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Abstract
End-stage renal disease (ESRD) continues to be a disease process with a high rate of hospitalization and mortality. There has been little innovation in nephrology over the last few decades compared to revolutionary high-tech advancements in other areas like oncology and cardiovascular medicine. Kidney transplantation, the only available alternative to renal replacement therapy, is limited in its availability. It is essential to have advances in this field to improve the efficiency of currently available treatments and devise new therapies. The current description of renal replacement therapy is inappropriate as it only replaces the filtration function of the failed kidney without addressing its other vital metabolic, endocrinologic, and immunologic roles and portability. Hence, it is critical to have newer therapies focusing on total replacement and portability, not just clearance. This review will address the developments in hemodialysis therapy. Advances in hemodialysis therapy include hemodiafiltration, portable machines, wearable artificial kidneys, and bioartificial kidneys. Although promising, newer technologies in this direction are still far from clinical application. Several organizations and enterprises including the Kidney Health Initiative and Kidney X: The Kidney Innovation Accelerator, as well as The Advancing American Kidney Health Initiative, are working in tandem to develop new therapies that could customize the treatment of ESRD.
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Affiliation(s)
- Bijin Thajudeen
- Division of Nephrology, Banner University of Arizona, 1501 N Campbell Ave, Tucson, AZ 85724, USA
| | - Dany Issa
- WG (Bill) Hefner VA Medical Center, 1601 Brenner Ave, Salisbury, NC 28144, USA
| | - Prabir Roy-Chaudhury
- UNC Kidney Center, University of North Carolina at Chapel Hill, 101 Manning Dr, Chapel Hill, NC 27514, USA
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2
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Blauvelt DG, Chui BW, Higgins NC, Baltazar FJ, Roy S. Silicon membranes for extracorporeal life support: a comparison of design and fabrication methodologies. Biomed Microdevices 2022; 25:2. [PMID: 36472672 DOI: 10.1007/s10544-022-00639-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2022] [Indexed: 12/12/2022]
Abstract
Extracorporeal life support is an advanced therapy that circulates blood through an extracorporeal oxygenator, performing gas exchange outside the body. However, its use is limited by severe complications, including bleeding, clotting, and hemolysis. Semiconductor silicon-based membranes have emerged as an alternative to traditional hollow-fiber semipermeable membranes. These membranes offer excellent gas exchange efficiency and the potential to increase hemocompatibility by improving flow dynamics. In this work, we evaluate two next-generation silicon membrane designs, which are intended to be mechanically robust and efficient in gas exchange, while simultaneously reducing fabrication complexity. The "window" design features 10 µm pores on one side and large windows on the back side. The "cavern" design also uses 10 µm pores but contains a network of interconnected buried caverns to distribute the sweep gas from smaller inlet holes. Both designs were shown to be technically viable and able to be reproducibly fabricated. In addition, they both were mechanically robust and withstood 30 psi of transmembrane pressure without breakage or bubbling. At low sweep gas pressures, gas transfer efficiency was similar, with the partial pressure of oxygen in water increasing by 10.7 ± 2.3 mmHg (mean ± standard deviation) and 13.6 ± 1.9 mmHg for the window and cavern membranes, respectively. Gas transfer efficiency was also similar at higher pressures. At 10 psi, oxygen tension increased by 16.8 ± 5.7 mmHg (window) and 18.9 ± 1.3 mmHg (cavern). We conclude that silicon membranes featuring a 10 µm pore size can simplify the fabrication process and improve mechanical robustness while maintaining excellent efficiency.
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Affiliation(s)
- David G Blauvelt
- Department of Pediatrics, University of California, San Francisco, CA, USA
| | - Benjamin W Chui
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Nicholas C Higgins
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Francisco J Baltazar
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Shuvo Roy
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA.
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3
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Lu D, Liu H, Tang Z, Wang M, Song Z, Zhu H, Qian D, Shi X, Li G, Li B. Anti-Pectin Fouling Performance of Dopamine and (3-Aminopropy) Triethoxysilane-Coated PVDF Ultrafiltration Membrane. MEMBRANES 2022; 12:membranes12080740. [PMID: 36005654 PMCID: PMC9415628 DOI: 10.3390/membranes12080740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/22/2022] [Accepted: 07/23/2022] [Indexed: 02/01/2023]
Abstract
Due to the diversity and complexity of the components in traditional Chinese medicine (TCM) extracts, serious membrane fouling has become an obstacle that limits the application of membrane technology in TCM. Pectin, a heteropolysaccharide widely existing in plant cells, is the main membrane-fouling substance in TCM extracts. In this study, a hydrophilic hybrid coating was constructed on the surface of a polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane co-deposited with polydopamine (pDA) and (3-Aminopropy) triethoxysilane (KH550) for pectin antifouling. Characterization analysis showed that hydrophilic coating containing hydrophilic groups (–NH3, Si-OH, Si-O-Si) formed on the surface of the modified membrane. Membrane filtration experiments showed that, compared with a matched group (FRR: 28.66%, Rr: 26.87%), both the flux recovery rate (FRR) and reversible pollution rate (Rr) of the pDA and KH550 coated membrane (FRR: 48.07%, Rr: 44.46%) increased, indicating that pectin absorbed on the surface of membranes was more easily removed. Based on the extended Derjaguin–Laudau–Verwey–Overbeek (XDLVO) theory, the fouling mechanism of a PVDF UF membrane caused by pectin was analyzed. It was found that, compared with the pristine membrane (144.21 kT), there was a stronger repulsive energy barrier (3572.58 kT) to confront the mutual adsorption between the coated membrane and pectin molecule. The total interface between the modified membrane and the pectin molecule was significantly greater than the pristine membrane. Therefore, as the repulsion between them was enhanced, pectin molecules were not easily adsorbed on the surface of the coated membrane.
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Affiliation(s)
- Dengrong Lu
- Co-Construction Collaborative Innovation Center for Chinese Medicine Resources Industrialization by Shaanxi & Education Ministry, Shaanxi University of Chinese Medicine, Xianyang 712038, China; (D.L.); (M.W.); (Z.S.); (X.S.); (G.L.)
- State Key Laboratory of Research & Development of Characteristic Qin Medicine Resources (Cultivation), Shaanxi University of Chinese Medicine, Xianyang 712038, China
| | - Hongbo Liu
- Co-Construction Collaborative Innovation Center for Chinese Medicine Resources Industrialization by Shaanxi & Education Ministry, Shaanxi University of Chinese Medicine, Xianyang 712038, China; (D.L.); (M.W.); (Z.S.); (X.S.); (G.L.)
- State Key Laboratory of Research & Development of Characteristic Qin Medicine Resources (Cultivation), Shaanxi University of Chinese Medicine, Xianyang 712038, China
- Correspondence: (H.L.); (Z.T.)
| | - Zhishu Tang
- Co-Construction Collaborative Innovation Center for Chinese Medicine Resources Industrialization by Shaanxi & Education Ministry, Shaanxi University of Chinese Medicine, Xianyang 712038, China; (D.L.); (M.W.); (Z.S.); (X.S.); (G.L.)
- State Key Laboratory of Research & Development of Characteristic Qin Medicine Resources (Cultivation), Shaanxi University of Chinese Medicine, Xianyang 712038, China
- China Academy of Chinese Medical Sciences, Beijing 100700, China
- Correspondence: (H.L.); (Z.T.)
| | - Mei Wang
- Co-Construction Collaborative Innovation Center for Chinese Medicine Resources Industrialization by Shaanxi & Education Ministry, Shaanxi University of Chinese Medicine, Xianyang 712038, China; (D.L.); (M.W.); (Z.S.); (X.S.); (G.L.)
- Wang Jing Hospital of China Academy of Chinese Medical Sciences, Beijing 100102, China
| | - Zhongxing Song
- Co-Construction Collaborative Innovation Center for Chinese Medicine Resources Industrialization by Shaanxi & Education Ministry, Shaanxi University of Chinese Medicine, Xianyang 712038, China; (D.L.); (M.W.); (Z.S.); (X.S.); (G.L.)
- State Key Laboratory of Research & Development of Characteristic Qin Medicine Resources (Cultivation), Shaanxi University of Chinese Medicine, Xianyang 712038, China
| | - Huaxu Zhu
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, Nanjing 210023, China; (H.Z.); (D.Q.); (B.L.)
- Jiangsu Botanical Medicine Refinement Engineering Research Center, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Dawei Qian
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, Nanjing 210023, China; (H.Z.); (D.Q.); (B.L.)
| | - Xinbo Shi
- Co-Construction Collaborative Innovation Center for Chinese Medicine Resources Industrialization by Shaanxi & Education Ministry, Shaanxi University of Chinese Medicine, Xianyang 712038, China; (D.L.); (M.W.); (Z.S.); (X.S.); (G.L.)
- State Key Laboratory of Research & Development of Characteristic Qin Medicine Resources (Cultivation), Shaanxi University of Chinese Medicine, Xianyang 712038, China
| | - Guolong Li
- Co-Construction Collaborative Innovation Center for Chinese Medicine Resources Industrialization by Shaanxi & Education Ministry, Shaanxi University of Chinese Medicine, Xianyang 712038, China; (D.L.); (M.W.); (Z.S.); (X.S.); (G.L.)
- State Key Laboratory of Research & Development of Characteristic Qin Medicine Resources (Cultivation), Shaanxi University of Chinese Medicine, Xianyang 712038, China
| | - Bo Li
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, Nanjing 210023, China; (H.Z.); (D.Q.); (B.L.)
- Jiangsu Botanical Medicine Refinement Engineering Research Center, Nanjing University of Chinese Medicine, Nanjing 210023, China
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Arshad F, Aubry C, Zou L. Highly Permeable MoS 2 Nanosheet Porous Membrane for Organic Matter Removal. ACS OMEGA 2022; 7:2419-2428. [PMID: 35071929 PMCID: PMC8772329 DOI: 10.1021/acsomega.1c06480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/29/2021] [Indexed: 05/14/2023]
Abstract
MoS2 nanosheets were synthesized by a bottom-up green chemical process where l-cysteine was used as a sulfur precursor. With specific concentrations, molar ratio of reactants, and pre-mixing conditions, MoS2 nanosheets of 200-300 nm in size and 4.2 nm in average thickness were successfully obtained. Porous membranes were then prepared by depositing the MoS2 nanosheet suspension on a 0.1 μm pore size poly(vinylidene difluoride) membrane filter in a multiple batch procedure. The membrane deposited with 12 batches of MoS2 nanosheets achieved 93.78% removal of bovine serum albumin. Acid red removal of 95.65% was also achieved after the second filtration pass. The porous MoS2 nanosheet membrane also demonstrated a high water flux of 182 ± 2.0 L/(m2 h). This result overcame the trade-off between selectivity and permeability faced by polymeric ultrafiltration membranes. The MoS2 nanosheets as building blocks formed not only intersheet slit pores with a narrow half-width to restrict the passage of organic molecules but also macro-channels allowing easy passage of water. The assembled MoS2 nanosheet membrane delivered promising separation of protein molecules and a high flux, attributing to its porous nanostructure, and could be a potential membrane for various water applications.
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Affiliation(s)
- Fathima Arshad
- Department
of Civil Infrastructure and Environment Engineering, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
| | - Cyril Aubry
- Department
of Research Laboratories Operations, Khalifa
University of Science and Technology, Abu Dhabi 127788, United
Arab Emirates
| | - Linda Zou
- Department
of Civil Infrastructure and Environment Engineering, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
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6
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Baraket A, Alcaraz JP, Gondran C, Costa G, Nonglaton G, Gaillard F, Cinquin P, Cosnier ML, Martin DK. Long duration stabilization of porous silicon membranes in physiological media: Application for implantable reactors. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 108:110359. [PMID: 31923938 DOI: 10.1016/j.msec.2019.110359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 10/01/2019] [Accepted: 10/21/2019] [Indexed: 10/25/2022]
Abstract
The natural biodegradabilty of porous silicon (pSi) in physiological media limits its wider usage for implantable systems. We report the stabilization of porous silicon (pSi) membranes by chemical surface oxidation using RCA1 and RCA2 protocols, which was followed by a PEGylation process using a silane-PEG. These surface modifications stabilized the pSi to allow a long period of immersion in PBS, while leaving the pSi surface sufficiently hydrophilic for good filtration and diffusion of several biomolecules of different sizes without any blockage of the pSi structure. The pore sizes of the pSi membranes were between 5 and 20 nm, with the membrane thickness around 70 μm. The diffusion coefficient for fluorescein through the membrane was 2 × 10-10 cm2 s-1, and for glucose was 2.2 × 10-9 cm2 s-1. The pSi membrane maintained that level of glucose diffusion for one month of immersion in PBS. After 2 months immersion in PBS the pSi membrane continued to operate, but with a reduced glucose diffusion coefficient. The chemical stabilization of pSi membranes provided almost 1 week stable and functional biomolecule transport in blood plasma and opens the possibility for its short-term implantation as a diffusion membrane in biocompatible systems.
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Affiliation(s)
- Abdoullatif Baraket
- ISA, Institut des Sciences Analytiques, Département LSA, 5, rue de la Doua, 69100, Villeurbanne, France
| | - Jean-Pierre Alcaraz
- Université Grenoble Alpes / CNRS / TIMC-IMAG UMR 5525 (SyNaBi), Grenoble, France, Faculté de Médecine, 38706, La Tronche cedex, France
| | - Chantal Gondran
- Univ. Grenoble Alpes, CNRS, DCM UMR 5250, F 38000, Grenoble, France
| | - Guillaume Costa
- CEA LETI Grenoble - DRT/DTBS, 17 avenue des martyrs, 38054, Grenoble cedex 9, France
| | - Guillaume Nonglaton
- CEA LETI Grenoble - DRT/DTBS, 17 avenue des martyrs, 38054, Grenoble cedex 9, France
| | - Frédéric Gaillard
- CEA LETI Grenoble - DRT/DTBS, 17 avenue des martyrs, 38054, Grenoble cedex 9, France
| | - Philippe Cinquin
- Université Grenoble Alpes / CNRS / TIMC-IMAG UMR 5525 (SyNaBi), Grenoble, France, Faculté de Médecine, 38706, La Tronche cedex, France
| | - Marie-Line Cosnier
- CEA LETI Grenoble - DRT/DTBS, 17 avenue des martyrs, 38054, Grenoble cedex 9, France
| | - Donald K Martin
- Université Grenoble Alpes / CNRS / TIMC-IMAG UMR 5525 (SyNaBi), Grenoble, France, Faculté de Médecine, 38706, La Tronche cedex, France.
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7
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Storr M, Ward RA. Membrane innovation: closer to native kidneys. Nephrol Dial Transplant 2019; 33:iii22-iii27. [PMID: 30281130 PMCID: PMC6168921 DOI: 10.1093/ndt/gfy228] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 06/19/2018] [Indexed: 12/11/2022] Open
Abstract
Modern methods in analytical biochemistry have established that uraemia is associated with the retention of proteins, both in their native state and post-translationally modified, over a wide range of molecular weights up to 60 kDa. Evidence is accumulating that these higher molecular weight retention solutes are important uraemic toxins, and therapies such as online haemodiafiltration (HDF), which enhance their removal, are associated with improved outcomes. However, HDF has limitations regarding cost, clinical implementation and the need for an external source of sterile substitution solution to maintain fluid balance. New membranes that have a solute removal profile more closely approaching that of the glomerular filtration barrier when used for conventional haemodialysis, while at the same time not allowing the passage of clinically significant amounts of beneficial proteins, are needed to address these limitations. Tighter control of the molecular characteristics of the polymers used for membrane fabrication, along with the introduction of additives and improvements in the manufacturing process, has led to membranes with a tighter pore size distribution that allows the use of an increased absolute pore size without leaking substantial amounts of albumin. At the same time, the wall thickness and internal diameter of membrane fibres have been decreased, enhancing convective transport within the dialyser without the need for an external source of substitution solution. These new expanded range membranes provide a solute removal profile more like that of the native kidney than currently available membranes when used in conventional haemodialysis.
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Affiliation(s)
- Markus Storr
- Baxter International, Research and Development, Hechingen, Germany
- Correspondence and offprint requests to: Markus Storr; E-mail:
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8
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Iqbal Z, Kim S, Moyer J, Moses W, Abada E, Wright N, Kim EJ, Park J, Fissell WH, Vartanian S, Roy S. In vitro and in vivo hemocompatibility assessment of ultrathin sulfobetaine polymer coatings for silicon-based implants. J Biomater Appl 2019; 34:297-312. [PMID: 30862226 DOI: 10.1177/0885328219831044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Zohora Iqbal
- 1 Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, USA
| | - Steven Kim
- 1 Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, USA
| | - Jarrett Moyer
- 1 Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, USA
| | - Willieford Moses
- 1 Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, USA
| | - Emily Abada
- 1 Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, USA
| | - Nathan Wright
- 1 Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, USA
| | - Eun Jung Kim
- 1 Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, USA
| | - Jaehyun Park
- 1 Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, USA
| | | | - Shant Vartanian
- 3 Division of Vascular & Endovascular Surgery, University of California, San Francisco, USA
| | - Shuvo Roy
- 1 Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, USA
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9
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Ozcelik HG, Barisik M. Electric charge of nanopatterned silica surfaces. Phys Chem Chem Phys 2019; 21:7576-7587. [DOI: 10.1039/c9cp00706g] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The surface charge density of a nanopatterned silica decreased at the pits but increased at the tips of surface patterns. For a case of self-repeating surface structures, the average of local surface charges becomes lower than the theoretical predictions. Our phenomenological model developed as an extension to the existing flat surface theory predicts the average surface charge on a nanopatterned surface as a function of surface pattern size, ionic concentration and pH.
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Affiliation(s)
- H. Gokberk Ozcelik
- Department of Mechanical Engineering
- Izmir Institute of Technology
- IZMIR
- Turkey
| | - Murat Barisik
- Department of Mechanical Engineering
- Izmir Institute of Technology
- IZMIR
- Turkey
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10
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Feinberg BJ, Hsiao JC, Park J, Zydney AL, Fissell WH, Roy S. Slit pores preferred over cylindrical pores for high selectivity in biomolecular filtration. J Colloid Interface Sci 2017; 517:176-181. [PMID: 29425954 DOI: 10.1016/j.jcis.2017.12.056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 12/19/2017] [Accepted: 12/19/2017] [Indexed: 10/18/2022]
Abstract
Microelectromechanical systems (MEMS) have enabled the fabrication of silicon nanopore membranes (SNM) with uniform non-overlapping "slit shaped" pores. The application of SNM has been suggested for high selectivity of biomolecules in a variety of medical filtration applications. The aim of this study was to rigorously quantify the differences in sieving between slit pore SNM and more commonly modeled cylindrical pore membranes, including effects of the extended Derjaguin, Landau, Verwey, and Overbeek (XDLVO) interactions. Applying equations derived for SNM in previous work, we compare the partition coefficient of slit and cylindrical pore membranes while accounting for both steric and XDLVO interactions. Simple, steric approximations demonstrate that slit pore membranes exhibit significantly lower partition coefficients than cylindrical pore models. Incorporating XDLVO interactions results in an even more marked difference between slit pore and cylindrical pore membranes. These partition coefficients were used to evaluate changes in beta-2-microglobulin (B2M) selectivity. The data demonstrate that XDLVO interactions increase the selectivity advantage that slit pores possess over cylindrical pores, particularly for larger values of the acid-base decay constant. Finally, the bovine serum albumin (BSA) to B2M selectivity ratio was investigated. The selectivity ratio appears larger in slit pores than cylindrical pores for all cases, indicating that slit pores are particularly well suited for hemofiltration applications. The results of this study have significant implications for the application of SNM in membrane processes where highly selective separation of biomolecules is desirable.
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Affiliation(s)
- Benjamin J Feinberg
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Jeff C Hsiao
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Jaehyun Park
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Andrew L Zydney
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - William H Fissell
- Department of Medicine and Division of Nephrology and Hypertension, Vanderbilt University, Nashville, TN, USA
| | - Shuvo Roy
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
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Delavari A, Baltus R. The Effect of the Pore Entrance on Particle Motion in Slit Pores: Implications for Ultrathin Membranes. MEMBRANES 2017; 7:membranes7030042. [PMID: 28796197 PMCID: PMC5618127 DOI: 10.3390/membranes7030042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 07/25/2017] [Accepted: 07/31/2017] [Indexed: 11/16/2022]
Abstract
Membrane rejection models generally neglect the effect of the pore entrance on intrapore particle transport. However, entrance effects are expected to be particularly important with ultrathin membranes, where membrane thickness is typically comparable to pore size. In this work, a 2D model was developed to simulate particle motion for spherical particles moving at small Re and infinite Pe from the reservoir outside the pore into a slit pore. Using a finite element method, particles were tracked as they accelerated across the pore entrance until they reached a steady velocity in the pore. The axial position in the pore where particle motion becomes steady is defined as the particle entrance length (PEL). PELs were found to be comparable to the fluid entrance length, larger than the pore size and larger than the thickness typical of many ultrathin membranes. Results also show that, in the absence of particle diffusion, hydrodynamic particle-membrane interactions at the pore mouth result in particle "funneling" in the pore, yielding cross-pore particle concentration profiles focused at the pore centerline. The implications of these phenomena on rejection from ultrathin membranes are examined.
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Affiliation(s)
- Armin Delavari
- Department of Chemical & Biomolecular Engineering, Clarkson University, Potsdam, NY 13699-5705, USA.
| | - Ruth Baltus
- Department of Chemical & Biomolecular Engineering, Clarkson University, Potsdam, NY 13699-5705, USA.
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