Microfluidics and MEMS Technology for Membranes

A special issue of Membranes (ISSN 2077-0375). This special issue belongs to the section "Membrane Applications".

Deadline for manuscript submissions: closed (20 December 2021) | Viewed by 27401

Special Issue Editor

Mechanical Engineering Department, Technical University of Catalonia-BarcelonaTech, 08034 Barcelona, Spain
Interests: microfluidics; MEMS; micro-particle image velocimetry; plasma separation
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Microfluidic technologies are key in the development of novel applications in different fields. In the field of separation, microfluidics-based nano- and micro-scale membranes or separation systems provide superior control over the physico-chemical characteristics of the final product. Microfluidics provide a physiological microenvironment close to reality capable of reproducing biological and physical properties (i.e., organ-on-chip) and use biomimetic approaches for separation or classification. Microfluidic systems are also the basis to reduce the time-to-market in the development of new diagnosis tools or even the first step towards personalized medicine. Furthermore, significant efforts have been devoted to the development of miniaturized systems for localized, controlled delivery of pharmaceutical agents to cells and/or tissues or for the separation of undesired particles. These are some of the applications where appropriate filtration to minute particles needs to be eliminated but microfluidic-membranes-based technology is expanding the number of applications to other fields and is more industry driven.

In view of the potential translation of this technology, further efforts should be devoted to: (i) improving scaling-up, high-throughput, operation robustness, and usability by non-specialized personnel; (ii) developing multi-modal delivery systems (i.e., for combined imaging, targeting and therapy, or combining sensing with actuation); (iii) design innovative, cost-effective materials compatible with long-term clinical and industrial applications.

In this Special Issue, we aim to showcase research papers, short communications, and review articles focusing on the development of microfluidics-based technologies applied to membranes relevant either for clinical safety, localized delivery/storage of target cells and/or tissues or particular points of interest in environment/system or industrial applications. We particularly welcome contributions dealing with ongoing challenges and focusing on translational research.

Prof. Dr. Jasmina Casals-Terré
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Membranes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • microfluidics
  • separation
  • microfiltration
  • nanoporous

Published Papers (11 papers)

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Editorial

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3 pages, 208 KiB  
Editorial
Microfluidics and MEMS Technology for Membranes
by Jasmina Casals-Terré
Membranes 2022, 12(6), 586; https://doi.org/10.3390/membranes12060586 - 31 May 2022
Viewed by 1347
Abstract
Nowadays manufacturing processes at nano and microscale provide reliable platform for the development of novel applications, specially in the membrane’s field [...] Full article
(This article belongs to the Special Issue Microfluidics and MEMS Technology for Membranes)

Research

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12 pages, 5446 KiB  
Article
A Strategy toward Realizing Narrow Line with High Electrical Conductivity by Electrohydrodynamic Printing
by Hongfu Liang, Rihui Yao, Guanguang Zhang, Xu Zhang, Zhihao Liang, Yuexin Yang, Honglong Ning, Jinyao Zhong, Tian Qiu and Junbiao Peng
Membranes 2022, 12(2), 141; https://doi.org/10.3390/membranes12020141 - 24 Jan 2022
Cited by 3 | Viewed by 2335
Abstract
Over the past few decades, electrohydrodynamic (EHD) printing has proved to be an environmentally friendly, cost-effective and powerful tool in manufacturing electronic devices with a wire width of less than 50 μm. In particular, EHD printing is highly valued for the printing of [...] Read more.
Over the past few decades, electrohydrodynamic (EHD) printing has proved to be an environmentally friendly, cost-effective and powerful tool in manufacturing electronic devices with a wire width of less than 50 μm. In particular, EHD printing is highly valued for the printing of ultrafine wire-width silver electrodes, which is important in manufacturing large-area, high-resolution micron-scale or even nanoscale structures. In this paper, we compare two methods of surface modification of glass substrate: UV treatment and oxygen plasma treatment. We found that oxygen plasma was better than UV treatment in terms of wettability and uniformity. Secondly, we optimized the annealing temperature parameter, and found that the conductivity of the electrode was the highest at 200 °C due to the smoothing silver electrode and the oxidation-free internal microstructure. Thirdly, we used EHD printing to fabricate silver electrodes on the glass substrate. Due to the decrease of conductivity as a result of the skin effect and the decrease of silver content, we found that driving voltage dropped, line width decreased, and the conductivity of silver line decreased. After the optimization of the EHD printing process, Ag electrode line width and conductivity reached 19.42 ± 0.24 μm and 6.01 × 106 S/m, demonstrating the potential of electro-hydraulic printing in the manufacturing of flexible, wearable, high-density, low-power-consumption electronics. Full article
(This article belongs to the Special Issue Microfluidics and MEMS Technology for Membranes)
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7 pages, 2335 KiB  
Communication
Transparent Flexible IGZO Thin Film Transistors Fabricated at Room Temperature
by Honglong Ning, Xuan Zeng, Hongke Zhang, Xu Zhang, Rihui Yao, Xianzhe Liu, Dongxiang Luo, Zhuohui Xu, Qiannan Ye and Junbiao Peng
Membranes 2022, 12(1), 29; https://doi.org/10.3390/membranes12010029 - 27 Dec 2021
Cited by 12 | Viewed by 2957
Abstract
Flexible and fully transparent thin film transistors (TFT) were fabricated via room temperature processes. The fabricated TFT on the PEN exhibited excellent performance, including a saturation mobility (μsat) of 7.9 cm2/V·s, an Ion/Ioff ratio of 4.58 [...] Read more.
Flexible and fully transparent thin film transistors (TFT) were fabricated via room temperature processes. The fabricated TFT on the PEN exhibited excellent performance, including a saturation mobility (μsat) of 7.9 cm2/V·s, an Ion/Ioff ratio of 4.58 × 106, a subthreshold swing (SS) of 0.248 V/dec, a transparency of 87.8% at 550 nm, as well as relatively good stability under negative bias stress (NBS) and bending stress, which shows great potential in smart, portable flexible display, and wearable device applications. Full article
(This article belongs to the Special Issue Microfluidics and MEMS Technology for Membranes)
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13 pages, 3090 KiB  
Article
A Driving Method for Reducing Oil Film Splitting in Electrowetting Displays
by Wenjun Zeng, Zichuan Yi, Yiming Zhao, Li Wang, Jitao Zhang, Xichen Zhou, Liming Liu, Feng Chi, Jianjun Yang and Chongfu Zhang
Membranes 2021, 11(12), 920; https://doi.org/10.3390/membranes11120920 - 24 Nov 2021
Cited by 3 | Viewed by 1340
Abstract
Electrowetting displays (EWDs) are one of the most potential electronic papers. However, they have the problem of oil film splitting, which could lead to a low aperture ratio of EWDs. In this paper, a driving waveform was proposed to reduce oil film splitting. [...] Read more.
Electrowetting displays (EWDs) are one of the most potential electronic papers. However, they have the problem of oil film splitting, which could lead to a low aperture ratio of EWDs. In this paper, a driving waveform was proposed to reduce oil film splitting. The driving waveform was composed of a rising stage and a driving stage. First, the rupture voltage of oil film was analyzed by testing the voltage characteristic curve of EWDs. Then, a quadratic function waveform with an initial voltage was applied at the rising stage to suppress oil film splitting. Finally, a square wave was applied at the driving stage to maintain the aperture ratio of EWDs. The experimental results show that the luminance was increased by 8.78% and the aperture ratio was increased by 4.47% compared with an exponential function driving waveform. Full article
(This article belongs to the Special Issue Microfluidics and MEMS Technology for Membranes)
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13 pages, 4718 KiB  
Article
Fabrication and Characterization of Sulfonated Graphene Oxide-Doped Polymeric Membranes with Improved Anti-Biofouling Behavior
by Muhammad Zahid, Anum Rashid, Saba Akram, H. M. Fayzan Shakir, Zulfiqar Ahmad Rehan, Talha Javed, Rubab Shabbir and Mahmoud M. Hessien
Membranes 2021, 11(8), 563; https://doi.org/10.3390/membranes11080563 - 27 Jul 2021
Cited by 11 | Viewed by 2685
Abstract
In this study, cellulose acetate (CA) was blended with sulfonated graphene oxide (SGO) nanomaterials to endow a nanocomposite membrane for wastewater treatment with improved hydrophilicity and anti-biofouling behavior. The phase inversion method was employed for membrane fabrication using tetrahydrofuran (THF) as the solvent. [...] Read more.
In this study, cellulose acetate (CA) was blended with sulfonated graphene oxide (SGO) nanomaterials to endow a nanocomposite membrane for wastewater treatment with improved hydrophilicity and anti-biofouling behavior. The phase inversion method was employed for membrane fabrication using tetrahydrofuran (THF) as the solvent. The characteristics of CA-SGO-doped membranes were investigated through thermal analysis, contact angle, SEM, FTIR, and anti-biofouling property. Results indicated that anti-biofouling property and hydrophilicity of CA-SGO nanocomposite membranes were enhanced with addition of hydrophilic SGO nanomaterials in comparison to pristine CA membrane. FTIR analysis confirmed the successful decoration of SGO groups on CA membrane surface while revealing its morphological properties through SEM analysis. Thermal analysis performed using DSC confirmed the increase in thermal stability of CA-SGO membranes with addition of SGO content than pure CA membrane. Full article
(This article belongs to the Special Issue Microfluidics and MEMS Technology for Membranes)
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13 pages, 5399 KiB  
Article
Investigating the Antibacterial Activity of Polymeric Membranes Fabricated with Aminated Graphene Oxide
by Muhammad Zahid, Saba Akram, Anum Rashid, Zulfiqar Ahmad Rehan, Talha Javed, Rubab Shabbir, Mahmoud M. Hessien and Mahmoud E. El-Sayed
Membranes 2021, 11(7), 510; https://doi.org/10.3390/membranes11070510 - 07 Jul 2021
Cited by 22 | Viewed by 3346
Abstract
A novel, functionalized graphene oxide–based cellulose acetate membrane was fabricated using the phase inversion method to improve the membrane characteristics and performance. We studied the effect of aminated graphene oxide (NH2–GO) composite on the CA membrane characteristics and performance in terms [...] Read more.
A novel, functionalized graphene oxide–based cellulose acetate membrane was fabricated using the phase inversion method to improve the membrane characteristics and performance. We studied the effect of aminated graphene oxide (NH2–GO) composite on the CA membrane characteristics and performance in terms of membrane chemistry, hydrophilicity, thermal and mechanical stability, permeation flux, and antibacterial activity. The results of contact angle and water flux indicate the improved hydrophilic behavior of composite membranes in comparison to that of the pure CA membrane. The AGO-3 membrane showed the highest water flux of about 153 Lm−2h−1. The addition of hydrophilic AGO additive in CA membranes enhanced the antibacterial activity of AGO–CA membranes, and the thermal stability of the resulting membrane also improved since it increases the Tg value in comparison to that of a pristine CA membrane. The aminated graphene oxide (NH2–GO) was, therefore, found to be a promising additive for the fabrication of composite membranes with potent applications in wastewater treatment. Full article
(This article belongs to the Special Issue Microfluidics and MEMS Technology for Membranes)
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13 pages, 3323 KiB  
Article
Effect of Temperature and Flow Rate on the Cell-Free Area in the Microfluidic Channel
by Angeles Ivón Rodríguez-Villarreal, Manuel Carmona-Flores and Jordi Colomer-Farrarons
Membranes 2021, 11(2), 109; https://doi.org/10.3390/membranes11020109 - 03 Feb 2021
Cited by 4 | Viewed by 1807
Abstract
Blood cell manipulation in microdevices is an interesting task for the separation of particles, by their size, density, or to remove them from the buffer, in which they are suspended, for further analysis, and more. This study highlights the cell-free area (CFA) widening [...] Read more.
Blood cell manipulation in microdevices is an interesting task for the separation of particles, by their size, density, or to remove them from the buffer, in which they are suspended, for further analysis, and more. This study highlights the cell-free area (CFA) widening based on experimental results of red blood cell (RBC) flow, suspended in a microfluidic device, while temperature and flow rate incrementally modify RBC response within the microflow. Studies of human red blood cell flow, at a concentration of 20%, suspended in its autologous plasma and phosphate-buffered saline (PBS) buffer, were carried out at a wide flow rate, varying between 10 and 230 μL/min and a temperature range of 23 °C to 50 °C. The plotted measures show an increment in a CFA near the channel wall due to cell flow inertia after a constricted channel, which becomes more significant as temperature and flow rate increase. The temperature increment widened the CFA up to three times. In comparison, flow rate increment increased the CFA up to 20 times in PBS and 11 times in plasma. Full article
(This article belongs to the Special Issue Microfluidics and MEMS Technology for Membranes)
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13 pages, 2886 KiB  
Article
MEMS Membranes with Nanoscale Holes for Analytical Applications
by Alvise Bagolini, Raffaele Correale, Antonino Picciotto, Maurizio Di Lorenzo and Marco Scapinello
Membranes 2021, 11(2), 74; https://doi.org/10.3390/membranes11020074 - 20 Jan 2021
Cited by 5 | Viewed by 2359
Abstract
Micro-electro-mechanical membranes having nanoscale holes were developed, to be used as a nanofluidic sample inlet in novel analytical applications. Nanoscopic holes can be used as sampling points to enable a molecular flow regime, enhancing the performance and simplifying the layout of mass spectrometers [...] Read more.
Micro-electro-mechanical membranes having nanoscale holes were developed, to be used as a nanofluidic sample inlet in novel analytical applications. Nanoscopic holes can be used as sampling points to enable a molecular flow regime, enhancing the performance and simplifying the layout of mass spectrometers and other analytical systems. To do this, the holes must be placed on membranes capable of consistently withstanding a pressure gradient of 1 bar. To achieve this goal, a membrane-in-membrane structure was adopted, where a larger and thicker membrane is microfabricated, and smaller sub-membranes are then realized in it. The nanoscopic holes are opened in the sub-membranes. Prototype devices were fabricated, having hole diameters from 300 to 600 nm, a membrane side of 80 μm, and a simulated maximum displacement of less than 150 nm under a 1 bar pressure gradient. The obtained prototypes were tested in a dedicated vacuum system, and a method to calculate the effective orifice diameter using gas flow measurements at different pressure gradients was implemented. The calculated diameters were in good agreement with the target diameter sizes. Micro-electro-mechanical technology was successfully used to develop a novel micromembrane with nanoscopic holes, and the fabricated prototypes were successfully used as a gas inlet in a vacuum system for mass spectrometry and other analytical systems. Full article
(This article belongs to the Special Issue Microfluidics and MEMS Technology for Membranes)
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14 pages, 45644 KiB  
Article
Fluid-Structure Interaction Analysis on Membrane Behavior of a Microfluidic Passive Valve
by Zhen-hao Lin, Xiao-juan Li, Zhi-jiang Jin and Jin-yuan Qian
Membranes 2020, 10(10), 300; https://doi.org/10.3390/membranes10100300 - 21 Oct 2020
Cited by 9 | Viewed by 2733
Abstract
In this paper, the effect of membrane features on flow characteristics in the microfluidic passive valve (MPV) and the membrane behavior against fluid flow are studied using the fluid-structure interaction (FSI) analysis. Firstly, the microvalve model with different numbers of microholes and pitches [...] Read more.
In this paper, the effect of membrane features on flow characteristics in the microfluidic passive valve (MPV) and the membrane behavior against fluid flow are studied using the fluid-structure interaction (FSI) analysis. Firstly, the microvalve model with different numbers of microholes and pitches of microholes are designed to investigate the flow rate of the MPV. The result shows that the number of microholes on the membrane has a significant impact on the flow rate of the MPV, while the pitch of microholes has little effect on it. The constant flow rate maintained by the microvalve (the number of microholes n = 4) is 5.75 mL/min, and the threshold pressure to achieve the flow rate is 4 kPa. Secondly, the behavior of the membrane against the fluid flow is analyzed. The result shows that as the inlet pressure increases, the flow resistance of the MPV increases rapidly, and the deformation of the membrane gradually becomes stable. Finally, the effect of the membrane material on the flow rate and the deformation of the membrane are studied. The result shows that changes in the material properties of the membrane cause a decrease in the amount of deformation in all stages the all positions of the membrane. This work may provide valuable guidance for the optimization of microfluidic passive valve in microfluidic system. Full article
(This article belongs to the Special Issue Microfluidics and MEMS Technology for Membranes)
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Review

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13 pages, 2511 KiB  
Review
Recent Impact of Microfluidics on Skin Models for Perspiration Simulation
by Genís Rabost-Garcia, Josep Farré-Lladós and Jasmina Casals-Terré
Membranes 2021, 11(2), 150; https://doi.org/10.3390/membranes11020150 - 21 Feb 2021
Cited by 7 | Viewed by 3227
Abstract
Skin models offer an in vitro alternative to human trials without their high costs, variability, and ethical issues. Perspiration models, in particular, have gained relevance lately due to the rise of sweat analysis and wearable technology. The predominant approach to replicate the key [...] Read more.
Skin models offer an in vitro alternative to human trials without their high costs, variability, and ethical issues. Perspiration models, in particular, have gained relevance lately due to the rise of sweat analysis and wearable technology. The predominant approach to replicate the key features of perspiration (sweat gland dimensions, sweat rates, and skin surface characteristics) is to use laser-machined membranes. Although they work effectively, they present some limitations at the time of replicating sweat gland dimensions. Alternative strategies in terms of fabrication and materials have also showed similar challenges. Additional research is necessary to implement a standardized, simple, and accurate model representing sweating for wearable sensors testing. Full article
(This article belongs to the Special Issue Microfluidics and MEMS Technology for Membranes)
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51 pages, 1535 KiB  
Review
Curvature-Dependent Electrostatic Field as a Principle for Modelling Membrane-Based MEMS Devices. A Review
by Mario Versaci, Paolo di Barba and Francesco Carlo Morabito
Membranes 2020, 10(11), 361; https://doi.org/10.3390/membranes10110361 - 21 Nov 2020
Cited by 11 | Viewed by 1848
Abstract
The evolution of engineering applications is increasingly shifting towards the embedded nature, resulting in low-cost solutions, micro/nano dimensional and actuators being exploited as fundamental components to connect the physical nature of information with the abstract one, which is represented in the logical form [...] Read more.
The evolution of engineering applications is increasingly shifting towards the embedded nature, resulting in low-cost solutions, micro/nano dimensional and actuators being exploited as fundamental components to connect the physical nature of information with the abstract one, which is represented in the logical form in a machine. In this context, the scientific community has gained interest in modeling membrane Micro-Electro-Mechanical-Systems (MEMS), leading to a wide diffusion on an industrial level owing to their ease of modeling and realization. Physically, once the external voltage is applied, an electrostatic field, orthogonal to the tangent line of the membrane, is established inside the device, producing an electrostatic pressure that acts on the membrane, deforming it. Evidently, the greater the amplitude of the electrostatic field is, the greater the curvature of the membrane. Thus, it seems natural to consider the amplitude of the electrostatic field proportional to the curvature of the membrane. Starting with this principle, the authors are actively involved in developing a second-order semi-linear elliptic model in 1D and 2D geometries, obtaining important results regarding the existence, uniqueness and stability of solutions as well as evaluating the particular operating conditions of use of membrane MEMS devices. In this context, the idea of providing a survey matures to discussing the similarities and differences between the analytical and numerical results in detail, thereby supporting the choice of certain membrane MEMS devices according to the industrial application. Finally, some original results about the stability of the membrane in 2D geometry are presented and discussed. Full article
(This article belongs to the Special Issue Microfluidics and MEMS Technology for Membranes)
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