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Vannoy KJ, Edwards MQ, Renault C, Dick JE. An Electrochemical Perspective on Reaction Acceleration in Microdroplets. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2024; 17:149-171. [PMID: 38594942 DOI: 10.1146/annurev-anchem-061622-030919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Analytical techniques operating at the nanoscale introduce confinement as a tool at our disposal. This review delves into the phenomenon of accelerated reactivity within micro- and nanodroplets. A decade of accelerated reactivity observations was succeeded by several years of fundamental studies aimed at mechanistic enlightenment. Herein, we provide a brief historical context for rate enhancement in and around micro- and nanodroplets and summarize the mechanisms that have been proposed to contribute to such extraordinary reactivity. We highlight recent electrochemical reports that make use of restricted mass transfer to enhance electrochemical reactions and/or quantitatively measure reaction rates within droplet-confined electrochemical cells. A comprehensive approach to nanodroplet reactivity is paramount to understanding how nature takes advantage of these systems to provide life on Earth and, in turn, how to harness the full potential of such systems.
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Affiliation(s)
- Kathryn J Vannoy
- 1Department of Chemistry, Purdue University, West Lafayette, Indiana, USA;
| | | | - Christophe Renault
- 1Department of Chemistry, Purdue University, West Lafayette, Indiana, USA;
- 2Current Address: Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, Illinois, USA
| | - Jeffrey E Dick
- 1Department of Chemistry, Purdue University, West Lafayette, Indiana, USA;
- 3Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana, USA
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2
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Zhang JH, Song DM, Zhou YG. Impact electrochemistry for biosensing: advances and future directions. Analyst 2024; 149:2498-2506. [PMID: 38629127 DOI: 10.1039/d4an00170b] [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: 04/30/2024]
Abstract
Impact electrochemistry allows for the investigation of the properties of single entities, ranging from nanoparticles (NPs) to soft bio-particles. It has introduced a novel dimension in the field of biological analysis, enhancing researchers' ability to comprehend biological heterogeneity and offering a new avenue for developing novel diagnostic devices for quantifying biological analytes. This review aims to summarize the recent advancements in impact electrochemistry-based biosensing over the past two to three years and provide insights into the future directions of this field.
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Affiliation(s)
- Jian-Hua Zhang
- School of Chemistry and Chemical Engineering, Linyi University, Linyi, Shandong 276005, China.
| | - Dian-Mei Song
- Institute of Laser Manufacturing, Henan Academy of Sciences, Zhengzhou, 450046, P. R. China
| | - Yi-Ge Zhou
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China.
- Greater Bay Area Institute for Innovation, Hunan University, Guangzhou, 511340, Guangdong Province, China
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Kim P, Moon H, Lee HC, Park JH. Electrochemical Detection of Single Aqueous Droplets in Organic Solvents via Pitting Collisions. Anal Chem 2024; 96:4528-4534. [PMID: 38453627 DOI: 10.1021/acs.analchem.3c05231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
We report a novel detection method for single aqueous droplets in organic solvents by the collisional contact of the droplet, inducing the partial deformation of the ultramicroelectrode (UME) surface. For various chemical reactions in organic solvents, water impurities affect the catalytic activity, leading to a loss of productivity and selectivity. Therefore, it is necessary to monitor the water content of organic solvents in real time between many chemical production processes, from the laboratory to the industrial scale. Our method enables the detection of water contamination by real-time monitoring of the electrochemical signals or observing morphological changes in the microelectrode. When an aqueous droplet collides with the UME, the contact area of the electrode is electrolyzed, forming pits on the surface where the droplet falls. Current transient analysis shows a unique current spike corresponding to the reaction inside the adsorbed single aqueous droplet, which differs from those detected by the faradaic/nonfaradaic reaction of collision of other particles. Moreover, this analytical method can record the history of collision events from pits on the UME surface, implying that inspecting the UME surface could be a quick screening method for solvent contamination. Based on a comparison of the electrochemical signals and morphological changes of the electrode after each event, the sizes of the pits and droplets are related. A COMSOL simulation is performed to explain the shape of the peak current and pit formation during collision events. This experimental concept elucidates the dynamic behavior of aqueous droplets on a positively biased metal electrode.
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Affiliation(s)
- Pankyu Kim
- Department of Chemistry, Chungbuk National University, Cheongju 28644, South Korea
| | - Hyeongkwon Moon
- Department of Chemistry, Chungbuk National University, Cheongju 28644, South Korea
| | - Heung Chan Lee
- Samsung Advanced Institute of Technology, Suwon 16678, South Korea
| | - Jun Hui Park
- Department of Chemistry, Chungbuk National University, Cheongju 28644, South Korea
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Park H, Park JH. Electrochemical Characterization of Neurotransmitters in a Single Submicron Droplet. BIOSENSORS 2024; 14:102. [PMID: 38392021 PMCID: PMC10886559 DOI: 10.3390/bios14020102] [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: 01/22/2024] [Revised: 02/08/2024] [Accepted: 02/15/2024] [Indexed: 02/24/2024]
Abstract
Single-entity electrochemistry, which employs electrolysis during the collision of single particles on ultramicroelectrodes, has witnessed significant advancements in recent years, enabling the observation and characterization of individual particles. Information on a single aqueous droplet (e.g., size) can also be studied based on the redox species contained therein. Dopamine, a redox-active neurotransmitter, is usually present in intracellular vesicles. Similarly, in the current study, the electrochemical properties of neurotransmitters in submicron droplets were investigated. Because dopamine oxidation is accompanied by proton transfer, unique electrochemical properties of dopamine were observed in the droplet. We also investigated the electrochemical properties of the adsorbed droplets containing DA and the detection of oxidized dopamine by the recollision phenomenon.
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Affiliation(s)
| | - Jun Hui Park
- Department of Chemistry, Chungbuk National University, Cheongju 28644, Republic of Korea
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Du M, Zhang L, Meng Y, Chen J, Liu F. Impact of Surface Chemistry on Emulsion-Electrode Interactions and Electron-Transfer Kinetics in the Single-Entity Electrochemistry. Anal Chem 2024; 96:1038-1045. [PMID: 38181449 DOI: 10.1021/acs.analchem.3c03462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2024]
Abstract
Single-entity electrochemistry (SEE) provides powerful means to track a single particle, single cell, and even single molecule from the nano to microscale. The electrode serves as not only the detector of collision but also the surface supplier in SEE, and the fundamental understanding of the electrode surface chemistry on the dynamic particle-electrode interactions and electrochemical responses of a single particle still remains unexplored, particularly for soft particles. Herein, dynamic interactions of microemulsions and the interaction-controlled electron-transfer (ET) kinetics are studied employing SEE and fluorescence spectroscopy. The o/w-type nitrobenzene emulsions were prepared with the surfactant-type room temperature ionic liquids (RTILs). Biased the electrode potential for the reduction of 7,7,8,8-tetracyanoquinodimethane within emulsions, it is surprising to see the distinct collision current signals on the carbon fiber ultramicroelectrode (C UME) and Au ultramicroelectrode (Au UME) in the late stage of chronoamperometric measurements. Theoretical understanding was made to determine the ET kinetics behind the disparate current signals. It is believed that the electrode surface chemistry, i.e., the surface energy, has a great influence on the dynamic emulsion-electrode interactions and ET kinetics. On the hydrophilic surface of Au UME, emulsions tend to decompose/detach from the electrode surface immediately after colliding. In contrast, on the lipophilic surface of C UME with lower surface energy, a layer of oil phase accumulated by the coalescence of emulsions and the migration of the precedent colliding emulsions, which would serve as a barrier to block ET via tunneling as manifested by the gradual slowdown of ET rate and the reduced collision frequency in the late stage of measurement. The impacts of the emulsion size and amphiphilicity of RTILs on the C UME-emulsion interactions and ET kinetics were also investigated.
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Affiliation(s)
- Minshu Du
- School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China
| | - Lizhu Zhang
- School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China
| | - Yao Meng
- Shaanxi Huaqin New Energy Technology Co., Ltd, Xi'an, Shaanxi 710119, China
| | - Jiajia Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Feng Liu
- School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China
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Lu SM, Vannoy KJ, Dick JE, Long YT. Multiphase Chemistry under Nanoconfinement: An Electrochemical Perspective. J Am Chem Soc 2023; 145:25043-25055. [PMID: 37934860 DOI: 10.1021/jacs.3c07374] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Most relevant systems of interest to modern chemists rarely consist of a single phase. Real-world problems that require a rigorous understanding of chemical reactivity in multiple phases include the development of wearable and implantable biosensors, efficient fuel cells, single cell metabolic characterization techniques, and solar energy conversion devices. Within all of these systems, confinement effects at the nanoscale influence the chemical reaction coordinate. Thus, a fundamental understanding of the nanoconfinement effects of chemistry in multiphase environments is paramount. Electrochemistry is inherently a multiphase measurement tool reporting on a charged species traversing a phase boundary. Over the past 50 years, electrochemistry has witnessed astounding growth. Subpicoampere current measurements are routine, as is the study of single molecules and nanoparticles. This Perspective focuses on three nanoelectrochemical techniques to study multiphase chemistry under nanoconfinement: stochastic collision electrochemistry, single nanodroplet electrochemistry, and nanopore electrochemistry.
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Affiliation(s)
- Si-Min Lu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P.R. China
| | - Kathryn J Vannoy
- Department of Chemistry, Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jeffrey E Dick
- Department of Chemistry, Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Yi-Tao Long
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P.R. China
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Sudalaimani S, Arun S, Esokkiya A, Sanjeev Kumar K, Sivakumar C, Giribabu K. Disposable-micropipette tip supported electrified liquid-organogel interface as a platform for sensing acetylcholine. Analyst 2023; 148:1451-1459. [PMID: 36804568 DOI: 10.1039/d2an01663j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Sensing acetylcholine has been predominantly based on enzymatic strategies using acetylcholine esterase and choline oxidase because of its electrochemical inertness. Electrified liquid-liquid interfaces are not limited to oxidation/reduction processes, and can be utilized to detect non-redox molecules which cannot be detected using conventional solid electrodes. In this study, a disposable micropipette tip based liquid-organogel interface, in the presence/absence of calixarene has been developed as a platform for sensing acetylcholine. We also explored a liquid-liquid interface approach for sensing acetylcholine using a pre-pulled glass micropipette. In both approaches, the configuration, i.e., liquid-organogel and liquid-liquid interface-current linearly increases during the backward transfer of acetylcholine. The simple and facilitated ion transfer of acetylcholine across the liquid-organogel exhibited a linear range of 10-50 μM and 1-30 μM with a detection limit of 0.18 μM and 0.23 μM and a sensitivity of 9.52 nA μM-1 and 9.20 nA μM-1, respectively. Whereas, the detection limit of simple and facilitated ion transfer of liquid-liquid interface using pre-pulled glass micropipette was found to be 0.42 μM and 0.13 μM with a sensitivity of 5 × 10-3 nA μM-1 and 3.39 × 10-2 nA μM-1. The results indicate that the liquid-organogel configuration supported on a disposable micropipette tip without any pre-fabrication is highly suitable for electrified soft interface sensing applications.
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Affiliation(s)
- S Sudalaimani
- Electrodics and Electrocatalysis Division, CSIR-Central Electrochemical Research Institute, Karaikudi-630 003, Tamil Nadu, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - S Arun
- Electrodics and Electrocatalysis Division, CSIR-Central Electrochemical Research Institute, Karaikudi-630 003, Tamil Nadu, India.
| | - A Esokkiya
- Electrodics and Electrocatalysis Division, CSIR-Central Electrochemical Research Institute, Karaikudi-630 003, Tamil Nadu, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - K Sanjeev Kumar
- Electrodics and Electrocatalysis Division, CSIR-Central Electrochemical Research Institute, Karaikudi-630 003, Tamil Nadu, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - C Sivakumar
- Electrodics and Electrocatalysis Division, CSIR-Central Electrochemical Research Institute, Karaikudi-630 003, Tamil Nadu, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - K Giribabu
- Electrodics and Electrocatalysis Division, CSIR-Central Electrochemical Research Institute, Karaikudi-630 003, Tamil Nadu, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
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Mao C, Soda Y, Robinson KJ, Forrest T, Bakker E. Mass Transfer from Ion-Sensing Component-Loaded Nanoemulsions into Ion-Selective Membranes: An Electrochemical Quartz Crystal Microbalance and Thin-Film Coulometry Study. ACS MEASUREMENT SCIENCE AU 2023; 3:45-52. [PMID: 36817005 PMCID: PMC9936608 DOI: 10.1021/acsmeasuresciau.2c00053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/22/2022] [Accepted: 09/22/2022] [Indexed: 06/18/2023]
Abstract
Recent work has shown that ion-selective components may be transferred from nanoemulsions (NEs) to endow polymeric membranes with ion-selective sensing properties. This approach has also been used for nanopipette electrodes to achieve single-entity electrochemistry, thereby sensing the ion-selective response of single adhered nanospheres. To this date, however, the mechanism and rate of component transfer remain unclear. We study here the transfer of lipophilic ionic compounds from nanoemulsions into thin plasticized poly(vinyl chloride) (PVC-DOS) films by chronoamperometry and quartz crystal microbalance. Thin-film cyclic coulovoltammetry measurements serve to quantify the uptake of lipophilic species into blank PVC-DOS membranes. Electrochemical quartz crystal microbalance data indicate that the transfer of the emulsion components is insignificant, ruling out simple coalescence with the membrane film. Ionophores and ion-exchangers are shown to transfer into the membrane at rates that correlate with their lipophilicity if mass transport is not rate-limiting, which is the case with more lipophilic compounds (calcium and sodium ionophores). On the other hand, with less lipophilic compounds (valinomycin and cation-exchanger salts), transfer rates are limited by mass transport. This is confirmed with rotating disk electrode experiments in which a linear relationship between the diffusion layer thickness and current is observed. The data suggests that once the nanoemulsion container approaches the membrane surface, transfer of components occur by a three-phase partition mechanism where the aqueous phase serves as a kinetic barrier. The results help better understand and quantify the interaction between nanoemulsions and ion-selective membranes and predict membrane doping rates for a range of components.
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Moon H, Park JH. Electrochemical Analysis of Attoliter Water Droplets in Organic Solutions through Partitioning Equilibrium. SENSORS (BASEL, SWITZERLAND) 2023; 23:2157. [PMID: 36850752 PMCID: PMC9959340 DOI: 10.3390/s23042157] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
Herein, we report the electrochemical monitoring of attoliters of water droplets in an organic medium by the electrolysis of an extracted redox species from the continuous phase upon collisional events on an ultramicroelectrode. To obtain information about a redox-free water droplet in an organic solvent, redox species with certain concentrations need to be contained inside it. The redox species inside the droplet were delivered by a partitioning equilibrium between the organic phase and the water droplets. The mass transfer of the redox species from the surrounding organic phase to the droplet is very fast because of the radial diffusion, which resultantly establishes the equilibrium. Upon the collisional contact between the droplet and the electrode, the extracted redox species in the water droplets were selectively electrolyzed, even though the redox species in the organic continuous phase remained unreacted because of the different solvent environments. The electrolysis of the redox species in the droplets, where the concentration is determined by the equilibrium constant of the redox species in water/oil, can be used to estimate the size of single water droplets in an organic solution.
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Affiliation(s)
| | - Jun Hui Park
- Correspondence: ; Tel.: +82-43-261-2287; Fax: +82-43-267-2279
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Itagaki R, Takizawa SY, Chang HC, Nakada A. Light-induced electron transfer/phase migration of a redox mediator for photocatalytic C-C coupling in a biphasic solution. Dalton Trans 2022; 51:9467-9476. [PMID: 35678270 DOI: 10.1039/d2dt01334g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photocatalytic molecular conversions that lead to value-added chemicals are of considerable interest. To achieve highly efficient photocatalytic reactions, it is equally important as it is challenging to construct systems that enable effective charge separation. Here, we demonstrate that the rational construction of a biphasic solution system with a ferrocenium/ferrocene (Fc+/Fc) redox couple enables efficient photocatalysis by spatial charge separation using the liquid-liquid interface. In a single-phase system, exposure of a 1,2-dichloroethane (DCE) solution containing a Ru(II)- or Ir(III)-based photosensitizer, Fc, and benzyl bromide (Bn-Br) to visible-light irradiation failed to generate any product. However, the photolysis in a H2O/DCE biphasic solution, where the compounds are initially distributed in the DCE phase, facilitated the reductive coupling of Bn-Br to dibenzyl (Bn2) using Fc as an electron donor. The key result of this study is that Fc+, generated by photooxidation of Fc in the DCE phase, migrates to the aqueous phase due to the drastic change in its partition coefficient compared to that of Fc. This liquid-liquid phase migration of the mediator is essential for facilitating the reduction of Bn-Br in the DCE phase as it suppresses backward charge recombination. The co-existence of anions can further modify the driving force of phase migration of Fc+ depending on their hydrophilicity; the best photocatalytic activity was obtained with a turnover frequency of 79.5 h-1 and a quantum efficiency of 0.2% for the formation of Bn2 by adding NBu4+Br- to the biphasic solution. This study showcases a potential approach for rectifying electron transfer with suppressed charge recombination to achieve efficient photocatalysis.
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Affiliation(s)
- Ren Itagaki
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.
| | - Shin-Ya Takizawa
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Ho-Chol Chang
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.
| | - Akinobu Nakada
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan. .,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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Reyes-Morales J, Moazeb M, Colón-Quintana GS, Dick JE. The Electroneutrality Condition Allows for Electrodeposition of Gold Nanoparticles from Aqueous Nanodroplets. Chem Commun (Camb) 2022; 58:10663-10666. [DOI: 10.1039/d2cc03645b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nanodroplet-mediated electrodeposition is a reliable method for electrodepositing nanoparticles by confining a small amount of metal-salt precursor in water nanodroplets (radius ~400 nm) suspended in an oil continuous phase. This...
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