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Ben Trad F, Delacotte J, Lemaître F, Guille-Collignon M, Arbault S, Sojic N, Labbé E, Buriez O. Shadow electrochemiluminescence imaging of giant liposomes opening at polarized electrodes. Analyst 2024; 149:3317-3324. [PMID: 38742381 DOI: 10.1039/d4an00470a] [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: 05/16/2024]
Abstract
In this work, the release of giant liposome (∼100 μm in diameter) content was imaged by shadow electrochemiluminescence (ECL) microscopy. Giant unilamellar liposomes were pre-loaded with a sucrose solution and allowed to sediment at an ITO electrode surface immersed in a solution containing a luminophore ([Ru(bpy)3]2+) and a sacrificial co-reactant (tri-n-propylamine). Upon polarization, the electrode exhibited illumination over its entire surface thanks to the oxidation of ECL reagents. However, as soon as liposomes reached the electrode surface, dark spots appeared and then spread over time on the surface. This observation reflected a blockage of the electrode surface at the contact point between the liposome and the electrode surface, followed by the dilution of ECL reagents after the rupture of the liposome membrane and release of its internal ECL-inactive solution. Interestingly, ECL reappeared in areas where it initially faded, indicating back-diffusion of ECL reagents towards the previously diluted area and thus confirming liposome permeabilization. The whole process was analyzed qualitatively and quantitatively within the defined region of interest. Two mass transport regimes were identified: a gravity-driven spreading process when the liposome releases its content leading to ECL vanishing and a diffusive regime when ECL recovers. The reported shadow ECL microscopy should find promising applications for the imaging of transient events such as molecular species released by artificial or biological vesicles.
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Affiliation(s)
- Fatma Ben Trad
- PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - Jérôme Delacotte
- PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - Frédéric Lemaître
- PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - Manon Guille-Collignon
- PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - Stéphane Arbault
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, F-33600 Pessac, France
| | - Neso Sojic
- Univ. Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255 CNRS, 33400 Talence, France.
| | - Eric Labbé
- PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - Olivier Buriez
- PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
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Linfield S, Gawinkowski S, Nogala W. Toward the Detection Limit of Electrochemistry: Studying Anodic Processes with a Fluorogenic Reporting Reaction. Anal Chem 2023; 95:11227-11235. [PMID: 37461137 PMCID: PMC10398625 DOI: 10.1021/acs.analchem.3c00694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Recently, shot noise has been shown to be an inherent part of all charge-transfer processes, leading to a practical limit of quantification of 2100 electrons (≈0.34 fC) [ Curr. Opin. Electrochem. 2020, 22, 170-177]. Attainable limits of quantification are made much larger by greater background currents and insufficient instrumentation, which restricts progress in sensing and single-entity applications. This limitation can be overcome by converting electrochemical charges into photons, which can be detected with much greater sensitivity, even down to a single-photon level. In this work, we demonstrate the use of fluorescence, induced through a closed bipolar setup, to monitor charge-transfer processes below the detection limit of electrochemical workstations. During this process, the oxidation of ferrocenemethanol (FcMeOH) in one cell is used to concurrently drive the oxidation of Amplex Red (AR), a fluorogenic redox molecule, in another cell. The spectroelectrochemistry of AR is investigated and new insights on the commonplace practice of using deprotonated glucose to limit AR photooxidation are presented. The closed bipolar setup is used to produce fluorescence signals corresponding to the steady-state voltammetry of FcMeOH on a microelectrode. Chronopotentiometry is then used to show a linear relationship between the charge passed through FcMeOH oxidation and the integrated AR fluorescence signal. The sensitivity of the measurements obtained at different timescales varies between 2200 and 500 electrons per detected photon. The electrochemical detection limit is approached using a diluted FcMeOH solution in which no faradaic current signal is observed. Nevertheless, a fluorescence signal corresponding to FcMeOH oxidation is still seen, and the detection of charges down to 300 fC is demonstrated.
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Affiliation(s)
- Steven Linfield
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Sylwester Gawinkowski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Wojciech Nogala
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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Seddiki I, N’Diaye BI, Skene WG. Survey of Recent Advances in Molecular Fluorophores, Unconjugated Polymers, and Emerging Functional Materials Designed for Electrofluorochromic Use. Molecules 2023; 28:molecules28073225. [PMID: 37049988 PMCID: PMC10096808 DOI: 10.3390/molecules28073225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 03/06/2023] [Accepted: 03/08/2023] [Indexed: 04/08/2023] Open
Abstract
In this review, recent advances that exploit the intrinsic emission of organic materials for reversibly modulating their intensity with applied potential are surveyed. Key design strategies that have been adopted during the past five years for developing such electrofluorochromic materials are presented, focusing on molecular fluorophores that are coupled with redox-active moieties, intrinsically electroactive molecular fluorophores, and unconjugated emissive organic polymers. The structural effects, main challenges, and strides toward addressing the limitations of emerging fluorescent materials that are electrochemically responsive are surveyed, along with how these can be adapted for their use in electrofluorochromic devices.
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Affiliation(s)
- Ilies Seddiki
- Laboratoire de Caractérisation Photophysique des Matériaux Conjugués Département de Chimie, Campus MIL, Université de Montréal, CP 6128, Succ. Centre-Ville, Montreal, QC H3C 3J7, Canada
| | - Brelotte Idriss N’Diaye
- Laboratoire de Caractérisation Photophysique des Matériaux Conjugués Département de Chimie, Campus MIL, Université de Montréal, CP 6128, Succ. Centre-Ville, Montreal, QC H3C 3J7, Canada
| | - W. G. Skene
- Laboratoire de Caractérisation Photophysique des Matériaux Conjugués Département de Chimie, Campus MIL, Université de Montréal, CP 6128, Succ. Centre-Ville, Montreal, QC H3C 3J7, Canada
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