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Kanike C, Lu Q, Wu H, Unsworth LD, Atta A, Zhang X. Plasmonic Nanostructures Grown from Reacting Droplet-In-Microwell Array on Flexible Films for Quantitative Surface-Enhanced Raman Spectroscopy in Plant Wearable In Situ Detection. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2405576. [PMID: 39039736 DOI: 10.1002/adma.202405576] [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: 04/19/2024] [Revised: 06/20/2024] [Indexed: 07/24/2024]
Abstract
Plant wearable detection has garnered significant interest in advancing agricultural intelligence and promoting sustainable food production amidst the challenges of climate change. Accurately monitoring plant health and agrochemical residue levels necessitates qualities such as precision, affordability, simplicity, and noninvasiveness. Here, a novel attachable plasmonic film is introduced and designed for on-site detection of agrochemical residues utilizing surface-enhanced Raman spectroscopy (SERS). By functionalizing a thin polydimethylsiloxane film with silver nanoparticles via controlled droplet reactions in micro-well arrays, a plasmonic film is achieved that not only maintains optical transparency for precise analyte localization but also conforms closely to the plant surface, facilitating highly sensitive SERS measurements. The reliability of this film enables accurate identification and quantification of individual compounds and their mixtures, boasting an ultra-low detection limit ranging from 10-16 to 10-13 m, with mini mal relative standard deviation. To showcase its potential, on-field detection of pesticide residues on fruit surfaces is conducted using a handheld Raman spectrometer. This advancement in fabricating plasmonic nanostructures on flexible films holds promise for expanding SERS applications beyond plant monitoring, including personalized health monitoring, point-of-care diagnosis, wearable devices for human-machine interface, and on-site monitoring of environmental pollutants.
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Affiliation(s)
- Chiranjeevi Kanike
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
- Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India
| | - Qiuyun Lu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
| | - Hongyan Wu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
| | - Larry D Unsworth
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
| | - Arnab Atta
- Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
- Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede, NB, 7522, The Netherlands
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Faramarzi P, Jang W, Oh D, Kim B, Kim JH, You JB. Microfluidic Detection and Analysis of Microplastics Using Surface Nanodroplets. ACS Sens 2024; 9:1489-1498. [PMID: 38440995 DOI: 10.1021/acssensors.3c02627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2024]
Abstract
Detection of microplastics from water is crucial for various reasons, such as food safety monitoring, monitoring of the fate and transport of microplastics, and development of preventive measures for their occurrence. Currently, microplastics are detected by isolating them using filtration, separation by centrifugation, or membrane filtration, subsequently followed by analysis using well-established analytical methods, such as Raman spectroscopy. However, due to their variability in shape, color, size, and density, isolation using the conventional methods mentioned above is cumbersome and time-consuming. In this work, we show a surface-nanodroplet-decorated microfluidic device for isolation and analysis of small microplastics (diameter of 10 μm) from water. Surface nanodroplets are able to capture nearby microplastics as water flows through the microfluidic device. Using a model microplastic solution, we show that microplastics of various sizes and types can be captured and visualized by using optical and fluorescence microscopy. More importantly, as the surface nanodroplets are pinned on the microfluidic channel, the captured microplastics can also be analyzed using a Raman spectroscope, which enables both physical (i.e., size and shape) and chemical (i.e., type) characterization of microplastics at a single-particle level. The technique shown here can be used as a simple, fast, and economical detection method for small microplastics.
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Affiliation(s)
- Paniz Faramarzi
- Department of Energy Convergence and Climate Change, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Wonik Jang
- Department of Chemical Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Donghyeon Oh
- Department of Chemical Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Byeunggon Kim
- Department of Chemical Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Ju Hyeon Kim
- Interface Materials and Chemical Engineering Research Center, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
| | - Jae Bem You
- Department of Energy Convergence and Climate Change, Kyungpook National University, Daegu 41566, Republic of Korea
- Department of Chemical Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
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Wu H, Le QN, Zeng B, Zhang X. Nanoextraction from a flow of a highly diluted solution for much-improved sensitivity in offline chemical detection and quantification. Anal Chim Acta 2023; 1274:341529. [PMID: 37455069 DOI: 10.1016/j.aca.2023.341529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 05/13/2023] [Accepted: 06/12/2023] [Indexed: 07/18/2023]
Abstract
Preconcentration of the target compound is a critical step that ensures the accuracy of the subsequent chemical analysis. In this work, we present a straightforward yet effective liquid-liquid extraction approach based on surface nanodroplets (i.e., nanoextraction) for offline analysis of highly diluted sample solutions. The extraction and sample collection were streamlined in a 3-m microcapillary tube. The concentration of the target analyte in surface nanodroplets was significantly increased compared to the concentration in the sample solution, reaching several orders of magnitude. A limit of detection (LOD) was decreased by a factor of ∼103 for an organic model compound in Fourier-transform infrared spectroscopy (FTIR) measurements and ∼105 for a model fluorescent dye in fluorescence detection. The quantitative analysis of the organic compound was also achieved in a wide concentration region from 10-3 M to 10-4 M. The total volume of surface nanodroplets can be manipulated to further enhance extraction efficiency, according to the principle that governs droplet formation by solvent exchange. Additionally, our method exhibited significantly improved sensitivity compared to traditional dispersive liquid-liquid microextraction (DLLME). The LOD of the fluorescent dye and the organic model compound obtained with DLLME was 3 orders of magnitude and 20 times higher than the LOD achieved through nanoextraction approach. The nanoextraction developed in this work can be applied to preconcentrate multi-compounds from river water samples, without clear interference from each other. This can further extend its applicability for the detection and quantification of target analytes in complex aqueous samples by common analytical instruments.
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Affiliation(s)
- Hongyan Wu
- Department of Chemical and Materials Engineering, University of Alberta, Alberta, T6G 1H9, Canada
| | - Quynh Nhu Le
- Department of Chemical and Materials Engineering, University of Alberta, Alberta, T6G 1H9, Canada
| | - Binglin Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Alberta, T6G 1H9, Canada
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Alberta, T6G 1H9, Canada; Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede, 7522 NB, the Netherlands.
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Lim E, Kim B, Seok Oh M, Bem You J. Microfluidic formation of surface nanodroplets using green deep eutectic solvents for liquid-liquid nanoextraction and controlled precipitation. J Colloid Interface Sci 2023; 643:82-91. [PMID: 37054546 DOI: 10.1016/j.jcis.2023.03.201] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 04/05/2023]
Abstract
HYPOTHESIS Surface nanodroplets have recently been employed for in situ chemical analysis leveraging their low volume, e.g. O(10-15 L), that enables rapid analyte extraction and pre-concentration. So far, most surface nanodroplets have been formed using single organic solvents such as 1-octanol, toluene, among others. Designing multicomponent surface nanodroplet with controllable composition is highly desirable for extending their application as extractant. EXPERIMENT Here, we formed surface nanodroplets using green deep eutectic solvent (gDES) composed of thymol and decanoic acid, both of which are naturally occurring chemicals. The influence of parameters such as flowrate and the composition of deep eutectic solvent on the surface nanodroplet formation were studied. As proof-of-concept, the gDES surface nanodroplets were further used to extract and detect trace amounts of fluorescent rhodamine 6G dye and copper ions from water. FINDINGS The formation of gDES surface nanodroplets follows the theoretical model which states that the final droplet volume (Vf) scales with the Peclét number (Pe) of the flow during formation by the solvent exchange process, that is Vf ∼ Pe3/4, and the nanodroplets demonstrate excellent ability as extractant for rhodamine 6G and copper ions from water. Surprisingly, the confined volume of gDES surface nanodroplets enables fast and controlled formation of Cu (II)-decanoate crystal.
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Li Z, Wu H, You JB, Wang X, Zeng H, Lohse D, Zhang X. Surface Nanodroplet-Based Extraction Combined with Offline Analytic Techniques for Chemical Detection and Quantification. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:11227-11235. [PMID: 36067516 DOI: 10.1021/acs.langmuir.2c01242] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Liquid-liquid extraction based on surface nanodroplets can be a green and sustainable technique to extract and concentrate analytes from a sample flow. However, because of the extremely small volume of each droplet (<10 fL, tens of micrometers in base radius and a few or less than 1 μm in height), only a few in situ analytical techniques, such as surface-enhanced Raman spectroscopy, were applicable for the online detection and analysis based on nanodroplet extraction. To demonstrate the versatility of surface nanodroplet-based extraction, in this work, the formation of octanol surface nanodroplets and extraction were performed inside a 3 m Teflon capillary tube. After extraction, surface nanodroplets were collected by injecting air into the tube, by which the contact line of surface droplets was collected by the capillary force. As the capillary allows for the formation of ∼1012 surface nanodroplets on the capillary wall, ≥2 mL of octanol can be collected after extraction. The volume of the collected octanol was enough for the analysis of offline analytical techniques such as UV-vis, GC-MS, and others. Coupled with UV-vis, reliable extraction and detection of two common water pollutants, triclosan and chlorpyrifos, was shown by a linear relationship between the analyte concentration in the sample solution and UV-vis absorbance. Moreover, the limit of detection (LOD) as low as 2 × 10-9 M for triclosan (∼0.58 μg/L) and 3 × 10-9 M for chlorpyrifos (∼1.05 μg/L) could be achieved. The collected surface droplets were also analyzed via gas chromatography (GC) and fluorescence microscopy. Our work shows that surface nanodroplet extraction may potentially streamline the process in sample pretreatment for sensitive chemical detection and quantification by using common analytic tools.
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Affiliation(s)
- Zhengxin Li
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
| | - Hongyan Wu
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
| | - Jae Bem You
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
- Department of Chemical Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Xiaomeng Wang
- Natural Resources Canada, CanmetENERGY Devon, Alberta T9G 1A8, Canada
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
| | - Detlef Lohse
- Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede 7522 NB, The Netherlands
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
- Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede 7522 NB, The Netherlands
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Wu H, Kanike C, Atta A, Zhang X. Nanoextraction based on surface nanodroplets for chemical preconcentration and determination. BIOMICROFLUIDICS 2022; 16:051502. [PMID: 36330200 PMCID: PMC9625837 DOI: 10.1063/5.0121912] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 09/28/2022] [Indexed: 05/04/2023]
Abstract
Liquid-liquid extraction based on surface nanodroplets, namely nanoextraction, can continuously extract and enrich target analytes from the flow of a sample solution. This sample preconcentration technique is easy to operate in a continuous flow system with a low consumption of organic solvent and a high enrichment factor. In this review, the evolution from single drop microextraction to advanced nanoextraction will be briefly introduced. Moreover, the formation principle and key features of surface nanodroplets will be summarized. Further, the major findings of nanoextraction combined with in-droplet chemistry toward sensitive and quantitative detection will be discussed. Finally, we will give our perspectives for the future trend of nanoextraction.
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Affiliation(s)
- Hongyan Wu
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
| | | | - Arnab Atta
- Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Xuehua Zhang
- Author to whom correspondence should be addressed:. URL:https://sites.google.com/view/soft-matter-interfaces/home
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Dabodiya TS, Yu H, Li M, Zhang X. Sequential droplet reactions for surface-bound gold nanocrater array. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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8
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Li Z, Zeng H, Zhang X. Growth Rates of Hydrogen Microbubbles in Reacting Femtoliter Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:6638-6646. [PMID: 35588476 DOI: 10.1021/acs.langmuir.2c00516] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Chemical reactions in small droplets are extensively explored to accelerate the discovery of new materials and increase the efficiency and specificity in catalytic biphasic conversion and high-throughput analytics. In this work, we investigate the local rate of the gas-evolution reaction within femtoliter droplets immobilized on a solid surface. The growth rate of hydrogen microbubbles (≥500 nm in radius) produced from the reaction was measured online with high-resolution confocal microscopic images. The growth rate of bubbles was faster in smaller droplets and near the droplet rim in the same droplet. The results were consistent for both pure and binary reacting droplets and on substrates of different wettability. Our theoretical analysis based on diffusion, chemical reaction, and bubble growth predicted that the concentration of the reactant depended on the droplet size and the bubble location inside the droplet, in good agreement with experimental results. Our results reveal that the reaction rate may be spatially nonuniform in the reacting microdroplets. The findings may have implications for formulating the chemical properties and uses of these droplets.
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Affiliation(s)
- Zhengxin Li
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
- Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede 7522 NB, The Netherlands
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Ji Y, Zheng J, Geng Z, Tan T, Hu J, Zhang L, Zhang Y. Controllable formation of bulk perfluorohexane nanodroplets by solvent exchange. SOFT MATTER 2022; 18:425-433. [PMID: 34905593 DOI: 10.1039/d1sm01457a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Perfluorocarbon (PFC) nanodroplets have rapidly developed into useful ultrasound imaging agents in modern medicine due to their non-toxic and stable chemical properties that facilitate disease diagnosis and targeted therapy. In addition, with the good capacity for carrying breathing gases and the anti-infection ability, they are employed as blood substitutes and are the most ideal liquid respirators. However, it is still a challenge to prepare stable PFC nanodroplets of uniform size and high concentration for their efficient use. Herein, we developed a simple and highly reproducible method, i.e., propanol-water exchange, to prepare highly homogeneous and stable perfluorohexane (PFH) bulk nanodroplets. Interestingly, the size distribution and concentration of formed nanodroplets could be regulated by controlling the volume fraction of PFH and percentage of propanol in the propanol-water mixture. We demonstrated good reproducibility in the formation of bulk nanodroplets with PFH volume fractions of 1/2000-1/200 and propanol percentage of 5-40%, with uniform particle size distribution and high droplet concentration. Also, the prepared nanodroplets were very stable and could survive for several hours. We constructed a ternary phase diagram to describe the relationship between the PFH volume ratio, propanol concentration, and the size distribution and concentration of the formed PFH nanodroplets. This study provides a very useful method to prepare uniform size, high concentration and stable PFC nanodroplets for their medical applications.
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Affiliation(s)
- Yuwen Ji
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jin Zheng
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhanli Geng
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201204, China
| | - Tingyuan Tan
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Hu
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
- Zhangjiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
| | - Lijuan Zhang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
- Zhangjiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
| | - Yi Zhang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
- Zhangjiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
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Sadeghi J, Patrone PN, Kearsley AJ, Cooksey GA. Optofluidic flow meter for sub-nanoliter per minute flow measurements. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:017001. [PMID: 35102729 PMCID: PMC8802908 DOI: 10.1117/1.jbo.27.1.017001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
SIGNIFICANCE Performance improvements in microfluidic systems depend on accurate measurement and fluid control on the micro- and nanoscales. New applications are continuously leading to lower volumetric flow rates. AIM We focus on improving an optofluidic system for measuring and calibrating microflows to the sub-nanoliter per minute range. APPROACH Measurements rely on an optofluidic system that delivers excitation light and records fluorescence in a precise interrogation region of a microfluidic channel. Exploiting a scaling relationship between the flow rate and fluorescence emission after photobleaching, the system enables real-time determination of flow rates. RESULTS Here, we demonstrate improved calibration of a flow controller to 1% uncertainty. Further, the resolution of the optofluidic flow meter improved to less than 1 nL / min with 5% uncertainty using a molecule with a 14-fold smaller diffusion coefficient than our previous report. CONCLUSIONS We demonstrate new capabilities in sub-nanoliter per minute flow control and measurement that are generalizable to cutting-edge light-material interaction and molecular diffusion for chemical and biomedical industries.
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Affiliation(s)
- Jalal Sadeghi
- University of Maryland, Department of Chemistry and Biochemistry, College Park, Maryland, United States
- National Institute of Standards and Technology, Microsystems and Nanotechnology Division, Gaithersburg, Maryland, United States
| | - Paul N. Patrone
- National Institute of Standards and Technology, Applied and Computational Mathematics Division, Gaithersburg, Maryland, United States
| | - Anthony J. Kearsley
- National Institute of Standards and Technology, Applied and Computational Mathematics Division, Gaithersburg, Maryland, United States
| | - Gregory A. Cooksey
- National Institute of Standards and Technology, Microsystems and Nanotechnology Division, Gaithersburg, Maryland, United States
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Zhou L, Yang S, Quan N, Geng Z, Wang S, Zhao B, Wang X, Dong Y, Tai R, Hu J, Zhang L. Wetting Behavior of Surface Nanodroplets Regulated by Periodic Nanostructured Surfaces. ACS APPLIED MATERIALS & INTERFACES 2021; 13:55726-55734. [PMID: 34761672 DOI: 10.1021/acsami.1c17139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Surfaces with nanostructure patterning are broadly encountered in nature, and they play a significant role in regulating various phenomena such as phase transition at the liquid/solid interface. Here, we designed two kinds of template substrates with periodic nanostructure patterns [i.e., nanotrench (NT) and nanopore (NP)]. Surface nanodroplets produced on these nanostructure surfaces were characterized to acquire their morphology and wetting properties. We show that nanostructure patterning could effectively regulate the shape, contact radius, and nucleate site of nanodroplets. While nanodroplets on the NT structure are constrained in one dimension, nanodroplets on the NP structure have enhanced the wetting property with constraints from two dimensions. Further numerical analysis indicates that the morphology and contact angles of nanodroplets on the NT structure depend on the substrate wettability and the droplet volume. These observations demonstrate how physical geometry and chemical heterogeneity of a substrate surface affect the growth and spreading of surface nanodroplets, which deepens our understanding on nanoscale phase separation.
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Affiliation(s)
- Limin Zhou
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
| | - Shumin Yang
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
| | - Nannan Quan
- Life and Environment Science College, Shanghai Normal University, Shanghai 200234, China
| | - Zhanli Geng
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201204, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuo Wang
- The Shenzhen International Innovation Institutes of Advanced Electronic Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Binyu Zhao
- Leibniz Institute of Polymer Research Dresden, Dresden 01069, Germany
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Xingya Wang
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Yaming Dong
- Life and Environment Science College, Shanghai Normal University, Shanghai 200234, China
| | - Renzhong Tai
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
| | - Jun Hu
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences, Shanghai 201800, China
| | - Lijuan Zhang
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences, Shanghai 201800, China
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Wei Z, Dabodiya TS, Chen J, Lu Q, Qian J, Meng J, Zeng H, Qian H, Zhang X. In-situ fabrication of metal oxide nanocaps based on biphasic reactions with surface nanodroplets. J Colloid Interface Sci 2021; 608:2235-2245. [PMID: 34750004 DOI: 10.1016/j.jcis.2021.10.093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 10/06/2021] [Accepted: 10/16/2021] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Surface-bound nanomaterials are widely used in clean energy techniques from solar-driven evaporation in desalination to hydrogen production by photocatalytic electrolysis. Reactive surface nanodroplets may potentially streamline the process of fabrication of a range of surface-bound nanomaterials invoking biphasic reactions at interfaces. EXPERIMENTS In this work, we demonstrate the feasibility of reactive surface nanodroplets for in situ synthesis and anchoring of nanocaps of metal oxides with tailored porous structures. FINDINGS Spatial arrangement and surface coverage of nanocaps are predetermined during the formation of nanodroplets, while the crystalline structures of metal oxides can be controlled by thermal treatment of organometallic nanodroplets produced from the biphasic reactions. Notably, tuning the ratio of reactive and nonreactive components in surface nanodroplets enables the formation of porous nanocaps that can double photocatalytic efficiency in the degradation of organic contaminants in water, compared to smooth nanocaps. In total, we demonstrate in situ fabrication of four types of metal oxides in the shape of nanocaps. Our work shows that reactive surface nanodroplets may open the door to a general, fast and tuneable route for preparing surface-bound materials. This fabrication approach may develop new nanomaterials needed for photocatalytic reactions, wastewater treatment, optical focusing, solar energy conversion and other clean energy techniques.
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Affiliation(s)
- Zixiang Wei
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada.
| | - Tulsi Satyavir Dabodiya
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada; Centre for Nanoscience and Technology, Madanjeet School of Green Energy Technologies, Pondicherry University (A Central University), Dr. R. Vankataraman Nagar, Kalapet, Puducherry 605014, India
| | - Jian Chen
- Nanotechnology Research Center, National Research Council Canada, Edmonton, AB T6G 2M9, Canada
| | - Qiuyun Lu
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
| | - Jiasheng Qian
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
| | - Jia Meng
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
| | - Hui Qian
- Nanotechnology Research Center, National Research Council Canada, Edmonton, AB T6G 2M9, Canada
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada; Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede, 7522 NB, the Netherlands
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14
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You JB, Lohse D, Zhang X. Surface nanodroplet-based nanoextraction from sub-milliliter volumes of dense suspensions. LAB ON A CHIP 2021; 21:2574-2585. [PMID: 34008650 DOI: 10.1039/d1lc00139f] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A greener analytical technique for quantifying compounds in dense suspensions is needed for wastewater and environmental analysis, chemical or bio-conversion process monitoring, biomedical diagnostics, and food quality control, among others. In this work, we introduce a green, fast, one-step method called nanoextraction for extraction and detection of target analytes from sub-milliliter dense suspensions using surface nanodroplets without toxic solvents and pre-removal of the solid contents. With nanoextraction, we achieve a limit of detection (LOD) of 10-9 M for a fluorescent model analyte obtained from a particle suspension sample. The LOD is lower than that in water without particles (10-8 M), potentially due to the interaction of particles and the analyte. The high particle concentration in the suspension sample, thus, does not reduce the extraction efficiency, although the extraction process was slowed down up to 5 min. As a proof of principle, we demonstrate the nanoextraction for the quantification of model compounds in wastewater slurry containing 30 wt% solids and oily components (i.e. heavy oils). The nanoextraction and detection technology developed in this work may be used in fast analytical technologies for complex slurry samples in the environment, industrial waste, or in biomedical diagnostics.
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Affiliation(s)
- Jae Bem You
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada. and Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede 7522 NB, The Netherlands
| | - Detlef Lohse
- Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede 7522 NB, The Netherlands
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada. and Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede 7522 NB, The Netherlands
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15
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Tan BH, Ohl CD, An H. Transient Solubility Gradients Mediate Oversaturation during Solvent Exchange. PHYSICAL REVIEW LETTERS 2021; 126:234502. [PMID: 34170149 DOI: 10.1103/physrevlett.126.234502] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 04/28/2021] [Indexed: 06/13/2023]
Abstract
Solvent exchange facilitates high-density nucleation of sessile nanodroplets or nanobubbles by successively wetting a surface with two solvents of contrasting solubility with respect to a target species. Yet the key physical mechanisms underlying its efficacy have yet to be theoretically explained. We develop a minimal model for solvent exchange, for the prototypical example of water and ethanol as the solvents and nitrogen as the target species. Our calculations show that solvent exchange is mediated by transient solubility gradients that dominate over the intrinsic concentration gradient of nitrogen in the incipient moments after exchange. Solubility gradients advect nitrogen toward the substrate during ethanol-water exchange but away from it in water-ethanol exchange, consistent with the directionality observed in experiments.
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Affiliation(s)
- Beng Hau Tan
- KB Corporation, 7500A Beach Road, 199591 Singapore
| | - Claus-Dieter Ohl
- Otto von Guericke University Magdeburg, Institute of Experimental Physics, Universittsplatz 2, 39016 Magdeburg, Germany
| | - Hongjie An
- Queensland Micro and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
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16
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Zhang X, You JB, Arends GF, Qian J, Chen Y, Lohse D, Shaw JM. Propelling microdroplets generated and sustained by liquid-liquid phase separation in confined spaces. SOFT MATTER 2021; 17:5362-5374. [PMID: 33956922 DOI: 10.1039/d1sm00231g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Flow transport in confined spaces is ubiquitous in technological processes, ranging from separation and purification of pharmaceutical ingredients by microporous membranes and drug delivery in biomedical treatment to chemical and biomass conversion in catalyst-packed reactors and carbon dioxide sequestration. In this work, we suggest a distinct pathway for enhanced liquid transport in a confined space via propelling microdroplets. These microdroplets can form spontaneously from localized liquid-liquid phase separation as a ternary mixture is diluted by a diffusing poor solvent. High speed images reveal how the microdroplets grow, break up and propel rapidly along the solid surface, with a maximal velocity up to ∼160 μm s-1, in response to a sharp concentration gradient resulting from phase separation. The microdroplet propulsion induces a replenishing flow between the walls of the confined space towards the location of phase separation, which in turn drives the mixture out of equilibrium and leads to a repeating cascade of events. Our findings on the complex and rich phenomena of propelling droplets suggest an effective approach to enhanced flow motion of multicomponent liquid mixtures within confined spaces for time effective separation and smart transport processes.
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Affiliation(s)
- Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada. and Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede 7522 NB, The Netherlands
| | - Jae Bem You
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada. and Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede 7522 NB, The Netherlands
| | - Gilmar F Arends
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada.
| | - Jiasheng Qian
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada.
| | - Yibo Chen
- Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede 7522 NB, The Netherlands
| | - Detlef Lohse
- Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede 7522 NB, The Netherlands and Max Planck Institute for Dynamics and Self-Organization, 37077 Göttingen, Germany
| | - John M Shaw
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada.
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17
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Choi H, Wei Z, You JB, Yang H, Zhang X. Effects of Chemical and Geometric Microstructures on the Crystallization of Surface Droplets during Solvent Exchange. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:5290-5298. [PMID: 33891427 DOI: 10.1021/acs.langmuir.1c00354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this work, we investigate the crystallization of droplets formed on micropatterned surfaces. By solvent exchange in a microchamber, a ternary solution consisting of a model compound β-alanine, water, and isopropanol was displaced by a flow of isopropanol. In the process, oiling-out droplets formed and crystallized. Our results showed that the shape and size of the crystals on surfaces with chemical micropatterns could be simply mediated by the flow conditions of solvent exchange. More uniform crystals formed on hydrophilic microdomains compared to hydrophobic microdomains or homogeneous surfaces. Varying flow rates or channel heights led to the formation of thin films with microholes, connected networks of crystals, or small diamond-shaped crystals. Physical microstructures (represented by microlenses) on the surface allowed the easy detachment of crystals from the surface. Beyond oiling-out crystallization, we demonstrated that the crystal formation of another solute dissolved in the droplets could be triggered by solvent exchange. The length of crystal fibers after the solvent-exchange process was shorter at a faster flow rate. This study may provide further understanding to effectively obtain the crystallization of surface droplets through the solvent-exchange approach.
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Affiliation(s)
- Howon Choi
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
| | - Zixiang Wei
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
| | - Jae Bem You
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
| | - Huaiyu Yang
- Department of Chemical Engineering, Loughborough University, Loughborough LE11 3TU, U.K
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Alberta T6G 1H9, Canada
- Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, JM Burgers Center for Fluid Dynamics, Mesa+, Department of Science and Technology, University of Twente, Enschede 7522 NB, The Netherlands
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18
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Meng J, You JB, Arends GF, Hao H, Tan X, Zhang X. Microfluidic device coupled with total internal reflection microscopy for in situ observation of precipitation. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:57. [PMID: 33877477 DOI: 10.1140/epje/s10189-021-00066-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 04/01/2021] [Indexed: 06/12/2023]
Abstract
In situ observation of precipitation or phase separation induced by solvent addition is important in studying its dynamics. Combined with optical and fluorescence microscopy, microfluidic devices have been leveraged in studying the phase separation in various materials including biominerals, nanoparticles, and inorganic crystals. However, strong scattering from the subphases in the mixture is problematic for in situ study of phase separation with high temporal and spatial resolution. In this work, we present a quasi-2D microfluidic device combined with total internal reflection microscopy as an approach for in situ observation of phase separation. The quasi-2D microfluidic device comprises of a shallow main channel and a deep side channel. Mixing between a solution in the main channel (solution A) and another solution (solution B) in the side channel is predominantly driven by diffusion due to high fluid resistance from the shallow height of the main channel, which is confirmed using fluorescence microscopy. Moreover, relying on diffusive mixing, we can control the composition of the mixture in the main channel by tuning the composition of solution B. We demonstrate the application of our method for in situ observation of asphaltene precipitation and [Formula: see text]-alanine crystallization.
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Affiliation(s)
- Jia Meng
- Department of Chemical and Materials Engineering, University of Alberta, Alberta, T6G 1H9, Canada
| | - Jae Bem You
- Department of Chemical and Materials Engineering, University of Alberta, Alberta, T6G 1H9, Canada
| | - Gilmar F Arends
- Department of Chemical and Materials Engineering, University of Alberta, Alberta, T6G 1H9, Canada
| | - Hao Hao
- Central Faculty Office (FSET), Swinburne University, Melbourne, 3122, Australia
| | - Xiaoli Tan
- Department of Chemical and Materials Engineering, University of Alberta, Alberta, T6G 1H9, Canada
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Alberta, T6G 1H9, Canada.
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19
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Kamamoto K, Kiyama A, Tagawa Y, Zhang X. Ouzo Column under Impact: Formation of Emulsion Jet and Oil-Lubricated Droplet. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:2056-2064. [PMID: 33527827 DOI: 10.1021/acs.langmuir.0c01692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We investigated the dynamics of a liquid column consisting of ouzo emulsion under the impact generated when the liquid container lands on a hard ground. At a cavitation number of 0.36, where cavitation is expected to occur, our high-speed videography captured the traveling jet and cavitation bubbles while the oil microdroplets in ouzo after different runs of impact were visualized by an optical microscope. Importantly, the impact on an ouzo column can eject a focused jet of the emulsion and deposit a small volume of emulsion on a solid substrate. As revealed by our still photography, the deposited emulsion formed an oil-lubricated drop immediately. Our findings have implications for jetting applications such as inkjet printing of emulsions or fast deposition of self-lubricating drops for assembling supraparticles. We also discuss the jet formation mechanism in terms of the existence of oil microdroplets.
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Affiliation(s)
- Kyota Kamamoto
- Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Akihito Kiyama
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Yoshiyuki Tagawa
- Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Xuehua Zhang
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
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20
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Li M, Cao R, Dyett B, Zhang X. Encapsulated Nanodroplets for Enhanced Fluorescence Detection by Nano-Extraction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2004162. [PMID: 33103337 DOI: 10.1002/smll.202004162] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/18/2020] [Indexed: 05/21/2023]
Abstract
Enhancement of the detection signal of fluorescence microscopy in highly diluted solutions is of great importance in chemical analysis, sensing, and bioassay applications. Surface nanodroplets with atto- to femto-liter volumes are promising tools for sensitive online detection by integrating their extremely efficient nano-extraction and optical advantages. In this paper, the development of novel basic units of nanodroplets-in-a-microdroplet by simple solvent exchange is reported. The encapsulated nanodroplets are applied for ultrasensitive and online detection in fluorescence imaging. The biphasic nature of the droplet composite enables simultaneous extraction and enrichment of both hydrophobic and hydrophilic compounds. Furthermore, the desirable lensing effect of the curved surface of the nanodroplets enhances the collection of light emitted from the fluorophore extracted in the droplets by ≈60-fold, allowing sensitive and quantitative analysis of the fluorophore using fluorescence microscopy. The results highlight the potential of encapsulated nanodroplets as a simple and innovative method of signal enhancement in chemical analysis. By integrating selective concentration, extraction, and sensitive detection, the encapsulated nanodroplets reported here may have broad applications in many chemical and biological matrices.
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Affiliation(s)
- Miaosi Li
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China
- Guangzhou New Chemical Material Technology Ltd., Guangzhou, 510640, China
| | - Rong Cao
- Key Laboratory of Tropical Translational Medicine of Ministry of Education and Hainan Provincial Key Laboratory of Tropical Medicine, Hainan Medical University, Haikou, 571199, China
| | - Brendan Dyett
- School of Science, RMIT University, Melbourne, Victoria, 3001, Australia
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Alberta, T6G 1H9, Canada
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21
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Dyett BP, Zhang X. Accelerated Formation of H 2 Nanobubbles from a Surface Nanodroplet Reaction. ACS NANO 2020; 14:10944-10953. [PMID: 32692921 DOI: 10.1021/acsnano.0c03059] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The compartmentalization of chemical reactions within droplets has advantages in low costs, reduced consumption of reagents, and increased throughput. Reactions in small droplets have also been shown to greatly accelerate the rate of many chemical reactions. The accelerated growth rate of nanobubbles from nanodroplet reactions is demonstrated in this work. The gaseous products from the reaction at the nanodroplet surface promoted nucleation of hydrogen nanobubbles within multiple organic liquid nanodroplets. The nanobubbles were confined within the droplets and selectively grew and collapsed at the droplet perimeter, as visualized by microscopy with high spatial and temporal resolutions. The growth rate of the bubbles was significantly accelerated within small droplets and scaled inversely with droplet radius. The acceleration was attributed to confinement from the droplet volume and effect from the surface area on the interfacial chemical reaction for gas production. The results of this study provide further understanding for applications in droplet enhanced production of nanobubbles and the on-demand liberation of hydrogen.
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Affiliation(s)
- Brendan P Dyett
- School of Science, RMIT University, Melbourne, VIC 3001, Australia
| | - Xuehua Zhang
- Department of Chemical & Materials Engineering, University of Alberta, Edmonton T6G1H9, Alberta, Canada
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22
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Wei Z, Li M, Zeng H, Zhang X. Integrated Nanoextraction and Colorimetric Reactions in Surface Nanodroplets for Combinative Analysis. Anal Chem 2020; 92:12442-12450. [DOI: 10.1021/acs.analchem.0c02239] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Zixiang Wei
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Miaosi Li
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
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23
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Zhang R, Mei RA, Botto L, Yang Z. Modified Voronoi Analysis of Spontaneous Formation of Interfacial Droplets on Immersed Oil-Solid Substrates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5400-5407. [PMID: 32337992 DOI: 10.1021/acs.langmuir.9b03806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The nucleation and growth of liquid droplets on solid substrates have received much attention because of the significant relevance of these multiphase processes to both nature and practical applications. There have been extensive studies on the condensation of water from the air phase on solid substrates. Here, we focus on water diffusion through the oil phase and subsequent settlement on solid substrates because such interfacial droplets are formed. Voronoi diagram analysis is proposed to statistically characterize the size distribution of the growing droplets. It is found that modification of the standard Voronoi diagram is required for systems of interfacial droplets which have a noncircular shape and/or whose centers change with time. The modified Voronoi analysis of the growing droplets provides an automatic quantification of the droplet distribution and reveals that (i) during the nucleation stage, the interfacial droplets do not nucleate at the same time because the nucleation of newly formed droplets competes with the growth of the existing ones; (ii) the growth of interfacial droplets comes from water diffusion from the bulk water layer, and/or from adjacent interfacial droplets, and/or from coalescence of interfacial droplets; and (iii) the sizes of interfacial droplets become more polydispersed on P-glass but more monodispersed on OTS-glass as time goes. This work opens a new perspective on the formation of interfacial droplets at the interface between oil and the solid substrate and demonstrates the capability of an automatic analysis method, which can be potentially applied to similar interfacial multiphase systems.
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Affiliation(s)
- Ran Zhang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Ran Andy Mei
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Lorenzo Botto
- Process & Energy Department, Faculty of Mechanical, Maritime and Materials Engineering, TU Delft, Delft 2628 CB, The Netherlands
| | - Zhongqiang Yang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
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24
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Zhang R, Wang Y, Yang Z. Spatially arranging interfacial droplets at the oil-solid interface. SOFT MATTER 2020; 16:107-113. [PMID: 31651918 DOI: 10.1039/c9sm01720h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The controlling and patterning of small droplets on a solid surface is of significant interest to understand interfacial phenomena and for practical applications. Among interfacial phenomena, the formation of interfacial droplets attracts scientists' attention, as the mechanism of this phenomenon where water molecules can spontaneously accumulate at the hydrophobic oil/solid interface is still not fully understood. Further investigation is needed to find out specifically where the driving force comes from and how to spatially arrange the interfacial droplets. Herein, self-assembled monolayers are formed on a gold substrate, and it turns out that the hydrophobic surface with a monolayer formed from HS(CH2)11CH3 could inhibit the formation of interfacial droplets; by contrast, the hydrophilic surfaces with monolayers formed from HS(CH2)11COOH, HS(CH2)11NH3·Cl and HS(CH2)11OH, all promote water accumulation. It suggests that the hydrogen bonding between the surface and water proves to be critical in inducing interfacial droplet formation but this has been neglected in past studies. Taking advantage of microcontact printing, the surface chemistry can be controlled at the micron scale and allows spatial arrangement of interfacial droplets at specific regions. This work moves a further step in understanding the mechanism of interfacial droplet formation, and can be potentially exploited for the collection of water and fabrication of microtemplates.
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Affiliation(s)
- Ran Zhang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China.
| | - Yao Wang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China.
| | - Zhongqiang Yang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China.
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25
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Qian J, Arends GF, Zhang X. Surface Nanodroplets: Formation, Dissolution, and Applications. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:12583-12596. [PMID: 31132276 DOI: 10.1021/acs.langmuir.9b01051] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Droplets at solid-liquid interfaces play essential roles in a broad range of fields, such as compartmentalized chemical reactions and conversions, high-throughput analysis and sensing, and super-resolution near-field imaging. Our recent work has focused on understanding and controlling the nanodroplet formation on solid surfaces in ternary liquid mixtures. These surface nanodroplets resemble tiny liquid lenses with a typical height of <1 μm and a volume of subfemtoliters. The solvent exchange is based on the process of displacing a droplet liquid solution by a poor solvent to create a transient oversaturation for droplet formation. A quantitative understanding of growth dynamics of surface nanodroplets in ternary liquid mixtures not only provides insight into the liquid-liquid phase separation induced by solvent addition in general but also has made it possible to control the droplet size well. This review article will summarize our findings in the last ∼5 years from the research with our collaborators. The first part will explain the fundamental aspects that are key to the formation and stability of surface nanodroplets. In the second part, we will highlight the applications of nanodroplets in chemical analysis and functional surface fabrication and finally point out future directions in droplet-based applications.
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Affiliation(s)
- Jiasheng Qian
- Department of Chemical and Materials Engineering , University of Alberta , Alberta T6G 1H9 , Canada
| | - Gilmar F Arends
- Department of Chemical and Materials Engineering , University of Alberta , Alberta T6G 1H9 , Canada
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering , University of Alberta , Alberta T6G 1H9 , Canada
- Physics of Fluids Group, Max-Planck-Center Twente for Complex Fluid Dynamics, Mesa+ Institute and J. M. Burgers Centre for Fluid Dynamics, Department of Science and Technology , University of Twente , P.O. Box 217, 7500 AE Enschede , The Netherlands
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26
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Xie Q, Harting J. The effect of the liquid layer thickness on the dissolution of immersed surface droplets. SOFT MATTER 2019; 15:6461-6468. [PMID: 31292583 DOI: 10.1039/c9sm01048c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Droplets on a liquid-immersed solid surface are key elements in many applications, such as high-throughput chemical analysis and droplet-templated porous materials. Such surface droplets dissolve when the surrounding liquid is undersaturated and the dissolution process is usually treated analogous to a sessile droplet evaporating in air. Typically, theoretical models predict the mass loss rate of dissolving droplets as a function of droplet geometrical factors (radius, constant angle), and droplet material properties (diffusion constant and densities), where the thickness of the surrounding liquid layer is neglected. Here, we investigate, both numerically and theoretically, the effect of the liquid layer thickness on the dissolution of surface droplets. We perform 3D lattice Boltzmann simulations and obtain the density distribution and time evolution of droplet height during dissolution. Moreover, we find that the dissolution slows down and the lifetime linearly increases with increasing the liquid layer thickness. We propose a theoretical model based on a quasistatic diffusion equation which agrees quantitatively with simulation results for thick liquid layers. Our results offer insight to the fundamental understanding of dissolving surface droplets and can provide valuable guidelines for the design of devices where the droplet lifetime is of importance.
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Affiliation(s)
- Qingguang Xie
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, The Netherlands.
| | - Jens Harting
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, The Netherlands. and Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Forschungszentrum Jülich, Fürther Str. 248, 90429 Nürnberg, Germany
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27
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Bao L, Pinchasik BE, Lei L, Xu Q, Hao H, Wang X, Zhang X. Control of Femtoliter Liquid on a Microlens: A Way to Flexible Dual-Microlens Arrays. ACS APPLIED MATERIALS & INTERFACES 2019; 11:27386-27393. [PMID: 31268287 DOI: 10.1021/acsami.9b06390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Microlens arrays are key elements for light management in optoelectronic devices. The recent advancement in the wearable intelligent electronics has driven the development of flexible microlenses. In this work, we show a controllable and scalable surface-droplet-based strategy to create unconventional flexible polymer microlens arrays. The technique is underpinned by the morphological transition of femtoliter liquid on the surface of a microlens surrounded by a planar area. We found that the droplet liquid wetted the rim of the microlens first and gradually moved upward to the microlens surface with an increase in the liquid volume. The morphology evolution of the droplet is in good agreement with the predication from our simulations based on the interfacial energy minimization under the condition of the pinned boundary. The shape of the droplet on the microlens is well controlled by the droplet volume, aspect ratio of the microlens, and the interfacial energy of the droplets on the microlens. As a result, the obtained structures of one microlens partially covered by a droplet can be produced in arrays over a large scale, serving as templates for fabricating transparent polymer double microlens arrays for improved light emission from the optoelectronic device.
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Affiliation(s)
- Lei Bao
- School of Engineering , RMIT University , Melbourne , VIC 3001 , Australia
| | - Bat-El Pinchasik
- Department of Physics at Interfaces , Max Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany
- School of Mechanical Engineering, Faculty of Engineering , Tel-Aviv University , Ramat Aviv , 69978 Tel-Aviv , Israel
| | - Lei Lei
- School of Engineering , RMIT University , Melbourne , VIC 3001 , Australia
- School of Civil Engineering , Xuzhou University of Technology , Xuzhou , Jiangsu Province 221000 , China
| | - Qiwei Xu
- Department of Electrical and Computer Engineering , University of Alberta , Edmonton , Alberta T6G 2V4 , Canada
| | - Hao Hao
- Department of Chemistry and Biotechnology, School of Science , Swinburne University of Technology , Hawthorn , VIC 3122 , Australia
| | - Xihua Wang
- Department of Electrical and Computer Engineering , University of Alberta , Edmonton , Alberta T6G 2V4 , Canada
| | - Xuehua Zhang
- Department of Chemical & Materials Engineering, Faculty of Engineering , University of Alberta , Edmonton , Alberta T6G 1H9 , Canada
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28
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Li M, Dyett B, Zhang X. Automated Femtoliter Droplet-Based Determination of Oil–Water Partition Coefficient. Anal Chem 2019; 91:10371-10375. [DOI: 10.1021/acs.analchem.9b02586] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Miaosi Li
- School of Engineering, RMIT University, Melbourne, Victoria 3000, Australia
| | - Brendan Dyett
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
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29
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Lyu T, Wu S, Mortimer RJG, Pan G. Nanobubble Technology in Environmental Engineering: Revolutionization Potential and Challenges. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:7175-7176. [PMID: 31180652 DOI: 10.1021/acs.est.9b02821] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- Tao Lyu
- School of Animal, Rural and Environmental Sciences , Nottingham Trent University, Brackenhurst Campus , Nottinghamshire NG25 0QF , United Kingdom
- Centre of Integrated Water-Energy-Food studies (iWEF) , Nottingham Trent University , Nottinghamshire NG25 0QF , United Kingdom
| | - Shubiao Wu
- Aarhus Institute of Advanced Studies , Aarhus University , Høegh-Guldbergs Gade 6B , DK-8000 Aarhus C , Denmark
| | - Robert J G Mortimer
- School of Animal, Rural and Environmental Sciences , Nottingham Trent University, Brackenhurst Campus , Nottinghamshire NG25 0QF , United Kingdom
- Centre of Integrated Water-Energy-Food studies (iWEF) , Nottingham Trent University , Nottinghamshire NG25 0QF , United Kingdom
| | - Gang Pan
- School of Animal, Rural and Environmental Sciences , Nottingham Trent University, Brackenhurst Campus , Nottinghamshire NG25 0QF , United Kingdom
- Centre of Integrated Water-Energy-Food studies (iWEF) , Nottingham Trent University , Nottinghamshire NG25 0QF , United Kingdom
- Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , 18 Shuangqing Road , Beijing 100085 , China
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30
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Controlled addition of new liquid component into surface droplet arrays by solvent exchange. J Colloid Interface Sci 2019; 543:164-173. [DOI: 10.1016/j.jcis.2019.02.046] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 02/14/2019] [Accepted: 02/15/2019] [Indexed: 11/20/2022]
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31
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Ke S, Xiao W, Quan N, Dong Y, Zhang L, Hu J. Formation and Stability of Bulk Nanobubbles in Different Solutions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5250-5256. [PMID: 30909695 DOI: 10.1021/acs.langmuir.9b00144] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The existence of bulk nanobubbles is still controversial in spite of their significance in a large range of applications. Here, we developed a new method of compression-decompression to produce controllably bulk nanobubbles. Then, we further investigated the generation of bulk nanobubbles in pure water, acid, alkaline, and salt solutions using nanoparticle tracking analysis. The results indicated that the concentration of bulk nanobubbles depends on the decompression time and would reach a maximum value when the decompression time is about 30 min for the pure water system. More importantly, we gave a relatively direct evidence of the existence of bulk nanobubbles by measuring the X-ray fluorescence intensity of Kr in acid, alkaline, and salt solutions. It is shown that the decrease tendency in intensity of Kr in alkaline solution is similar to that in the concentration of bulk nanobubbles with the deposited time, indicating that the bulk nanobubbles produced indeed have gas inside. Furthermore, the concentration and stability of bulk nanobubbles in an alkaline solution are greatest compared with other two solutions regardless of gas types. The concentration of bulk nanobubbles will decrease in the order alkaline > acid/pure water > salt solutions. We believe that our results should be very helpful in understanding the formation and stability of bulk nanobubbles in different solutions.
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Affiliation(s)
- Shuo Ke
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- Life and Environment Science College , Shanghai Normal University , Shanghai 200234 , China
| | - Wei Xiao
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- School of Resources Engineering , Xi'an University of Architecture and Technology , Xi'an 710055 , China
| | - Nannan Quan
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- Life and Environment Science College , Shanghai Normal University , Shanghai 200234 , China
| | - Yaming Dong
- Life and Environment Science College , Shanghai Normal University , Shanghai 200234 , China
| | - Lijuan Zhang
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800 , China
| | - Jun Hu
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800 , China
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32
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Abstract
Currently, nanotechnology-based products are gaining tremendous interest in the development of nanocarriers for drug delivery and nano-diagnostic devices. Nanodroplets (NDs) emerge as novel carriers for delivery of gases and actives with a wide range of applications in fields of theranostics, drug delivery and diagnostic devices. NDs are multifunctional carriers composed of an outer shell of drug and polymer that encapsulates the inner core of gases and liquid molecules. This review focuses on properties of NDs, mathematical theories, different polymers used in the preparation of NDs, characterisation, animal models, toxicity and applications of NDs. These nanocarriers are advantageous due to their cost-effectiveness and compatibility with both gaseous and liquid core molecules. NDs are increasingly utilised in the field of healthcare due to their properties like large effective surface area for drug loading and target specificity. These nanocarriers are also employed in the treatment of hypoxia, multiple sclerosis and cancer. In the near future, NDs will advance in fields of personalised medicine and precise theranostics.
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Affiliation(s)
- Pravin Shende
- Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM'S NMIMS , Mumbai , India
| | - Sajal Jain
- Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM'S NMIMS , Mumbai , India
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33
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Li M, Dyett B, Yu H, Bansal V, Zhang X. Functional Femtoliter Droplets for Ultrafast Nanoextraction and Supersensitive Online Microanalysis. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1804683. [PMID: 30488558 DOI: 10.1002/smll.201804683] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 11/14/2018] [Indexed: 05/21/2023]
Abstract
A universal femtoliter surface droplet-based platform for direct quantification of trace of hydrophobic compounds in aqueous solutions is presented. Formation and functionalization of femtoliter droplets, concentrating the analyte in the solution, are integrated into a simple fluidic chamber, taking advantage of the long-term stability, large surface-to-volume ratio, and tunable chemical composition of these droplets. In situ quantification of the extracted analytes is achieved by surface-enhanced Raman scattering (SERS) spectroscopy by nanoparticles on the functionalized droplets. Optimized extraction efficiency and SERS enhancement by tuning droplet composition enable quantitative determination of hydrophobic model compounds of rhodamine 6G, methylene blue, and malachite green with the detection limit of 10-9 to 10-11 m and a large linear range of SERS signal from 10-9 to 10-6 m of the analytes. The approach addresses the current challenges of reproducibility and the lifetime of the substrate in SERS measurements. This novel surface droplet platform combines liquid-liquid extraction and highly sensitive and reproducible SERS detection, providing a promising technique in current chemical analysis related to environment monitoring, biomedical diagnosis, and national security monitoring.
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Affiliation(s)
- Miaosi Li
- School of Engineering, RMIT University, Melbourne, VIC, 3000, Australia
| | - Brendan Dyett
- School of Engineering, RMIT University, Melbourne, VIC, 3000, Australia
| | - Haitao Yu
- School of Engineering, RMIT University, Melbourne, VIC, 3000, Australia
| | - Vipul Bansal
- School of Science, RMIT University, Melbourne, VIC, 3000, Australia
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
- Physics of Fluids Group, Max-Planck-Center Twente for Complex Fluid Dynamics, Department of Science and Technology, University of Twente, P.O. Box 217, 7500, AE, Enschede, The Netherlands
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34
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Peng S, Spandan V, Verzicco R, Lohse D, Zhang X. Growth dynamics of microbubbles on microcavity arrays by solvent exchange: Experiments and numerical simulations. J Colloid Interface Sci 2018; 532:103-111. [DOI: 10.1016/j.jcis.2018.07.111] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/24/2018] [Accepted: 07/25/2018] [Indexed: 11/30/2022]
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35
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Dyett B, Zhang Q, Xu Q, Wang X, Zhang X. Extraordinary Focusing Effect of Surface Nanolenses in Total Internal Reflection Mode. ACS CENTRAL SCIENCE 2018; 4:1511-1519. [PMID: 30555903 PMCID: PMC6276033 DOI: 10.1021/acscentsci.8b00501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Indexed: 05/30/2023]
Abstract
Microscopic lenses are paramount in solar energy harvesting, optical devices, and imaging technologies. This work reports an extraordinary focusing effect exhibited by a surface nanolens (i.e., with at least one dimension of subwavelength) that is situated in an evanescent field from the total internal reflection (TIR) of light illuminated to the supporting substrate above the critical angle. Our measurements show that the position, shape, and size of the surface area with enhanced light intensity are determined by the geometry of the nanolens and the incident angle, in good agreement with simulation results. This strong focusing effect of the surface nanolens is shown to significantly promote the plasmonic effect of deposited gold nanoparticles on the lens surface inlight conversion and to vaporize surrounding water to microbubbles by using low laser power. This work further demonstrates that the light redistribution by the surface nanolens in TIR enables a range of novel applications in selectively local visualization of specimens in fluorescence imaging, optical trapping of colloids from an external flow, and selective materials deposition from photoreactions.
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Affiliation(s)
- Brendan Dyett
- Soft Matter & Interfaces Group, School of Engineering and Laboratory of Artificial
Intelligence Nanophotonics, School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Qiming Zhang
- Soft Matter & Interfaces Group, School of Engineering and Laboratory of Artificial
Intelligence Nanophotonics, School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Qiwei Xu
- Department of Electrical
& Computer Engineering and Department of Chemical & Materials
Engineering, University of Alberta, Edmonton T6G1H9, Alberta, Canada
| | - Xihua Wang
- Department of Electrical
& Computer Engineering and Department of Chemical & Materials
Engineering, University of Alberta, Edmonton T6G1H9, Alberta, Canada
| | - Xuehua Zhang
- Soft Matter & Interfaces Group, School of Engineering and Laboratory of Artificial
Intelligence Nanophotonics, School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
- Department of Electrical
& Computer Engineering and Department of Chemical & Materials
Engineering, University of Alberta, Edmonton T6G1H9, Alberta, Canada
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36
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Dyett B, Zychowski L, Bao L, Meikle TG, Peng S, Yu H, Li M, Strachan J, Kirby N, Logan A, Conn CE, Zhang X. Crystallization of Femtoliter Surface Droplet Arrays Revealed by Synchrotron Small-Angle X-ray Scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:9470-9476. [PMID: 30021434 DOI: 10.1021/acs.langmuir.8b01252] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The crystallization of oil droplets is critical in the processing and storage of lipid-based food and pharmaceutical products. Arrays of femtoliter droplets on a surface offer a unique opportunity to study surfactant-free colloidlike systems. In this work, the crystal growth process in these confined droplets was followed by cooling a model lipid (trimyristin) from a liquid state utilizing synchrotron small-angle X-ray scattering (SAXS). The measurements by SAXS demonstrated a reduced crystallization rate and a greater degree of supercooling required to trigger lipid crystallization in droplets compared to those of bulk lipids. These results suggest that surface droplets crystallize in a stochastic manner. Interestingly, the crystallization rate is slower for larger femtoliter droplets, which may be explained by the onset of crystallization from the three-phase contact line. The larger surface nanodroplets exhibit a smaller ratio of droplet volume to the length of three-phase contact line and hence a slower crystallization rate.
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Affiliation(s)
| | - Lisa Zychowski
- CSIRO Agriculture and Food , Werribee , Victoria 3030 , Australia
| | | | | | | | | | | | | | - Nigel Kirby
- Australian Synchrotron , 800 Blackburn Road , Clayton , Victoria 3169 , Australia
| | - Amy Logan
- CSIRO Agriculture and Food , Werribee , Victoria 3030 , Australia
| | | | - Xuehua Zhang
- Department of Chemical and Materials Engineering , University of Alberta , Edmonton , T6G1H9 Alberta , Canada
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37
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Huang Z, Yang Q, Su M, Li Z, Hu X, Li Y, Pan Q, Ren W, Li F, Song Y. A General Approach for Fluid Patterning and Application in Fabricating Microdevices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802172. [PMID: 29920800 DOI: 10.1002/adma.201802172] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/14/2018] [Indexed: 06/08/2023]
Abstract
Engineering the fluid interface such as the gas-liquid interface is of great significance for solvent processing applications including functional material assembly, inkjet printing, and high-performance device fabrication. However, precisely controlling the fluid interface remains a great challenge owing to its flexibility and fluidity. Here, a general method to manipulate the fluid interface for fluid patterning using micropillars in the microchannel is reported. The principle of fluid patterning for immiscible fluid pairs including air, water, and oils is proposed. This understanding enables the preparation of programmable multiphase fluid patterns and assembly of multilayer functional materials to fabricate micro-optoelectronic devices. This general strategy of fluid patterning provides a promising platform to study the fundamental processes occurring on the fluid interface, and benefits applications in many subjects, such as microfluidics, microbiology, chemical analysis and detection, material synthesis and assembly, device fabrication, etc.
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Affiliation(s)
- Zhandong Huang
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, Beijing National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Qiang Yang
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Meng Su
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, Beijing National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
| | - Zheng Li
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, Beijing National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Xiaotian Hu
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, Beijing National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Yifan Li
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, Beijing National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Qi Pan
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, Beijing National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Wanjie Ren
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, Beijing National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Fengyu Li
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, Beijing National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
| | - Yanlin Song
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, Beijing National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190, P. R. China
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38
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Yatsyshin P, Durán-Olivencia MA, Kalliadasis S. Microscopic aspects of wetting using classical density functional theory. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:274003. [PMID: 29786608 DOI: 10.1088/1361-648x/aac6fa] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Wetting is a rather efficient mechanism for nucleation of a phase (typically liquid) on the interface between two other phases (typically solid and gas). In many experimentally accessible cases of wetting, the interplay between the substrate structure, and the fluid-fluid and fluid-substrate intermolecular interactions brings about an entire 'zoo' of possible fluid configurations, such as liquid films with a thickness of a few nanometers, liquid nanodrops and liquid bridges. These fluid configurations are often associated with phase transitions occurring at the solid-gas interface and at lengths of just several molecular diameters away from the substrate. In this special issue article, we demonstrate how a fully microscopic classical density-functional framework can be applied to the efficient, rational and systematic exploration of the rich phase space of wetting phenomena. We consider a number of model prototype systems such as wetting on a planar wall, a chemically patterned wall and a wedge. Through density-functional computations we demonstrate that for these simply structured substrates the behaviour of the solid-gas interface is already highly complex and non-trivial.
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Affiliation(s)
- P Yatsyshin
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, United Kingdom
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39
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Tung HY, Guan ZY, Liu TY, Chen HY. Vapor sublimation and deposition to build porous particles and composites. Nat Commun 2018; 9:2564. [PMID: 29967443 PMCID: PMC6028631 DOI: 10.1038/s41467-018-04975-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 04/30/2018] [Indexed: 11/09/2022] Open
Abstract
The vapor deposition of polymers on regular stationary substrates is widely known to form uniform thin films. Here we report porous polymer particles with sizes controllable down to the nanometer scale can be produced using a fabrication process based on chemical vapor deposition (CVD) on a dynamic substrate, i.e., sublimating ice particles. The results indicate that the vapor deposition of a polymer is directed by the sublimation process; instead of forming a thin film polymer, the deposited polymers replicated the size and shape of the ice particle. Defined size and porosity of the polymer particles are controllable with respect to varying the processing time. Extendable applications are shown to install multiple functional sites on the particles in one step and to localize metals/oxides forming composite particles. In addition, one fabrication cycle requires approximately 60 min to complete, and potential scaling up the production of the porous particles is manageable.
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Affiliation(s)
- Hsing-Ying Tung
- Department of Chemical Engineering, National Taiwan University, Taipei, 10617, Taiwan
| | - Zhen-Yu Guan
- Department of Chemical Engineering, National Taiwan University, Taipei, 10617, Taiwan
| | - Ting-Yu Liu
- Department of Materials Engineering, Ming Chi University of Technology, New Taipei City, 24301, Taiwan
| | - Hsien-Yeh Chen
- Department of Chemical Engineering, National Taiwan University, Taipei, 10617, Taiwan.
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40
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Dyett B, Kiyama A, Rump M, Tagawa Y, Lohse D, Zhang X. Growth dynamics of surface nanodroplets during solvent exchange at varying flow rates. SOFT MATTER 2018; 14:5197-5204. [PMID: 29780988 DOI: 10.1039/c8sm00705e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Solvent exchange is a simple solution-based process to produce surface nanodroplets over a large area. The final size of the droplets is determined by both the flow and solution conditions for a given substrate. In this work, we investigate the growth dynamics of surface nanodroplets during solvent exchange by using total internal reflection fluorescence microscopy (TIRF). The results show that during the solvent exchange, the formation of surface nanodroplets advanced on the surface in the direction of the flow. The time for the number density and surface coverage of the droplets to reach their respective plateau values is determined by the flow rate. From the observed evolution of the droplet volume and of the size of individual growing droplets, we are able to determine that the growth time of the droplets scales with the Peclet number Pe with a power law ∝Pe-1/2. This is consistent with Taylor-Aris dispersion, shedding light on the diffusive growth dynamics during the solvent exchange. Further, the spatial rearrangement of the droplets during coalescence demonstrates a preference in position shift based on size inequality, namely, the coalesced droplet resides closer to the larger of the two parent droplets. These findings provide a valuable insight toward controlling droplet size and spatial distribution.
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Affiliation(s)
- Brendan Dyett
- Soft Matter & Interfaces Group, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia.
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41
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Otero J, Meeker S, Clegg PS. Compositional ripening of particle-stabilized drops in a three-liquid system. SOFT MATTER 2018; 14:3783-3790. [PMID: 29714797 DOI: 10.1039/c7sm02502e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We present experimental studies of two aqueous drops, stabilized by colloidal silica, which are placed close to each other in a bath of toluene, ethanol and surplus colloidal silica. If one of the drops is enriched in ethanol while the other is pure water then we observe the spontaneous formation of small droplets at the surface of the water drop closest to its neighbour. These droplets are then observed to form all along the path to the ethanol enriched drop until they make a complete bridge. We relate this behaviour to the diffusion pathways on the underlying three-fluid phase diagram. We argue that the phenomena is a version of compositional ripening where the transfer of the dispersed phase leads to the spontaneous formation of droplets in the continuous phase. We show that, while the large drops are particle-stabilized, the spontaneously formed droplets are not. Instead the presence of surplus particles leads to the droplets gelling as an elastic bridge. The phenomenology at long times and at low particle concentrations becomes increasingly surprising.
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Affiliation(s)
- Javier Otero
- School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK.
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42
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Feng W, Ueda E, Levkin PA. Droplet Microarrays: From Surface Patterning to High-Throughput Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1706111. [PMID: 29572971 DOI: 10.1002/adma.201706111] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 11/29/2017] [Indexed: 05/09/2023]
Abstract
High-throughput screening of live cells and chemical reactions in isolated droplets is an important and growing method in areas ranging from studies of gene functions and the search for new drug candidates, to performing combinatorial chemical reactions. Compared with microfluidics and well plates, the facile fabrication, high density, and open structure endow droplet microarrays on planar surfaces with great potential in the development of next-generation miniaturized platforms for high-throughput applications. Surfaces with special wettability have served as substrates to generate and/or address droplets microarrays. Here, the formation of droplet microarrays with designed geometry on chemically prepatterned surfaces is briefly described and some of the newer and emerging applications of these microarrays that are currently being explored are highlighted. Next, some of the available technologies used to add (bio-)chemical libraries to each droplet in parallel are introduced. Current challenges and future prospects that would benefit from using such droplet microarrays are also discussed.
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Affiliation(s)
- Wenqian Feng
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Erica Ueda
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Pavel A Levkin
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Institute of Organic Chemistry, Karlsruhe Institute of Technology, 76131, Karlsruhe, Germany
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43
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Yukisada R, Kiyama A, Zhang X, Tagawa Y. Enhancement of Focused Liquid Jets by Surface Bubbles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:4234-4240. [PMID: 29551073 DOI: 10.1021/acs.langmuir.8b00246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We investigate the enhancement of the velocity of focused liquid jets by surface bubbles preformed on the inner surface of the container. The focused jets are created from the impact on a liquid-filled cylindrical tube at cavitation numbers of 0.37 (strong impact where cavitation is likely to occur on unprocessed surfaces) and 2.1 (weak impact where cavitation does not occur from the impact). The bubbles with a base diameter up to hundreds of micrometers were formed via the process of solvent exchange using air-equilibrated ethanol and water. Our measurements by high-speed imaging show that at both cavitation numbers, the jet velocities with preformed bubbles are significantly higher than those without preformed bubbles. Furthermore, our results show that after the process of solvent exchange, a large number of expanding bubbles are observed at cavitation number of 0.37, indicating that possibly both sub-millimeter and sub-micrometer bubbles on the surface contribute to the jet velocity enhancement. At the cavitation number of 2.1, the surface bubbles are observed to oscillate immediately after the impact. The measurements of the liquid pressure after the impact reveal that at both cavitation numbers, the negative pressure is damped by the preformed surface bubbles, contributing to the increase of the jet velocity. This work sheds light on the crucial role of surface bubbles on the impulsive motion of liquids. Our findings have significant implications for the focusing jet technology, opening the opportunities for jetting fragile samples such as biological samples.
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Affiliation(s)
- Ryosuke Yukisada
- Department of Mechanical Systems Engineering , Tokyo University of Agriculture and Technology , Nakacho 2-24-16 , Koganei , Tokyo 184-8588 , Japan
| | - Akihito Kiyama
- Department of Mechanical Systems Engineering , Tokyo University of Agriculture and Technology , Nakacho 2-24-16 , Koganei , Tokyo 184-8588 , Japan
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, Faculty of Engineering , University of Alberta , Edmonton , Alberta T6G1H9 , Canada
- Soft Matter & Interfaces Group, School of Engineering , RMIT University , Melbourne , Victoria 3001 , Australia
- Institute of Global Innovation Research , Tokyo University of Agriculture and Technology , Harumicho 3-8-1 , Fuchu , Tokyo 183-8538 , Japan
| | - Yoshiyuki Tagawa
- Department of Mechanical Systems Engineering , Tokyo University of Agriculture and Technology , Nakacho 2-24-16 , Koganei , Tokyo 184-8588 , Japan
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Dyett B, Hao H, Lohse D, Zhang X. Coalescence driven self-organization of growing nanodroplets around a microcap. SOFT MATTER 2018; 14:2628-2637. [PMID: 29546893 DOI: 10.1039/c7sm02490h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The coalescence between growing droplets is important for the surface coverage and spatial arrangements of droplets on surfaces. In this work, total internal reflection fluorescence (TIRF) microscopy is utilized to in situ investigate the formation of nanodroplets around the rim of a polymer microcap, with sub-micron spatial and millisecond temporal resolution. We observe that the coalescence among droplets occurs frequently during their growth by solvent exchange. Our experimental results show that the position of the droplet from two merged droplets is related to the size of the parent droplets. The position of the coalesced droplet and the ratio of parent droplet sizes obey a scaling law, reflecting a coalescence preference based on the size inequality. As a result of droplet coalescence, the angles between the centroids of two neighbouring droplets increase with time, obeying a nearly symmetrical arrangement of droplets at various time intervals. The evolution of the position and number from coalescence of growing droplets is modelled. The mechanism for coalescence driven self-organization of growing droplets is general, applicable to microcaps of different sizes and droplets of different liquids. The understanding from this work may be valuable for positioning nanodroplets by nucleation and growth without using templates.
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Affiliation(s)
- Brendan Dyett
- Soft Matter & Interfaces Group, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia
| | - Hao Hao
- Electrical and Biomedical Engineering, RMIT University, Melbourne, VIC 3001, Australia
| | - Detlef Lohse
- Physics of Fluids Group, Department of Science and Engineering, Mesa+ Institute, J. M. Burgers Centre for Fluid Dynamics and the Max Planck Center Twente for Complex Fluid Dynamics, University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands
| | - Xuehua Zhang
- Department of Chemical & Materials Engineering, Faculty of Engineering, University of Alberta, Edmonton, Alberta T6G1H9, Canada. and Soft Matter & Interfaces Group, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia and Physics of Fluids Group, Department of Science and Engineering, Mesa+ Institute, J. M. Burgers Centre for Fluid Dynamics and the Max Planck Center Twente for Complex Fluid Dynamics, University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands
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45
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Bao L, Spandan V, Yang Y, Dyett B, Verzicco R, Lohse D, Zhang X. Flow-induced dissolution of femtoliter surface droplet arrays. LAB ON A CHIP 2018; 18:1066-1074. [PMID: 29487930 DOI: 10.1039/c7lc01321c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The dissolution of liquid nanodroplets is a crucial step in many applied processes, such as separation and dispersion in the food industry, crystal formation of pharmaceutical products, concentrating and analysis in medical diagnosis, and drug delivery in aerosols. In this work, using both experiments and numerical simulations, we quantitatively study the dissolution dynamics of femtoliter surface droplets in a highly ordered array under a uniform flow. Our results show that the dissolution of femtoliter droplets strongly depends on their spatial positions relative to the flow direction, drop-to-drop spacing in the array, and the imposed flow rate. In some particular cases, the droplet at the edge of the array can dissolve about 30% faster than the ones located near the centre. The dissolution rate of the droplet increases by 60% as the inter-droplet spacing is increased from 2.5 μm to 20 μm. Moreover, the droplets close to the front of the flow commence to shrink earlier than those droplets in the center of the array. The average dissolution rate is faster for the faster flow. As a result, the dissolution time (Ti) decreases with the Reynolds number (Re) of the flow as Ti ∝ Re-3/4. The experimental results are in good agreement with the numerical simulations where the advection-diffusion equation for the concentration field is solved and the concentration gradient on the surface of the drop is computed. The findings suggest potential approaches to manipulate nanodroplet sizes in droplet arrays simply by dissolution controlled by an external flow. The obtained droplets with varying curvatures may serve as templates for generating multifocal microlenses in one array.
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Affiliation(s)
- Lei Bao
- Soft Matter & Interfaces Group, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia
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46
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Zhu X, Verzicco R, Zhang X, Lohse D. Diffusive interaction of multiple surface nanobubbles: shrinkage, growth, and coarsening. SOFT MATTER 2018; 14:2006-2014. [PMID: 29457812 DOI: 10.1039/c7sm02523h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Surface nanobubbles are nanoscopic spherical-cap shaped gaseous domains on immersed substrates which are stable, even for days. After the stability of a single surface nanobubble has been theoretically explained, i.e. contact line pinning and gas oversaturation are required to stabilize it against diffusive dissolution [Lohse and Zhang, Phys. Rev. E, 2015, 91, 031003(R)], here we focus on the collective diffusive interaction of multiple nanobubbles. For that purpose we develop a finite difference scheme for the diffusion equation with the appropriate boundary conditions and with the immersed boundary method used to represent the growing or shrinking bubbles. After validation of the scheme against the exact results of Epstein and Plesset for a bulk bubble [J. Chem. Phys., 1950, 18, 1505] and of Lohse and Zhang for a surface bubble, the framework of these simulations is used to describe the coarsening process of competitively growing nanobubbles. The coarsening process for such diffusively interacting nanobubbles slows down with advancing time and increasing bubble distance. The present results for surface nanobubbles are also applicable for immersed surface nanodroplets, for which better controlled experimental results of the coarsening process exist.
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Affiliation(s)
- Xiaojue Zhu
- Physics of Fluids Group and Max Planck Center Twente for Complex Fluid Dynamics, MESA+ Institute and J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands.
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47
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Lei L, Li J, Yu H, Bao L, Peng S, Zhang X. Formation, growth and applications of femtoliter droplets on a microlens. Phys Chem Chem Phys 2018; 20:4226-4237. [PMID: 29364296 DOI: 10.1039/c7cp06861a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Formation and growth of femtoliter droplets on surface microstructures are important in many fundamental and practical interfacial processes, such as water collection, vapour condensation in cooling devices, drop self-removal on anti-icing surfaces and fabrication of droplet-templated functional microstructures. In this work, we experimentally and theoretically investigate the growth of femtoliter oil-like liquid on the microlens surrounded by a hydrophilic planar area. The droplets were produced by solvent exchange, a process where the droplets nucleate and grow from an oversaturation created by displacing a good solvent by a poor solvent of the droplet liquid. Our results showed that the droplet fully coats the lens surface and the contact angle of the droplet relative to the flat surface is finely tuned over a large range by the droplet volume. The growth of the droplet on a microlens is largely described by the constant contact radius model. To demonstrate the new opportunities provided by the controlled formation of the droplet situated on a microlens, we will show a simple and effective approach for production of arrays of composite microlenses consisting of two types of polymers with different refractive indices. A high curvature of the composite microlens results in desirable diffraction patterns with potential application for enhanced light harvesting. Moreover, we demonstrate that extraction of traces of a hydrophobic solute from the flow is much faster as the droplet is lifted up from the channel wall by the microlens, promising a time effective in situ detection process in narrow channels.
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Affiliation(s)
- Lei Lei
- School of Electrical and Power Engineering, China University of Mining and Technology, Xuzhou, Jiangsu Province 221000, China
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48
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Yu H, Rump M, Maheshwari S, Bao L, Zhang X. Growth of nanodroplets on a still microfiber under flow conditions. Phys Chem Chem Phys 2018; 20:18252-18261. [DOI: 10.1039/c8cp02353k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Coupled effects from droplet formation and the local flow dramatically enhanced the droplet growth on a microfiber in flow.
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Affiliation(s)
- Haitao Yu
- Soft Matter & Interfaces Group
- School of Engineering
- RMIT University
- Melbourne
- Australia
| | - Maaike Rump
- Physics of Fluids group
- Department of Applied Physics
- Mesa + Institute
- J. M. Burgers Centre for Fluid Dynamics & Max Planck Center Twente for Complex Fluid Dynamics
- University of Twente
| | - Shantanu Maheshwari
- Physics of Fluids group
- Department of Applied Physics
- Mesa + Institute
- J. M. Burgers Centre for Fluid Dynamics & Max Planck Center Twente for Complex Fluid Dynamics
- University of Twente
| | - Lei Bao
- Soft Matter & Interfaces Group
- School of Engineering
- RMIT University
- Melbourne
- Australia
| | - Xuehua Zhang
- Soft Matter & Interfaces Group
- School of Engineering
- RMIT University
- Melbourne
- Australia
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49
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Petsev ND, Leal LG, Shell MS. Coupling discrete and continuum concentration particle models for multiscale and hybrid molecular-continuum simulations. J Chem Phys 2017; 147:234112. [DOI: 10.1063/1.5001703] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Nikolai D. Petsev
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - L. Gary Leal
- Department of Chemical Engineering, University of California at Santa Barbara, Santa Barbara, California 93106-5080, USA
| | - M. Scott Shell
- Department of Chemical Engineering, University of California at Santa Barbara, Santa Barbara, California 93106-5080, USA
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50
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Wang Y, Lu T, Li X, Ren S, Bi S. Robust nanobubble and nanodroplet segmentation in atomic force microscope images using the spherical Hough transform. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:2572-2582. [PMID: 29259872 PMCID: PMC5727802 DOI: 10.3762/bjnano.8.257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 11/16/2017] [Indexed: 05/25/2023]
Abstract
Interfacial nanobubbles (NBs) and nanodroplets (NDs) have been attracting increasing attention due to their potential for numerous applications. As a result, the automated segmentation and morphological characterization of NBs and NDs in atomic force microscope (AFM) images is highly awaited. The current segmentation methods suffer from the uneven background in AFM images due to thermal drift and hysteresis of AFM scanners. In this study, a two-step approach was proposed to segment NBs and NDs in AFM images in an automated manner. The spherical Hough transform (SHT) and a boundary optimization operation were combined to achieve robust segmentation. The SHT was first used to preliminarily detect NBs and NDs. After that, the so-called contour expansion operation was applied to achieve optimized boundaries. The principle and the detailed procedure of the proposed method were presented, followed by the demonstration of the automated segmentation and morphological characterization. The result shows that the proposed method gives an improved segmentation result compared with the thresholding and circle Hough transform method. Moreover, the proposed method shows strong robustness of segmentation in AFM images with an uneven background.
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Affiliation(s)
- Yuliang Wang
- School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, P. R. China
| | - Tongda Lu
- School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, P. R. China
| | - Xiaolai Li
- School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, P. R. China
| | - Shuai Ren
- School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, P. R. China
| | - Shusheng Bi
- School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, P. R. China
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