1
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Cutri AR, Sundaresan V, Shrout JD, Bohn PW. Spectroelectrochemical behavior of parallel arrays of single vertically oriented Pseudomonas aeruginosa cells. CELL REPORTS. PHYSICAL SCIENCE 2023; 4:101368. [PMID: 37469850 PMCID: PMC10355145 DOI: 10.1016/j.xcrp.2023.101368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic human pathogen responsible for a number of healthcare-associated infection. It is currently difficult to assess single cell behaviors of P. aeruginosa that might contribute to acquisition of antibiotic resistance, intercellular communication, biofilm development, or virulence, because mechanistic behavior is inferred from ensemble collections of cells, thus averaging effects over a population. Here, we develop and characterize a device that can capture and trap arrays of single P. aeruginosa cells in individual micropores in order to study their behaviors using spectroelectrochemistry. Focused ion beam milling is used to fabricate an array of micropores in a Au/dielectric/Au/SiO2-containing multilayer substrate, in which individual micropores are formed with dimensions that facilitate the capture of single P. aeruginosa cells in a predominantly vertical orientation. The bottom Au ring is then used as a working electrode to explore the spectroelectrochemical behavior of parallel arrays of individual P. aeruginosa cells. Application of step-potential or swept-potential waveforms produces changes in the fluorescence emission that can be imaged and correlated with applied potential. Arrays of P. aeruginosa cells typically exhibit three characteristic fluorescence behaviors that are sensitive to nutritional stress and applied potential. The device developed here enables the study of parallel collections of single bacterial cells with well-defined orientational order and should facilitate efforts to elucidate methods of bacterial communication and multidrug resistance at the single cell level.
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Affiliation(s)
- Allison R. Cutri
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Vignesh Sundaresan
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Joshua D. Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556 USA
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Paul W. Bohn
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 USA
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556 USA
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2
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Lee H, Kim K, Kang CM, Choo A, Han D, Kim J. In Situ Confocal Fluorescence Lifetime Imaging of Nanopore Electrode Arrays with Redox Active Fluorogenic Amplex Red. Anal Chem 2023; 95:1038-1046. [PMID: 36577440 DOI: 10.1021/acs.analchem.2c03742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Direct imaging of electrochemical processes on electrode surfaces is a central part of understanding spatially heterogeneous electrochemical processes on the surfaces. Herein, we report a strategy for the spatially resolved imaging of local faradaic processes on nanoscale electrochemical interfaces. This strategy is based on fluorescence lifetime imaging microscopy (FLIM) with the use of Amplex Red as a fluorogenic redox probe. After verifying the capability of Amplex Red for fluorescence lifetime imaging, we demonstrated the turn-on FLIM-based imaging of faradaic processes on the electrochemical interfaces of different dimensions. In particular, we achieved spatially resolved visualization of the local electrochemical processes occurring on even nanopore electrode arrays as well as conventional microelectrodes, including disk-shaped ultramicroelectrodes and interdigitated array microelectrodes.
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Affiliation(s)
- Hyein Lee
- Department of Chemistry, Research Institute for Basic Sciences, Kyung Hee University, Seoul02447, Republic of Korea
| | - Kyoungsoo Kim
- Department of Chemistry, The Catholic University of Korea, Bucheon14662, Gyeonggi-do, Republic of Korea
| | - Chung Mu Kang
- Electrochemistry Laboratory, Advanced Institutes of Convergence Technology, Suwon16229, Gyeonggi-do, Republic of Korea
| | - Aeri Choo
- Department of Chemistry, Research Institute for Basic Sciences, Kyung Hee University, Seoul02447, Republic of Korea
| | - Donghoon Han
- Department of Chemistry, The Catholic University of Korea, Bucheon14662, Gyeonggi-do, Republic of Korea
| | - Joohoon Kim
- Department of Chemistry, Research Institute for Basic Sciences, Kyung Hee University, Seoul02447, Republic of Korea.,KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul02447, Republic of Korea
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3
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Alhourani A, Førde JL, Nasrollahzadeh M, Eichacker LA, Herfindal L, Hagland HR. Graphene-based phenformin carriers for cancer cell treatment: a comparative study between oxidized and pegylated pristine graphene in human cells and zebrafish. NANOSCALE ADVANCES 2022; 4:1668-1680. [PMID: 36134366 PMCID: PMC9417205 DOI: 10.1039/d1na00778e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/27/2022] [Indexed: 06/16/2023]
Abstract
Graphene is an attractive choice for the development of an effective drug carrier in cancer treatment due to its high adsorption area and pH-responsive drug affinity. In combination with the highly potent metabolic drug phenformin, increased doses could be efficiently delivered to cancer cells. This study compares the use of graphene oxide (GO) and polyethylene glycol stabilized (PEGylated) pristine graphene nanosheets (PGNSs) for drug delivery applications with phenformin. The cytotoxicity and mitotoxicity of the graphene-based systems were assessed in human cells and zebrafish larvae. Targeted drug release from GO and PGNSs was evaluated at different pH levels known to arise in proliferating tumor microenvironments. PGNSs were less cytotoxic and mitotoxic than GO, and showed an increased release of phenformin at lower pH in cells, compared to GO. In addition, the systemic phenformin effect was mitigated in zebrafish larvae when bound to GO and PGNSs compared to free phenformin, as measured by flavin metabolic lifetime imaging. These results pave the way for improved phenformin-based cancer therapy using graphene nano-sheets, where PGNSs were superior to GO.
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Affiliation(s)
- Abdelnour Alhourani
- Department of Chemistry, Biosciences and Environmental Engineering, University of Stavanger Stavanger Norway
| | - Jan-Lukas Førde
- Centre for Pharmacy, Department of Clinical Science, University of Bergen Bergen Norway
- Department of Internal Medicine, Haukeland University Hospital Bergen Norway
| | - Mojdeh Nasrollahzadeh
- Department of Chemistry, Biosciences and Environmental Engineering, University of Stavanger Stavanger Norway
| | - Lutz Andreas Eichacker
- Department of Chemistry, Biosciences and Environmental Engineering, University of Stavanger Stavanger Norway
| | - Lars Herfindal
- Centre for Pharmacy, Department of Clinical Science, University of Bergen Bergen Norway
| | - Hanne Røland Hagland
- Department of Chemistry, Biosciences and Environmental Engineering, University of Stavanger Stavanger Norway
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4
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Baek S, Han D, Kwon SR, Sundaresan V, Bohn PW. Electrochemical Zero-Mode Waveguide Potential-Dependent Fluorescence of Glutathione Reductase at Single-Molecule Occupancy. Anal Chem 2022; 94:3970-3977. [PMID: 35213143 PMCID: PMC8904319 DOI: 10.1021/acs.analchem.1c05091] [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] [Indexed: 02/08/2023]
Abstract
Understanding functional states of individual redox enzymes is important because electron-transfer reactions are fundamental to life, and single-enzyme molecules exhibit molecule-to-molecule heterogeneity in their properties, such as catalytic activity. Zero-mode waveguides (ZMW) constitute a powerful tool for single-molecule studies, enabling investigations of binding reactions up to the micromolar range due to the ability to trap electromagnetic radiation in zeptoliter-scale observation volumes. Here, we report the potential-dependent fluorescence dynamics of single glutathione reductase (GR) molecules using a bimodal electrochemical ZMW (E-ZMW), where a single-ring electrode embedded in each of the nanopores of an E-ZMW array simultaneously serves to control electrochemical potential and to confine optical radiation within the nanopores. Here, the redox state of GR is manipulated using an external potential control of the Au electrode in the presence of a redox mediator, methyl viologen (MV). Redox-state transitions in GR are monitored by correlating electrochemical and spectroscopic signals from freely diffusing MV/GR in 60 zL effective observation volumes at single GR molecule average pore occupancy, ⟨n⟩ ∼ 0.8. Fluorescence intensities decrease (increase) at reducing (oxidizing) potentials for MV due to the MV-mediated control of the GR redox state. The spectroelectrochemical response of GR to the enzyme substrate, i.e., glutathione disulfide (GSSG), shows that GSSG promotes GR oxidation via enzymatic reduction. The capabilities of E-ZMWs to probe spectroelectrochemical phenomena in zL-scale-confined environments show great promise for the study of single-enzyme reactions and can be extended to important technological applications, such as those in molecular diagnostics.
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Affiliation(s)
- Seol Baek
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Donghoon Han
- Department of Chemistry, The Catholic University of Korea, Bucheon, Gyeonggi-do 14662, South Korea
| | - Seung-Ryong Kwon
- Department of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, South Korea
| | - Vignesh Sundaresan
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Paul W Bohn
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.,Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
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5
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Sundaresan V, Do H, Shrout JD, Bohn PW. Electrochemical and spectroelectrochemical characterization of bacteria and bacterial systems. Analyst 2021; 147:22-34. [PMID: 34874024 PMCID: PMC8791413 DOI: 10.1039/d1an01954f] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Microbes, such as bacteria, can be described, at one level, as small, self-sustaining chemical factories. Based on the species, strain, and even the environment, bacteria can be useful, neutral or pathogenic to human life, so it is increasingly important that we be able to characterize them at the molecular level with chemical specificity and spatial and temporal resolution in order to understand their behavior. Bacterial metabolism involves a large number of internal and external electron transfer processes, so it is logical that electrochemical techniques have been employed to investigate these bacterial metabolites. In this mini-review, we focus on electrochemical and spectroelectrochemical methods that have been developed and used specifically to chemically characterize bacteria and their behavior. First, we discuss the latest mechanistic insights and current understanding of microbial electron transfer, including both direct and mediated electron transfer. Second, we summarize progress on approaches to spatiotemporal characterization of secreted factors, including both metabolites and signaling molecules, which can be used to discern how natural or external factors can alter metabolic states of bacterial cells and change either their individual or collective behavior. Finally, we address in situ methods of single-cell characterization, which can uncover how heterogeneity in cell behavior is reflected in the behavior and properties of collections of bacteria, e.g. bacterial communities. Recent advances in (spectro)electrochemical characterization of bacteria have yielded important new insights both at the ensemble and the single-entity levels, which are furthering our understanding of bacterial behavior. These insights, in turn, promise to benefit applications ranging from biosensors to the use of bacteria in bacteria-based bioenergy generation and storage.
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Affiliation(s)
- Vignesh Sundaresan
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Hyein Do
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Joshua D Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556, USA
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Paul W Bohn
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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6
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Sundaresan V, Cutri AR, Metro J, Madukoma CS, Shrout JD, Hoffman AJ, Willets KA, Bohn PW. Potential dependent spectroelectrochemistry of electrofluorogenic dyes on indium‐tin oxide. ELECTROCHEMICAL SCIENCE ADVANCES 2021; 2. [DOI: 10.1002/elsa.202100094] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Vignesh Sundaresan
- Department of Chemical and Biomolecular Engineering University of Notre Dame Notre Dame Indiana
| | - Allison R. Cutri
- Department of Chemistry and Biochemistry University of Notre Dame Notre Dame Indiana
| | - Jarek Metro
- Department of Chemistry and Biochemistry University of Notre Dame Notre Dame Indiana
| | - Chinedu S. Madukoma
- Department of Civil and Environmental Engineering and Earth Sciences University of Notre Dame Notre Dame Indiana
- Eck Institute for Global Health University of Notre Dame Notre Dame Indiana
| | - Joshua D. Shrout
- Department of Civil and Environmental Engineering and Earth Sciences University of Notre Dame Notre Dame Indiana
- Eck Institute for Global Health University of Notre Dame Notre Dame Indiana
- Department of Biological Sciences University of Notre Dame Notre Dame Indiana
| | - Anthony J. Hoffman
- Department of Electrical Engineering University of Notre Dame Notre Dame Indiana
| | | | - Paul W. Bohn
- Department of Chemical and Biomolecular Engineering University of Notre Dame Notre Dame Indiana
- Department of Chemistry and Biochemistry University of Notre Dame Notre Dame Indiana
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7
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Abstract
We present the results of acid–base experiments performed at the single ion (H+ or OH−) limit in ∼6 aL volume nanopores incorporating electrochemical zero-mode waveguides (E-ZMWs). At pH 3 each E-ZMW nanopore contains ca. 3600H+ ions, and application of a negative electrochemical potential to the gold working electrode/optical cladding layer reduces H+ to H2, thereby depleting H+ and increasing the local pH within the nanopore. The change in pH was quantified by tracking the intensity of fluorescein, a pH-responsive fluorophore whose intensity increases with pH. This behavior was translated to the single ion limit by changing the initial pH of the electrolyte solution to pH 6, at which the average pore occupancy 〈n〉pore ∼3.6H+/nanopore. Application of an electrochemical potential sufficiently negative to change the local pH to pH 7 reduces the proton nanopore occupancy to 〈n〉pore ∼0.36H+/nanopore, demonstrating that the approach is sensitive to single H+ manipulations, as evidenced by clear potential-dependent changes in fluorescein emission intensity. In addition, at high overpotential, the observed fluorescence intensity exceeded the value predicted from the fluorescence intensity-pH calibration, an observation attributed to the nucleation of H2 nanobubbles as confirmed both by calculations and the behavior of non-pH responsive Alexa 488 fluorophore. Apart from enhancing fundamental understanding, the approach described here opens the door to applications requiring ultrasensitive ion sensing, based on the optical detection of H+ population at the single ion limit. Visualizing dynamic change in the number of protons during electroreduction of protons in attoliter volume zero-mode waveguides.![]()
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Affiliation(s)
- Vignesh Sundaresan
- Department of Chemical and Biomolecular Engineering, University of Notre Dame Notre Dame IN 46556 USA
| | - Paul W Bohn
- Department of Chemical and Biomolecular Engineering, University of Notre Dame Notre Dame IN 46556 USA .,Department of Chemistry and Biochemistry, University of Notre Dame Notre Dame IN 46556 USA
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8
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Tassy B, Dauphin AL, Man HM, Le Guenno H, Lojou E, Bouffier L, de Poulpiquet A. In Situ Fluorescence Tomography Enables a 3D Mapping of Enzymatic O 2 Reduction at the Electrochemical Interface. Anal Chem 2020; 92:7249-7256. [PMID: 32298094 DOI: 10.1021/acs.analchem.0c00844] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Getting information about the fate of immobilized enzymes and the evolution of their environment during turnover is a mandatory step toward bioelectrode optimization for effective use in biodevices. We demonstrate here the proof-of-principle visual characterization of the reactivity at an enzymatic electrode thanks to fluorescence confocal laser scanning microscopy (FCLSM) implemented in situ during the electrochemical experiment. The enzymatic O2 reduction involves proton-coupled electron transfers. Therefore, fluorescence variation of a pH-dependent fluorescent dye in the electrode vicinity enables reaction visualization. Simultaneous collection of electrochemical and fluorescence signals gives valuable space- and time-resolved information. Once the technical challenges of such a coupling are overcome, in situ FCLSM affords a unique way to explore reactivity at the electrode surface and in the electrolyte volume. Unexpected features are observed, especially the pH evolution of the enzyme environment, which is also indicated by a characteristic concentration profile within the diffusion layer. This coupled approach also gives access to a cartography of the electrode surface response (i.e., heterogeneity), which cannot be obtained solely by an electrochemical means.
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Affiliation(s)
- Bastien Tassy
- Aix-Marseille Univ., CNRS, UMR 7281, Bioenergetics and Protein Engineering, 13402 Marseille, France
| | - Alice L Dauphin
- Univ. Bordeaux, CNRS, Bordeaux INP, UMR 5255, Institute of Molecular Sciences, F-33400 Talence, France
| | - Hiu Mun Man
- Aix-Marseille Univ., CNRS, UMR 7281, Bioenergetics and Protein Engineering, 13402 Marseille, France
| | - Hugo Le Guenno
- Microscopy Facility, CNRS, FR 3479, Mediterranean Institute of Microbiology, 13402 Marseille, France
| | - Elisabeth Lojou
- Aix-Marseille Univ., CNRS, UMR 7281, Bioenergetics and Protein Engineering, 13402 Marseille, France
| | - Laurent Bouffier
- Univ. Bordeaux, CNRS, Bordeaux INP, UMR 5255, Institute of Molecular Sciences, F-33400 Talence, France
| | - Anne de Poulpiquet
- Aix-Marseille Univ., CNRS, UMR 7281, Bioenergetics and Protein Engineering, 13402 Marseille, France
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9
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Fu K, Kwon SR, Han D, Bohn PW. Single Entity Electrochemistry in Nanopore Electrode Arrays: Ion Transport Meets Electron Transfer in Confined Geometries. Acc Chem Res 2020; 53:719-728. [PMID: 31990518 PMCID: PMC8020881 DOI: 10.1021/acs.accounts.9b00543] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Electrochemical measurements conducted in confined volumes provide a powerful and direct means to address scientific questions at the nexus of nanoscience, biotechnology, and chemical analysis. How are electron transfer and ion transport coupled in confined volumes and how does understanding them require moving beyond macroscopic theories? Also, how do these coupled processes impact electrochemical detection and processing? We address these questions by studying a special type of confined-volume architecture, the nanopore electrode array, or NEA, which is designed to be commensurate in size with physical scaling lengths, such as the Debye length, a concordance that offers performance characteristics not available in larger scale structures.The experiments described here depend critically on carefully constructed nanoscale architectures that can usefully control molecular transport and electrochemical reactivity. We begin by considering the experimental constraints that guide the design and fabrication of zero-dimensional nanopore arrays with multiple embedded electrodes. These zero-dimensional structures are nearly ideal for exploring how permselectivity and unscreened ion migration can be combined to amplify signals and improve selectivity by enabling highly efficient redox cycling. Our studies also highlight the benefits of arrays, in that molecules escaping from a single nanopore are efficiently captured by neighboring pores and returned to the population of active redox species being measured, benefits that arise from coupling ion accumulation and migration. These tools for manipulating redox species are well-positioned to explore single molecule and single particle electron transfer events through spectroelectrochemistry, studies which are enabled by the electrochemical zero-mode waveguide (ZMW), a special hybrid nanophotonic/nanoelectronic architecture in which the lower ring electrode of an NEA nanopore functions both as a working electrode to initiate electron transfer reactions and as the optical cladding layer of a ZMW. While the work described here is largely exploratory and fundamental, we believe that the development of NEAs will enable important applications that emerge directly from the unique coupled transport and electron-transfer capabilities of NEAs, including in situ molecular separation and detection with external stimuli, redox-based electrochemical rectification in individually encapsulated nanopores, and coupled sorters and analyzers for nanoparticles.
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Affiliation(s)
- Kaiyu Fu
- Department of Radiology, Stanford University, Stanford, CA, 94306
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94306
| | - Seung-Ryong Kwon
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556
| | - Donghoon Han
- Department of Chemistry, The Catholic University of Korea, Bucheon, Gyeonggi-do, 14662 Republic of Korea
| | - Paul W. Bohn
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
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10
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Zigah D, Lojou E, Poulpiquet A. Micro‐ and Nanoscopic Imaging of Enzymatic Electrodes: A Review. ChemElectroChem 2019. [DOI: 10.1002/celc.201901065] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Dodzi Zigah
- Univ. Bordeaux, CNRSBordeaux INP ISM UMR 5255 33400 Talence France
| | - Elisabeth Lojou
- Aix-Marseille Univ., CNRSBIP, UMR 7281 31 Chemin Aiguier 13009 Marseille France
| | - Anne Poulpiquet
- Aix-Marseille Univ., CNRSBIP, UMR 7281 31 Chemin Aiguier 13009 Marseille France
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11
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Optical methods for studying local electrochemical reactions with spatial resolution: A critical review. Anal Chim Acta 2019; 1074:1-15. [DOI: 10.1016/j.aca.2019.02.053] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 02/21/2019] [Accepted: 02/22/2019] [Indexed: 11/19/2022]
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12
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Wu M, Liu W, Hu J, Zhong Z, Rujiralai T, Zhou L, Cai X, Ma J. Fluorescence enhancement in an over-etched gold zero-mode waveguide. OPTICS EXPRESS 2019; 27:19002-19018. [PMID: 31252834 DOI: 10.1364/oe.27.019002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/18/2019] [Indexed: 05/26/2023]
Abstract
The fluorescence enhancement in an over-etched gold zero-mode waveguide (ZMW) was investigated through both numerical simulation and experiments. Using Cy3 and Cy5 as the fluorescent probes, the simulation showed that the undercut not only enhances the fluorescence signals of both fluorophores, but also greatly improves the radial uniformity of the excitation fields in the ZMW. Furthermore, using a focused-ion-beam tool, we fabricated Au-ZMW arrays with different radius and undercut. The fluorescence enhancement per molecule and the effective excitation volume of the Au-ZMW were then measured as functions of its radial size and over-etching depth by using fluorescence correlation spectroscopy. It was found that the undercut can significantly enhance the fluorescence signal per molecule in the ZMW, but it also slightly increased the excitation volume. Decreasing the radial size of the ZMW can efficiently reduce the excitation volume and also further enhance the fluorescence per molecule. These results together indicate that combining the undercut and reduction of radius of the ZMW can serve as a simple and effective way to essentially improve the performance of an Au-ZMW for single molecule fluorescence detection.
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13
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Fu K, Xu W, Hu J, Lopez A, Bohn PW. Microscale and Nanoscale Electrophotonic Diagnostic Devices. Cold Spring Harb Perspect Med 2019; 9:a034249. [PMID: 30104197 PMCID: PMC6417966 DOI: 10.1101/cshperspect.a034249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Detecting and identifying infectious agents and potential pathogens in complex environments and characterizing their mode of action is a critical need. Traditional diagnostics have targeted a single characteristic (e.g., spectral response, surface receptor, mass, intrinsic conductivity, etc.). However, advances in detection technologies have identified emerging approaches in which multiple modes of action are combined to obtain enhanced performance characteristics. Particularly appealing in this regard, electrophotonic devices capable of coupling light to electron translocation have experienced rapid recent growth and offer significant advantages for diagnostics. In this review, we explore three specific promising approaches that combine electronics and photonics: (1) assays based on closed bipolar electrochemistry coupling electron transfer to color or fluorescence, (2) sensors based on localized surface plasmon resonances, and (3) emerging nanophotonics approaches, such as those based on zero-mode waveguides and metamaterials.
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Affiliation(s)
- Kaiyu Fu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Wei Xu
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Jiayun Hu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Arielle Lopez
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Paul W Bohn
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556
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14
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Sabri L, Huang Q, Liu JN, Cunningham BT. Design of anapole mode electromagnetic field enhancement structures for biosensing applications. OPTICS EXPRESS 2019; 27:7196-7212. [PMID: 30876288 DOI: 10.1364/oe.27.007196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 02/18/2019] [Indexed: 06/09/2023]
Abstract
The design of an all-dielectric nanoantenna based on nonradiating "anapole" modes is studied for biosensing applications in an aqueous environment, using FDTD electromagnetic simulation. The strictly confined electromagnetic field within a circular or rectangular opening at the center of a cylindrical silicon disk produces a single point electromagnetic hotspot with up to 6.5x enhancement of |E|, for the 630-650 nm wavelength range, and we can increase the value up to 25x by coupling additional electromagnetic energy from an underlying PEC-backed substrate. We characterize the effects of the substrate design and slot dimensions on the field enhancement magnitude, for devices operating in a water medium.
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15
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Fan Y, Hao R, Han C, Zhang B. Counting Single Redox Molecules in a Nanoscale Electrochemical Cell. Anal Chem 2018; 90:13837-13841. [DOI: 10.1021/acs.analchem.8b04659] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Yunshan Fan
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Rui Hao
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Chu Han
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Bo Zhang
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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16
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Ponzellini P, Zambrana-Puyalto X, Maccaferri N, Lanzanò L, De Angelis F, Garoli D. Plasmonic zero mode waveguide for highly confined and enhanced fluorescence emission. NANOSCALE 2018; 10:17362-17369. [PMID: 30199084 DOI: 10.1039/c8nr04103b] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We fabricate a plasmonic nanoslot that is capable of performing enhanced single molecule detection at 10 μM concentrations. The nanoslot combines the tiny detection volume of a zero-mode waveguide and the field enhancement of a plasmonic nanohole. The nanoslot is fabricated on a bi-metallic film formed by the sequential deposition of gold and aluminum on a transparent substrate. Simulations of the structure yield an average near-field intensity enhancement of two orders of magnitude at its resonant frequency. Experimentally, we measure the fluorescence stemming from the nanoslot and compare it with that of a standard aluminum zero-mode waveguide. We also compare the detection volume for both structures. We observe that while both structures have a similar detection volume, the nanoslot yields a 25-fold fluorescence enhancement.
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Affiliation(s)
- Paolo Ponzellini
- Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
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17
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Singh R, Rathore D, Pandey CM, Geetanjali, Srivastava R. Electrochemical and Spectroscopic Studies of Riboflavin. ANALYTICAL CHEMISTRY LETTERS 2018; 8:653-664. [DOI: 10.1080/22297928.2018.1498018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/30/2018] [Indexed: 06/15/2023]
Affiliation(s)
- Ram Singh
- Department of Applied Chemistry, Delhi Technological University, Delhi - 110 042, India
| | - Deepshikha Rathore
- Department of Applied Chemistry, Delhi Technological University, Delhi - 110 042, India
| | - Chandra Mouli Pandey
- Department of Applied Chemistry, Delhi Technological University, Delhi - 110 042, India
| | - Geetanjali
- Department of Chemistry, Kirori Mal College, University of Delhi, Delhi - 110 007, India
| | - Richa Srivastava
- Department of Applied Chemistry, Delhi Technological University, Delhi - 110 042, India
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18
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Crouch GM, Han D, Bohn PW. Zero-Mode Waveguide Nanophotonic Structures for Single Molecule Characterization. JOURNAL OF PHYSICS D: APPLIED PHYSICS 2018; 51:193001. [PMID: 34158676 PMCID: PMC8216246 DOI: 10.1088/1361-6463/aab8be] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Single-molecule characterization has become a crucial research tool in the chemical and life sciences, but limitations, such as limited concentration range, inability to control molecular distributions in space, and intrinsic phenomena, such as photobleaching, present significant challenges. Recent developments in non-classical optics and nanophotonics offer promising routes to mitigating these restrictions, such that even low affinity (K D ~ mM) biomolecular interactions can be studied. Here we introduce and review specific nanophotonic devices used to support single molecule studies. Optical nanostructures, such as zero-mode waveguides (ZMWs), are usually fabricated in thin gold or aluminum films and serve to confine the observation volume of optical microspectroscopy to attoliter to zeptoliter volumes. These simple nanostructures allow individual molecules to be isolated for optical and electrochemical analysis, even when the molecules of interest are present at high concentration (μM - mM) in bulk solution. Arrays of ZMWs may be combined with optical probes such as single molecule fluorescence, single molecule fluorescence resonance energy transfer (smFRET), and fluorescence correlation spectroscopy (FCS) for distributed analysis of large numbers of single-molecule reactions or binding events in parallel. Furthermore, ZMWs may be used as multifunctional devices, for example by combining optical and electrochemical functions in a single discrete architecture to achieve electrochemical ZMWs (E-ZMW). In this review, we will describe the optical properties, fabrication, and applications of ZMWs for single-molecule studies, as well as the integration of ZMWs into systems for chemical and biochemical analysis.
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Affiliation(s)
- Garrison M. Crouch
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556
| | - Donghoon Han
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556
| | - Paul W. Bohn
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556
- Departmemt of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
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19
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Duan BK, Cavanagh PE, Li X, Walt DR. Ultrasensitive Single-Molecule Enzyme Detection and Analysis Using a Polymer Microarray. Anal Chem 2018; 90:3091-3098. [PMID: 29425025 DOI: 10.1021/acs.analchem.7b03980] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This report describes a novel method for isolating and detecting individual enzyme molecules using polymer arrays of picoliter microwells. A fluidic flow-cell device containing an array of microwells is fabricated in cyclic olefin polymer (COP). The use of COP microwell arrays simplifies experiments by eliminating extensive device preparation and surface functionalization that are common in other microwell array formats. Using a simple and robust loading method to introduce the reaction solution, individual enzyme molecules are trapped in picoliter microwells and subsequently isolated and sealed by fluorinated oil. The sealing is stable for hours in the COP device. The picoliter microwell device can measure enzyme concentrations in the low-femtomolar range by counting the number of active wells using a digital read-out. These picoliter microwell arrays can also easily be regenerated and reused.
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Affiliation(s)
- Barrett K Duan
- Department of Pathology , Harvard Medical School , Brigham and Women's Hospital, Wyss Institute for Biologically Inspired Engineering, Building for Transformative Medicine, 60 Fenwood Road , Boston , Massachusetts 02115 , United States
| | - Peter E Cavanagh
- Department of Pathology , Harvard Medical School , Brigham and Women's Hospital, Wyss Institute for Biologically Inspired Engineering, Building for Transformative Medicine, 60 Fenwood Road , Boston , Massachusetts 02115 , United States
| | - Xiang Li
- Department of Pathology , Harvard Medical School , Brigham and Women's Hospital, Wyss Institute for Biologically Inspired Engineering, Building for Transformative Medicine, 60 Fenwood Road , Boston , Massachusetts 02115 , United States
| | - David R Walt
- Department of Pathology , Harvard Medical School , Brigham and Women's Hospital, Wyss Institute for Biologically Inspired Engineering, Building for Transformative Medicine, 60 Fenwood Road , Boston , Massachusetts 02115 , United States
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20
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Fu K, Bohn PW. Nanopore Electrochemistry: A Nexus for Molecular Control of Electron Transfer Reactions. ACS CENTRAL SCIENCE 2018; 4:20-29. [PMID: 29392173 PMCID: PMC5785767 DOI: 10.1021/acscentsci.7b00576] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Indexed: 05/12/2023]
Abstract
Pore-based structures occur widely in living organisms. Ion channels embedded in cell membranes, for example, provide pathways, where electron and proton transfer are coupled to the exchange of vital molecules. Learning from mother nature, a recent surge in activity has focused on artificial nanopore architectures to effect electrochemical transformations not accessible in larger structures. Here, we highlight these exciting advances. Starting with a brief overview of nanopore electrodes, including the early history and development of nanopore sensing based on nanopore-confined electrochemistry, we address the core concepts and special characteristics of nanopores in electron transfer. We describe nanopore-based electrochemical sensing and processing, discuss performance limits and challenges, and conclude with an outlook for next-generation nanopore electrode sensing platforms and the opportunities they present.
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Affiliation(s)
- Kaiyu Fu
- Department
of Chemistry and Biochemistry and Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Paul W. Bohn
- Department
of Chemistry and Biochemistry and Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
- E-mail: . Tel: +1 574 631 1849. Fax: +1 574 631 8366
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21
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Han D, Crouch GM, Fu K, Zaino Iii LP, Bohn PW. Single-molecule spectroelectrochemical cross-correlation during redox cycling in recessed dual ring electrode zero-mode waveguides. Chem Sci 2017; 8:5345-5355. [PMID: 28970913 PMCID: PMC5609146 DOI: 10.1039/c7sc02250f] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 06/18/2017] [Indexed: 11/21/2022] Open
Abstract
The ability of zero-mode waveguides (ZMW) to guide light into subwavelength-diameter nanoapertures has been exploited for studying electron transfer dynamics in zeptoliter-volume nanopores under single-molecule occupancy conditions. In this work, we report the spectroelectrochemical detection of individual molecules of the redox-active, fluorogenic molecule flavin mononucleotide (FMN) freely diffusing in solution. Our approach is based on an array of nanopore-confined recessed dual ring electrodes, wherein repeated reduction and oxidation of a single molecule at two closely spaced annular working electrodes yields amplified electrochemical signals. We have articulated these structures with an optically transparent bottom, so that the nanopores are bifunctional, exhibiting both nanophotonic and nanoelectrochemical behaviors allowing the coupling between electron transfer and fluorescence dynamics to be studied under redox cycling conditions. We also investigated the electric field intensity in electrochemical ZMWs (E-ZMW) through finite-element simulations, and the amplification of fluorescence by redox cycling agrees well with predictions based on optical confinement effects inside the E-ZMW. Proof-of-principle experiments are conducted showing that electrochemical and fluorescence signals may be correlated to reveal single molecule fluctuations in the array population. Cross-correlation of single molecule fluctuations in amperometric response and single photon emission provides unequivocal evidence of single molecule sensitivity.
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Affiliation(s)
- Donghoon Han
- Department of Chemical and Biomolecular Engineering , University of Notre Dame , Notre Dame , IN 46556 , USA . ; ; Tel: +1 574 631 1849
| | - Garrison M Crouch
- Department of Chemical and Biomolecular Engineering , University of Notre Dame , Notre Dame , IN 46556 , USA . ; ; Tel: +1 574 631 1849
| | - Kaiyu Fu
- Departmemt of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , IN 46556 , USA
| | - Lawrence P Zaino Iii
- Departmemt of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , IN 46556 , USA
| | - Paul W Bohn
- Department of Chemical and Biomolecular Engineering , University of Notre Dame , Notre Dame , IN 46556 , USA . ; ; Tel: +1 574 631 1849.,Departmemt of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , IN 46556 , USA
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22
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Fu K, Han D, Ma C, Bohn PW. Ion selective redox cycling in zero-dimensional nanopore electrode arrays at low ionic strength. NANOSCALE 2017; 9:5164-5171. [PMID: 28393950 DOI: 10.1039/c7nr00206h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Surface charge characteristics and the electrical double layer (EDL) effect govern the transport of ions into and out of nanopores, producing a permselective concentration polarization, which dominates the electrochemical response of nanoelectrodes in solutions of low ionic strength. In this study, highly ordered, zero-dimensional nanopore electrode arrays (NEAs), with each nanopore presenting a pair of recessed electrodes, were fabricated to couple EDL effects with redox cycling, thereby achieving electrochemical detection with improved sensitivity and selectivity. These NEAs exhibit current amplification as high as 55-fold due to the redox cycling effect, which can be further increased by ∼500-fold upon the removal of the supporting electrolyte. The effect of nanopore geometry, which is a key factor determining the magnitude of the EDL effect, is fully characterized, as is the effect of the magnitude and sign of the charge of the redox-active species. The observed changes in limiting current with the concentration of the supporting electrolyte confirm the accumulation of cations and repulsion of anions in NEAs presenting negative surface charge. Exploiting this principle, dopamine was selectively determined in the presence of a 3000-fold excess of ascorbic acid within the NEA.
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Affiliation(s)
- Kaiyu Fu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
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23
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Lu J, Fan Y, Howard MD, Vaughan JC, Zhang B. Single-Molecule Electrochemistry on a Porous Silica-Coated Electrode. J Am Chem Soc 2017; 139:2964-2971. [PMID: 28132499 DOI: 10.1021/jacs.6b10191] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Here we report the direct observation and quantitative analysis of single redox events on a modified indium-tin oxide (ITO) electrode. The key in the observation of single redox events are the use of a fluorogenic redox species and the nanoconfinement and hindered redox diffusion inside 3-nm-diameter silica nanochannels. A simple electrochemical process was used to grow an ultrathin silica film (∼100 nm) consisting of highly ordered parallel nanochannels exposing the electrode surface from the bottom. The electrode-supported 3-nm-diameter nanochannels temporally trap fluorescent resorufin molecules resulting in hindered molecular diffusion in the vicinity of the electrode surface. Adsorption, desorption, and heterogeneous redox events of individual resorufin molecules can be studied using total-internal reflection fluorescence (TIRF). The rate constants of adsorption and desorption processes of resorufin were characterized from single-molecule analysis to be (1.73 ± 0.08) × 10-4 cm·s-1 and 15.71 ± 0.76 s-1, respectively. The redox events of resorufin to the non-fluorescent dihydroresorufin were investigated by analyzing the change in surface population of single resorufin molecules with applied potential. The scan-rate-dependent molecular counting results (single-molecule fluorescence voltammetry) indicated a surface-controlled electrochemical kinetics of the resorufin reduction on the modified ITO electrode. This study demonstrates the great potential of mesoporous silica as a useful modification scheme for studying single redox events on a variety of transparent substrates such as ITO electrodes and gold or carbon film coated glass electrodes. The ability to electrochemically grow and transfer mesoporous silica films onto other substrates makes them an attractive material for future studies in spatial heterogeneity of electrocatalytic surfaces.
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Affiliation(s)
- Jin Lu
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Yunshan Fan
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Marco D Howard
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Joshua C Vaughan
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Bo Zhang
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
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24
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Mattei M, Kang G, Goubert G, Chulhai DV, Schatz GC, Jensen L, Van Duyne RP. Tip-Enhanced Raman Voltammetry: Coverage Dependence and Quantitative Modeling. NANO LETTERS 2017; 17:590-596. [PMID: 27936805 DOI: 10.1021/acs.nanolett.6b04868] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Electrochemical atomic force microscopy tip-enhanced Raman spectroscopy (EC-AFM-TERS) was employed for the first time to observe nanoscale spatial variations in the formal potential, E0', of a surface-bound redox couple. TERS cyclic voltammograms (TERS CVs) of single Nile Blue (NB) molecules were acquired at different locations spaced 5-10 nm apart on an indium tin oxide (ITO) electrode. Analysis of TERS CVs at different coverages was used to verify the observation of single-molecule electrochemistry. The resulting TERS CVs were fit to the Laviron model for surface-bound electroactive species to quantitatively extract the formal potential E0' at each spatial location. Histograms of single-molecule E0' at each coverage indicate that the electrochemical behavior of the cationic oxidized species is less sensitive to local environment than the neutral reduced species. This information is not accessible using purely electrochemical methods or ensemble spectroelectrochemical measurements. We anticipate that quantitative modeling and measurement of site-specific electrochemistry with EC-AFM-TERS will have a profound impact on our understanding of the role of nanoscale electrode heterogeneity in applications such as electrocatalysis, biological electron transfer, and energy production and storage.
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Affiliation(s)
| | | | | | - Dhabih V Chulhai
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | | | - Lasse Jensen
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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25
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Al-Kutubi H, Zafarani HR, Rassaei L, Mathwig K. Electrofluorochromic systems: Molecules and materials exhibiting redox-switchable fluorescence. Eur Polym J 2016. [DOI: 10.1016/j.eurpolymj.2016.04.033] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Abstract
The reduction and oxidation of the flavin system is an important electron transfer reaction in biological systems. Several reaction pathways exist to connect oxidized to fully reduced riboflavin, each with unique intermediates including a semi-quinone radical. By performing surface-enhanced Raman scattering (SERS) with simultaneous electrochemical detection of riboflavin at different pH values, we are able to correlate reversible changes in spectral features to the current changes observed in the cyclic voltammetry. Multivariate curve resolution analysis of the SERS spectra indicates that three distinct components were present at the SERS electrode at each pH during the potential sweep. To verify and better understand the variations in Raman bands across the voltammogram, density functional theory (DFT) calculations were performed to model the effect of pH and oxidation state on the riboflavin Raman spectrum. The calculated spectra show qualitative agreement with the species identified in the chemometric analysis. This combination of results indicates the presence of the oxidized, semi-quinone, and reduced forms of riboflavin and provides insight into the mechanism of the flavin redox system.
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Affiliation(s)
- Matthew R Bailey
- University of Notre Dame, Department of Chemistry and Biochemistry, Notre Dame, IN 46556, USA.
| | - Zachary D Schultz
- University of Notre Dame, Department of Chemistry and Biochemistry, Notre Dame, IN 46556, USA.
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27
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Gooding JJ, Gaus K. Single‐Molecule Sensors: Challenges and Opportunities for Quantitative Analysis. Angew Chem Int Ed Engl 2016; 55:11354-66. [DOI: 10.1002/anie.201600495] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 04/17/2016] [Indexed: 11/09/2022]
Affiliation(s)
- J. Justin Gooding
- The University of New South Wales School of Chemistry, Australian Centre for NanoMedicine and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, UNSW Sydney 2052 Australia
| | - Katharina Gaus
- The University of New South Wales EMBL Australia Node in Single Molecule Science ARC Centre of Excellence in Advanced Molecular Imaging Sydney 2052 Australia
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28
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Gooding JJ, Gaus K. Einzelmolekül‐Sensoren: Herausforderungen und Möglichkeiten für die quantitative Analyse. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201600495] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- J. Justin Gooding
- The University of New South Wales School of Chemistry, Australian Centre for NanoMedicine and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, UNSW Sydney 2052 Australien
| | - Katharina Gaus
- The University of New South Wales EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging,UNSW Sydney 2052 Australien
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29
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30
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Affiliation(s)
- Stephen M. Oja
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Yunshan Fan
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Chadd M. Armstrong
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Peter Defnet
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Bo Zhang
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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31
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Mathwig K, Chi Q, Lemay SG, Rassaei L. Handling and Sensing of Single Enzyme Molecules: From Fluorescence Detection towards Nanoscale Electrical Measurements. Chemphyschem 2015; 17:452-7. [DOI: 10.1002/cphc.201500686] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Klaus Mathwig
- Pharmaceutical Analysis; Groningen Research Institute of Pharmacy; University of Groningen; P.O. Box 196 9700 AD Groningen The Netherlands
| | - Qijin Chi
- Department of Chemistry; Technical University of Denmark; 2800 Kongens Lyngby Denmark
| | - Serge G. Lemay
- MESA+ Institute for Nanotechnology; University of Twente; P.O. Box 217 7500 AE Enschede The Netherlands
| | - Liza Rassaei
- Laboratory of Organic Materials and Interfaces; Department of Chemical Engineering; Delft University of Technology; Julianalaan 136 2628 BL Delft The Netherlands
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