Fabrication of ultrahigh-molecular-weight polyethylene porous implant for bone application

2020 ◽  
Vol 40 (8) ◽  
pp. 685-692
Author(s):  
Beatriz Olalde ◽  
Ana Ayerdi-Izquierdo ◽  
Rubén Fernández ◽  
Nerea García-Urkia ◽  
Garbiñe Atorrasagasti ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Structural Integrity ◽  
Fibre Diameter ◽  
Pore Wall ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Salt Leaching ◽  
Ultrahigh Molecular Weight

AbstractPorous implants play a crucial role in allowing ingrowth of host connective tissue and thereby help in keeping the implant in its place. With the aim of mimicking the microstructure of natural extracellular matrix, ultrahigh-molecular-weight polyethylene (UHMWPE) porous samples with a desirable pore size distribution were developed by combining thermally induced phase separation and salt leaching techniques. The porous UHMWPE samples consisted of a nanofibrous UHMWPE matrix with a fibre diameter smaller than 500 nm, highly interconnected, with a controllable pore diameter from nanoscale to 300 µm. Moreover, a porous UHMWPE sample was also developed as a continuous and homogeneous coating onto the UHMWPE dense sample. The dense/porous UHMWPE sample supported human foetal osteoblast 1.19 cell line proliferation and differentiation, indicating the potential of porous UHMWPE with a desirable pore size distribution for bone application. An osseointegration model in the sheep revealed substantial bone formation within the pore layer at 12 weeks via SEM evaluation. Ingrown bone was more closely opposed to the pore wall when compared to the dense UHMWPE control. These results indicate that dense/porous UHMWPE could provide improved osseointegration while maintaining the structural integrity necessary for load-bearing orthopaedic application.

Nanofiltration membranes with narrowed pore size distribution via pore wall modification

2016 ◽  
Vol 52 (55) ◽  
pp. 8589-8592 ◽  
Author(s):  
Yong Du ◽  
Yan Lv ◽  
Wen-Ze Qiu ◽  
Jian Wu ◽  
Zhi-Kang Xu
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Pore Wall ◽  
Nanofiltration Membranes ◽  
Novel Method

A novel method has been proposed to modify the pore wall of nanofiltration membranes (NFMs) by filtrating molecules that are reactive to the NFMs, leading to narrowed pore size distribution.

Study of Structural Features of Porous TINI-Based Materials Produced by SHS and Sintering

2015 ◽  
Vol 1085 ◽  
pp. 430-435 ◽  
Author(s):  
Sergey G. Anikeev ◽  
Valentina N. Khodorenko ◽  
Oleg V. Kokorev ◽  
Timofey L. Chekalkin ◽  
Victor E. Gunter
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Pore Wall ◽  
Structural Features ◽  
Strength Properties ◽  
Material Strength ◽  
Powder Metallurgy Method ◽  
Sintered Alloy ◽  
Shs Method

Structural properties of porous TiNi-based materials produced by SHS method and sintering have been investigated. The material having different pore wall surface topography, porosity and pore size distribution was shown to be produced depending on the powder metallurgy method for porous TiNi-based alloy. All the materials having porosity of 55-70%, mean pore size 90-150 μm, as well as normal pore size distribution are most preferable. Ultimate strength and breaking point were determined to depend on porosity, pore size distribution, pore intersections and phase chemical composition of the material. Strength properties of the sintered alloy are twice as much compared to the SHS-produced ones due to homogeneity of its macrostructure, low chemical heterogeneity and TiNi3 precipitations strengthening the TiNi matrix.

Macroporous Thermosets via Chemically Induced Phase Separation

1996 ◽  
Vol 431 ◽  
Author(s):  
J. Kiefer ◽  
R. Porouchani ◽  
D. Mendels ◽  
J. B. Ferrer ◽  
C. Fond ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
New Technology ◽  
Curing Temperature ◽  
Low Molecular Weight ◽  
Closed Cell ◽  
Chemically Induced

AbstractWe have explored a new technology based on chemically induced phase separation that yields porous epoxies and cyanurates with a closed cell morphology and micrometer sized pores with a narrow pore size distribution. When the precursor monomers are cured in the presence of a low molecular weight liquid, the desired morphology results from a phase separation and a chemical quench. After phase separation, the porosity is achieved by thermal removal of the secondary liquid phase, specifically by diffusion through the crosslinked matrix. In respect to the thermodynamics and kinetics, the origin of the phase separation process can be identified as nucleation and growth. The influence of internal and external reaction parameters, such as chemical nature of the low molecular weight liquid, its concentration and the curing temperature on the final morphology are presented. Thus, the morphology can be controlled ranging from a monomodal to bimodal pore size distribution with pore sizes inbetween 1 to 10 μm. These porous thermosets are characterized by a significantly lower density, without any loss in thermal stability compared to the neat matrix. Such new materials demonstrate great interest for lowering the dielectric constant and for improving the fundamental understanding of the role of voids in stress relaxation and toughening.

scholarly journals How Molecular Weight Cut-Offs and Physicochemical Properties of Polyether Sulfone Membranes Affect Peptide Migration and Selectivity during Electrodialysis with Filtration Membranes

Membranes ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 153 ◽  
Author(s):  
Sabita Kadel ◽  
Geneviève Pellerin ◽  
Jacinthe Thibodeau ◽  
Véronique Perreault ◽  
Carole Lainé ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Physicochemical Properties ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Negative Charge ◽  
Protein Hydrolysate ◽  
Filtration Membranes ◽  
Polyether Sulfone ◽  
Wide Range

Filtration membranes (FMs) are an integral part of electrodialysis with filtration membranes (EDFM), a green and promising technology for bioactive peptide fractionation. Therefore, it is paramount to understand how physicochemical properties of FMs impact global and selective peptide migration to anionic (A−RC) and cationic (C+RC) peptide recovery compartments during their simultaneous separation by EDFM. In this context, six polyether sulfone (PES) membranes with molecular weight cut-offs (MWCO) of 5, 10, 20, 50, 100 and 300 kDa were characterized and used during EDFM to separate peptides from a complex whey protein hydrolysate. Surface charge, roughness, thickness and surface/pores nature of studied PES membranes were similar with small differences in conductivity, porosity and pore size distribution. Interestingly, global peptides migration to both recovery compartments increased linearly as a function of MWCO. However, peptide selectivity changed according to the recovery compartments and/or the peptide’s charge and MW with an increase in MWCO of FMs. Indeed, in A−RC, the relative abundance (RA) of peptides having low negative charge and MW (IDALNENK and VLVLDTDYK) decreased (45% to 19%) with an increase in MWCO, while the opposite for peptides having high negative charge and MW (TPEVDDEALEK, TPEVDDEALEKFDK & VYVEELKPTPEGDLEILLQK) (increased from 16% to 43%). Concurrently, in C+RC, regardless of MWCO used, the highest RA was observed for peptides having low positive charge and MW (IPAVFK & ALPMHIR). It was the first time that the significant impact of charge, MWCO and pore size distribution of PES membranes on a wide range of MWCO was demonstrated on EDFM performances.

Fouling mechanism of hollow fiber ultrafiltration membrane with pretreatment by coagulation/sedimentation process

2001 ◽  
Vol 1 (4) ◽  
pp. 49-56
Author(s):  
S. Minegishi ◽  
N.-Y. Jang ◽  
Y. Watanabe ◽  
S. Hirata ◽  
G. Ozawa
Keyword(s):  
Mathematical Model ◽  
Molecular Weight ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Humic Substances ◽  
Size Distribution ◽  
High Molecular Weight ◽  
Hollow Fiber ◽  
Fouling Mechanism ◽  
Sedimentation Process

The fouling mechanism of the hollow fiber UF membrane with a pretreatment by coagulation/sedimentation process was investigated. The experiments were carried out in three different feed water conditions: river surface water, coagulated water containing micro flocs and clarified water from the coagulation/sedimentation process. The river water contained a lot of suspended particles (high turbidity) and natural organic matter (NOM) such as humic substances. From analysis of the data obtained in the three membrane processes, the mathematical model expressing the change of the filtration resistance is proposed and proved, which includes the pore size distribution of the membrane. The effect of DOC and DOC/E260 on the membrane fouling was also discussed. The analysis of the pore size distribution change with increasing filtration time suggests that the primary mechanism of the fouling is the decrease in the pore number by the high molecular weight humic substances. As a result of experiments and mathematical model analysis, it could be concluded that the coagulation/sedimentation pretreatment process was very effective for expanding ultrafiltration membrane life, because the coagulation/sedimentation process could remove the primary foulants such as high molecular weight humic substances.

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