPs for FAC-HCR with polyetherimide-based nanoparticles, the activity of APE1 in living cells can be imaged. In summary, this study could provide a new idea to design an FA-based HCR and improve the performance of HCRs in live cell imaging.
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Affiliation(s)
- Meixi Liu
- State Key Laboratory of Digital Medical Engineering, School of Biomedical Engineering, Hainan University, Sanya 572024, China; (M.L.); (Y.T.); (C.Z.); (Z.F.)
- Key Laboratory of Biomedical Engineering of Hainan Province, One Health Institute, Hainan University, Sanya 572024, China
| | - Yunjie Tan
- State Key Laboratory of Digital Medical Engineering, School of Biomedical Engineering, Hainan University, Sanya 572024, China; (M.L.); (Y.T.); (C.Z.); (Z.F.)
- Key Laboratory of Biomedical Engineering of Hainan Province, One Health Institute, Hainan University, Sanya 572024, China
| | - Chen Zhou
- State Key Laboratory of Digital Medical Engineering, School of Biomedical Engineering, Hainan University, Sanya 572024, China; (M.L.); (Y.T.); (C.Z.); (Z.F.)
- Key Laboratory of Biomedical Engineering of Hainan Province, One Health Institute, Hainan University, Sanya 572024, China
| | - Zhaoming Fu
- State Key Laboratory of Digital Medical Engineering, School of Biomedical Engineering, Hainan University, Sanya 572024, China; (M.L.); (Y.T.); (C.Z.); (Z.F.)
- Key Laboratory of Biomedical Engineering of Hainan Province, One Health Institute, Hainan University, Sanya 572024, China
| | - Ru Huang
- State Key Laboratory of Digital Medical Engineering, School of Biomedical Engineering, Hainan University, Sanya 572024, China; (M.L.); (Y.T.); (C.Z.); (Z.F.)
- Key Laboratory of Biomedical Engineering of Hainan Province, One Health Institute, Hainan University, Sanya 572024, China
| | - Jin Li
- Department of Painology, Hainan Cancer Hospital, Haikou 570311, China
| | - Le Li
- NHC Key Laboratory of Tropical Disease Control, Hainan Medical University, Haikou 571199, China;
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2
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Gu L, Zheng J, Zhang Y, Wang D, Liu J. Selection and Characterization of DNA Aptamers for Cytidine and Uridine. Chembiochem 2024; 25:e202300656. [PMID: 38180305 DOI: 10.1002/cbic.202300656] [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: 09/25/2023] [Revised: 11/30/2023] [Indexed: 01/06/2024]
Abstract
Cytidine and uridine are two essential pyrimidine ribonucleotides, and accurate detection of these nucleosides holds significant biological importance. While many aptamers were reported to bind purines, little success was achieved for pyrimidine binding. This study employs the library-immobilization capture-SELEX technique to isolate aptamers capable of selectively binding to cytidine and uridine. First, a selection was performed using a mixture of cytidine and uridine as the target. This selection led to the isolation of a highly selective aptamer for cytidine with a dissociation constant (Kd ) of 0.9 μM as determined by isothermal titration calorimetry (ITC). In addition, a dual-recognition aptamer was also discovered, which exhibited selective binding to both cytidine and uridine. Subsequently, a separate selection was carried out using uridine as the sole target, and the resulting uridine aptamer displayed a Kd of 4 μM based on a thioflavin T fluorescence assay and a Kd of 102 μM based on ITC. These aptamers do not have a strict requirement of metal ions for binding, and they showed excellent selectivity since no binding was observed with their nucleobases or nucleotides. This study has resulted three aptamers for pyrimidines, which can be employed in biosensors and DNA switches.
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Affiliation(s)
- Lide Gu
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian, 361102, China
- Department of Chemistry, Waterloo Institute for Nanotechnology University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Jiajie Zheng
- Department of Chemistry, Waterloo Institute for Nanotechnology University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Yao Zhang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian, 361102, China
| | - Deli Wang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian, 361102, China
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
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3
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Shi L, Jin Y, Liu J. Intramolecular aptamer switches. Analyst 2024; 149:745-750. [PMID: 38193253 DOI: 10.1039/d3an02022c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Aptamer switches as effective biosensing tools have become a focal point of research in engineered aptasensors. Intramolecular aptamer switches are more versatile, affordable, and simpler than classical "open-close" and strand displacement-based aptamer switches. Recently, many new aptamers with an overall hairpin structure have been reported. In this study, intramolecular aptamer switches were developed by adding new base pairs to the end of aptamers. The additional nucleotides can pair with the internal domains of the aptamer, causing a change in its conformation from the original secondary structure without a target. When a target binds to an aptamer, a marked change in the structure of the aptamer is expected. As models for testing this intramolecular aptamer switch idea, aptamers of oxytetracycline (OTC), 17β-estradiol (E2), and adenosine were employed. When the additional base pairs are too long, binding the target to the aptamer becomes more challenging. This research offers valuable insights into the development of intramolecular aptamer switches and their potential applications in biosensor design.
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Affiliation(s)
- Lu Shi
- Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China.
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
| | - Yan Jin
- Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China.
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
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Ding Y, Gu L, Wang X, Zhang Z, Zhang H, Liu J. Affinity-Guided Coevolution of Aptamers for Guanine, Xanthine, Hypoxanthine, and Adenine. ACS Chem Biol 2024; 19:208-216. [PMID: 38194356 DOI: 10.1021/acschembio.3c00660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
The simultaneous evolution of multiple aptamers can drastically increase the speed of aptamer discovery. Most previous studies used the same concentration for different targets, leading to the dominance of the libraries by one or a few aptamers and a low success rate. To foster the best aptamers to grow independently in the sequence space, it is important to (1) use low target concentrations close to their dissociation constants and (2) stop at an early round before any sequence starts to dominate. In this study, we demonstrate this affinity-guided selection concept using the capture-SELEX method to isolate aptamers for four important purines: guanine (5 μM), xanthine (50 μM), hypoxanthine (10 μM), and adenine (10 μM). The round 9 library was split, and in round 10, the four targets were individually used to elute the binding sequences. Using thioflavin T fluorescence spectroscopy and isothermal titration calorimetry, we confirmed highly selective aptamers for xanthine, guanine, and adenine. These aptamers have Kd values below 1 μM and around 100-fold selectivity against most competing analytes, and they compare favorably with existing RNA aptamers and riboswitches. A separate selection was performed using hypoxanthine alone, and no selective aptamer was achieved, even with negative selection, explaining the lack of its aptamer in our mixed selection. This affinity-guided multiplex SELEX study offers fundamental insights into aptamer selection and provides high-quality aptamers for three important purines.
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Affiliation(s)
- Yuzhe Ding
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Lide Gu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Xiaoqin Wang
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Ziyu Zhang
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Hanxiao Zhang
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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Shi L, Jin Y, Liu J. Electrostatic-Mediated Binding of DNA to Lysozymes: Evaluation of Aptamer-Based Assays for Highly Positively Charged Targets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:14774-14781. [PMID: 37782842 DOI: 10.1021/acs.langmuir.3c02208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Lysozymes are a highly popular protein target for the development of aptamer-based biosensors. Because a lysozyme is a polycation and DNA is a polyanion, it is essential to separate the contribution of nonspecific electrostatic interactions from specific aptamer binding. In this study, various factors affecting the binding of DNA and lysozymes, including the DNA sequence, DNA length, pH, and salt concentration, were explored using fluorescence polarization. We concluded that direct fluorescence polarization and fluorescence intensity changes are unlikely to be directly applicable for aptamer-based biosensors to detect lysozymes because all of the tested DNA sequences showed binding. These fundamental studies confirm the dominant role of electrostatic binding. We further evaluated three other methods, including label-free fluorescent detection using a DNA staining dye, label-free colorimetric detection using gold nanoparticles, and a fluorescent sensor based on the strand displacement reaction. In each case, we focused on a random DNA sequence that is not expected to bind to the lysozyme as an aptamer. Of all the methods, only the strand displacement strategy can be potentially used to evaluate aptamer binding, as the other methods all responded to nonaptamer sequences. This study provides valuable insights for assaying aptamer binding to cationic proteins that can exhibit a nonspecific attraction to DNA.
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Affiliation(s)
- Lu Shi
- Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Yan Jin
- Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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Zheng M, Wang Y, Zhang D, Zhu M. Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging. BIOSENSORS 2023; 13:906. [PMID: 37887099 PMCID: PMC10605574 DOI: 10.3390/bios13100906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 10/28/2023]
Abstract
Fluorescent materials have great potential for use in biomedical applications due to their ease of functionalization and tunable fluorescence color [...].
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Affiliation(s)
- Meng Zheng
- State Key Laboratory of Digital Medical Engineering, School of Biomedical Engineering, Hainan University, Haikou 570228, China; (M.Z.); (M.Z.)
- R&D Center of Polymer Materials, Qingdao Haiwan Science and Technology Industry Research Institute Co., Ltd. (HWSTI), Qingdao 266031, China
| | - Yalong Wang
- State Key Laboratory of Digital Medical Engineering, School of Biomedical Engineering, Hainan University, Haikou 570228, China; (M.Z.); (M.Z.)
| | - Deteng Zhang
- Institute of Neuroregeneration and Neurorehabilitation, Qingdao University, Qingdao 266071, China
| | - Mingqiang Zhu
- State Key Laboratory of Digital Medical Engineering, School of Biomedical Engineering, Hainan University, Haikou 570228, China; (M.Z.); (M.Z.)
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
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Ding Y, Xie Y, Li AZ, Huang PJJ, Liu J. Cross-Binding of Four Adenosine/ATP Aptamers to Caffeine, Theophylline, and Other Methylxanthines. Biochemistry 2023; 62:2280-2288. [PMID: 37433121 DOI: 10.1021/acs.biochem.3c00260] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023]
Abstract
The classical DNA aptamer for adenosine and ATP was selected twice using ATP as the target in 1995 and 2005, respectively. In 2022, this motif appeared four more times from selections using adenosine, ATP, theophylline, and caffeine as targets, suggesting that this aptamer can also bind methylxanthines. In this work, using thioflavin T fluorescence spectroscopy, this classical DNA aptamer showed Kd values for adenosine, theophylline, and caffeine of 9.5, 101, and 131 μM, respectively, and similar Kd values were obtained using isothermal titration calorimetry. Binding to the methylxanthines was also observed for the newly selected Ade1301 aptamer but not for the Ade1304 aptamer. The RNA aptamer for ATP also had no binding to the methylxanthines. Molecular dynamics simulations were performed using the classical DNA and RNA aptamers based on their NMR structures, and the simulation results were consistent with the experimental observations, explaining the selectivity profiles. This study suggests that a broader range of target analogues need to be tested for aptamers. For the detection of adenosine and ATP, the Ade1304 aptamer is a better choice due to its better selectivity.
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Affiliation(s)
- Yuzhe Ding
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Yachen Xie
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Albert Zehan Li
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Po-Jung Jimmy Huang
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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