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Modeling Hypoxic Stress In Vitro Using Human Embryonic Stem Cells Derived Cardiomyocytes Matured by FGF4 and Ascorbic Acid Treatment. Cells 2021; 10:cells10102741. [PMID: 34685725 PMCID: PMC8534799 DOI: 10.3390/cells10102741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/08/2021] [Accepted: 10/11/2021] [Indexed: 11/23/2022] Open
Abstract
Mature cardiomyocytes (CMs) obtained from human pluripotent stem cells (hPSCs) have been required for more accurate in vitro modeling of adult-onset cardiac disease and drug discovery. Here, we found that FGF4 and ascorbic acid (AA) induce differentiation of BG01 human embryonic stem cell–cardiogenic mesoderm cells (hESC-CMCs) into mature and ventricular CMs. Co-treatment of BG01 hESC-CMCs with FGF4+AA synergistically induced differentiation into mature and ventricular CMs. FGF4+AA-treated BG01 hESC-CMs robustly released acute myocardial infarction (AMI) biomarkers (cTnI, CK-MB, and myoglobin) into culture medium in response to hypoxic injury. Hypoxia-responsive genes and potential cardiac biomarkers proved in the diagnosis and prognosis of coronary artery diseases were induced in FGF4+AA-treated BG01 hESC-CMs in response to hypoxia based on transcriptome analyses. This study demonstrates that it is feasible to model hypoxic stress in vitro using hESC-CMs matured by soluble factors.
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Fercher C, Jones ML, Mahler SM, Corrie SR. Recombinant Antibody Engineering Enables Reversible Binding for Continuous Protein Biosensing. ACS Sens 2021; 6:764-776. [PMID: 33481587 DOI: 10.1021/acssensors.0c01510] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Engineering antibodies to improve target specificity, reduce detection limits, or introduce novel functionality is an important research area for biosensor development. While various affinity biosensors have been developed to generate an output signal upon varying analyte concentrations, reversible and continuous protein monitoring in complex biological samples remains challenging. Herein, we explore the concept of directed evolution to modulate dissociation kinetics of a high affinity anti-epidermal growth factor receptor (EGFR) single-chain variable antibody fragment (scFv) to enable continuous protein sensing in a label-free binding assay. A mutant scFv library was generated from the wild type (WT) fragment via targeted permutation of four residues in the antibody-antigen-binding interface. A single round of phage display biopanning complemented with high-throughput screening methods then permitted isolation of a specific binder with fast reaction kinetics. We were able to obtain ∼30 times faster dissociation rates when compared to the WT without appreciably affecting overall affinity and specificity by targeting a single paratope that is known to contribute to the binding interaction. Suitability of a resulting mutant fragment to sense varying antigen concentrations in continuous mode was demonstrated in a modified label-free binding assay, achieving low nanomolar detection limits (KD = 8.39 nM). We also confirmed these results using an independent detection mechanism developed previously by our group, incorporating a polarity-dependent fluorescent dye into the scFv and reading out EGFR binding based on fluorescence wavelength shifts. In future, this generic approach could be employed to generate improved or novel binders for proteins of interest, ready for deployment in a broad range of assay platforms.
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Affiliation(s)
- Christian Fercher
- Australian Institute for Bioengineering and Nanotechnology, ARC Training Centre for Biopharmaceutical Innovation, The University of Queensland, St. Lucia, Queensland, 4072 Australia
- Australian Institute for Bioengineering and Nanotechnology, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Queensland, St. Lucia, Queensland, 4072 Australia
| | - Martina L. Jones
- Australian Institute for Bioengineering and Nanotechnology, ARC Training Centre for Biopharmaceutical Innovation, The University of Queensland, St. Lucia, Queensland, 4072 Australia
| | - Stephen M. Mahler
- Australian Institute for Bioengineering and Nanotechnology, ARC Training Centre for Biopharmaceutical Innovation, The University of Queensland, St. Lucia, Queensland, 4072 Australia
| | - Simon R. Corrie
- Department of Chemical Engineering, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Clayton, Victoria 3800 Australia
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Normal-incidence type solution immersed silicon (SIS) biosensor for ultra-sensitive, label-free detection of cardiac troponin I. Biosens Bioelectron 2020; 168:112525. [PMID: 32858415 DOI: 10.1016/j.bios.2020.112525] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 01/25/2023]
Abstract
Early diagnosis of acute myocardial infarction (AMI) significantly reduce the mortality rate and can be achieved via high-sensitive detection of AMI specific cardiac troponin I (cTnI) biomarker. Here, we present normal-incident type solution-immersed silicon (NI-SIS) ellipsometric biosensor, designed for ultra-high sensitive, high-throughput, label-free detection of the target protein. The NI-SIS sensors are equipped with a specially designed prism that maintains the angle of incidence close to the Brewster angle during operation, which significantly reduces SIS noise signals induced by the refractive index fluctuations of the surrounding medium, improves the signal-to-noise ratio, in-results lowers the detection limit. We applied NI-SIS biosensor for ultra-sensitive detection of cTnI biomarkers in human serum. The optimized sensor chip fabrication and detection operation procedures are proposed. The wide linear concentration ranges of fg/mL to ng/mL is achieved with the detection limit of 22.0 fg/mL of cTnI. The analytical correlation was assessed by linear regression analysis with the results of the Pathfast reference system. These impressive biosensing capabilities of NI-SIS technology have huge potentials for accurate detection of target species in different application areas, such as diagnosis, drug discovery, and food contaminations.
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Real-time Monitoring of Biomarkers in Serum for Early Diagnosis of Target Disease. BIOCHIP JOURNAL 2020. [DOI: 10.1007/s13206-020-4102-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Abstract
Perhaps because they are such commonly used tools, many researchers view antibodies one-dimensionally: Antibody Y binds antigen X. Although few techniques require a comprehensive understanding of any particular antibody's characteristics, well-executed experiments do require a basic appreciation of what is known and, equally as important, what is not known about the antibody being used. Ignorance of the relevant antibody characteristics critical for a particular assay can easily lead to loss of precious resources (time, money, and limiting amounts of sample) and, in worst-case scenarios, erroneous conclusions. Here, we describe various antibody characteristics to provide a more well-rounded perspective of these critical reagents. With this information, it will be easier to make informed decisions on how best to choose and use the available antibodies, as well as knowing when it is essential and how to determine a particular as yet-undefined characteristic.
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On/off-switchable LSPR nano-immunoassay for troponin-T. Sci Rep 2017; 7:44027. [PMID: 28382946 PMCID: PMC5382532 DOI: 10.1038/srep44027] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 01/31/2017] [Indexed: 12/25/2022] Open
Abstract
Regeneration of immunosensors is a longstanding challenge. We have developed a re-usable troponin-T (TnT) immunoassay based on localised surface plasmon resonance (LSPR) at gold nanorods (GNR). Thermosensitive poly(N-isopropylacrylamide) (PNIPAAM) was functionalised with anti-TnT to control the affinity interaction with TnT. The LSPR was extremely sensitive to the dielectric constant of the surrounding medium as modulated by antigen binding after 20 min incubation at 37 °C. Computational modelling incorporating molecular docking, molecular dynamics and free energy calculations was used to elucidate the interactions between the various subsystems namely, IgG-antibody (c.f., anti-TnT), PNIPAAM and/or TnT. This study demonstrates a remarkable temperature dependent immuno-interaction due to changes in the PNIPAAM secondary structures, i.e., globular and coil, at above or below the lower critical solution temperature (LCST). A series of concentrations of TnT were measured by correlating the λLSPR shift with relative changes in extinction intensity at the distinct plasmonic maximum (i.e., 832 nm). The magnitude of the red shift in λLSPR was nearly linear with increasing concentration of TnT, over the range 7.6 × 10−15 to 9.1 × 10−4 g/mL. The LSPR based nano-immunoassay could be simply regenerated by switching the polymer conformation and creating a gradient of microenvironments between the two states with a modest change in temperature.
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Studies on an on/off-switchable immunosensor for troponin T. Biosens Bioelectron 2015; 73:100-107. [DOI: 10.1016/j.bios.2015.05.055] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 05/24/2015] [Accepted: 05/25/2015] [Indexed: 11/22/2022]
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Dorokhin D, van IJzendoorn LJ, de Jong AM, Nieto L, Brunsveld L, Orsel JG, Prins MWJ. Molecular interference in antibody-antigen interaction studied with magnetic force immunoassay. N Biotechnol 2015; 32:450-7. [PMID: 25676839 DOI: 10.1016/j.nbt.2015.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/30/2015] [Accepted: 01/31/2015] [Indexed: 10/24/2022]
Abstract
Molecular interferences are an important challenge in biotechnologies based on antibody-antigen interactions, such as sandwich immunoassays. We report how a sandwich immunoassay with magnetic particles as label can be used to probe interference by surfactants. Surfactants are often used to improve the performance of immunoassays, however the surfactants can affect the involved proteins and the mechanism of action of surfactant molecules on the antibody-antigen system is mostly unknown. As an example, we investigated molecular interference by a nonionic surfactant (Pluronic F-127) in a cardiac troponin (cTn) sandwich immunoassay with two monoclonal antibodies. The influence of the surfactant below the critical micelle concentration (0.00-0.04%) on dissociation properties was quantified in a magnetic tweezers setup, where a force is applied to the molecules via magnetic particle labels. The force-dependent dissociation curves revealed the existence of two distinct cTn-dependent bond types, namely a weak bond attributable to non-specific binding of cTn, and a strong bond attributable to the specific binding of cTn. The dissociation rate constant of the strong bonds increased with the surfactant concentration by about a factor of two. Circular dichroism spectroscopy data showed that the nonionic surfactant influences the conformation of cTn while not noticeably affecting the two monoclonal antibodies. This suggests that the surfactant-induced increase of the dissociation rate of the specific sandwich-type cTn binding may be related to a conformational change of the antigen molecule. The described methodology is an effective tool to study the influence of surfactants and other interferences on assays based on protein interactions.
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Affiliation(s)
- D Dorokhin
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - L J van IJzendoorn
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - A M de Jong
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - L Nieto
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - L Brunsveld
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - J G Orsel
- Philips Research, High Tech Campus 11, Eindhoven, The Netherlands
| | - M W J Prins
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands; Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands.
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Jang JH, Kim DH, Paek SH, Woo EJ, Kim YW. Construction of an antimyoglobin single-chain variable fragment with rapid reaction kinetics. Biotechnol Appl Biochem 2015; 63:22-30. [DOI: 10.1002/bab.1349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 01/03/2015] [Indexed: 01/19/2023]
Affiliation(s)
- Jun-Hyuck Jang
- Department of Food and Biotechnology; Korea University; Sejong Republic of Korea
| | - Dong-Hyung Kim
- Department of Biotechnology and Bioinformatics; Korea University; Sejong Republic of Korea
| | - Se-Hwan Paek
- Department of Biotechnology and Bioinformatics; Korea University; Sejong Republic of Korea
| | - Eui-Jeon Woo
- Medical Proteomics Research Center; Korea Research Institute of Bioscience and Biotechnology; Daejeon Republic of Korea
| | - Young-Wan Kim
- Department of Food and Biotechnology; Korea University; Sejong Republic of Korea
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Song HN, Kim DH, Park SG, Lee MK, Paek SH, Woo EJ. Purification and characterization of Fab fragments with rapid reaction kinetics against myoglobin. Biosci Biotechnol Biochem 2015; 79:718-24. [PMID: 25561012 DOI: 10.1080/09168451.2014.993354] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Myoglobin is an early biomarker for acute myocardial infarction. Recently, we isolated the antibody IgG-Myo2-7ds, which exhibits unique rapid reaction kinetics toward human myoglobin antigen. Antibodies with rapid dissociation kinetics are thought to be premature IgG forms that are produced during the early stage of in vivo immunization. In the present study, we identified the epitope region of the IgG-Myo2-7ds antibody to be the C-terminal region of myoglobin, which corresponds to 144-154 aa. The Fab fragment was directly purified by papain cleavage and protein G affinity chromatography and demonstrated kinetics of an association constant of 4.02 × 10(4) M(-1) s(-1) and a dissociation constant of 2.28 × 10(-2) s(-1), which retained the unique reaction kinetics of intact IgG-Myo2-7ds antibodies. Because a rapid dissociation antibody can be utilized for antibody recycling, the results from this study would provide a platform for the development of antibody engineering in potential diagnostic areas such as a continuous monitoring system for heart disease.
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Affiliation(s)
- Hyung-Nam Song
- a Functional Genomic Center , Korea Research Institute of Bioscience & Biotechnology , Daejeon , Republic of Korea
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Song HN, Jang JH, Kim YW, Kim DH, Park SG, Lee MK, Paek SH, Woo EJ. Refolded scFv antibody fragment against myoglobin shows rapid reaction kinetics. Int J Mol Sci 2014; 15:23658-71. [PMID: 25530617 PMCID: PMC4284786 DOI: 10.3390/ijms151223658] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/01/2014] [Accepted: 12/12/2014] [Indexed: 02/06/2023] Open
Abstract
Myoglobin is one of the early biomarkers for acute myocardial infarction. Recently, we have screened an antibody with unique rapid reaction kinetics toward human myoglobin antigen. Antibodies with rapid reaction kinetics are thought to be an early IgG form produced during early stage of in vivo immunization. We produced a recombinant scFv fragment for the premature antibody from Escherichia coli using refolding technology. The scFv gene was constructed by connection of the V(H)-V(L) sequence with a (Gly4Ser)3 linker. The scFv fragment without the pelB leader sequence was expressed at a high level, but the solubility was extremely low. A high concentration of 8 M urea was used for denaturation. The dilution refolding process in the presence of arginine and the redox reagents GSH and GSSH successfully produced a soluble scFv protein. The resultant refolded scFv protein showed association and dissociation values of 9.32 × 10⁻⁴ M⁻¹·s⁻¹ and 6.29 × 10⁻³ s⁻¹, respectively, with an affinity value exceeding 10⁷ M⁻¹ (k(on)/k(off)), maintaining the original rapid reaction kinetics of the premature antibody. The refolded scFv could provide a platform for protein engineering for the clinical application for diagnosis of heart disease and the development of a continuous biosensor.
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Affiliation(s)
- Hyung-Nam Song
- Medical Proteomics Research Center, Korea Research Institute of Bioscience & Biotechnology, Daejeon 305-806, Korea.
| | - Jun-Hyuck Jang
- Department of Food and Biotechnology, Korea University, Sejong 339-700, Korea.
| | - Young-Wan Kim
- Department of Food and Biotechnology, Korea University, Sejong 339-700, Korea.
| | - Dong-Hyung Kim
- Department of Biotechnology and Bioinformatics, Korea University, Sejong 339-700, Korea.
| | - Sung-Goo Park
- Medical Proteomics Research Center, Korea Research Institute of Bioscience & Biotechnology, Daejeon 305-806, Korea.
| | - Myung Kyu Lee
- Medical Proteomics Research Center, Korea Research Institute of Bioscience & Biotechnology, Daejeon 305-806, Korea.
| | - Se-Hwan Paek
- Department of Biotechnology and Bioinformatics, Korea University, Sejong 339-700, Korea.
| | - Eui-Jeon Woo
- Medical Proteomics Research Center, Korea Research Institute of Bioscience & Biotechnology, Daejeon 305-806, Korea.
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Kim DH, Seo SM, Cho HM, Hong SJ, Lim DS, Paek SH. Continuous immunosensing of myoglobin in human serum as potential companion diagnostics technique. Biosens Bioelectron 2014; 62:234-41. [DOI: 10.1016/j.bios.2014.06.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 06/02/2014] [Accepted: 06/19/2014] [Indexed: 11/29/2022]
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