scholarly journals Effect of Graphene Addition on Polycaprolactone Scaffolds Fabricated Using Melt-Electrowriting

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 319
Author(s):  
Johnson H. Y. Chung ◽  
Sepidar Sayyar ◽  
Gordon G. Wallace
Keyword(s):  
Tissue Engineering ◽  
Degradation Process ◽  
Suitable Material ◽  
Enhanced Resolution ◽  
Loss And Damage ◽  
Micron Size ◽  
Extrusion Printing ◽  
Rapid Mass ◽  
Study Offer ◽  
Better Than

Melt-electrowriting (MEW) is an emerging method that combines electrospinning and extrusion printing, allowing the fabrication of micron-scale structures suitable for tissue engineering. Compared to other additive fabrication methods, melt-electro written structures can offer more appropriate substrates for cell culture due to filament size and mechanical characteristics of the fabricated scaffolds. In this study, polycaprolactone (PCL)/graphene composites were investigated for fabrication of micron-size scaffolds through MEW. It was demonstrated that the addition of graphene can considerably improve the processability of PCL to fabricate micron-scale scaffolds with enhanced resolution. The tensile strength of the scaffold prepared from PCL/graphene composite (with only 0.5 wt.% graphene) was proved significantly (by more than 270%), better than that of the pristine PCL scaffold. Furthermore, graphene was demonstrated to be a suitable material for tailoring the degradation process to avoid undesirable bulk degradation, rapid mass loss and damage to the internal matrix of the polymer. The findings of this study offer a promising route for the fabrication of high-resolution scaffolds with micron-scale resolution for tissue engineering.

Influence of Collagen Status on Microstructures of Porous Collagen/TCP Composites

2007 ◽  
Vol 330-332 ◽  
pp. 495-498
Author(s):  
Chao Zou ◽  
Wen Jian Weng ◽  
Xu Liang Deng ◽  
Kui Cheng ◽  
Pi Yi Du ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Cell Growth ◽  
Tricalcium Phosphate ◽  
Freeze Drying ◽  
Alkali Treatment ◽  
Test Results ◽  
Collagen Matrices ◽  
The Difference ◽  
Porous Composites ◽  
Better Than

Two starting collagens, sponge and floc collagen, were used to prepare collagen/tricalcium phosphate (TCP) composites. The resulting composites were porous and had 200μm pore size. However, there was a difference in the microstructure of the pore walls for the composites derived from the two collagens, the pore walls in sponge collagen/TCP composite were still porous and had 200 nm micropores size, TCP particles were trapped in collagen matrices. While floc collagen/TCP composite had smooth and dense walls in which TCP particles were embedded. The difference could be attributed to the starting collagen with different status. Sponge collagen has a soft structure, which easily becomes disassembled fibrils during alkali treatment, the disassembled fibrils are integrated again to form a dense morphology for pore walls after freeze-drying. While floc collagen has already a low disassembly degree, the alkali treatment could not be able to separate the fibrils, this remains as micropores in pore walls after freeze-drying. Both porous composites are significant in bone tissue engineering or regeneration. MTT test results showed the two composites had good cytocompatibility, and sponge collagen/TCP composite was somewhat better than floc collagen/TCP composite, which could result from that micropores derived roughness in pore walls of sponge collagen/TCP composite is suitable for cell growth.

Multiple-Instrument Analyses of Single Micron-Size Particles

2005 ◽  
Vol 11 (4) ◽  
pp. 354-362 ◽  
Author(s):  
Uri Admon ◽  
David Donohue ◽  
Helmut Aigner ◽  
Gabriele Tamborini ◽  
Olivier Bildstein ◽  
...  
Keyword(s):  
Size Range ◽  
Standard Specimen ◽  
Environmental Research ◽  
Physical Chemical ◽  
Isotopic Analyses ◽  
Micron Size ◽  
Secondary Ion ◽  
Individual Particles ◽  
Testing And Evaluation ◽  
Better Than

Physical, chemical, and isotopic analyses of individual radioactive and other particles in the micron-size range, key tools in environmental research and in nuclear forensics, require the ability to precisely relocate particles of interest (POIs) in the secondary ion mass spectrometer (SIMS) or in another instrument, after having been located, identified, and characterized in the scanning electron microscope (SEM). This article describes the implementation, testing, and evaluation of the triangulation POIs re-location method, based on microscopic reference marks imprinted on or attached to the sample holder, serving as an inherent coordinate system. In SEM-to-SEM and SEM-to-SIMS experiments re-location precision better than 10 μm and 20 μm, respectively, is readily attainable for instruments using standard specimen stages. The method is fast, easy to apply, and facilitates repeated analyses of individual particles in different instruments and laboratories.

scholarly journals Adhesion and Proliferation of Osteoblast-Like Cells on Porous Polyetherimide Scaffolds

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yanbo Zhang ◽  
Ruiyan Li ◽  
Wenzheng Wu ◽  
Yun’an Qing ◽  
Xiongfeng Tang ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Contact Angle ◽  
Cell Adhesion ◽  
Phase Composition ◽  
Cell Morphology ◽  
Solvent Casting ◽  
Water Contact ◽  
Particulate Leaching ◽  
Cell Adhesion And Proliferation ◽  
Better Than

The purpose of this work was to investigate the porous polyetherimide scaffold (P-PEIs) as an alternative biopolymer for bone tissue engineering. The P-PEIs was fabricated via solvent casting and particulate leaching technique. The morphology, phase composition, roughness, hydrophilicity, and biocompatibility of P-PEIs were evaluated and compared with polyetherimide (PEI) and Ti6Al4V disks. P-PEIs showed a biomimetic porous structure with a modulus of 78.95 ± 2.30 MPa. The water contact angle of P-PEIs was 75.4 ± 3.39°, which suggested that P-PEIs had a wettability surface. Moreover, P-PEIs provides a feasible environment for cell adhesion and proliferation. The relative cell adhesion capability and the cell morphology on P-PEIs were better than PEI and Ti6Al4V samples. Furthermore, the MC3T3-E1 cells on P-PEIs showed faster proliferation rate than other groups. It was revealed that the P-PEIs could be a potential material for the application of bone regeneration.

scholarly journals Bladder Substitution: The Role of Tissue Engineering and Biomaterials

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1643
Author(s):  
Martina Casarin ◽  
Alessandro Morlacco ◽  
Fabrizio Dal Moro
Keyword(s):  
Tissue Engineering ◽  
Urinary Diversion ◽  
Mucus Production ◽  
Reconstructive Procedures ◽  
Suitable Material ◽  
Orthotopic Urinary Diversion ◽  
Bladder Substitution ◽  
Materials Used ◽  
Bowel Segments

Tissue engineering could play a major role in the setting of urinary diversion. Several conditions cause the functional or anatomic loss of urinary bladder, requiring reconstructive procedures on the urinary tract. Three main approaches are possible: (i) incontinent cutaneous diversion, such as ureterocutaneostomy, colonic or ileal conduit, (ii) continent pouch created using different segments of the gastrointestinal system and a cutaneous stoma, and (iii) orthotopic urinary diversion with an intestinal segment with spherical configuration and anastomosis to the urethra (neobladder, orthotopic bladder substitution). However, urinary diversions are associated with numerous complications, such as mucus production, electrolyte imbalances and increased malignant transformation potential. In this context, tissue engineering would have the fundamental role of creating a suitable material for urinary diversion, avoiding the use of bowel segments, and reducing complications. Materials used for the purpose of urinary substitution are biological in case of acellular tissue matrices and naturally derived materials, or artificial in case of synthetic polymers. However, only limited success has been achieved so far. The aim of this review is to present the ideal properties of a urinary tissue engineered scaffold and to examine the results achieved so far. The most promising studies have been highlighted in order to guide the choice of scaffolds and cells type for further evolutions.

scholarly journals Heterogeneous Fenton-Like Catalytic Degradation of 2,4-Dichlorophenoxyacetic Acid by Nano-Scale Zero-Valent Iron Assembled on Magnetite Nanoparticles

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2909 ◽  
Author(s):  
Xiaofan Lv ◽  
Yiyang Ma ◽  
Yangyang Li ◽  
Qi Yang
Keyword(s):  
Hydrogen Peroxide ◽  
Synergistic Effects ◽  
Degradation Process ◽  
Zero Valent Iron ◽  
Dichlorophenoxyacetic Acid ◽  
Heterogeneous Fenton ◽  
Reaction Conditions ◽  
Nano Zero Valent Iron ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Better Than

Fe0@Fe3O4 nanoparticles with dispersibility and stability better than single nano zero-valent iron (nZVI) were synthesized and combined with hydrogen peroxide to constitute a heterogeneous Fenton-like system, which was creatively applied in the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D). The effects of different reaction conditions like pH, hydrogen peroxide concentration, temperature, and catalyst dosage on the removal of 2,4-D were evaluated. The target pollutant was completely removed in 90min; nearly 66% of them could be mineralized, and the main intermediate product was 2,4-dichlorophenol. Synergistic effects between nZVI and Fe3O4 made the 2,4-D degradation efficiency in the Fe0@Fe3O4/H2O2 system greater than in either of them alone. More than a supporter, Fe3O4 could facilitate the degradation process by releasing ferrous and ferric ions from the inner structure. The reduction of 2,4-D was mainly attributed to hydroxyl radicals including surface-bound ∙OH and free ∙OH in solution and was dominated by the former. The possible mechanism of this Fe0@Fe3O4 activated Fenton-like system was proposed.

Effect of Solution Content ZnO Nanoparticles on Thermal Stability of Polyvinyl Chloride

2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Farshad Farahbod ◽  
Narges Bagheri ◽  
Fereshteh Madadpour
Keyword(s):  
Thermal Stability ◽  
Chain Length ◽  
Polyvinyl Chloride ◽  
Zno Nanoparticles ◽  
Degradation Process ◽  
Treatment Conditions ◽  
Thermal Degradation Process ◽  
The Stability ◽  
Thermal Stability Of ◽  
Better Than

Today's pipe made of polyvinyl chloride (PVC) is used as basic good in different industries. The thermal stability of the PVC while is filled with ZnO nanoparticles was studied in this paper. This paper show that the stability of the PVC resin mixed with ZnO nanoparticles solution and Sn was better than that of the PVC resin mixed with Sn alone. The UV (ultraviolet)–vis spectra is showed that under certain heat treatment conditions, the PVC samples without ZnO nanoparticles solution embodied relatively high content of the conjugated double bonds with the chain length of about 3–5. However, the content of the conjugated double bond with the chain length of about 6 was greatly increased when the nanoparticles was filled into the PVC resin. This work shows the ZnO nanoparticles could inhibit the thermal degradation process of PVC resin in ionic mechanism.

Electro-Assisted Photocatalytic Degradation of Methyl Orange on TiO2 Film Using CaСl2 as Electrolyte

2012 ◽  
Vol 487 ◽  
pp. 635-639
Author(s):  
Wen Jie Zhang ◽  
Hong Liang Xin ◽  
Hong Bo He
Keyword(s):  
Methyl Orange ◽  
Photocatalytic Degradation ◽  
Tio2 Film ◽  
Sol Gel ◽  
Degradation Process ◽  
Applied Potential ◽  
Methyl Orange Degradation ◽  
Degradation Rates ◽  
Smooth Film ◽  
Better Than

Porous and smooth TiO2 film electrodes prepared by sol-gel method were used on methyl orange degradation by an electro-assisted photocatalytic degradation process. Methyl orange cannot be degraded under applied potential solely below 2.0 V. When the applied potential was below 1.3 V, methyl orange degradation rates on porous TiO2 film increased from 5% at 0 V to 65.3% at 1.3 V, and degradation rates on smooth TiO2 film changed from 2.2% at 0 V to 61.1% at 1.3 V. Electro-assisted photocatalytic degradation rate on porous film was better than that on smooth film in the whole electrolyte concentration range. Electro-assisted degradation exhibited the same rising trend along with reaction time on the porous and smooth films.

Comparison of Conventional K–Ar and 40Ar/39Ar Dating of Young Mafic Volcanic Rocks

2000 ◽  
Vol 53 (3) ◽  
pp. 294-301 ◽  
Author(s):  
Marvin A. Lanphere
Keyword(s):  
Crater Lake ◽  
Volcanic Rocks ◽  
Snake River Plain ◽  
High Quality ◽  
Modern Equipment ◽  
Suitable Material ◽  
Mount Adams ◽  
River Plain ◽  
Isotope Correlation ◽  
Better Than

AbstractK–Ar and 40Ar/39Ar ages have been measured on nine mafic volcanic rocks younger than 1 myr from the Snake River Plain (Idaho), Mount Adams (Washington), and Crater Lake (Oregon). The K–Ar ages were calculated from Ar measurements made by isotope dilution and K2O measurements by flame photometry. The 40Ar/39Ar ages are incremental-heating experiments using a low-blank resistance-heated furnace. The results indicate that high-quality ages can be measured on young, mafic volcanic rocks using either the K–Ar or the 40Ar/39Ar technique. The precision of an 40Ar/39Ar plateau age generally is better than the precision of a K–Ar age because the plateau age is calculated by pooling the ages of several gas increments. The precision of a plateau age generally is better than the precision of an isotope correlation (isochron) age for the same sample. For one sample the intercept of the isochron yielded an 40Ar/36Ar value significantly different from the atmospheric value of 295.5. Recalculation of increment ages using the isochron intercept for the composition of nonradiogenic Ar in the sample resulted in much better agreement of ages for this sample. The results of this study also indicate that, given suitable material and modern equipment, precise K–Ar and 40Ar/39Ar ages can be measured on volcanic rocks as young as the latest Pleistocene, and perhaps even the Holocene.

Reversible physical crosslinking strategy with optimal temperature for 3D bioprinting of human chondrocyte-laden gelatin methacryloyl bioink

2018 ◽  
Vol 33 (5) ◽  
pp. 609-618 ◽  
Author(s):  
Yawei Gu ◽  
Lei Zhang ◽  
Xiaoyu Du ◽  
Ziwen Fan ◽  
Long Wang ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Three Dimensional ◽  
Optimal Temperature ◽  
Chondrocyte Viability ◽  
Human Chondrocyte ◽  
Tunable Mechanical Properties ◽  
Dimensional Cell ◽  
Physical Crosslinking ◽  
Better Than

Gelatin methacryloyl is a promising material in tissue engineering and has been widely studied in three-dimensional bioprinting. Although gelatin methacryloyl possesses excellent biocompatibility and tunable mechanical properties, its poor printability/processability has hindered its further applications. In this study, we report a reversible physical crosslinking strategy for precise deposition of human chondrocyte-laden gelatin methacryloyl bioink at low concentration without any sacrificial material by using extrusive three-dimensional bioprinting. The precise printing temperature was determined by the rheological properties of gelatin methacryloyl with temperature. Ten percent (w/v) gelatin methacryloyl was chosen as the printing formula due to highest biocompatibility in three-dimensional cell cultures in gelatin methacryloyl hydrogel disks. Primary human chondrocyte-laden 10% (w/v) gelatin methacryloyl was successfully printed without any construct deformation or collapse and was permanently crosslinked by ultraviolet light. The printed gelatin methacryloyl hydrogel constructs remained stable in long-term culture. Chondrocyte viability and proliferation that were printed under this optimal temperature were better than that of chondrocytes printed under lower temperatures and were similar to that of chondrocytes in the non-printed gelatin methacryloyl hydrogels. The results indicate that with this strategy, 10% (w/v) gelatin methacryloyl bioink presented excellent printability and printing resolution with high cell viability, which appears to be suitable for printing primary human chondrocytes in cartilage biofabrication and can be extensively applied in tissue engineering of other organs or in other biomedical fields.

Preparation of Small Crystalline ZSM-5 and its Application in Conversion of Methanol to Aromatic

2012 ◽  
Vol 457-458 ◽  
pp. 245-248 ◽  
Author(s):  
Jian Jun Song ◽  
Zuo Xing Di ◽  
Cheng Yang ◽  
Jin Hu Wu
Keyword(s):  
Hydrothermal Synthesis ◽  
Surface Area ◽  
Micron Size ◽  
Synthesis Procedure ◽  
Better Than

Small crystalline ZSM-5 was synthesized by a hydrothermal synthesis procedure and was characterized by XRD, SEM and N2-absorption. The results show that small crystalline ZSM-5 particles grow into larger agglomerates with a diameter of 100-400 nm, resulting in mesopore and higher surface area. During conversion of methanol to aromatics, small crystalline ZSM-5 catalyst performances better than micron-size ZSM-5 catalyst in aromatic selectivity and lifetime. The aromatic selectivity could reach to 21.7%, and the small crystalline ZSM-5 catalyst shows no deactivation during first 24h.

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