Micro/Nanofluidics and Structures Based Sensing, Material Processing and Energy Conversion

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30 October 2024

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30 December 2024

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Topic Information

Dear Colleagues,

Micro/nanofluidics platform technology and templates with micro/nanostructures have attracted significant interest among the scientific community due to their novelty and have been applied in a wide range of areas, such as chemical/biological detection and analysis, drug screening, point-of-care testing, food safety inspection, environmental monitoring, synthesis of micro/nanoparticles, energy conversion, self-cleaning, etc. Thanks to its characteristic length in the micro/nano-scale, unique phenomena steer researchers to tackle issues at different angles with different strategies. Hence, micro-/nanofluidics-based resolutions/alternatives to conventional approaches have been constantly proposed and demonstrated, and the templates with micro/nanostructures having unique functions have been fabricated, even though it has been almost 40 years since their emergence. In this Theme Topic, the focus will be on sensing, material processing, and energy conversion via micro-/nanofluidics platform technology and/or utilization of templates with micro/nanostructures. For sensing, research topics related to various sensing techniques, such as fluorescence detection, surface plasmon resonance, Raman spectroscopy, electrochemical detection, etc., which are applied to detect chemical compounds, biological species or biomolecules such as DNA, proteins, cells, pathogens, glucose, and so on are welcome. Pressure sensing, temperature sensing, gas/liquid concentration sensing, etc. via using templates with micro/nanostructures are included in this subject as well. Since microfluidics provides chemical or biochemical microenvironments with controlled processing conditions, it allows producing materials with homogeneity at a shorter reaction time. Material processing covers the approaches to fabricate micro-/nanoparticles, crystals, fibers, chemical compounds, polymers, bio-inspired materials, etc. As for energy conversion, it includes subjects around fuel cell, blue energy, energy storage, energy absorption/actuation/harvesting, etc., and the fundamental studies. It is our pleasure to invite you to submit a manuscript to this Theme Topic, including full papers, reviews, and short communications.

Prof. Dr. Yi-Je Juang
Dr. Yan-Cheng Lin
Prof. Dr. Li-Hsien Yeh
Prof. Dr. Yen-Wen Lu
Topic Editors

Keywords

Participating Journals

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Micromachines micromachines	3.4	4.7	2010	16.1 Days	CHF 2600	Submit
Nanomanufacturing nanomanufacturing	-	-	2021	23 Days	CHF 1000	Submit
Nanomaterials nanomaterials	5.3	7.4	2010	13.6 Days	CHF 2900	Submit
Polymers polymers	5.0	6.6	2009	13.7 Days	CHF 2700	Submit
Sensors sensors	3.9	6.8	2001	17 Days	CHF 2600	Submit

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Published Papers (9 papers)

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All Micromachines Nanomanufacturing Nanomaterials Polymers Sensors

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13 pages, 3984 KiB  

Open AccessArticle

A Microfluidic Chip for Single-Cell Capture Based on Stagnation Point Flow and Boundary Effects

by Long Cheng, Xiao Lv, Wenchao Zhou, Huan Li, Qiushuang Yang, Xing Chen and Yihui Wu

Micromachines 2024, 15(4), 456; https://doi.org/10.3390/mi15040456 - 28 Mar 2024

Viewed by 533

Abstract

The capture of individual cells using microfluidic chips represents a widely adopted and efficient approach for investigating the biochemical microenvironment of singular cells. While conventional methods reliant on boundary effects pose challenges in precisely manipulating individual cells, single-cell capture grounded in the principle [...] Read more.

The capture of individual cells using microfluidic chips represents a widely adopted and efficient approach for investigating the biochemical microenvironment of singular cells. While conventional methods reliant on boundary effects pose challenges in precisely manipulating individual cells, single-cell capture grounded in the principle of stagnation point flow offers a solution to this limitation. Nevertheless, such capture mechanisms encounter inconsistency due to the instability of the flow field and stagnation point. In this study, a microfluidic device for the stable capture of single cells was designed, integrating the principle of fluid mechanics by amalgamating stagnation point flow and boundary effects. This innovative microfluidic chip transcended the limitations associated with single methodologies, leveraging the strengths of both stagnation point flow and boundary effects to achieve reliable single-cell capture. Notably, the incorporation of capture ports at the stagnation point not only harnessed boundary effects but also enhanced capture efficiency significantly, elevating it from 31.9% to 83.3%, thereby augmenting capture stability. Furthermore, computational simulations demonstrated the efficacy of the capture ports in entrapping particles of varying diameters, including 9 μm, 14 μm, and 18 μm. Experiment validation underscored the capability of this microfluidic system to capture single cells within the chip, maintaining stability even under flow rate perturbations spanning from 60 μL/min to 120 μL/min. Consequently, cells with dimensions between 8 μm and 12 μm can be reliably captured. The designed microfluidic system not only furnishes a straightforward and efficient experimental platform but also holds promise for facilitating deeper investigations into the intricate interplay between individual cells and their surrounding microenvironment. Full article

(This article belongs to the Topic Micro/Nanofluidics and Structures Based Sensing, Material Processing and Energy Conversion)

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16 pages, 4332 KiB  

Open AccessArticle

Design and Fabrication of Polymer Triboelectric Nanogenerators for Self-Powered Insole Applications

by You-Jun Huang and Chen-Kuei Chung

Polymers 2023, 15(20), 4035; https://doi.org/10.3390/polym15204035 - 10 Oct 2023

Viewed by 994

Abstract

Triboelectric nanogenerators (TENGs) are a kind of mechanical energy harvester with a larger force sensing range and good energy conversion, which is often applied to human kinetic energy collection and motion sensing devices. Polymer materials are the most commonly used materials in TENGs’ [...] Read more.

Triboelectric nanogenerators (TENGs) are a kind of mechanical energy harvester with a larger force sensing range and good energy conversion, which is often applied to human kinetic energy collection and motion sensing devices. Polymer materials are the most commonly used materials in TENGs’ triboelectric layers due to their high plasticity and good performance. Regarding the application of TENGs in insoles, research has often used brittle Teflon for high output performance together with hard materials, such as springs, for the mechanism to maintain its stability. However, these combined materials increase the weight and hardness of the insoles. Here, we propose a polyethylene terephthalate (PET)-based TENG with a micro-needle polydimethylsiloxane (PDMS) elastomer, referred to as MN-PDMS-TENG, to enhance performance and maintain comfort flexibility, and structural stability. Compared with a flat PDMS, the TENG with a microstructure enhances the output open-circuit voltage (Voc) from 54.6 V to 129.2 V, short-circuit current (Isc) from 26.16 μA to 64.00 μA, power from 684 µW to 4.1 mW, and ability to light up from 70 to 120 LEDs. A special three-layer TENG insole mechanism fabricated with the MN-PDMS-TENG and elastic materials gives the TENG insole high stability and the ability to maintain sufficient flexibility to fit in a shoe. The three-layer TENG insole transforms human stepping force into electric energy of 87.2 V, which is used as a self-powered force sensor. Moreover, with the calibration curve between voltage and force, it has a sensitivity of 0.07734 V/N with a coefficient of determination of R² = 0.91 and the function between force and output voltage is derived as F = 12.93 V − 92.10 under human stepping force (300~550 N). Combined with a micro-control unit (MCU), the three-layer TENG insole distinguishes the user’s motion force at different parts of the foot and triggers a corresponding device, which can potentially be applied in sports and on rehabilitation fields to record information or prevent injury. Full article

(This article belongs to the Topic Micro/Nanofluidics and Structures Based Sensing, Material Processing and Energy Conversion)

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11 pages, 2107 KiB  

Open AccessArticle

Acoustofluidics-Assisted Coating of Microparticles

by Ming-Lin Yeh, Geng-Ming Chang and Yi-Je Juang

Polymers 2023, 15(19), 4033; https://doi.org/10.3390/polym15194033 - 09 Oct 2023

Viewed by 1084

Abstract

Microparticles have been applied in many areas, ranging from drug delivery, diagnostics, cosmetics, personal care, and the food industry to chemical and catalytic reactions, sensing, and environmental remediation. Coating further provides additional functionality to the microparticles, such as controlled release, surface modification, bio-fouling [...] Read more.

Microparticles have been applied in many areas, ranging from drug delivery, diagnostics, cosmetics, personal care, and the food industry to chemical and catalytic reactions, sensing, and environmental remediation. Coating further provides additional functionality to the microparticles, such as controlled release, surface modification, bio-fouling resistance, stability, protection, etc. In this study, the conformal coating of microparticles with a positively charged polyelectrolyte (polyallylamine hydrochloride, PAH) by utilizing an acoustofluidic microchip was proposed and demonstrated. The multiple laminar streams, including the PAH solution, were formed inside the microchannel, and, under the traveling surface acoustic wave, the microparticles traversed through the streams, where they were coated with PAH. The results showed that the coating of microparticles can be achieved in a rapid fashion via a microfluidic approach compared to that obtained by the batch method. Moreover, the zeta potentials of the microparticles coated via the microfluidic approach were more uniform. For the unfunctionalized microparticles, the charge reversal occurred after coating, and the zeta potential increased as the width of the microchannel or the concentration of the PAH solution increased. As for the carboxylate-conjugated microparticles, the charge reversal again occurred after coating; however, the magnitudes of the zeta potentials were similar when using the microchannels with different widths or different concentrations of PAH solution. Full article

(This article belongs to the Topic Micro/Nanofluidics and Structures Based Sensing, Material Processing and Energy Conversion)

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13 pages, 4790 KiB  

Open AccessArticle

A Microfluidic, Flow-Through, Liquid Reagent Fluorescence Sensor Applied to Oxygen Concentration Measurement

by Dominik Gril and Denis Donlagic

Sensors 2023, 23(10), 4984; https://doi.org/10.3390/s23104984 - 22 May 2023

Cited by 1 | Viewed by 1445

Abstract

A concept of a microfluidic fluorescent chemical sensing system is presented and demonstrated as a sensor for measurement of dissolved oxygen in water. The system utilizes on-line mixing of a fluorescent reagent with the analyzed sample, while it measures the fluorescence decay time [...] Read more.

A concept of a microfluidic fluorescent chemical sensing system is presented and demonstrated as a sensor for measurement of dissolved oxygen in water. The system utilizes on-line mixing of a fluorescent reagent with the analyzed sample, while it measures the fluorescence decay time of the mixture. The system is built entirely out of silica capillaries and optical fibers, and allows for very low consumption of the reagent (of the order of mL/month) and the analyzed sample (of the order of L/month). The proposed system can, thus, be applied to continuous on-line measurements, while utilizing a broad variety of different and proven fluorescent reagents or dyes. The proposed system allows for the use of relatively high-excitation light powers, as the flow-through concept of the system reduces the probability of the appearance of bleaching, heating, or other unwanted effects on the fluorescent dye/reagent caused significantly by the excitation light. The high amplitudes of fluorescent optical signals captured by an optical fiber allow for low-noise and high-bandwidth optical signal detection, and, consequently, the possibility for utilization of reagents with nanosecond fluorescent lifetimes. Full article

(This article belongs to the Topic Micro/Nanofluidics and Structures Based Sensing, Material Processing and Energy Conversion)

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16 pages, 8301 KiB  

Open AccessFeature PaperEditor’s ChoiceArticle

Nanoparticle Printing for Microfluidic Applications: Bipolar Electrochemistry and Localized Raman Sensing Spots

by Alessia Broccoli, Anke R. Vollertsen, Pauline Roels, Aaike van Vugt, Albert van den Berg and Mathieu Odijk

Micromachines 2023, 14(2), 453; https://doi.org/10.3390/mi14020453 - 15 Feb 2023

Cited by 1 | Viewed by 2363

Abstract

The local integration of metal nanoparticle films on 3D-structured polydimethylsiloxane (PDMS)-based microfluidic devices is of high importance for applications including electronics, electrochemistry, electrocatalysis, and localized Raman sensing. Conventional processes to locally deposit and pattern metal nanoparticles require multiple steps and shadow masks, or [...] Read more.

The local integration of metal nanoparticle films on 3D-structured polydimethylsiloxane (PDMS)-based microfluidic devices is of high importance for applications including electronics, electrochemistry, electrocatalysis, and localized Raman sensing. Conventional processes to locally deposit and pattern metal nanoparticles require multiple steps and shadow masks, or access to cleanroom facilities, and therefore, are relatively imprecise, or time and cost-ineffective. As an alternative, we present an aerosol-based direct-write method, in which patterns of nanoparticles generated via spark ablation are locally printed with sub-mm size and precision inside of microfluidic structures without the use of lithography or other masking methods. As proof of principle, films of Pt or Ag nanoparticles were printed in the chambers of a multiplexed microfluidic device and successfully used for two different applications: Screening electrochemical activity in a high-throughput fashion, and localized sensing of chemicals via surface-enhanced Raman spectroscopy (SERS). The versatility of the approach will enable the generation of functional microfluidic devices for applications that include sensing, high-throughput screening platforms, and microreactors using catalytically driven chemical conversions. Full article

(This article belongs to the Topic Micro/Nanofluidics and Structures Based Sensing, Material Processing and Energy Conversion)

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22 pages, 9856 KiB  

Open AccessArticle

Effects of Porous Size and Membrane Pattern on Shear Stress Characteristic in Gut-on-a-Chip with Peristalsis Motion

by Pannasit Borwornpiyawat, Ekachai Juntasaro, Sasitorn Aueviriyavit, Varangrat Juntasaro, Witsaroot Sripumkhai, Pattaraluck Pattamang, Rattanawan Meananeatra, Kornphimol Kulthong, Ratjika Wongwanakul, Numfon Khemthongcharoen, Nithi Atthi and Wutthinan Jeamsaksiri

Micromachines 2023, 14(1), 22; https://doi.org/10.3390/mi14010022 - 22 Dec 2022

Cited by 3 | Viewed by 1654

Abstract

Dynamic gut-on-a-chip platform allows better recreation of the intestinal environment in vitro compared to the traditional static cell culture. However, the underlying mechanism is still not fully discovered. In this study, the shear stress behavior in a gut-on-a-chip device with porous membrane subjected [...] Read more.

Dynamic gut-on-a-chip platform allows better recreation of the intestinal environment in vitro compared to the traditional static cell culture. However, the underlying mechanism is still not fully discovered. In this study, the shear stress behavior in a gut-on-a-chip device with porous membrane subjected to peristalsis motion is numerically investigated using CFD simulation for three different pore sizes and two pattern layouts. The results reveal that, in the stationary microchannel, the average shear stress on the porous membrane is approximately 15% greater than that of the flat membrane, regardless of the pore size. However, when subjected to cyclic deformation, the porous membrane with smaller pore size experiences stronger variation of shear stress which is ±5.61%, ±10.12% and ±34.45% from its average for the pore diameters of 10 μm, 5 μm and 1 μm, respectively. The shear stress distribution is more consistent in case of the staggered pattern layout while the in-line pattern layout allows for a 32% wider range of shear stress at the identical pore size during a cyclic deformation. These changes in the shear stress caused by peristalsis motion, porous size and membrane pattern could be the key factors that promote cell differentiation in the deforming gut-on-a-chip model. Full article

(This article belongs to the Topic Micro/Nanofluidics and Structures Based Sensing, Material Processing and Energy Conversion)

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25 pages, 14056 KiB  

Open AccessArticle

Enhancing Performance of a MEMS-Based Piezoresistive Pressure Sensor by Groove: Investigation of Groove Design Using Finite Element Method

by Phongsakorn Thawornsathit, Ekachai Juntasaro, Hwanjit Rattanasonti, Putapon Pengpad, Karoon Saejok, Chana Leepattarapongpan, Ekalak Chaowicharat and Wutthinan Jeamsaksiri

Micromachines 2022, 13(12), 2247; https://doi.org/10.3390/mi13122247 - 17 Dec 2022

Cited by 3 | Viewed by 1986

Abstract

The optimal groove design of a MEMS piezoresistive pressure sensor for ultra-low pressure measurement is proposed in this work. Two designs of the local groove and one design of the annular groove are investigated. The sensitivity and linearity of the sensor are investigated [...] Read more.

The optimal groove design of a MEMS piezoresistive pressure sensor for ultra-low pressure measurement is proposed in this work. Two designs of the local groove and one design of the annular groove are investigated. The sensitivity and linearity of the sensor are investigated due to the variations of two dimensionless geometric parameters of these grooves. The finite element method is used to determine the stress and deflection of the diaphragm in order to find the sensor performances. The sensor performances can be enhanced by creating the annular or local groove on the diaphragm with the optimal dimensionless groove depth and length. In contrast, the performances are diminished when the local groove is created on the beam at the piezoresistor. The sensitivity can be increased by increasing the dimensionless groove length and depth. However, to maintain low nonlinearity error, the annular and local grooves should be created on the top of the diaphragm. With the optimal designs of annular and local grooves, the net volume of the annular groove is four times greater than that of the local groove. Finally, the functional forms of the stress and deflection of the diaphragm are constructed for both annular and local groove cases. Full article

(This article belongs to the Topic Micro/Nanofluidics and Structures Based Sensing, Material Processing and Energy Conversion)

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13 pages, 3204 KiB  

Open AccessArticle

Improving the Stability of Halide Perovskite Solar Cells Using Nanoparticles of Tungsten Disulfide

by Philip Nathaniel Immanuel, Song-Jeng Huang, Viktor Danchuk, Anastasiya Sedova, Johnathan Prilusky, Achiad Goldreich, Hila Shalom, Albina Musin and Lena Yadgarov

Nanomaterials 2022, 12(24), 4454; https://doi.org/10.3390/nano12244454 - 15 Dec 2022

Cited by 2 | Viewed by 1856

Abstract

Halide perovskites-based solar cells are drawing significant attention due to their high efficiency, versatility, and affordable processing. Hence, halide perovskite solar cells have great potential to be commercialized. However, the halide perovskites (HPs) are not stable in an ambient environment. Thus, the instability [...] Read more.

Halide perovskites-based solar cells are drawing significant attention due to their high efficiency, versatility, and affordable processing. Hence, halide perovskite solar cells have great potential to be commercialized. However, the halide perovskites (HPs) are not stable in an ambient environment. Thus, the instability of the perovskite is an essential issue that needs to be addressed to allow its rapid commercialization. In this work, WS₂ nanoparticles (NPs) are successfully implemented on methylammonium lead iodide (MAPbI₃) based halide perovskite solar cells. The main role of the WS₂ NPs in the halide perovskite solar cells is as stabilizing agent. Here the WS₂ NPs act as heat dissipater and charge transfer channels, thus allowing an effective charge separation. The electron extraction by the WS₂ NPs from the adjacent MAPbI₃ is efficient and results in a higher current density. In addition, the structural analysis of the MAPbI₃ films indicates that the WS₂ NPs act as nucleation sites, thus promoting the formation of larger grains of MAPbI₃. Remarkably, the absorption and shelf life of the MAPbI₃ layers have increased by 1.7 and 4.5-fold, respectively. Our results demonstrate a significant improvement in stability and solar cell characteristics. This paves the way for the long-term stabilization of HPs solar cells by the implementation of WS₂ NPs. Full article

(This article belongs to the Topic Micro/Nanofluidics and Structures Based Sensing, Material Processing and Energy Conversion)

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15 pages, 5778 KiB  

Open AccessArticle

Digitized Construction of Iontronic Pressure Sensor with Self-Defined Configuration and Widely Regulated Performance

by Honghao Wang, Chun Liang, Haozhe Zhang, Yan Diao, Hua Luo, Yangyang Han and Xiaodong Wu

Sensors 2022, 22(16), 6136; https://doi.org/10.3390/s22166136 - 16 Aug 2022

Cited by 7 | Viewed by 2186

Abstract

Flexible pressure sensors are essential components for wearable smart devices and intelligent systems. Significant progress has been made in this area, reporting on excellent sensor performance and fascinating sensor functionalities. Nevertheless, geometrical and morphological engineering of pressure sensors is usually neglected, which, however, [...] Read more.

Flexible pressure sensors are essential components for wearable smart devices and intelligent systems. Significant progress has been made in this area, reporting on excellent sensor performance and fascinating sensor functionalities. Nevertheless, geometrical and morphological engineering of pressure sensors is usually neglected, which, however, is significant for practical application. Here, we present a digitized manufacturing methodology to construct a new class of iontronic pressure sensors with optionally defined configurations and widely modulated performance. These pressure sensors are composed of self-defined electrode patterns prepared by a screen printing method and highly tunable pressure-sensitive microstructures fabricated using 3D printed templates. Importantly, the iontronic pressure sensors employ an iontronic capacitive sensing mechanism based on mechanically regulating the electrical double layer at the electrolyte/electrode interfaces. The resultant pressure sensors exhibit high sensitivity (58 kPa⁻¹), fast response/recovery time (45 ms/75 ms), low detectability (6.64 Pa), and good repeatability (2000 cycles). Moreover, our pressure sensors show remarkable tunability and adaptability in device configuration and performance, which is challenging to achieve via conventional manufacturing processes. The promising applications of these iontronic pressure sensors in monitoring various human physiological activities, fabricating flexible electronic skin, and resolving the force variation during manipulation of an object with a robotic hand are successfully demonstrated. Full article

(This article belongs to the Topic Micro/Nanofluidics and Structures Based Sensing, Material Processing and Energy Conversion)

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