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Gao J, Su H, Wang W. A microwell array-based approach for studying single nanoparticle catalysis with high turnover frequency. J Chem Phys 2021; 155:071101. [PMID: 34418929 DOI: 10.1063/5.0058402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Measuring the catalytical activities of single catalysts in the case of high turnover frequency (TOF, realistic conditions) is highly desirable to accurately evaluate the functional heterogeneities among individuals and to understand the catalytic mechanism. Herein, we report a microwell array-based method to in operando measure the photocatalytic kinetics of single CdS nanoparticles (NPs) with high TOF. This was realized by sealing individual CdS NPs into separated micrometer-sized polydimethylsiloxane wells, thus eliminating the diffusion of products among individuals in the case of high concentration of reactants. This method allowed us to monitor the activities of single catalysts with an average TOF up to 2.1 × 105 s-1. Interestingly, two types of catalytical behaviors were revealed during single CdS photocatalysis: a rapid decline in activity for most CdS NPs and an initial increase in activity followed by a decrease for a minor population of individuals. The developed method will facilitate the investigation of catalytic activities of single particles under realistic conditions and hold great potential in the fields of photo/electro-catalysts, enzymes, functional bacteria, and so on.
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Affiliation(s)
- Jia Gao
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Hua Su
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Wei Wang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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Zhdanov VP. Kinetics of Reaction on a Single Catalytic Particle in a Fluidic Nanochannel. Catal Letters 2019. [DOI: 10.1007/s10562-019-03082-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Abstract
One of the frontiers in heterogeneous catalysis is focused on reactions occurring on single catalytic nanoparticles. In this context, a reaction taking place on a single nanoparticle in a fluidic nanochannel is herein described by using the equation similar to that employed for a plug-flow reactor with dispersion. In the literature, one can find various boundary conditions for this equation. In the practically interesting case of a relatively long channel, the Dirichlet boundary conditions are shown to be valid. The corresponding analytical and numerical results illustrate the specifics of the profiles of the reactant concentration along the channel and the dependence of the reaction rate on the parameters. For comparison, the Danckwerts boundary conditions were used as well.
Graphic Abstract
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Levin S, Fritzsche J, Nilsson S, Runemark A, Dhokale B, Ström H, Sundén H, Langhammer C, Westerlund F. A nanofluidic device for parallel single nanoparticle catalysis in solution. Nat Commun 2019; 10:4426. [PMID: 31562383 PMCID: PMC6764984 DOI: 10.1038/s41467-019-12458-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 09/11/2019] [Indexed: 11/09/2022] Open
Abstract
Studying single catalyst nanoparticles, during reaction, eliminates averaging effects that are an inherent limitation of ensemble experiments. It enables establishing structure-function correlations beyond averaged properties by including particle-specific descriptors such as defects, chemical heterogeneity and microstructure. Driven by these prospects, several single particle catalysis concepts have been implemented. However, they all have limitations such as low throughput, or that they require very low reactant concentrations and/or reaction rates. In response, we present a nanofluidic device for highly parallelized single nanoparticle catalysis in solution, based on fluorescence microscopy. Our device enables parallel scrutiny of tens of single nanoparticles, each isolated inside its own nanofluidic channel, and at tunable reaction conditions, ranging from the fully mass transport limited regime to the surface reaction limited regime. In a wider perspective, our concept provides a versatile platform for highly parallelized single particle catalysis in solution and constitutes a promising application area for nanofluidics.
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Affiliation(s)
- Sune Levin
- Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Joachim Fritzsche
- Department of Physics, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Sara Nilsson
- Department of Physics, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - August Runemark
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Bhausaheb Dhokale
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Henrik Ström
- Department of Mechanics and Maritime Sciences, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Henrik Sundén
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Christoph Langhammer
- Department of Physics, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
| | - Fredrik Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
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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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Abstract
Over the last decade, femtoliter arrays have been used as a simple and robust way to encapsulate and monitor the kinetics of single enzyme molecules. Encapsulating individual enzyme molecules within a femtoliter-sized reaction chamber does not require immobilization of the enzyme molecules or fluorescent tagging of the enzyme molecules, which offers the unique advantage of observing unmodified single enzyme molecules free in solution. Several fascinating details about enzyme kinetics have been revealed using these femtoliter arrays, which were unattainable from traditional ensemble experiments. Here, we discuss various considerations to take into account when developing single-molecule enzyme assays in femtoliter arrays and the advantages and disadvantages of various protocols.
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Affiliation(s)
| | - D R Walt
- Tufts University, Medford, MA, United States.
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