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1
Protein separation using ultrafiltration — an example of multi-scale complex systems
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
China Particuology
Yayıncı:
Elsevier
Yazar(lar) :
Zhanfeng Cui
Yıl :
2005
Zhanfeng Cui
Yayıncı Web Sitesi
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Kaydet Alıntıla
In this mini-review, the complexity of protein fractionation using ultrafiltration is discussed. The coupling of the system hydrodynamics, boundary layer transport, membrane permeation, electrostatic and hydrophobic interactions and its effects on protein transmission and membrane selectivity are analysed. Although ultrafiltration is promising for larger scale protein purification and also with outstanding advantages both technically and economically, much needs to be done to derive the general guidance for membrane selection, process design and system operation. With fine tuning of operational and physiochemical conditions, the process can be greatly improved in terms of process productivity and protein purity. A coupled multi-scale approach might provide a way forward to analyse this complex system and improve the confidence in applying such a promising technology and predictability of the outcome.
DOI : 10.1016/s1672-2515(07)60213-9
Anahtar Kelimeler : protein purification, protein fractionation, ultrafiltration, membrane separation, multi-scale analysis
ISSN: 1672-2515
Sayı: 6
Cilt: 3
Sayfa: 343-348
Sınıflandırma :
2
A tri-component knee plug for the 3rd generation of autologous chondrocyte implantation
Dergi Makalesi

Dergi Makalesi
Kaynak :
Springer Nature
Dergi:
Scientific Reports
Yayıncı:
Springer Science and Business Media LLC
Yazar(lar) :
Lobat Tayebi , Zhanfeng Cui , Hua YeLobat Tayebi , Zhanfeng Cui , Hua Ye
Yıl :
2020
Zhanfeng Cui Zhanfeng Cui
Yayıncı Web Sitesi
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Kaydet Alıntıla
Abstract\n Here, we report a newly designed knee plug to be used in the 3rd generation of Autologous Chondrocyte Implantation (ACI) in order to heal the damaged knee cartilage. It is composed of three components: The first component (Bone Portion) is a 3D printed hard scaffold with large pores (~ 850 µm), made by hydroxyapatite and β-tricalcium phosphate to accommodate the bony parts underneath the knee cartilage. It is a cylinder with a diameter of 20 mm and height of 7.5 mm, with a slight dome shape on top. The plug also comprises a Cartilage Portion (component 2) which is a 3D printed gelatin/elastin/sodium-hyaluronate soft thick porous membrane with large pores to accommodate chondrocytes. Cartilage Portion is secured on top of the Bone Portion using mechanical interlocking by designing specific knobs in the 3D printed construct of the Cartilage Portion. The third component of the plug (Film) is a stitchable permeable membrane consisting of polycaprolactone (PCL) on top of the Cartilage Portion to facilitate sliding of the knee joint and to hold the entire plug in place while allowing nutrients delivery to the Cartilage Portion. The PCL Film is prepared using a combination of film casting and sacrificial material leaching with a pore size of 10 µm. It is surface modified to have specific affinity with the Cartilage Portion. The detailed design criteria and production process of this plug is presented in this report. Full in vitro analyses have been performed, which indicate the compatibility of the different components of the plug relative to their expected functions.
DOI : 10.1038/s41598-020-73863-x
ISSN: 2045-2322
Sayı: 1
Cilt: 10
3
Enhancement of ultrafiltration using gas sparging: a comparison of different membrane modules
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Journal of Chemical Technology & Biotechnology
Yazar(lar) :
Zhanfeng Cui , Taha Taha
Konu :
Biotechnology, Fuel Technology, Inorganic Chemistry, Renewable Energy, Sustainability and the Environment, Organic Chemistry, Waste Management and Disposal, Pollution, General Chemical Engineering
Yıl :
2003
Zhanfeng Cui
Yayıncı Web Sitesi
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Kaydet Alıntıla
Ultrafiltration is widely used in the chemical, pharmaceutical, food and water industries. Practical difficulties arise in designing and operating the process due to concentration polarisation and membrane fouling. Enhancement of ultrafiltration is highly desirable to achieve a higher permeate flux at a fixed energy input, or a reduced energy input whilst maintaining the level of permeate flux, or an improved selectivity of the membrane. One effective, simple, and economic technique used to enhance ultrafiltration is the use of gas bubbles, ie injecting gas into the feed stream to create a gas–liquid two‐phase cross‐flow operation. In this paper, an attempt is made to compare the effect of ‘bubbling’ on the ultrafiltration performance, using different membrane modules (in particular, tubular and hollow fibre membrane modules). The difference in performance can be related to the feature of two‐phase flow hydrodynamics and its respective effect on mass transfer. The advantages and drawbacks of using this technique to enhance ultrafiltration are discussed.
DOI : 10.1002/jctb.763
ISSN: 0268-2575
Sayı: 2-3
Cilt: 78
Sayfa: 249-253
4
Biological engineering
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Current Opinion in Chemical Engineering
Yayıncı:
Elsevier
Yazar(lar) :
Zhanfeng Cui , Kyongbum Lee
Yıl :
2013
Zhanfeng Cui
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DOI : 10.1016/j.coche.2013.01.006
ISSN: 2211-3398
Sayı: 1
Cilt: 2
Sayfa: 1-2
Sınıflandırma :
5
Analysis of protein transport and polarization through membranes using pulsed sample injection technique
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Journal of Membrane Science
Yayıncı:
Elsevier
Yazar(lar) :
Raja Ghosh , Zhanfeng Cui
Yıl :
2000
Zhanfeng Cui
Yayıncı Web Sitesi
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Kaydet Alıntıla
Protein fractionation using ultrafiltration is feasible after extensive process optimization. However, conventional process optimisation methods are time consuming and require large amounts of pure proteins, which are sometimes very expensive. Pulsed sample injection ultrafiltration allows rapid determination of sieving coefficient data and may prove to be an efficient process optimisation technique. Very small amounts of pure protein are required for these experiments. A ‘quasi-steady state’ approximation is proposed for calculating the actual bulk and membrane surface concentrations from permeate concentration data. The sieving coefficient data obtained from the pulsed sample injection technique are in good agreement with data obtained from ‘steady-state’ ultrafiltration experiments. Experimental data clearly suggest that for a given permeate flux, the sieving coefficients are independent of the value of the feed concentration. The permeate concentration–time curves show that at higher permeate flux, lower time duration is required for the development of concentration polarization.
DOI : 10.1016/s0376-7388(00)00397-5
Anahtar Kelimeler : Ultrafiltration, Pulsed injection, Sieving coefficient, Protein, Permeate flux
ISSN: 0376-7388
Sayı: 1
Cilt: 175
Sayfa: 75-84
Sınıflandırma :
6
Flow and sediment simulation around spur dike with free surface using 3-D turbulent model
Dergi Makalesi

Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Journal of Hydrodynamics
Yazar(lar) :
Zhanfeng Cui , Xiaofeng Zhang
Konu :
Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, Modelling and Simulation
Yıl :
2006
Zhanfeng Cui
Yayıncı Web Sitesi
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Kaydet Alıntıla
Treatments of irregular boundary, bed deformation and free surface are main problems in 3-D flow and sediment model. Based on control equations of turbulent flow considering irregular boundary from liquid-solid two phase flow theory, the k - ε model and the Wall Function are adopted to develop a new model. In the model, apart from k - ε model and the Wall Function, the VOF method and the porosity concept are adopted to simulate water surface, irregular boundary and bed deformation. Using the new model, flow field, changing of water level, turbulent kinetic energy and its dissipation rate, and local scour-deposition around spur dike are simulated. Computed result is compared with experimental data. The model developed can successfully simulate the separating structure of flow and circumfluence around the spur dike, secondary flow in the circumfluence area, scour hole profile and bed contours and agree well with the experimental data.
DOI : 10.1007/bf03400452
Anahtar Kelimeler : 3-D turbulent model, spur dike, sediment transport, VOF method, the porosity, wall function
ISSN: 1001-6058 1878-0342
Sayı: S1
Cilt: 18
Sayfa: 232-239
7
Unique journal: Bio-Design and Manufacturing
Dergi Makalesi

Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Bio-Design and Manufacturing
Yazar(lar) :
Huayong Yang , Zhanfeng Cui
Konu :
Industrial and Manufacturing Engineering, Materials Science (miscellaneous), Biomedical Engineering, Biotechnology
Yıl :
2018
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
DOI : 10.1007/s42242-018-0007-0
ISSN: 2096-5524 2522-8552
Sayı: 1
Cilt: 1
Sayfa: 1-1
8
Three-dimensional perfused cell culture
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Biotechnology Advances
Yayıncı:
Elsevier
Yazar(lar) :
Zhaohui Li , Zhanfeng Cui
Yıl :
2014
Zhanfeng Cui
Yayıncı Web Sitesi
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Kaydet Alıntıla
Compelling evidence suggests the limitation and shortcomings of the current and well established cell culture method using multi-well plates, flasks and Petri dishes. These are particularly important when cell functions are sensitive to the local microenvironment, cell–cell and cell–extracellular matrix interactions. There is a clear need for advanced cell culture systems which mimic in vivo and more physiological conditions. This review summarises and analyses recent progress in three dimensional (3D) cell culture with perfusion as the next generation cell culture tools, while excluding engineered tissue culture where three dimensional scaffold has to be used for structural support and perfusion for overcoming mass transfer control. Apart from research activities in academic community, product development in industry is also included in this review.
DOI : 10.1016/j.biotechadv.2013.10.006
Anahtar Kelimeler : Three-dimensional cell culture, Perfusion culture, Physiological microenvironment, Scaffolds, Tissue engineering, Extracellular matrix
ISSN: 0734-9750
Sayı: 2
Cilt: 32
Sayfa: 243-254
Sınıflandırma :
9
Experimental study on the enhancement of yeast microfiltration with gas sparging
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Journal of Chemical Technology & Biotechnology
Yazar(lar) :
Hwal W Sur , Zhanfeng Cui
Konu :
Biotechnology, Fuel Technology, Inorganic Chemistry, Renewable Energy, Sustainability and the Environment, Organic Chemistry, Waste Management and Disposal, Pollution, General Chemical Engineering
Yıl :
2001
Zhanfeng Cui
Yayıncı Web Sitesi
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Kaydet Alıntıla
Gas‐sparged microfiltration experiments with baker's yeast suspensions were performed using a 0.15 µm PCI multi‐tubular membrane module. The permeate flux and the enhancement from gas sparging were measured over the following operational parameter ranges: yeast suspension concentration 0.01–10% (wt), transmembrane pressure 0.5–4.0 bar, liquid crossflow velocity 0.36–1.8 ms−1, gas superficial velocity 0.18–1.02 ms−1. It was demonstrated that injecting air to create a gas–liquid two‐phase crossflow operation can significantly increase the permeate flux. The observed enhancement, resulting from injecting a relatively small amount of gas with a superficial velocity of 0.18 ms−1, ranges from 10% when fouling is insignificant to 135% when fouling tendency is severe. Controlled pulse injection leads to further increase in permeate flux. Examining the dependence of permeate flux on transmembrane pressure, it is clearly demonstrated that the injection of gas will elevate the value of the limiting flux. There is also evidence to show that the value of critical flux is increased when gas injection is applied. Further quantitative analysis will be performed in our future work.
DOI : 10.1002/jctb.411
ISSN: 0268-2575
Sayı: 5
Cilt: 76
Sayfa: 477-484
10
A Maxwell-Stefan approach to modelling the cross-flow ultrafiltration of protein solutions in tubular membranes
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Chemical Engineering Science
Yayıncı:
Elsevier
Yazar(lar) :
Sanjay R. Bellara , Zhanfeng Cui
Yıl :
1998
Zhanfeng Cui
Yayıncı Web Sitesi
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Kaydet Alıntıla
A non-parameterised model is developed to predict the crossflow membrane ultrafiltration permeate flux for protein solutions. A relatively simple hydrodynamic model is used to predict the rate of growth of the concentration polarisation boundary layer along the length of a tubular membrane. Protein transport within the boundary layer is evaluated using the Maxwell–Stefan transport equations, accounting for electrostatic interactions created by filtering charged protein molecules. Numeric simulations were performed with and without considering viscous interactions in the concentration polarisation boundary layer. In the main, the model appears to qualitatively describe the ultrafiltration process very well when tested for a range of different operating parameters and solution conditions. However, at high TMPs viscous interactions were exaggerated and the model underpredicted permeate flux. Under such conditions, use of the model without accounting for viscous interactions seemed more appropriate. The model predictions are tested against sample experimental data for the protein BSA and the results were highly encouraging.
DOI : 10.1016/s0009-2509(98)00062-1
Anahtar Kelimeler : Ultrafiltration, Maxwellu2013Stefan, model, BSA
ISSN: 0009-2509
Sayı: 12
Cilt: 53
Sayfa: 2153-2166
Sınıflandırma :
Kimya %32
11
A multi-paradigm modeling framework to simulate dynamic reciprocity in a bioreactor.
Dergi Makalesi

Dergi Makalesi
Open Access
Kaynak :
Directory of Open Access Journals (DOAJ)
Dergi:
PLoS ONE
Yazar(lar) :
Himanshu Kaul , Zhanfeng Cui , Yiannis Ventikos
Yıl :
2013
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Despite numerous technology advances, bioreactors are still mostly utilized as functional black-boxes where trial and error eventually leads to the desirable cellular outcome. Investigators have applied various computational approaches to understand the impact the internal dynamics of such devices has on overall cell growth, but such models cannot provide a comprehensive perspective regarding the system dynamics, due to limitations inherent to the underlying approaches. In this study, a novel multi-paradigm modeling platform capable of simulating the dynamic bidirectional relationship between cells and their microenvironment is presented. Designing the modeling platform entailed combining and coupling fully an agent-based modeling platform with a transport phenomena computational modeling framework. To demonstrate capability, the platform was used to study the impact of bioreactor parameters on the overall cell population behavior and vice versa. In order to achieve this, virtual bioreactors were constructed and seeded. The virtual cells, guided by a set of rules involving the simulated mass transport inside the bioreactor, as well as cell-related probabilistic parameters, were capable of displaying an array of behaviors such as proliferation, migration, chemotaxis and apoptosis. In this way the platform was shown to capture not only the impact of bioreactor transport processes on cellular behavior but also the influence that cellular activity wields on that very same local mass transport, thereby influencing overall cell growth. The platform was validated by simulating cellular chemotaxis in a virtual direct visualization chamber and comparing the simulation with its experimental analogue. The results presented in this paper are in agreement with published models of similar flavor. The modeling platform can be used as a concept selection tool to optimize bioreactor design specifications.
DOI : 10.1371/journal.pone.0059671
ISSN: 1932-6203
Cilt: 8
Sayı: 3
Sayfa: e59671
Sınıflandırma :
12
Design of a new 3D‐printed joint plug
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Asia-Pacific Journal of Chemical Engineering
Yazar(lar) :
Lobat Tayebi , Zhanfeng Cui , Hua Ye
Konu :
Renewable Energy, Sustainability and the Environment, Waste Management and Disposal, General Chemical Engineering
Yıl :
2019
Zhanfeng Cui
Yayıncı Web Sitesi
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Kaydet Alıntıla
This paper introduces a kit of parts as a novel three‐dimensional (3D)–printed joint plug, in which each of the parts function cooperatively to treat cartilage damage in joints of the human body (e.g., hips, wrists, elbow, knee, and ankle). Three required and one optional parts are involved in this plug. The first part is a 3D‐printed hard scaffold (bone portion) to accommodate bone cells, and the second is a 3D‐printed soft scaffold (cartilage portion) overlying the bone portion to accommodate chondrocytes. The third part of joint plug is a permeable membrane, termed film, to cover the entire plug to provide coordinated sliding of the joint during the regeneration of the cartilage. Film is also responsible for retention of the chondrocytes while allowing nutrients to diffuse through the membrane. The plug may further include a fourth part, called barrier, which is a membrane to assist the bone portion in avoiding the loss of chondrocytes from the cartilage portion beyond the barrier. Various engagement means among the parts of the plug are assumed, which are discussed in this paper. Moreover, the detailed design criteria and selection of suitable materials for different parts are elaborated. The 3D‐printing practice allows the plug to be personalized and fabricated to fit the shape/size of the target joint and the injured section. Also discussed are the configuration options of the plug to be surgically implanted in a joint. Although the focus of this paper is on the design, a brief overview of a prototype is presented.
DOI : 10.1002/apj.2360
ISSN: 1932-2135
Sayı: 6
Cilt: 14

13
Sacrificial Core-Based Electrospinning: a Facile and Versatile Approach to Fabricate Devices for Potential Cell and Tissue Encapsulation Applications.
Dergi Makalesi

Dergi Makalesi
Open Access
Kaynak 1:
PubMed
Kaynak 2:
Directory of Open Access Journals (DOAJ)
Dergi:
Nanomaterials (Basel)
Yazar(lar) :
Naresh Kasoju , Julian George , Hua Ye , Zhanfeng Cui
Yıl :
2018
Zhanfeng Cui
Piri Tam Metin Bulucu
Kaydet Alıntıla
Electrospinning uses an electric field to produce fine fibers of nano and micron scale diameters from polymer solutions. Despite innovation in jet initiation, jet path control and fiber collection, it is common to only fabricate planar and tubular-shaped electrospun products. For applications that encapsulate cells and tissues inside a porous container, it is useful to develop biocompatible hollow core-containing devices. To this end, by introducing a 3D-printed framework containing a sodium chloride pellet (sacrificial core) as the collector and through post-electrospinning dissolution of the sacrificial core, we demonstrate that hollow core containing polyamide 66 (nylon 66) devices can be easily fabricated for use as cell encapsulation systems. ATR-FTIR and TG/DTA studies were used to verify that the bulk properties of the electrospun device were not altered by contact with the salt pellet during fiber collection. Protein diffusion investigations demonstrated that the capsule allowed free diffusion of model biomolecules (insulin, albumin and Ig G). Cell encapsulation studies with model cell types (fibroblasts and lymphocytes) revealed that the capsule supports the viability of encapsulated cells inside the capsule whilst compartmentalizing immune cells outside of the capsule. Taken together, the use of a salt pellet as a sacrificial core within a 3D printed framework to support fiber collection, as well as the ability to easily remove this core using aqueous dissolution, results in a biocompatible device that can be tailored for use in cell and tissue encapsulation applications.
DOI : 10.3390/nano8100863
Anahtar Kelimeler : 3D printing, electrospinning, encapsulation, immuno-isolation, in vivo tissue engineering, nanofibers, protein diffusion, transplantation
Sınıflandırma :
14
High-resolution plasma protein fractionation using ultrafiltration
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Desalination
Yayıncı:
Elsevier
Yazar(lar) :
Yinhua Wan , Raja Ghosh , Zhanfeng Cui
Yıl :
2002
Zhanfeng Cui
Yayıncı Web Sitesi
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Kaydet Alıntıla
The effects of pH and ionic strength (salt concentration) on transmission of single protein human serum albumin (HSA) and human immunoglobulins (HIgG) through a 100 kDa molecular weight cut-off (MWCO) polyethersulfone membrane have been studied using a pulsed sample injection technique. Experimental results obtained clearly demonstrate the effectiveness of changing solution pH and ionic strength optimisation for selective transmission of HSA or HIgG. These also demonstrate the usefulness of pulsed injection experimental technique for the optimization of ultrafiltration processes. A pulse input carrier phase ultrafiltration (CPUF) was employed to fractionate a binary protein mixture of HSA and HIgG at low NaCl concentration, showing that it is feasible to separate the binary protein at optimised conditions.
DOI : 10.1016/s0011-9164(02)00332-6
Anahtar Kelimeler : Ultrafiltration, Protein transmission, Protein fractionation, Pulsed injection
ISSN: 0011-9164
Sayı: 1-3
Cilt: 144
Sayfa: 301-306
Sınıflandırma :
15
Design of cone-and-plate test cell for ultrafiltration
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Desalination
Yayıncı:
Elsevier
Yazar(lar) :
S.S. Vasan , Raja Ghosh , Zhanfeng Cui
Yıl :
2002
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
In ultrafiltration (UF) processes, the mass transfer coefficient depends on the hydrodynamic shear at the membrane surface. Unfortunately, in all the existing UF test devices, shear stress is non-uniform and only an average value is used. This paper discusses the theory, design, fabrication, and experimental validation of a next-generation cone-and-plate test cell (CPTC) to carry out UF under uniform surface shear of 2 μ ω secθ1 Pascals (where μ is viscosity, ω is angular velocity, and θ1 is the half-angle of the cone). This next-generation test cell provides experimental data under uniform shear, which would enable better validation of mathematical models for UF processes. Work is in progress to study transient shear and shear-reversal effects using the CPTC, by controlling the angular velocity and direction of rotation of the cone using a computerised servo-motor control system.
DOI : 10.1016/s0011-9164(02)00475-7
Anahtar Kelimeler : Cone-and-plate test cell, Membrane, Ultrafiltration, Uniform surface shear
ISSN: 0011-9164
Sayı: 1-3
Cilt: 146
Sayfa: 219-224
Sınıflandırma :
16
Strategy to separate lysozyme and ovalbumin from CEW using UF
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Desalination
Yayıncı:
Elsevier
Yazar(lar) :
Junren Lu , Yinhua Wan , Zhanfeng Cui
Yıl :
2006
Zhanfeng Cui
Yayıncı Web Sitesi
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Kaydet Alıntıla
DOI : 10.1016/j.desal.2006.03.402
ISSN: 0011-9164
Sayı: 1-3
Cilt: 200
Sayfa: 477-479
Sınıflandırma :
17
Separation of lysozyme from chicken egg white using ultrafiltration
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Separation and Purification Technology
Yayıncı:
Elsevier
Yazar(lar) :
Yinhua Wan , Junren Lu , Zhanfeng Cui
Yıl :
2006
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Using a methodology based on the combination of recently developed parameter scanning ultrafiltration with carrier phase ultrafiltration (CPUF), this article examines the separation of lysozyme directly from natural chicken egg white (CEW) solutions with 30 kDa membranes. The suitability of two membranes, i.e. Biomax 30 kDa polyethersulfone and Ultracel Amicon YM 30 kDa regenerated cellulose membranes were rapidly assessed and the physicochemical conditions likely to be optimal were identified by parameter scanning ultrafiltration. Under suitable conditions, with the Biomax 30 kDa membrane, lysozyme transmission from the CEW solution could be more than 80% and the lysozyme purity obtained in permeate was greater than 94% after one stage ultrafiltration process.
DOI : 10.1016/j.seppur.2005.07.003
Anahtar Kelimeler : Ultrafiltration, Lysozyme, Physicochemical
ISSN: 1383-5866
Sayı: 2
Cilt: 48
Sayfa: 133-142
Sınıflandırma :
18
A computational analysis of the impact of mass transport and shear on three-dimensional stem cell cultures in perfused micro-bioreactors
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Chinese Journal of Chemical Engineering
Yayıncı:
Elsevier
Yazar(lar) :
Himanshu Kaul , Yiannis Ventikos , Zhanfeng Cui
Yıl :
2016
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
In this study, Computational Fluid Dynamics (CFD) is used to investigate and compare the impact of bioreactor parameters (such as its geometry, medium flow-rate, scaffold configuration) on the local transport phenomena and, hence, their impact on human mesenchymal stem cell (hMSC) expansion. The geometric characteristics of the TissueFlex® (Zyoxel Limited, Oxford, UK) microbioreactor were considered to set up a virtual bioreactor containing alginate (in both slab and bead configuration) scaffolds. The bioreactor and scaffolds were seeded with cells that were modelled as glucose consuming entities. The widely used glucose medium, Dulbecco's Modified Eagle Medium (DMEM), supplied at two inlet flow rates of 25 and 100 μl·h− 1, was modelled as the fluid phase inside the bioreactors. The investigation, based on applying dimensional analysis to this problem, as well as on detailed three-dimensional transient CFD results, revealed that the default bioreactor design and boundary conditions led to internal and external glucose transport, as well as shear stresses, that are conducive to hMSC growth and expansion. Furthermore, results indicated that the ‘top-inout’ design (as opposed to its symmetric counterpart) led to higher shear stress for the same media inlet rate (25 μl·h− 1), a feature that can be easily exploited to induce shear-dependent differentiation. These findings further confirm the suitability of CFD as a robust design tool.
DOI : 10.1016/j.cjche.2015.11.017
Anahtar Kelimeler : Alginate scaffolds, Bioreactors, Fluid mechanics, Dimensionless quantities, Mass transfer, Modelling, Perfusion
ISSN: 1004-9541
Sayı: 1
Cilt: 24
Sayfa: 163-174
Sınıflandırma :
19
Effects of hypoxia on rat mesenchymal stem cells
Dergi Makalesi

Dergi Makalesi
Open Access
Kaynak :
Springer Nature
Dergi:
Cell Research
Yayıncı:
Springer Nature
Yazar(lar) :
Xiaoli Li , Lei Yang , Tianqing Liu , Xuehu Ma , Zhanfeng Cui
Konu :
Life Sciences, general, Cell Biology
Yıl :
2008
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
DOI : 10.1038/cr.2008.260
ISSN: 1748-7838
Cilt: 18
Sayı: 1
Sayfa: S170-S170
Sınıflandırma :
20
Enhancing hollow fibre ultrafiltration using slug-flow — a hydrodynamic study
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Desalination
Yayıncı:
Elsevier
Yazar(lar) :
Stanton Smith , Taha Taha , Zhanfeng Cui
Yıl :
2002
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Gas—liquid slug flow is commonly employed as an enhancement technique for cross-flow ultrafiltration. This technique worked well on flat sheet and larger diameter membrane modules, but hydrodynamics and mass transfer, hence optimal operation, differs for the smaller diameter hollow fibre membranes where the technique proved less effective. This study investigates slug-flow hydrodynamics in capillary tubes in order to characterise the flow and predict optimal operation in hollow fibre membranes. Experiments investigated the effect of bubble size, bubble-supply frequency, operating pressure and capillary diameter on bubble shape and rise-velocity in non-porous tubes of 0.89 mm bore. Computational fluid dynamics (CFD) was employed to predict the flow behaviour inside capillaries. The CFD model and experimental results compared well. The CFD model yielded detailed information of the flow parameters and the flow patterns inside the capillaries and this allowed for better understanding of the hydrodynamics of the capillary tube slug-flow process.
DOI : 10.1016/s0011-9164(02)00491-5
Anahtar Kelimeler : Slug-flow, Capillary, Hollow fibre, Ultrafiltration, Hydrodynamic study
ISSN: 0011-9164
Sayı: 1-3
Cilt: 146
Sayfa: 69-74
Sınıflandırma :
21
Fractionation of BSA and lysozyme using ultrafiltration: Effect of gas sparging
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
AIChE Journal
Yazar(lar) :
Raja Ghosh , Qiangyi Li , Zhanfeng Cui
Konu :
Biotechnology, Environmental Engineering, General Chemical Engineering
Yıl :
1998
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
DOI : 10.1002/aic.690440108
ISSN: 0001-1541
Sayı: 1
Cilt: 44
Sayfa: 61-67
22
Dead cell counts during serum cultivation are underestimated by the fluorescent live/dead assay
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Biotechnology Journal
Yazar(lar) :
Shengda Zhou , Zhanfeng Cui , Jill Urban
Konu :
Molecular Medicine, Applied Microbiology and Biotechnology, General Medicine
Yıl :
2011
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
The live/dead fluorescent assay provides a quick method for assessing the proportion of live and dead cells in cell culture systems or tissues and is widely used. Dead cells are detected by the fluorescence produced when propidium iodide (PI) binds to DNA; PI and similar molecules are excluded from live cells but can penetrate dead cells because of their loss of membrane integrity. Here we investigated the effect of serum in the culture medium on the reliability of the method. We assessed viability of chondrocytes with/without serum using both a live/dead assay kit and also trypan blue staining. We found that after 2 days of culture, the DNA‐binding dye PI could no longer detect dead cells if serum was present but they were readily detected in serum‐free medium or if an inhibitor to DNase I was added to the serum‐containing medium. Dead cells could be detected by trypan blue staining in all cultures. Hence dead cells are no longer detected as the DNase I present in serum degrades their DNA. DNA‐binding dyes may thus not give a reliable estimate of the number of dead cells in systems that have been cultured in the presence of serum for several days.
DOI : 10.1002/biot.201000254
ISSN: 1860-6768
Sayı: 5
Cilt: 6
Sayfa: 513-518
23
Human menstrual blood: a renewable and sustainable source of stem cells for regenerative medicine
Dergi Makalesi

Dergi Makalesi
Open Access
Kaynak 1:
Directory of Open Access Journals (DOAJ)
Kaynak 2:
PubMed
Dergi:
Stem Cell Research & Therapy
Yazar(lar) :
Haining Lv , Yali Hu , Zhanfeng Cui , Huidong Jia
Yıl :
2018
Zhanfeng Cui
Piri Tam Metin Bulucu
Kaydet Alıntıla
Abstract Stem cells (SCs) play an important role in autologous and even allogenic applications. Menstrual blood discharge has been identified as a valuable source of SCs which are referred to as menstrual blood-derived stem cells (MenSCs). Compared to SCs from bone marrow and adipose tissues, MenSCs come from body discharge and obtaining them is non-invasive to the body, they are easy to collect, and there are no ethical concerns. There is, hence, a growing interest in the functions of MenSCs and their potential applications in regenerative medicine. This review presents recent progress in research into MenSCs and their potential application. Clinical indications of using MenSCs for various regenerative medicine applications are emphasized, and future research is recommended to accelerate clinical applications of MenSCs.
DOI : 10.1186/s13287-018-1067-y
Anahtar Kelimeler : Menstrual blood, Menstrual blood-derived stem cells, Regenerative medicine
ISSN: 1757-6512
Cilt: 9
Sayı: 1
Sayfa: 1 - 11
24
Preface
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Chemical Engineering Journal
Yayıncı:
Elsevier
Yazar(lar) :
Xiongfu Zhang , Xuehu Ma , Zhanfeng Cui
Yıl :
2010
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
DOI : 10.1016/j.cej.2009.07.026
ISSN: 1385-8947
Sayı: 3
Cilt: 156
Sayfa: 511
25
Measurement of the chondrocyte membrane permeability to Me2SO, glycerol and 1,2-propanediol
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Medical Engineering & Physics
Yayıncı:
Elsevier
Yazar(lar) :
Xia Xu , Zhanfeng Cui , Jill P.G Urban
Yıl :
2003
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
The addition of cryopreservative agents (CPAs) to chondrocytes and natural and engineered cartilage is critical to protect the cells and tissues from freezing damage during cryopreservation, but this may cause cell damage, e.g. by osmotic shock. The damage could be minimized by the control of the cell volume excursion with the knowledge of cell membrane permeability. In this study, the cell volume responses of chondrocytes to three commonly used CPAs were evaluated using a perfusion microscope stage. The osmotic response of chondrocytes was measured to the perfusion with 1.4 M dimethyl sulfoxide (Me2SO), 1,2-propanediol and glycerol at 21 °C. Cell volumes and their transients were determined with image analysis. The cell membrane permeability parameters, including the hydraulic conductivity (Lp), the CPA permeability (ω) and the reflection coefficients (σ) in the Kedem–Katchalsky (K-K) model, and the Lp and ω in the two-parameter model were determined. The correlated K-K parameters at 21 °C were Lp=0.166±0.035, 0.149±0.061, 0.212±0.041 μm/min atm, ω=(7.630±0.174)×10−2, (1.428±0.627)×10−2, (2.744±0.775)×10−2 μm/s and σ=0.91±0.09, 0.82±0.11, 0.88±0.10 for Me2SO, glycerol and 1,2-propanediol, respectively. For the two-parameter model, the parameter values were Lp=0.163±0.040, 0.128±0.031, 0.169±0.025 μm/min atm, ω=(7.881±0.178)×10−2, (1.529±0.525)×10−2, (3.716±0.493)×10−2 μm/s for Me2SO, glycerol and 1,2-propanediol, respectively. No significant difference in the predictions of cell volume excursion during CPA addition was observed when using either the K-K model or the two-parameter model and it was hence advised to adopt the simple two-parameter model in the evaluation. The measured parameters can be used to optimise the CPA addition and removal protocols to maximize the cell survival during cryopreservation.
DOI : 10.1016/s1350-4533(03)00073-0
Anahtar Kelimeler : Chondrocyte, K-K model, Two-parameter model, Cryopreservative agent, Cell membrane permeability
ISSN: 1350-4533
Sayı: 7
Cilt: 25
Sayfa: 573-579
26
Nutrient gradients in engineered cartilage: Metabolic kinetics measurement and mass transfer modeling
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Biotechnology and Bioengineering
Yazar(lar) :
Shengda Zhou , Zhanfeng Cui , Jill P.G. Urban
Yıl :
2008
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Since tissue‐engineered cartilage is avascular, both nutrient supply and metabolic waste removal rely on diffusion. As a result, gradients of nutrients and wastes exist through the construct. Previous models usually calculate gradients of oxygen, glucose, and lactic acid separately, without taking into account the complex interdependence between concentrations of these substrates and rates of metabolism. In this study, these interactions were experimentally examined and incorporated into diffusion models. One‐dimensional diffusion‐reaction models were developed for three typical culture conditions, that is, static culture, perfusion culture, and suspended culture. The profiles of oxygen, glucose, lactic acid, and pH in the cultured constructs were calculated simultaneously using measured metabolic rates. The maximum construct size and cell density which could be supported before nutrients were depleted in the construct center was identified; a function predicting the relationship between construct dimension and the maximum viable cell density was developed. For constructs incubated under static culture the model demonstrated that the gradients which developed through the medium could not be neglected. Perfusion cultures could support a considerably higher cell density than static cultures, while for batch cultures in a rotating bioreactor, the volume of medium also influences the maximum cell density that could be supported. This study provides useful guidance for design of engineered cartilage constructs. Biotechnol. Bioeng. 2008;101: 408–421. © 2008 Wiley Periodicals, Inc.
DOI : 10.1002/bit.21887
ISSN: 0006-3592
Sayı: 2
Cilt: 101
Sayfa: 408-421
27
Hypoxic culture and expansion of mesenchymal stem cells in airlift loop hollow fiber membrane bioreactor
Dergi Makalesi

Dergi Makalesi
Open Access
Kaynak :
Springer Nature
Dergi:
Cell Research
Yayıncı:
Springer Nature
Yazar(lar) :
Xiangqin Li , Tianqing Liu , Kedong Song , Xuehu Ma , Zhanfeng Cui
Konu :
Life Sciences, general, Cell Biology
Yıl :
2008
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
DOI : 10.1038/cr.2008.259
ISSN: 1748-7838
Cilt: 18
Sayı: 1
Sayfa: S169-S169
Sınıflandırma :
28
A Maxwell–Stefan–Gouy–Debye model of the concentration profile of a charged solute in the polarisation layer
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Desalination
Yayıncı:
Elsevier
Yazar(lar) :
S.S. Vasan , Robert W. Field , Zhanfeng Cui
Yıl :
2006
Zhanfeng Cui
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Based on the Maxwell–Stefan equation and the Gouy–Chapman model (with the Debye–Hückel approximation), this paper gives an analytical equation to describe the concentration profile of a charged solute in the concentration polarisation layer in terms of three dimensionless numbers (the Debye number, the Nernst number, and the boundary layer Peclet number).
DOI : 10.1016/j.desal.2005.06.052
Anahtar Kelimeler : Charged solute, Concentration polarisation, Concentration profile, Gouyu2013Chapman model, Maxwellu2013Stefan equation, Membrane processes, Ultrafiltration
ISSN: 0011-9164
Sayı: 1-3
Cilt: 192
Sayfa: 356-363
Sınıflandırma :

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