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Yang X, Ma H, Chen Y, Venkateswaran S, Hsiao BS. Functionalization of cellulose acetate nanofibrous membranes for removal of particulate matters and dyes. Int J Biol Macromol 2024; 269:131852. [PMID: 38679253 DOI: 10.1016/j.ijbiomac.2024.131852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 04/08/2024] [Accepted: 04/23/2024] [Indexed: 05/01/2024]
Abstract
Particulates and organic toxins, such as microplastics and dye molecules, are contaminants in industrial wastewater that must be purified due to environmental and sustainability concerns. Carboxylated cellulose acetate (CTA-COOH) nanofibrous membranes were fabricated using electrospinning followed by an innovative one-step surface hydrolysis/oxidation replacing the conventional two-step reactions. This approach offers a new pathway for the modification strategy of cellulose-based membranes. The CTA-COOH membrane was utilized for the removal of particulates and cationic dyes through filtration and adsorption, respectively. The filtration performance of the CTA-COOH nanofibrous membrane was carried out; high separation efficiency and low pressure drop were achieved, in addition to the high filtration selectivity against 0.6-μm and 0.8-μm nanoparticles. A cationic Bismarck Brown Y, was employed to challenge the adsorption capability of the CTA-COOH nanofibrous membrane, where the maximum adsorption capacity of the membrane for BBY was 158.73 mg/g. The self-standing CTA-COOH membrane could be used to conduct adsorption-desorption for 17 cycles with the regeneration rate as high as 97.0 %. The CTA-COOH nanofibrous membrane has excellent mechanical properties and was employed to manufacture a spiral wound adsorption cartridge, which exhibited remarkable separation efficiency in terms of treated water volume, which was 5.96 L, and retention rate, which was 100 %.
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Affiliation(s)
- Xiao Yang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
| | - Hongyang Ma
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China; Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA.
| | - Yi Chen
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
| | - Shyam Venkateswaran
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Benjamin S Hsiao
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
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Shargh AK, Abdolrahim N. An interpretable deep learning approach for designing nanoporous silicon nitride membranes with tunable mechanical properties. NPJ COMPUTATIONAL MATERIALS 2023; 9:82. [PMID: 37273663 PMCID: PMC10221757 DOI: 10.1038/s41524-023-01037-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 05/07/2023] [Indexed: 06/06/2023]
Abstract
The high permeability and strong selectivity of nanoporous silicon nitride (NPN) membranes make them attractive in a broad range of applications. Despite their growing use, the strength of NPN membranes needs to be improved for further extending their biomedical applications. In this work, we implement a deep learning framework to design NPN membranes with improved or prescribed strength values. We examine the predictions of our framework using physics-based simulations. Our results confirm that the proposed framework is not only able to predict the strength of NPN membranes with a wide range of microstructures, but also can design NPN membranes with prescribed or improved strength. Our simulations further demonstrate that the microstructural heterogeneity that our framework suggests for the optimized design, lowers the stress concentration around the pores and leads to the strength improvement of NPN membranes as compared to conventional membranes with homogenous microstructures.
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Affiliation(s)
- Ali K. Shargh
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627 USA
| | - Niaz Abdolrahim
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627 USA
- Materials Science program, University of Rochester, Rochester, NY 14627 USA
- Laboratory for Laser Energetics, University of Rochester, Rochester, NY 14627 USA
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Klaczko ME, Lucas K, Salminen AT, McCloskey MC, Ozgurun B, Ward BM, Flax J, McGrath JL. Rapid and specific detection of intact viral particles using functionalized microslit silicon membranes as a fouling-based sensor. Analyst 2021; 147:213-222. [PMID: 34933322 DOI: 10.1039/d1an01504d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The COVID-19 pandemic demonstrated the public health benefits of reliable and accessible point-of-care (POC) diagnostic tests for viral infections. Despite the rapid development of gold-standard reverse transcription polymerase chain reaction (RT-PCR) assays for SARS-CoV-2 only weeks into the pandemic, global demand created logistical challenges that delayed access to testing for months and helped fuel the spread of COVID-19. Additionally, the extreme sensitivity of RT-PCR had a costly downside as the tests could not differentiate between patients with active infection and those who were no longer infectious but still shedding viral genomes. To address these issues for the future, we propose a novel membrane-based sensor that only detects intact virions. The sensor combines affinity and size based detection on a membrane-based sensor and does not require external power to operate or read. Specifically, the presence of intact virions, but not viral debris, fouls the membrane and triggers a macroscopically visible hydraulic switch after injection of a 40 μL sample with a pipette. The device, which we call the μSiM-DX (microfluidic device featuring a silicon membrane for diagnostics), features a biotin-coated microslit membrane with pores ∼2-3× larger than the intact virus. Streptavidin-conjugated antibody recognizing viral surface proteins are incubated with the sample for ∼1 hour prior to injection into the device, and positive/negative results are obtained within ten seconds of sample injection. Proof-of-principle tests have been performed using preparations of vaccinia virus. After optimizing slit pore sizes and porous membrane area, the fouling-based sensor exhibits 100% specificity and 97% sensitivity for vaccinia virus (n = 62). Moreover, the dynamic range of the sensor extends at least from 105.9 virions per mL to 1010.4 virions per mL covering the range of mean viral loads in symptomatic COVID-19 patients (105.6-107 RNA copies per mL). Forthcoming work will test the ability of our sensor to perform similarly in biological fluids and with SARS-CoV-2, to fully test the potential of a membrane fouling-based sensor to serve as a PCR-free alternative for POC containment efforts in the spread of infectious disease.
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Affiliation(s)
- Michael E Klaczko
- Department of Chemistry, University of Rochester, Rochester, NY, 14627 USA
| | - Kilean Lucas
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, 14627 USA.
| | - Alec T Salminen
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, 14627 USA.
| | - Molly C McCloskey
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, 14627 USA.
| | - Baturay Ozgurun
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, 14627 USA.
| | - Brian M Ward
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, 14642 USA
| | - Jonathan Flax
- Department of Urology, University of Rochester Medical Center, Rochester, NY, 14642 USA
| | - James L McGrath
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, 14627 USA.
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Lucas K, Dehghani M, Khire T, Gaborski T, Flax JD, Waugh RE, McGrath JL. A predictive model of nanoparticle capture on ultrathin nanoporous membranes. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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An experimental and numerical study of droplet spreading and imbibition on microporous membranes. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126191] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Madejski GR, Ahmad SD, Musgrave J, Flax J, Madejski JG, Rowley DA, DeLouise LA, Berger AJ, Knox WH, McGrath JL. Silicon Nanomembrane Filtration and Imaging for the Evaluation of Microplastic Entrainment along a Municipal Water Delivery Route. SUSTAINABILITY 2020; 12:10655. [PMID: 36938128 PMCID: PMC10022737 DOI: 10.3390/su122410655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
To better understand the origin of microplastics in municipal drinking water, we evaluated 50 mL water samples from different stages of the City of Rochester's drinking water production and transport route, from Hemlock Lake to the University of Rochester. We directly filtered samples using silicon nitride nanomembrane filters with precisely patterned slit-shaped pores, capturing many of the smallest particulates (<20 μm) that could be absorbed by the human body. We employed machine learning algorithms to quantify the shapes and quantity of debris at different stages of the water transport process, while automatically segregating out fibrous structures from particulate. Particulate concentrations ranged from 13 to 720 particles/mL at different stages of the water transport process and fibrous pollution ranged from 0.4 to 8.3 fibers/mL. A subset of the debris (0.2-8.6%) stained positively with Nile red dye which identifies them as hydrophobic polymers. Further spectroscopic analysis also indicated the presence of many non-plastic particulates, including rust, silicates, and calcium scale. While water leaving the Hemlock Lake facility is mostly devoid of debris, transport through many miles of piping results in the entrainment of a significant amount of debris, including plastics, although in-route reservoirs and end-stage filtration serve to reduce these concentrations.
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Affiliation(s)
- Gregory R. Madejski
- 306 Goergen Hall, Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA
- Correspondence: (G.R.M.); (J.L.M.); Tel.: +1-585-460-3113 (G.R.M.); +1-585-273-5489 (J.L.M.)
| | - S. Danial Ahmad
- 306 Goergen Hall, Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA
| | - Jonathan Musgrave
- 508 Goergen Hall, The Institute of Optics, University of Rochester, Rochester, NY 14627, USA
| | - Jonathan Flax
- 306 Goergen Hall, Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA
| | - Joseph G. Madejski
- 306 Goergen Hall, Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA
| | - David A. Rowley
- Rochester Water Bureau, 7412 Rix Hill Rd, Hemlock, NY 14466, USA
| | - Lisa A. DeLouise
- 306 Goergen Hall, Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA
- Department of Dermatology, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Andrew J. Berger
- 405 Goergen Hall, The Institute of Optics, University of Rochester, Rochester, NY 14627, USA
| | - Wayne H. Knox
- 508 Goergen Hall, The Institute of Optics, University of Rochester, Rochester, NY 14627, USA
| | - James L. McGrath
- 306 Goergen Hall, Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA
- Correspondence: (G.R.M.); (J.L.M.); Tel.: +1-585-460-3113 (G.R.M.); +1-585-273-5489 (J.L.M.)
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Lucas K, Ahmad SD, Dehghani M, Gaborski T, McGrath J. Critical flux behavior of ultrathin membranes in protein-rich solutions. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2020.117342] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Cimadoro J, Goyanes S. Reversible swelling as a strategy in the development of smart membranes from electrospun polyvinyl alcohol nanofiber mats. JOURNAL OF POLYMER SCIENCE 2020. [DOI: 10.1002/pol.20190156] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Jonathan Cimadoro
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Departamento de Física, Laboratorio de Polímeros y Materiales Compuestos (LP&MC)Instituto de Física de Buenos Aires (IFIBA‐CONICET) Buenos Aires Argentina
| | - Silvia Goyanes
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Departamento de Física, Laboratorio de Polímeros y Materiales Compuestos (LP&MC)Instituto de Física de Buenos Aires (IFIBA‐CONICET) Buenos Aires Argentina
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Khire TS, Salminen AT, Swamy H, Lucas KS, McCloskey MC, Ajalik RE, Chung HH, Gaborski TR, Waugh RE, Glading AJ, McGrath JL. Microvascular Mimetics for the Study of Leukocyte-Endothelial Interactions. Cell Mol Bioeng 2020; 13:125-139. [PMID: 32175026 DOI: 10.1007/s12195-020-00611-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 01/24/2020] [Indexed: 02/06/2023] Open
Abstract
Introduction The pathophysiological increase in microvascular permeability plays a well-known role in the onset and progression of diseases like sepsis and atherosclerosis. However, how interactions between neutrophils and the endothelium alter vessel permeability is often debated. Methods In this study, we introduce a microfluidic, silicon-membrane enabled vascular mimetic (μSiM-MVM) for investigating the role of neutrophils in inflammation-associated microvascular permeability. In utilizing optically transparent silicon nanomembrane technology, we build on previous microvascular models by enabling in situ observations of neutrophil-endothelium interactions. To evaluate the effects of neutrophil transmigration on microvascular model permeability, we established and validated electrical (transendothelial electrical resistance and impedance) and small molecule permeability assays that allow for the in situ quantification of temporal changes in endothelium junctional integrity. Results Analysis of neutrophil-expressed β1 integrins revealed a prominent role of neutrophil transmigration and basement membrane interactions in increased microvascular permeability. By utilizing blocking antibodies specific to the β1 subunit, we found that the observed increase in microvascular permeability due to neutrophil transmigration is constrained when neutrophil-basement membrane interactions are blocked. Having demonstrated the value of in situ measurements of small molecule permeability, we then developed and validated a quantitative framework that can be used to interpret barrier permeability for comparisons to conventional Transwell™ values. Conclusions Overall, our results demonstrate the potential of the μSiM-MVM in elucidating mechanisms involved in the pathogenesis of inflammatory disease, and provide evidence for a role for neutrophils in inflammation-associated endothelial barrier disruption.
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Affiliation(s)
- Tejas S Khire
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627 USA
| | - Alec T Salminen
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627 USA
| | - Harsha Swamy
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14627 USA
| | - Kilean S Lucas
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627 USA
| | - Molly C McCloskey
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627 USA
| | - Raquel E Ajalik
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627 USA
| | - Henry H Chung
- Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, NY 14623 USA
| | - Thomas R Gaborski
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627 USA.,Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, NY 14623 USA
| | - Richard E Waugh
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627 USA
| | - Angela J Glading
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14627 USA
| | - James L McGrath
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627 USA
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Dehghani M, Lucas K, Flax J, McGrath J, Gaborski T. Tangential flow microfluidics for the capture and release of nanoparticles and extracellular vesicles on conventional and ultrathin membranes. ADVANCED MATERIALS TECHNOLOGIES 2019; 4:1900539. [PMID: 32395607 PMCID: PMC7212937 DOI: 10.1002/admt.201900539] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Indexed: 05/04/2023]
Abstract
Membranes have been used extensively for the purification and separation of biological species. A persistent challenge is the purification of species from concentrated feed solutions such as extracellular vesicles (EVs) from biological fluids. We investigated a new method to isolate micro- and nano-scale species termed tangential flow for analyte capture (TFAC), which is an extension of traditional tangential flow filtration (TFF). Initially, EV purification from plasma on ultrathin nanomembranes was compared between both normal flow filtration (NFF) and TFAC. NFF resulted in rapid formation of a protein cake which completely obscured any captured EVs and also prevented further transport across the membrane. On the other hand, TFAC showed capture of CD63 positive small EVs (sEVs) with minimal contamination. We explored the use of TFAC to capture target species over membrane pores, wash and then release in a physical process that does not rely upon affinity or chemical interactions. This process of TFAC was studied with model particles on both ultrathin nanomembranes and conventional thickness membranes (polycarbonate track-etch). Successful capture and release of model particles was observed using both membranes. Ultrathin nanomembranes showed higher efficiency of capture and release with significantly lower pressures indicating that ultrathin nanomembranes are well-suited for TFAC of delicate nanoscale particles such as EVs.
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Affiliation(s)
- Mehdi Dehghani
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, United States
- Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, NY, United States
| | - Kilean Lucas
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, United States
| | - Jonathan Flax
- Department of Urology, University of Rochester Medical School, Rochester, NY, United States
| | - James McGrath
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, United States
| | - Thomas Gaborski
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, United States
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, United States
- Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, NY, United States
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Madejski GR, Briggs K, DesOrmeaux JP, Miller JJ, Roussie JA, Tabard-Cossa V, McGrath JL. Monolithic Fabrication of NPN/SiN x Dual Membrane Cavity for Nanopore-based DNA Sensing. ADVANCED MATERIALS INTERFACES 2019; 6:1900684. [PMID: 32577337 PMCID: PMC7310959 DOI: 10.1002/admi.201900684] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Indexed: 06/11/2023]
Abstract
Nanoscale preconfinement of DNA has been shown to reduce the variation of passage times through solid-state nanopores. Preconfinement has been previously achieved by forming a femtoliter-sized cavity capped with a highly porous layer of nanoporous silicon nitride (NPN). This cavity was formed by sealing a NPN nanofilter membrane against a substrate chip using water vapor delamination. Ultimately, this method of fabrication cannot keep a consistent spacing between the filter and solid-state nanopore due to thermal fluctuations and wrinkles in the membrane, nor can it be fabricated on thousands of individual devices reliably. To overcome these issues, we present a method to fabricate the femtoliter cavity monolithically, using a selective XeF2 etch to hollow out a polysilicon spacer sandwiched between silicon nitride layers. These monolithically fabricated cavities behave identically to their counterparts formed by vapor delamination, exhibiting similar translocation passage time variation reduction and folding suppression of DNA without requiring extensive manual assembly. The ability to form nanocavity sensors with nanometer-scale precision and to reliably manufacture them at scale using batch wafer processing techniques will find numerous applications, including motion control of polymers for single-molecule detection applications, filtering of dirty samples prior to nanopore detection, and simple fabrication of single-molecule nanobioreactors.
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Affiliation(s)
- Gregory R. Madejski
- Department of Biomedical Engineering, University of Rochester, Robert B. Goergen Hall Box 270168 Rochester, NY 14627, USA
| | - Kyle Briggs
- Department of Physics, University of Ottawa, 150 Louis-Pasteur Pvt, Ottawa, ON, K1N6N5, Canada
| | | | - Joshua J. Miller
- SiMPore Inc, 150 Lucius Gordon Dr, West Henrietta, NY, 14586, USA
| | - James A. Roussie
- SiMPore Inc, 150 Lucius Gordon Dr, West Henrietta, NY, 14586, USA
| | - Vincent Tabard-Cossa
- Department of Physics, University of Ottawa, 150 Louis-Pasteur Pvt, Ottawa, ON, K1N6N5, Canada
| | - James L. McGrath
- Department of Biomedical Engineering, University of Rochester, Robert B. Goergen Hall Box 270168 Rochester, NY 14627, USA
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Pazouki M, Noelle Wilton A, Latulippe DR. An experimental study on sterile filtration of fluorescently labeled nanoparticles – the importance of surfactant concentration. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2019.02.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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13
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Treatment of Palm Oil Mill Effluent Using Membrane Bioreactor: Novel Processes and Their Major Drawbacks. WATER 2018. [DOI: 10.3390/w10091165] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Over the years, different types of alternative technologies have been developed and used for palm oil mill effluent (POME) treatment. Specifically, membrane bioreactor (MBR) has been employed to relegate pollutants contained in POME under different operating conditions, and the technology was found to be promising. The major challenge impeding the wider application of this technology is membrane fouling, which usually attracts high operating energy and running cost. In this regard, novel methods of mitigating membrane fouling through the treatment processes have been developed. Therefore, this review article specifically focuses on the recent treatment processes of POME using MBR, with particular emphasis on innovative processes conditions such as aerobic, anaerobic, and hybrid processing as well as their performance in relation to fouling minimization. Furthermore, the effects of sonication and thermophilic and mesophilic conditions on membrane blockage were critically reviewed. The types of foulants and fouling mechanism as influenced by different operating conditions were also analyzed censoriously.
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Madejski G, Lucas K, Pascut FC, Webb KF, McGrath JL. TEM Tomography of Pores with Application to Computational Nanoscale Flows in Nanoporous Silicon Nitride (NPN). MEMBRANES 2018; 8:membranes8020026. [PMID: 29865242 PMCID: PMC6027491 DOI: 10.3390/membranes8020026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 05/30/2018] [Accepted: 05/30/2018] [Indexed: 11/20/2022]
Abstract
Silicon nanomembrane technologies (NPN, pnc-Si, and others) have been used commercially as electron microscopy (EM) substrates, and as filters with nanometer-resolution size cut-offs. Combined with EM, these materials provide a platform for catching or suspending nanoscale-size structures for analysis. Usefully, the nanomembrane itself can be manufactured to achieve a variety of nanopore topographies. The size, shapes, and surfaces of nanopores will influence transport, fouling, sieving, and electrical behavior. Electron tomography (ET) techniques used to recreate nanoscale-sized structures would provide an excellent way to capture this variation. Therefore, we modified a sample holder to accept our standardized 5.4 mm × 5.4 mm silicon nanomembrane chips and imaged NPN nanomembranes (50–100 nm thick, 10–100 nm nanopore diameters) using transmission electron microscopy (TEM). After imaging and ET reconstruction using a series of freely available tools (ImageJ, TomoJ, SEG3D2, Meshlab), we used COMSOL Multiphysics™ to simulate fluid flow inside a reconstructed nanopore. The results show flow profiles with significantly more complexity than a simple cylindrical model would predict, with regions of stagnation inside the nanopores. We expect that such tomographic reconstructions of ultrathin nanopores will be valuable in elucidating the physics that underlie the many applications of silicon nanomembranes.
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Affiliation(s)
- Gregory Madejski
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA.
| | - Kilean Lucas
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA.
| | - Flavius C Pascut
- Department of Electrical & Electronic Engineering, University of Nottingham, Nottingham NG7 2RD, UK.
| | - Kevin F Webb
- Department of Electrical & Electronic Engineering, University of Nottingham, Nottingham NG7 2RD, UK.
| | - James L McGrath
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627, USA.
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15
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Smith KJ, May M, Baltus R, McGrath JL. A predictive model of separations in dead-end filtration with ultrathin membranes. Sep Purif Technol 2017. [DOI: 10.1016/j.seppur.2017.07.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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16
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Li X, Johnson D, Ma W, Chung H, Getpreecharsawas J, McGrath JL, Shestopalov AA. Modification of Nanoporous Silicon Nitride with Stable and Functional Organic Monolayers. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2017; 29:2294-2302. [PMID: 29651199 PMCID: PMC5892436 DOI: 10.1021/acs.chemmater.6b05392] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
This study describes the formation of functional organic monolayers on thin, nanoporous silicon nitride membranes. We demonstrate that the vapor-phase carbene insertion into the surface C-H bonds can be used to form sub-5 nm molecular coatings on nanoporous materials, which can be further modified with monolayers of polyethylene glycol (PEG) molecules. We investigate composition, thickness, and stability of the functionalized monolayers and the changes in the membrane permeability and pore size distribution. We show that, due to the low coating thickness (~7 nm), the functionalized membrane retains 80% of the original gas permeance and 40% of the original hydraulic permeability. We also show that the carbene/PEG functionalization is hydrolytically stable for up to 48 h of exposure to water and that it can suppress nonspecific adsorption of the proteins BSA and IgG. Our results suggest that the vapor-phase carbenylation can be used as a complementary technology to the traditional self-assembly and polymer brush chemistries in chemical functionalization of nanoporous materials, which are limited in their ability to serve as stable coatings that do not occlude nanomembrane pores.
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Affiliation(s)
- Xunzhi Li
- Department of Chemical Engineering, University of Rochester, Rochester, New York 14627, United States
| | - Dean Johnson
- Department of Biomedical Engineering, University of Rochester, Rochester, New York 14627, United States
| | - Wenchuan Ma
- Department of Chemical Engineering, University of Rochester, Rochester, New York 14627, United States
| | - Henry Chung
- Department of Biomedical Engineering, University of Rochester, Rochester, New York 14627, United States
| | - Jirachai Getpreecharsawas
- Department of Biomedical Engineering, University of Rochester, Rochester, New York 14627, United States
| | - James L. McGrath
- Department of Biomedical Engineering, University of Rochester, Rochester, New York 14627, United States
- Corresponding Authors: .
| | - Alexander A. Shestopalov
- Department of Chemical Engineering, University of Rochester, Rochester, New York 14627, United States
- Corresponding Authors: .
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