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He Y, Yu H, Duan G, Wang Y, Yang Q, Feng L, Zhang J. Thermal performance and experimental analysis of stainless steel flat plate solar collector with full-flow channels. Heliyon 2024; 10:e28255. [PMID: 38560198 PMCID: PMC10979057 DOI: 10.1016/j.heliyon.2024.e28255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 03/14/2024] [Accepted: 03/14/2024] [Indexed: 04/04/2024] Open
Abstract
The thermal performance of a flat plate solar collector (FPSC) is a critical indicator that depends on the environment, operational parameters, and dimensions. This study examines the impact of size on thermal performance improvement mechanisms. Firstly, numerical simulation models are introduced as the foundation for optimization research. This involves analyzing the flow resistance of microchannels and defining their structural parameters. Furthermore, experimental tests were conducted on a stainless steel flat plate solar collector (S/S FPSC) with the best design parameters to validate the accuracy of the mathematical model during the design phase. The results indicate that increasing the width of the microchannel and the height of corrugations can effectively enhance the thermal performance of the S/S FPSC. The momentary efficiency is projected to reach a remarkable 86.10% under ideal circumstances. Additionally, a mathematical expression was proposed to establish the relationship between the surrounding conditions and the momentary efficiency of the S/S FPSC. Moreover, the microchannel comprises S/S material, maintaining a homogeneous temperature distribution to maximize heat absorption. The use of stainless steel also extends the lifespan of the FPSC.
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Affiliation(s)
- Yi He
- The School of Architecture and Urban Planning, Shandong Jianzhu University, Jinan, 250101, China
| | - Hongwen Yu
- The School of Architecture and Urban Planning, Shandong Jianzhu University, Jinan, 250101, China
| | - Guangbin Duan
- School of Materials Science and Engineering, University of Jinan, Jinan, 250024, China
| | - Yong Wang
- School of Materials Science and Engineering, University of Jinan, Jinan, 250024, China
| | - Qianfu Yang
- Shandong Sangle Group Co., Ltd, Jinan, 250101, China
| | - Lei Feng
- Shandong Sangle Group Co., Ltd, Jinan, 250101, China
| | - Jiaming Zhang
- Zhongke Low Carbon Technology Co., Ltd, Jinan, 250014, China
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Bär J, de Barros A, Shimizu FM, Sigoli FA, Bufon CCB, Mazali IO. Synergy of shaped-induced enhanced Raman scattering to improve surface-enhanced Raman scattering signal in the thiram molecule detection. Spectrochim Acta A Mol Biomol Spectrosc 2024; 310:123907. [PMID: 38290277 DOI: 10.1016/j.saa.2024.123907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 01/10/2024] [Accepted: 01/15/2024] [Indexed: 02/01/2024]
Abstract
Herein, we explore the combined effect of Shaped-Induced Enhanced Raman Scattering (SIERS) and Surface-Enhanced Raman Scattering (SERS) for detecting thiram molecules. We fabricated V-shaped microchannels on a silicon (100) substrate through a standard lithography and etching process. The analysis of SIERS@SERS was performed for Si-V substrates modified with AuNRs with different thiram concentrations, 10-7 to 10-10 mol/L. The spectra were collected for different regions of the Si-V substrates, i.e., in the inside, edge, between (flat top), and far from Si-V (coffee-ring AuNRs aggregation) to assess the performance of Si-V microchannels obtained. The IDMAP statistical projection reveals a higher silhouette coefficient of 0.91 for the inside of Si-V, indicating a more excellent spectral reproducibility with closer relative intensities. The device platform used in this study stands out as a robust option for commercial sensors, demonstrating exceptional sensitivity in detecting a diverse range of molecules, even at low concentrations.
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Affiliation(s)
- Jaciara Bär
- Universidade Estadual de Campinas, Instituto de Química, Laboratorio de Materiais Funcionais, Campinas, SP, Brazil
| | - Anerise de Barros
- Universidade Estadual de Campinas, Instituto de Química, Laboratorio de Materiais Funcionais, Campinas, SP, Brazil
| | - Flavio Makoto Shimizu
- Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin, Campinas, SP, Brazil; Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Giuseppe Máximo Scolfaro 10000, Polo II de Alta Tecnologia, 13083-100 Campinas, SP, Brazil
| | - Fernando A Sigoli
- Universidade Estadual de Campinas, Instituto de Química, Laboratorio de Materiais Funcionais, Campinas, SP, Brazil
| | | | - Italo Odone Mazali
- Universidade Estadual de Campinas, Instituto de Química, Laboratorio de Materiais Funcionais, Campinas, SP, Brazil.
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Gracka M, Lima R, Miranda JM, Student S, Melka B, Ostrowski Z. Red blood cells tracking and cell-free layer formation in a microchannel with hyperbolic contraction: A CFD model validation. Comput Methods Programs Biomed 2022; 226:107117. [PMID: 36122496 DOI: 10.1016/j.cmpb.2022.107117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/16/2022] [Accepted: 09/05/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND OBJECTIVE In recent years, progress in microfabrication technologies has attracted the attention of researchers across disciplines. Microfluidic devices have the potential to be developed into powerful tools that can elucidate the biophysical behavior of blood flow in microvessels. Such devices can also be used to separate the suspended physiological fluid from whole in vitro blood, which includes cells. Therefore, it is essential to acquire a detailed description of the complex interaction between erythrocytes (red blood cells; RBCs) and plasma. RBCs tend to undergo axial migration caused by occurrence of the Fåhræus-Lindqvist effect. These dynamics result in a cell-free layer (CFL), or a low volume fraction of cells, near the vessel wall. The aim of the paper is to develop a numerical model capable of reproducing the behavior of multiphase flow in a microchannel obtained under laboratory conditions and to compare two multiphase modelling techniques Euler-Euler and Euler-Lagrange. METHODS In this work, we employed a numerical Computational Fluid Dynamics (CFD) model of the blood flow within microchannels with two hyperbolic contraction shapes. The simulation was used to reproduce the blood flow behavior in a microchannel under laboratory conditions, where the CFL formation is visible downstream of the hyperbolic contraction. The multiphase numerical model was developed using Euler-Euler and hybrid Euler-Lagrange approaches. The hybrid CFD simulation of the RBC transport model was performed using a Discrete Phase Model. Blood was assumed to be a nonhomogeneous mixture of two components: dextran, whose properties are consistent with plasma, and RBCs, at a hematocrit of 5% (percent by volume of RBCs). RESULTS The results show a 5 μm thick CFL in a microchannel with a broader contraction and a 35 μm thick CFL in a microchannel with a narrower contraction. The RBC volume fraction in the CFL is less than 2%, compared to 7-8% in the core flow. The results are consistent for both multiphase simulation techniques used. The simulation results were then validated against the experimentally-measured CFL in each of the studied microchannel geometries. CONCLUSIONS Reasonable agreement between experiments and simulations was achieved. A validated model such as the one tested in this study can expedite the microchannel design process by minimizing the need to prefabricate prototypes and test them under laboratory conditions.
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Affiliation(s)
- Maria Gracka
- Department of Thermal Technology, Biomedical Engineering Laboratory, Silesian University of Technology, Gliwice, Poland.
| | - Rui Lima
- MEtRiCS, DME, School of Engineering, University of Minho, Braga, Portugal; CEFT, Faculdade de Engenharia da Universidade do Porto (FEUP), Porto, Portugal
| | - João M Miranda
- CEFT, Faculdade de Engenharia da Universidade do Porto (FEUP), Porto, Portugal
| | - Sebastian Student
- Department of Systems Biology and Engineering, Silesian University of Technology, Gliwice, Poland; Biotechnology Centre, Silesian University of Technology, Gliwice, Poland
| | - Bartłomiej Melka
- Department of Thermal Technology, Biomedical Engineering Laboratory, Silesian University of Technology, Gliwice, Poland
| | - Ziemowit Ostrowski
- Department of Thermal Technology, Biomedical Engineering Laboratory, Silesian University of Technology, Gliwice, Poland
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Yang Z, Li W, Huang H, Ren S, Men Y, Li F, Yu X, Luo Q. Detection of serum phospholipids by microchannel-integrated black phosphorus-assisted laser desorption/ionization mass spectrometry. Talanta 2022; 237:122978. [PMID: 34736700 DOI: 10.1016/j.talanta.2021.122978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/14/2021] [Accepted: 10/16/2021] [Indexed: 10/20/2022]
Abstract
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been widely applied in the analysis of phospholipids in biological samples. However, it remains a challenge to improve the sensitivity and reproducibility and to control the background noise of matrices. In this study, black phosphorus nanomaterial was used as the matrix of MALDI-MS, and microchannel technique was combined. This microchannel-integrated black phosphorus-assisted laser desorption/ionization (BPALDI) MS approach can effectively detect a variety of lipids with a small amount of sample, and has high sensitivity for phosphatidylcholines (PC) and lysophosphatidylcholines (LPC) with a detection limit of 0.2 μg/mL. Compared with traditional matrices, BPALDI-MS has the advantages of high sensitivity, good reproducibility, and high salt tolerance. This method was successfully applied in the detection of serum PC/LPC ratios in children patients with asthma or bronchopneumonia. This work provides a novel application of black phosphorus matrix and microchannel technique, and gives new insights into method development of rapid screening and identification of disease indicators in biological fluids.
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Affiliation(s)
- Zhiyi Yang
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Wenbo Li
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Hao Huang
- Shenzhen Engineering Laboratory of Single-molecule Detection and Instrument Development, Shenzhen, 518055, China
| | - Songlei Ren
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Yongfan Men
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Fang Li
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China; Shenzhen Engineering Laboratory of Single-molecule Detection and Instrument Development, Shenzhen, 518055, China
| | - Xuefeng Yu
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Qian Luo
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China; Shenzhen Engineering Laboratory of Single-molecule Detection and Instrument Development, Shenzhen, 518055, China.
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Fonseca LR, Santos TP, Czaikoski A, Cunha RL. Microfluidics-based production of chitosan-gellan nanocomplexes encapsulating caffeine. Food Res Int 2022; 151:110885. [PMID: 34980412 DOI: 10.1016/j.foodres.2021.110885] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 11/16/2021] [Accepted: 12/07/2021] [Indexed: 11/04/2022]
Abstract
Electrostatic complexes produced by interactions between polysaccharides have promising applications in the medical, pharmaceutical and food fields. In this light, for the development of such particles, microfluidics emerges as a promising technique in which processes occur at a strict laminar flow regime, allowing diffusion-dominated transport and particle formation in highly-controlled conditions. As a proof of concept, we compared bulk versus microfluidic (different devices simulating a range of residence times) processes for the production of electrostatic complexes of gellan with either chitosan (molecular weight ∼ 28 kDa) or hydrolyzed chitosan (molecular weight ∼ 3 kDa). Regardless of the process, polysaccharide solutions (pH 4.5) were mixed in pre-defined concentrations (polysaccharide ratios) to form electrostatic complexes that were used to encapsulate caffeine. These complexes were characterized by zeta potential measurements and particle size distribution. Overall, microfluidics produced complexes with improved characteristics such as lower polydispersity index (PDI ∼ 0.1) and mean size (∼200 nm) when compared to the conventional bulk process (PDI ∼ 0.3 and mean size ∼ 400 nm). Moreover, hydrolyzed chitosan (HC) contributed to an even smaller size and PDI value of the complexes. Such outcome is associated with the lower molecular weight and higher solubility of HC when comparing to conventional chitosan, which in turn improves electrostatic complexation. Caffeine could also be encapsulated in all complexes, but the highest encapsulation efficiency was achieved using microfluidics (70%) and with the geometry that provided a longer residence time. Therefore, we were able to demonstrate that microfluidics is clearly an effective strategy for generating electrostatic complexes with improved properties. Ultimately, this technique demonstrated a high potential for the production of vehicles of bioactive compounds.
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Affiliation(s)
- Larissa Ribas Fonseca
- Department of Food Engineering and Technology, School of Food Engineering, University of Campinas (UNICAMP), 13083-862 Campinas, SP, Brazil
| | - Tatiana Porto Santos
- Department of Food Engineering and Technology, School of Food Engineering, University of Campinas (UNICAMP), 13083-862 Campinas, SP, Brazil
| | - Aline Czaikoski
- Department of Food Engineering and Technology, School of Food Engineering, University of Campinas (UNICAMP), 13083-862 Campinas, SP, Brazil
| | - Rosiane Lopes Cunha
- Department of Food Engineering and Technology, School of Food Engineering, University of Campinas (UNICAMP), 13083-862 Campinas, SP, Brazil.
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Dong J, Liang D, Yang X, Sun C. Influences of microparticle radius and microchannel height on SSAW-based acoustophoretic aggregation. Ultrasonics 2021; 117:106547. [PMID: 34419898 DOI: 10.1016/j.ultras.2021.106547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 07/30/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
The use of acoustic waves for microfluidic aggregation has become widespread in chemistry, biology and medicine. Although numerous experimental and analytical studies have been undertaken to study the acoustophoretic aggregation mechanisms, few studies have been conducted to optimise the device design. This paper presents a numerical investigation of the acoustophoresis of microparticles suspended in compressible liquid. The wall of the rectangular microchannel is made of Polydimethylsiloxane (PDMS), and Standing Surface Acoustic Waves (SSAW) are introduced into the channel from the bottom wall. First, the relative amplitude of the acoustic radiation force and the viscous drag force is evaluated for particles of different radii ranging from 0.1μm to 15μm. Only when the particle size is larger than a critical value can the particles accumulate at acoustic pressure nodes (PNs). The efficiency of the particle accumulation depends on the microchannel height, so an extensive parametric study is then undertaken to identify the optimum microchannel height. The optimum height, when normalised by the acoustic wavelength, is found to be between 0.57 and 0.82. These findings provide insights into the design of acoustophoretic devices.
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Affiliation(s)
- Jing Dong
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
| | - Dongfang Liang
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK.
| | - Xin Yang
- Department of Electrical and Electronic Engineering, School of Engineering, Cardiff University, Cardiff CF24 3AA, UK
| | - Chao Sun
- School of Life Sciences, Northwestern Polytechnical University, Xi'an 710129, PR China
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7
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Saepang K, Li SK, Chantasart D. Passive and iontophoretic transport of pramipexole dihydrochloride across human skin microchannels created by microneedles in vitro. Int J Pharm 2021; 609:121092. [PMID: 34530098 DOI: 10.1016/j.ijpharm.2021.121092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Skin microchannels (MCs) created by microneedles (MNs) provide a promising route for enhancing transdermal drug delivery. This study investigated passive and iontophoretic transport of pramipexole dihydrochloride (PXCl) across skin MCs created by polymer MN patches made of 1:2 polymethyl-vinyl-ether-co-maleic acid (PMVEMA) to polyvinyl alcohol (PVA) ratio. Permeation studies were performed in vitro using excised human skin under the conditions of (i) "poke-and-patch" and "poke-and-release" delivery approaches with varying concentration of PXCl in the formulations, (ii) drug-loaded dissolving MN (DMN) and hydrogel-forming MN (HGMN) type patches and (iii) combination of MNs and iontophoresis. The results showed that DMN patch greatly enhanced transdermal delivery of PXCl for both "poke-and-patch" and "poke-and-release" approaches as compared with the conventional delivery method. PXCl flux mainly resulted from the contribution of MC pathway created in skin and increased with increasing drug amounts in the formulations. Compared to DMN patch, HGMN patch provided more linear sustained drug delivery over 72 h. Electromigration was the main mechanism of PXCl iontophoresis through MCs and flux enhancement was found to be larger for HGMN patch than DMN patch. These results demonstrated the potential application of MN patches individually or combined with iontophoresis as an alternative method for PXCl administration.
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Affiliation(s)
- Kamchai Saepang
- Department of Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand
| | - S Kevin Li
- Division of Pharmaceutical Sciences, College of Pharmacy, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Doungdaw Chantasart
- Department of Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand.
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Takekawa VS, Marques LA, Strubinger E, Segato TP, Bogusz S, Brazaca LC, Carrilho E. Development of low-cost planar electrodes and microfluidic channels for applications in capacitively coupled contactless conductivity detection (C 4 D). Electrophoresis 2021; 42:1560-1569. [PMID: 34080201 DOI: 10.1002/elps.202000351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 01/11/2023]
Abstract
Electrochemical techniques are commonly applied to micro total analysis system (μTAS) devices mainly due to its high sensitivity and miniaturization capacity. Among many electrochemical techniques, capacitively coupled contactless conductivity detection (C4 D) stands out for not requiring direct electrode-solution contact, avoiding several problems such as electrolysis, bubble formation, and metal degradation. Furthermore, the instrumentation required for C4 D measurements is compact, low cost, and easy to use, allowing in situ measurements to be performed even by nonspecialized personal. Contrarily, the production of metallic electrodes and microchannels adequate for C4 D measurements commonly requires specialized facilities and workers, increasing the costs of applying these methods. We propose alternatives to batch manufacture metallic electrodes and polymeric microchannels for C4 D analysis using more straightforward equipment and lower-cost materials. Three devices with different dielectric layer compositions and electrode sizes were tested and compared regarding their analytical performance. The constructed platforms have shown a reduction of more than 64% in cost when compared to traditional techniques and displayed good linearity (R2 ≥ 0.994), reproducibility (RSD ≤ 4.07%, n = 3), and limits of detection (≤0.26 mmol/L) when measuring standard NaCl samples. Therefore, the proposed methods were successfully validated and are available for further C4 D applications such as diagnosis of dry-eye syndrome.
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Affiliation(s)
- Victor Sadanory Takekawa
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil.,Instituto Nacional de Ciência e Tecnologia de Bioanalítica-INCTBio, Campinas, São Paulo, Brazil
| | - Letícia Aparecida Marques
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil.,Instituto Nacional de Ciência e Tecnologia de Bioanalítica-INCTBio, Campinas, São Paulo, Brazil
| | - Ethan Strubinger
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil.,Instituto Nacional de Ciência e Tecnologia de Bioanalítica-INCTBio, Campinas, São Paulo, Brazil.,Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC
| | - Thiago Pinotti Segato
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil.,Instituto Nacional de Ciência e Tecnologia de Bioanalítica-INCTBio, Campinas, São Paulo, Brazil
| | - Stanislau Bogusz
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
| | - Laís Canniatti Brazaca
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil.,Instituto Nacional de Ciência e Tecnologia de Bioanalítica-INCTBio, Campinas, São Paulo, Brazil
| | - Emanuel Carrilho
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil.,Instituto Nacional de Ciência e Tecnologia de Bioanalítica-INCTBio, Campinas, São Paulo, Brazil
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Chen L, Tang Y, Zhao K, Liu J, Bai H, Wu Z. Absorptive and expansive behaviors of poly(methyl methacrylate-co-acrylic acid) bone cement. Colloids Surf B Biointerfaces 2020; 189:110848. [PMID: 32058255 DOI: 10.1016/j.colsurfb.2020.110848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 01/15/2020] [Accepted: 02/04/2020] [Indexed: 02/08/2023]
Abstract
Some additives had provided the expansion capacity to the polymethylmethacrylate (PMMA) bone cement and also reduced its maximum reaction temperature. However, the corresponding modified bone cement displayed inferior simulated body fluid (SBF) absorption capacity and expansion behavior, the mechanism of SBF absorption and the trend of expansion stress were ignored additionally. In this study, a homogeneous distribution of poly (methyl methacrylate-co-acrylic acid) [P(MMA-AA)] microspheres led to the formation of microchannels that favored the delivery of SBF to the interior, causing an increased absorption capacity and enhanced expansion behavior before solidification of the bone cement, with the maximum equilibrium absorption ratio and the expansion ratio reaching 27.3 % and 26.3 %, respectively, at an AA content of 50 %. In addition, the expansion stress induced by the expansion behavior experienced a gradual increase from the 0 s to 2590s, followed by a sharp climbed in a short period ranging from 2590s to 2900s, finally reaching maximum stress of 82.1 MPa. Furthermore, the expansion stress within the maximum value could be obtained by controlling the AA content in the P(MMA-AA) bone cement. With the above characteristics, the prepared P(MMA-AA) bone cement has potential applications as a filling and adhesive material in arthroplasties, vertebroplasties, joint replacements, bone screws, and dentistry.
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Affiliation(s)
- Lei Chen
- School of Materials Science and Engineering, Xi'an University of Technology, Xi'an, 710048, PR China
| | - Yufei Tang
- School of Materials Science and Engineering, Xi'an University of Technology, Xi'an, 710048, PR China.
| | - Kang Zhao
- School of Materials Science and Engineering, Xi'an University of Technology, Xi'an, 710048, PR China
| | - Jiaxin Liu
- School of Materials Science and Engineering, Xi'an University of Technology, Xi'an, 710048, PR China
| | - Hao Bai
- Institute of Orthopaedics, Xi'jing Hospital, Fourth Military Medical University, Xi'an, 710032, PR China
| | - Zixiang Wu
- Institute of Orthopaedics, Xi'jing Hospital, Fourth Military Medical University, Xi'an, 710032, PR China.
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Hussain G, Ge M, Zhao C, Silvester DS. Fast responding hydrogen gas sensors using platinum nanoparticle modified microchannels and ionic liquids. Anal Chim Acta 2019; 1072:35-45. [PMID: 31146863 DOI: 10.1016/j.aca.2019.04.042] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/27/2019] [Accepted: 04/18/2019] [Indexed: 11/30/2022]
Abstract
From a safety perspective, it is vital to have fast responding gas sensors for toxic and explosive gases in the event of a gas leak. Amperometric gas sensors have been developed for such a purpose, but their response times are often relatively slow - on the order of 50 seconds or more. In this work, we have developed sensors for hydrogen gas that demonstrate ultra-fast response times. The sensor consists of an array of gold microchannel electrodes, electrodeposited with platinum nanoparticles (PtNPs) to enable hydrogen electroactivity. Very thin layers (∼9 μm) of room temperature ionic liquids (RTILs) result in an extremely fast response time of only 2 s, significantly faster than the other conventional electrodes examined (unmodified Pt electrode, and PtNP modified Au electrode). The RTIL layer in the microchannels is much thinner than the channel length, showing an interesting yet complex diffusion pattern and characteristic thin-layer behavior. At short times (e.g. on the timescale of cyclic voltammetry), the oxidation current is smaller and steady-state in nature, compared to macrodisk electrodes. At longer times (e.g. using long-term chronoamperometry), the diffusion layer is large for all surfaces and extends to the liquid/gas phase boundary, where the gas is continuously replenished from the flowing gas stream. Thus, the current response is the largest on the microchannel electrode, resulting in the highest sensitivity and lowest limit of detection for hydrogen. These microchannel electrodes appear to be highly promising surfaces for the ultrafast detection of hydrogen gas, particularly at relevant concentrations close to, or below, the lower explosive limit of 4 vol-% H2.
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Affiliation(s)
- Ghulam Hussain
- Curtin Institute for Functional Molecules and Interfaces, School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, 6845, WA, Australia
| | - Mengchen Ge
- School of Chemistry, Faculty of Science, The University of New South Wales, Sydney, 2052, Australia
| | - Chuan Zhao
- School of Chemistry, Faculty of Science, The University of New South Wales, Sydney, 2052, Australia.
| | - Debbie S Silvester
- Curtin Institute for Functional Molecules and Interfaces, School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, 6845, WA, Australia.
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11
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Li Y, Pan C, Li Y, Kumacheva E, Ramachandran A. An exploration of the reflow technique for the fabrication of an in vitro microvascular system to study occlusive clots. Biomed Microdevices 2017; 19:82. [PMID: 28887730 DOI: 10.1007/s10544-017-0213-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Embolic ischemia and pulmonary embolism are health emergencies that arise when a particle such as a blood clot occludes a smaller blood vessel in the brain or the lungs, and restricts flow of blood downstream of the vessel. In this work, the reflow technique (Wang et al. Biomed. Microdevices 2007, 9, 657) was adapted to produce a microchannel network that mimics the occlusion process. The technique was first revisited and a simple geometrical model was developed to quantitatively explain the shapes of the resulting microchannels for different reflow parameters. A critical modification was introduced to the reflow protocol to fabricate nearly circular microchannels of different diameters from the same master, which is not possible with the traditional reflow technique. To simulate the phenomenon of occlusion by clots, a microchannel network with three generations of branches with different diameters and branching angles was fabricated, into which fibrin clots were introduced. At low constant pressure drop (ΔP), a clot blocked a branch entrance only partially, while at higher ΔP, the branch was completely blocked. Instances of simultaneous blocking of multiple channels by clots, and the consequent changes in the flow rates in the unblocked branches of the network, were also monitored. This work provides the framework for a systematic study of the distribution of clots in a network, and the rate of dissolution of embolic clots upon the introduction of a thrombolytic drug into the network.
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Affiliation(s)
- Yang Li
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, Toronto, Canada
| | - Chuer Pan
- Division of Engineering Science, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada
| | - Yunfeng Li
- Department of Chemistry, University of Toronto, Toronto, Canada
| | - Eugenia Kumacheva
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, Toronto, Canada
- Department of Chemistry, University of Toronto, Toronto, Canada
- Institute of Biomaterials & Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Arun Ramachandran
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, Toronto, Canada.
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12
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Simelane SM, Abelman S, Duncan FD. Microscale Gaseous Slip Flow in the Insect Trachea and Tracheoles. Acta Biotheor 2017; 65:211-231. [PMID: 28695410 DOI: 10.1007/s10441-017-9312-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 06/30/2017] [Indexed: 10/19/2022]
Abstract
An analytical investigation into compressible gas flow with slight rarefactions through the insect trachea and tracheoles during the closed spiracle phase is undertaken, and a complete set of asymptotic analytical solutions is presented. We first obtain estimates of the Reynolds and Mach numbers at the channel terminal ends where the tracheoles directly deliver respiratory gases to the cells, by comparing the magnitude of the different forces in the compressible gas flow. The 2D Navier-Stokes equations with a slip boundary condition are used to investigate compressibility and rarefied effects in the trachea and tracheoles. Expressions for the velocity components, pressure gradients and net flow inside the trachea are then presented. Numerical simulations of the tracheal compressible flow are performed to validate the analytical results from this study. This work extends previous work of Arkilic et al. (J Microelectromech Syst 6(2):167-178, 1997) on compressible flows through a microchannel. Novel devices for microfluidic compressible flow transport may be invented from results obtained in this study.
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13
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Fantuzzo JA, De Filippis L, McGowan H, Yang N, Ng YH, Halikere A, Liu JJ, Hart RP, Wernig M, Zahn JD, Pang ZP. μNeurocircuitry: Establishing in vitro models of neurocircuits with human neurons. Technology (Singap World Sci) 2017; 5:87-97. [PMID: 28781993 PMCID: PMC5541685 DOI: 10.1142/s2339547817500054] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Neurocircuits in the human brain govern complex behavior and involve connections from many different neuronal subtypes from different brain regions. Recent advances in stem cell biology have enabled the derivation of patient-specific human neuronal cells of various subtypes for the study of neuronal function and disease pathology. Nevertheless, one persistent challenge using these human-derived neurons is the ability to reconstruct models of human brain circuitry. To overcome this obstacle, we have developed a compartmentalized microfluidic device, which allows for spatial separation of cell bodies of different human-derived neuronal subtypes (excitatory, inhibitory and dopaminergic) but is permissive to the spreading of projecting processes. Induced neurons (iNs) cultured in the device expressed pan-neuronal markers and subtype specific markers. Morphologically, we demonstrate defined synaptic contacts between selected neuronal subtypes by synapsin staining. Functionally, we show that excitatory neuronal stimulation evoked excitatory postsynaptic current responses in the neurons cultured in a separate chamber.
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Affiliation(s)
- Joseph A Fantuzzo
- Child Health Institute of New Jersey, 89 French Street, New Brunswick, NJ 08901, USA
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, USA
| | - Lidia De Filippis
- Child Health Institute of New Jersey, 89 French Street, New Brunswick, NJ 08901, USA
- Department of Neuroscience and Cell Biology, Rutgers University, 675 Hoes Lane West, Piscataway, NJ 08854, USA
- Casa Sollievo della Sofferenza, Viale Cappuccini 1, 71013 San Giovanni Rotondo (FG), Italy
| | - Heather McGowan
- Child Health Institute of New Jersey, 89 French Street, New Brunswick, NJ 08901, USA
- Department of Neuroscience and Cell Biology, Rutgers University, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Nan Yang
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA
| | - Yi-Han Ng
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA
| | - Apoorva Halikere
- Child Health Institute of New Jersey, 89 French Street, New Brunswick, NJ 08901, USA
- Department of Neuroscience and Cell Biology, Rutgers University, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Jing-Jing Liu
- Child Health Institute of New Jersey, 89 French Street, New Brunswick, NJ 08901, USA
- Department of Neuroscience and Cell Biology, Rutgers University, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Ronald P Hart
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854, USA
| | - Marius Wernig
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA
| | - Jefrey D Zahn
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, USA
| | - Zhiping P Pang
- Child Health Institute of New Jersey, 89 French Street, New Brunswick, NJ 08901, USA
- Department of Neuroscience and Cell Biology, Rutgers University, 675 Hoes Lane West, Piscataway, NJ 08854, USA
- Department of Pediatrics, Robert Wood Johnson Medical School, Rutgers University, 1 Robert Wood Johnson Place, New Brunswick, NJ 08903, USA
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14
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Coppola S, Nasti G, Todino M, Olivieri F, Vespini V, Ferraro P. Direct Writing of Microfluidic Footpaths by Pyro-EHD Printing. ACS Appl Mater Interfaces 2017; 9:16488-16494. [PMID: 28446020 DOI: 10.1021/acsami.7b02633] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
In this study, we report a direct writing method for the fabrication of microfluidic footpaths by pyro-electrohydrodynamic (EHD) jet printing. Here, we propose the use of a nozzle-free three-dimensional printing technique for the fabrication of printed structures that can be embedded in a variety of soft, transparent, flexible, and biocompatible polymers and thus easily integrated into lab-on-chip devices. We prove the advantage of the high resolution and flexibility of pyro-EHD printing for the realization of microfluidic channels well below the standard limit in dimension of conventional ink-jet printing technique and simply adaptable to the end-user desires in terms of geometry and materials. Starting from the description of the innovative approach proposed for the channel fabrication, we demonstrate the design, fabrication, and proof of a microfluidic matrix of interconnected channels. The method described here could be a breakthrough technology for the fabrication of in situ implantable, stretchable, and biocompatible devices, opening new routes in the field of biomedical engineering and wearable electronics.
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Affiliation(s)
- Sara Coppola
- Institute of Applied Sciences and Intelligent System (CNR-ISASI) , Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Giuseppe Nasti
- Institute of Applied Sciences and Intelligent System (CNR-ISASI) , Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Michele Todino
- Institute of Applied Sciences and Intelligent System (CNR-ISASI) , Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Federico Olivieri
- Institute of Applied Sciences and Intelligent System (CNR-ISASI) , Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Veronica Vespini
- Institute of Applied Sciences and Intelligent System (CNR-ISASI) , Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - Pietro Ferraro
- Institute of Applied Sciences and Intelligent System (CNR-ISASI) , Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
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15
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Abstract
T Cells can form very stable (synapses) or very transient and migratory (kinapses) contacts with antigen-presenting cells. Here, we describe how microchannels can be used to conveniently study the distinct dynamics of T cells during antigen recognition. Microchannels provide a controlled confined environment that promotes T cell migration and recapitulates kinapse and synapse behaviors when coated with appropriate pMHC molecules. We also depict the advantages of this in vitro approach for addressing mechanistic issues and for analysis.
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16
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Gokaltun A, Yarmush ML, Asatekin A, Usta OB. Recent advances in nonbiofouling PDMS surface modification strategies applicable to microfluidic technology. Technology (Singap World Sci) 2017; 5:1-12. [PMID: 28695160 PMCID: PMC5501164 DOI: 10.1142/s2339547817300013] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In the last decade microfabrication processes including rapid prototyping techniques have advanced rapidly and achieved a fairly mature stage. These advances have encouraged and enabled the use of microfluidic devices by a wider range of users with applications in biological separations and cell and organoid cultures. Accordingly, a significant current challenge in the field is controlling biomolecular interactions at interfaces and the development of novel biomaterials to satisfy the unique needs of the biomedical applications. Poly(dimethylsiloxane) (PDMS) is one of the most widely used materials in the fabrication of microfluidic devices. The popularity of this material is the result of its low cost, simple fabrication allowing rapid prototyping, high optical transparency, and gas permeability. However, a major drawback of PDMS is its hydrophobicity and fast hydrophobic recovery after surface hydrophilization. This results in significant nonspecific adsorption of proteins as well as small hydrophobic molecules such as therapeutic drugs limiting the utility of PDMS in biomedical microfluidic circuitry. Accordingly, here, we focus on recent advances in surface molecular treatments to prevent fouling of PDMS surfaces towards improving its utility and expanding its use cases in biomedical applications.
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Affiliation(s)
- Aslihan Gokaltun
- Center for Engineering in Medicine at Massachusetts General Hospital, Harvard Medical School, and Shriners Hospital for Children, 51 Blossom St., Boston, MA 02114, USA
- Department of Chemical and Biological Engineering, Tufts University, 4 Colby Street, Medford, MA 02474, USA
- Department of Chemical Engineering, Hacettepe University, 06532, Beytepe, Ankara, Turkey
| | - Martin L Yarmush
- Center for Engineering in Medicine at Massachusetts General Hospital, Harvard Medical School, and Shriners Hospital for Children, 51 Blossom St., Boston, MA 02114, USA
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Rd., Piscataway, NJ 08854, USA
| | - Ayse Asatekin
- Department of Chemical and Biological Engineering, Tufts University, 4 Colby Street, Medford, MA 02474, USA
| | - O Berk Usta
- Center for Engineering in Medicine at Massachusetts General Hospital, Harvard Medical School, and Shriners Hospital for Children, 51 Blossom St., Boston, MA 02114, USA
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17
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Guo F, Guo D, Zhang W, Yan Q, Yang Y, Hong W, Yang G. Preparation of curcumin-loaded PCL-PEG-PCL triblock copolymeric nanoparticles by a microchannel technology. Eur J Pharm Sci 2017; 99:328-36. [PMID: 28062259 DOI: 10.1016/j.ejps.2017.01.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/28/2016] [Accepted: 01/02/2017] [Indexed: 11/22/2022]
Abstract
Biodegradable polymeric nanoparticles (NPs) have potential therapeutic applications; however, preparing NPs of a specific diameter and uniform size distribution is a challenge. In this work, we fabricated a microchannel system for the preparation of curcumin (Cur)-loaded NPs by the interfacial precipitation method, which rapidly and consistently generated stable NPs with a relatively smaller diameter, narrow size distribution, and higher drug-loading capacity and entrapment efficiency. Poly(ε-caprolactone)-poly(ethylene glycol)-poly (ε-caprolactone) triblock copolymers(PCEC) used as the carrier material was synthesized and characterized. Cur-loaded PCEC NPs had an average size of 167.2nm with a zeta potential of -29.23mV, and showed a loading capacity and drug entrapment efficiency of 15.28%±0.23% and 96.11%±0.13%, respectively. Meanwhile, the NPs demonstrated good biocompatibility and bioavailability, efficient cellular uptake, and long circulation time and a possible liver targeting effect in vivo. These results indicate that the Cur-loaded PCEC NPs can be used as drug carriers in controlled delivery systems and other biomedical applications.
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18
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Mathew B, Alazzam A, Abutayeh M, Stiharu I. Model-based analysis of a dielectrophoretic microfluidic device for field-flow fractionation. J Sep Sci 2016; 39:3028-36. [PMID: 27322871 DOI: 10.1002/jssc.201600350] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/26/2016] [Accepted: 05/26/2016] [Indexed: 11/05/2022]
Abstract
We present the development of a dynamic model for predicting the trajectory of microparticles in microfluidic devices, employing dielectrophoresis, for Hyperlayer field-flow fractionation. The electrode configuration is such that multiple finite-sized electrodes are located on the top and bottom walls of the microchannel; the electrodes on the walls are aligned with each other. The electric potential inside the microchannel is described using the Laplace equation while the microparticles' trajectory is described using equations based on Newton's second law. All equations are solved using finite difference method. The equations of motion account for forces including inertia, buoyancy, drag, gravity, virtual mass, and dielectrophoresis. The model is used for parametric study; the geometric parameters analyzed include microparticle radius, microchannel depth, and electrode/spacing lengths while volumetric flow rate and actuation voltage are the two operating parameters considered in the study. The trajectory of microparticles is composed of transient and steady state phases; the trajectory is influenced by all parameters. Microparticle radius and volumetric flow rate, above the threshold, do not influence the steady state levitation height; microparticle levitation is not possible below the threshold of the volumetric flow rate. Microchannel depth, electrode/spacing lengths, and actuation voltage influence the steady-state levitation height.
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Affiliation(s)
- Bobby Mathew
- Mechanical Engineering Department, Khalifa University, Abu Dhabi, UAE
| | - Anas Alazzam
- Mechanical Engineering Department, Khalifa University, Abu Dhabi, UAE
| | - Mohammad Abutayeh
- Mechanical Engineering Department, Khalifa University, Abu Dhabi, UAE
| | - Ion Stiharu
- Department of Mechanical and Industrial Engineering, Concordia University, Montreal, Canada
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19
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Pawar K, Prang P, Müller R, Caioni M, Bogdahn U, Kunz W, Weidner N. Intrinsic and extrinsic determinants of central nervous system axon outgrowth into alginate-based anisotropic hydrogels. Acta Biomater 2015; 27:131-139. [PMID: 26310676 DOI: 10.1016/j.actbio.2015.08.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 07/12/2015] [Accepted: 08/21/2015] [Indexed: 12/20/2022]
Abstract
Appropriate target reinnervation and functional recovery after spinal cord injury depend on longitudinally directed regrowth of injured axons. Anisotropic alginate-based capillary hydrogels (ACH) support peripheral nervous system derived axon growth, which is accompanied by glial supporting cell migration into the ACH. The aim of the present study was to analyze central nervous system (CNS) derived (entorhinal cortex, spinal cord slice cultures) axon regrowth into ACH containing linearly aligned capillaries of defined capillary sizes without and with gelatin constituent. Anisotropic ACH were prepared by ionotropic gel formation using Ba(2+), Cu(2+), Sr(2+), or Zn(2+) ions resulting in gels with average capillary diameters of 11, 13, 29, and 89μm, respectively. Postnatal rat entorhinal cortex or spinal cord slice cultures were placed on top of 500μm thick ACH. Seven days later axon growth and astroglial migration into the ACH were determined. Axon density within capillaries correlated positively with increasing capillary diameters, whereas longitudinally oriented axon outgrowth diminished with increasing capillary diameter. Axons growing into the hydrogels were always accompanied by astrocytes strongly suggesting that respective cells are required to mediate CNS axon elongation into ACH. Overall, midsize capillary diameter ACH appeared to be the best compromise between axon density and orientation. Taken together, ACH promote CNS axon ingrowth, which is determined by the capillary diameter and migration of slice culture derived astroglia into the hydrogel. STATEMENT OF SIGNIFICANCE Biomaterials are investigated as therapeutic tools to bridge irreversible lesions following traumatic spinal cord injury. The goal is to develop biomaterials, which promote longitudinally oriented regeneration of as many injured axons as possible as prerequisite for substantial functional recovery. Optimal parameters of the biomaterial have yet to be defined. In the present study we show that increasing capillary diameters within such hydrogels enhanced central nervous system axon regeneration at the expense of longitudinal orientation. Axon ingrowth into the hydrogels was only observed in the presence of glial supporting cells, namely astrocytes. This suggests that alginate-based hydrogels need to be colonized with respective cells in order to facilitate axon ingrowth.
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20
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Cheema MS, Dvivedi A, Sharma AK. Tool wear studies in fabrication of microchannels in ultrasonic micromachining. Ultrasonics 2015; 57:57-64. [PMID: 25465965 DOI: 10.1016/j.ultras.2014.10.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 06/04/2014] [Accepted: 10/21/2014] [Indexed: 06/04/2023]
Abstract
Form accuracy of a machined component is one of the performance indicators of a machining process. Ultrasonic micromachining is one such process in which the form accuracy of the micromachined component significantly depends upon the form stability of tool. Unlike macromachining, a very small amount of tool wear in micromachining could lead to considerable changes in the form accuracy of the machined component. Appropriate selection of tool material is essential to overcome this problem. The present study discusses the effect of tool material, abrasive size and step feed in fabrication of microchannels by ultrasonic machining on borosilicate glass. Development of microchannels using ultrasonic micromachining were rarely reported. It was observed that tungsten carbide tool provided a better form accuracy in comparison to the microchannel machined by stainless steel tool. The tool wear mechanism in both materials is proposed by considering scanning electron micrographs of the tool as evidence. A one factor at a time approach was used to study the effect of various process parameters.
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Affiliation(s)
- Manjot S Cheema
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee 247667, India.
| | - Akshay Dvivedi
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee 247667, India
| | - Apurbba K Sharma
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee 247667, India
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21
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Pilia M, Guda T, Pollot BE, Aguero V, Appleford MR. Local microarchitecture affects mechanical properties of deposited extracellular matrix for osteonal regeneration. Mater Sci Eng C Mater Biol Appl 2013; 35:122-33. [PMID: 24411360 DOI: 10.1016/j.msec.2013.10.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 09/23/2013] [Accepted: 10/19/2013] [Indexed: 10/26/2022]
Abstract
Multiple biomimetic approaches have been attempted to accelerate the regeneration of functional bone tissue. While most synthetic scaffolds are designed to mimic the architecture of trabecular bone, in the current study, cortical bone-like extracellular matrix was regenerated in vitro within organized structures. Biphasic calcium phosphate (BCaP) and hydroxyapatite (HAp) scaffolds were developed with longitudinal microchannels (250 μm diameter) that resembled native osteons in cortical bone. BCaP and HAp scaffolds had a compressive strength of 7.61±1.42 and 9.98±0.61 MPa respectively. The constructs were investigated in vitro to evaluate the organization and stiffness of the extracellular matrix (ECM) formed by human fetal osteoblasts (HFObs) cultured inside the microchannels. The ECM deposited on the BCaP scaffolds was found to have a higher micro-hardness (h) (1.93±0.40 GPa) than the ECM formed within the HAp microchannels (h=0.80±0.20 GPa) (p<0.05) or native bone (h=0.47-0.74 GPa). ECM deposition within the microchannels resembled osteoid organization and showed a significant increase in both osteoid area and thickness after 24 days (p<0.001). These observations indicate that controlled microarchitecture, specifically cylindrical microchannels, plays a fundamental role in stimulating the appropriate cellular response aimed at recreating organized, cortical bone-like matrix. These findings open the door for researchers to develop a new generation of cortical bone scaffolds that can restore strong, organized bone.
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Affiliation(s)
- M Pilia
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX, USA.
| | - T Guda
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX, USA
| | - B E Pollot
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX, USA
| | - V Aguero
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX, USA
| | - M R Appleford
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX, USA
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