scholarly journals Physical, thermal, and mechanical properties of highly porous polylactic acid/cellulose nanofibre scaffolds prepared by salt leaching technique

2021 ◽  
Vol 10 (1) ◽  
pp. 1469-1483
Author(s):  
Revati Radakisnin ◽  
Mohd Shukry Abdul Majid ◽  
Mohd Ridzuan Mohd Jamir ◽  
Mohd Faizal Mat Tahir ◽  
Cheng Ee Meng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Mechanical Performance ◽  
Cell Attachment ◽  
Composite Scaffold ◽  
Average Pore Size ◽  
Pennisetum Purpureum ◽  
Porous Scaffolds ◽  
Average Pore ◽  
Salt Leaching

Abstract This study aimed to prepare and characterise polylactic acid (PLA) reinforced with cellulose nanofibre (CNF) from a Pennisetum purpureum-based composite scaffold and determine its structural and mechanical properties. Porous scaffolds with CNF compositions of 5‒20 wt% in the PLA matrix were developed using solvent casting and particulate leaching of its porogen at 90 wt% of loadings. Morphology studies using field emission scanning electron microscopy revealed that the scaffolds had well-interconnected pores with an average pore size range of 67‒137 µm and porosity >76%. X-ray diffraction confirmed the interconnectivity and homogeneity of the pores and the fibrous structure of the scaffolds. The compressive strength of the fabricated scaffolds varied between 2.34 and 6.66 MPa, while their compressive modulus was between 1.95 and 6.04 MPa for various CNF contents. Furthermore, water absorption and thermal degradation studies showed that the scaffold had good hydrophilicity and improved thermal stability. These findings highlight the need to modify the pore structure and mechanical performance simultaneously for tissue engineering. Thus, this study concludes that the developed PLA scaffolds reinforced with CNF from Pennisetum purpureum are potential candidates for cell attachment and extracellular matrix generation.

scholarly journals Effect of Different Porosity Ratio on Mechanical Properties of Polycaprolactone and Polylactic Acid Scaffolds

2018 ◽  
Vol 1 (1) ◽  
pp. 1243-1248
Author(s):  
Adem Demir ◽  
Mustafa Keser ◽  
Fatih Çalışkan
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Pore Size ◽  
Polylactic Acid ◽  
Mechanical Performance ◽  
Patient Specific ◽  
Porous Scaffolds ◽  
Medical Field ◽  
Tissue Engineering Scaffolds ◽  
Porosity Ratio

In recent years, patient-specific solutions and additive manufacturing (AM) have become increasingly important in the treatment of bone defects in studies performed on the medical field. In this direction, additive manufacturing methods use in scaffold fabrication, and many advantages of these systems come to the forefront. Porosity affects the mechanical properties, biocompatibility, and biodegradability of tissue engineering scaffolds. In this study, the effect of different porosity ratios on the mechanical properties of scaffolds for polylactic acid (PLA) and polycaprolactone (PCL) scaffolds was studied. With this fabrication method can be formed entirely 3D interconnected porous scaffolds with pore size. Three different (20%, 35%, and 50%) porosity ratios were determined for both materials, and the mechanical properties of the samples were determined by compression test. The scaffolds fabricated with larger pore size showed lower mechanical performance compared to scaffolds with smaller pore size.

scholarly journals Preparation of Long Sisal Fiber-Reinforced Polylactic Acid Biocomposites with Highly Improved Mechanical Performance

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1124
Author(s):  
Zhifang Liang ◽  
Hongwu Wu ◽  
Ruipu Liu ◽  
Caiquan Wu
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Mechanical Performance ◽  
Tensile Elongation ◽  
Sisal Fiber ◽  
Fiber Reinforced ◽  
Impact Performance ◽  
The Matrix ◽  
Blending Process ◽  
Extension Direction

Green biodegradable plastics have come into focus as an alternative to restricted plastic products. In this paper, continuous long sisal fiber (SF)/polylactic acid (PLA) premixes were prepared by an extrusion-rolling blending process, and then unidirectional continuous long sisal fiber-reinforced PLA composites (LSFCs) were prepared by compression molding to explore the effect of long fiber on the mechanical properties of sisal fiber-reinforced composites. As a comparison, random short sisal fiber-reinforced PLA composites (SSFCs) were prepared by open milling and molding. The experimental results show that continuous long sisal fiber/PLA premixes could be successfully obtained from this pre-blending process. It was found that the presence of long sisal fibers could greatly improve the tensile strength of LSFC material along the fiber extension direction and slightly increase its tensile elongation. Continuous long fibers in LSFCs could greatly participate in supporting the load applied to the composite material. However, when comparing the mechanical properties of the two composite materials, the poor compatibility between the fiber and the matrix made fiber’s reinforcement effect not well reflected in SSFCs. Similarly, the flexural performance and impact performance of LSFCs had been improved considerably versus SSFCs.

scholarly journals Physicochemical and Mechanical Properties of Blow Spun Nanofibrous Prostheses Modified with Acrylic Acid and REDV Peptide

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1110
Author(s):  
Beata A. Butruk-Raszeja ◽  
Aleksandra Kuźmińska ◽  
Michał Wojasiński ◽  
Zuzanna Piotrowska
Keyword(s):  
Mechanical Properties ◽  
Fiber Diameter ◽  
Flow System ◽  
Average Pore Size ◽  
Internal Diameter ◽  
Optimal Parameters ◽  
Average Pore ◽  
Vascular Prostheses ◽  
Modification Process ◽  
Inner Surface

The paper presents a method of modifying the inner surface of nanofibrous vascular prostheses. The modification process involves two steps: introducing a hydrophilic linker, followed by a peptide containing the arginine-glutamic acid-aspartic acid-valine (REDV) sequence. The influence of the process parameters (reaction time, temperature, initiator concentration) on morphology and the distribution of fiber diameters were examined. For selected optimal parameters, the prostheses were modified in the flow system. Modifications along the entire length of the prosthesis were confirmed—the inlet and the outlet areas showed no significant (p > 0.05) differences in the value of the contact angle and the analyzed morphological parameters. The basic physicochemical and mechanical properties of modified prostheses were analyzed. The study showed that REDV-modified prosthesis has an average fiber diameter of 318 ± 99 nm, the average pore size of 3.0 ± 1.6 μm, the porosity of 48.4 ± 8.6% and Young’s modulus of 4.0 ± 0.4 MPa. The internal diameter of prostheses remains unchained and amounts to 3 mm. Such modified prostheses can reduce the risk of blood coagulation by increasing the surface’s wettability and, most of all, by introducing endothelial cell-selective peptide. As an effect, the proposed surfaces could recruit endothelial progenitor cells directly from the bloodstream and promote the endothelium formation after implantation.

scholarly journals Alginate/Gelatin Hydrogels Reinforced with TiO2 and β-TCP Fabricated by Microextrusion-based Printing for Tissue Regeneration

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 457 ◽  
Author(s):  
Rodrigo Urruela-Barrios ◽  
Erick Ramírez-Cedillo ◽  
A. Díaz de León ◽  
Alejandro Alvarez ◽  
Wendy Ortega-Lara
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Tissue Regeneration ◽  
Average Pore Size ◽  
Three Dimensional ◽  
Engineering Applications ◽  
Average Pore ◽  
Viscous Deformation ◽  
Freeze Dried ◽  
3D Printed

Three-dimensional (3D) printing technologies have become an attractive manufacturing process to fabricate scaffolds in tissue engineering. Recent research has focused on the fabrication of alginate complex shaped structures that closely mimic biological organs or tissues. Alginates can be effectively manufactured into porous three-dimensional networks for tissue engineering applications. However, the structure, mechanical properties, and shape fidelity of 3D-printed alginate hydrogels used for preparing tissue-engineered scaffolds is difficult to control. In this work, the use of alginate/gelatin hydrogels reinforced with TiO2 and β-tricalcium phosphate was studied to tailor the mechanical properties of 3D-printed hydrogels. The hydrogels reinforced with TiO2 and β-TCP showed enhanced mechanical properties up to 20 MPa of elastic modulus. Furthermore, the pores of the crosslinked printed structures were measured with an average pore size of 200 μm. Additionally, it was found that as more layers of the design were printed, there was an increase of the line width of the bottom layers due to its viscous deformation. Shrinkage of the design when the hydrogel is crosslinked and freeze dried was also measured and found to be up to 27% from the printed design. Overall, the proposed approach enabled fabrication of 3D-printed alginate scaffolds with adequate physical properties for tissue engineering applications.

Mechanical Properties of Micro-Porous Metals Produced by Space-Holding Sintering

2007 ◽  
Vol 29-30 ◽  
pp. 75-78 ◽  
Author(s):  
Takumi Banno ◽  
Yun Cang Li ◽  
Cui E Wen ◽  
Yasuo Yamada
Keyword(s):  
Mechanical Properties ◽  
Cell Structure ◽  
Deformation Behaviour ◽  
Average Pore Size ◽  
Chemical Vapour ◽  
Porous Nickel ◽  
Porous Metals ◽  
Average Pore ◽  
Nickel Foams ◽  
Compressive Tests

Micro-porous nickel foams with an open cell structure were fabricated by the space-holding sintering. The average pore size of the micro-porous nickel specimens ranged from 30 μm to 150 μm, and the porosity ranged from 60 % to 80 %. The porous characteristics of the nickel specimens were observed using scanning electron microscopy (SEM). The mechanical properties were studied using compressive tests. For comparison, macro-porous nickel foams prepared by the chemical vapour deposition method with pore sizes of 800 μm and 1300 μm and porosity of 95 % were also presented. Results indicated that the ratio value of 6 and higher for the specimen length to cell size (L/d) is satisfying for obtaining stable compressive properties. The micro-porous nickel specimens exhibited different deformation behaviour and dramatically increased mechanical properties, compared to those of the macro-porous nickel specimens.

Determination of Local Mechanical Properties of Si3N4 Based Foams

2014 ◽  
Vol 606 ◽  
pp. 213-216 ◽  
Author(s):  
Zuzana Vilčeková ◽  
Monika Kašiarová ◽  
Magdaléna Domanická ◽  
Miroslav Hnatko ◽  
Pavol Šajgalík
Keyword(s):  
Mechanical Properties ◽  
Silicon Nitride ◽  
Resonant Frequency ◽  
Volume Fraction ◽  
Average Pore Size ◽  
Polyurethane Foams ◽  
Average Pore ◽  
Replication Method ◽  
Highly Porous

Local mechanical properties, particularly the hardness and Youngs modulus of highly porous silicon nitride based foams were studied in this work. Silicon nitride foams were prepared using polyurethane foam replication method to obtain appropriate cellular structure suitable for bio-application. Two types of the polyurethane foams were used (with average pore size 0.48 mm and 0.62 mm). Some of these samples were prepared by single or multiple infiltrations. The effects of structures, temperature of calcination, volume fraction of Si3N4 powder and number of the infiltrations on the local mechanical properties were investigated. The Youngs modulus of studied samples range from 12 to 46 GPa at the macroscopic scale measured by resonant frequency technique and from 10 to 28 GPa at the microscopic scale measured by instrumented indentation. Results showed increase of the hardness and Youngs modulus with increasing of the calcination temperature, with increasing of the number of infiltrations and also with increasing of volume fraction of Si3N4 powder in suspension. The results obtained from nanoindentation carry out lower values in comparison with the values measured by resonant frequency technique.

Fabrication and Characterization of Mechanically Reinforced Collagen Sponge

2005 ◽  
Vol 288-289 ◽  
pp. 385-388
Author(s):  
Yosuke Hiraoka ◽  
Ueda Hiroki ◽  
Yu Kimura ◽  
Yasuhiko Tabata
Keyword(s):  
Cell Attachment ◽  
Average Pore Size ◽  
Collagen Sponge ◽  
Average Pore ◽  
Culture Studies ◽  
Collagen Solution ◽  
Freeze Dried ◽  
Interconnected Pore

This study describes an investigation of collagen sponge mechanically reinforced through the incorporation of poly(glycolic acid)(PGA) fiber. A collagen solution with PGA fiber homogeneously dispersed was freeze-dried, followed by dehydrothermal cross-linking to obtain collagen sponges incorporating PGA fiber. A collagen sponge without PGA fiber was prepared similarly by using the collagen solution. By scanning electron observation, the collagen sponges exhibited isotropic and interconnected pore structures with an average pore size of 180 µm, irrespective of PGA fiber incorporation. As expected, PGA fiber incorporation enabled the collagen sponge to significantly enhance the compression strength. In vitro cell culture studies revealed that the number of L929 fibroblasts initially attached was significantly greater for the collagen sponge incorporating PGA fiber than for the collagen sponge. In vitro cell proliferation studies revealed that the proliferation of cell was higher for the collagen sponge incorporating PGA fiber, by day 21, than the collagen sponge without PGA fiber. It is possible that shrinkage suppression results in the superior cell attachment and proliferation of sponge incorporating PGA fiber. After subcutaneous implantation into the backs of mice, the residual volume of collagen sponge incorporating PGA fiber was significantly large compared with that of collagen sponge. We concluded that the incorporation of PGA fiber is a simple way to reinforce collagen sponge without impairing the biocompatibility.

scholarly journals Polycaprolactone Foam Functionalized With Chitosan Microparticles – a Suitable Scaffold for Cartilage Regeneration

2016 ◽  
pp. 121-131 ◽  
Author(s):  
E. FILOVÁ ◽  
B. JAKUBCOVÁ ◽  
I. DANILOVÁ ◽  
E. KUŽELOVÁ KOŠŤÁKOVÁ ◽  
T. JAROŠÍKOVÁ ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Growth ◽  
Dna Content ◽  
Viscoelastic Properties ◽  
Cartilage Regeneration ◽  
Biomechanical Properties ◽  
Porous Scaffolds ◽  
Chitosan Microparticles ◽  
Salt Leaching ◽  
Cell Growth And Differentiation

For biodegradable porous scaffolds to have a potential application in cartilage regeneration, they should enable cell growth and differentiation and should have adequate mechanical properties. In this study, our aim was to prepare biocompatible scaffolds with improved biomechanical properties. To this end, we have developed foam scaffolds from poly-Ɛ-caprolactone (PCL) with incorporated chitosan microparticles. The scaffolds were prepared by a salt leaching technique from either 10 or 15 wt% PCL solutions containing 0, 10 and 20 wt% chitosan microparticles, where the same amount and size of NaCl was used as a porogen in all the cases. PCL scaffolds without and with low amounts of chitosan (0 and 10 wt% chitosan) showed higher DNA content than scaffolds with high amounts of chitosan during a 22-day experiment. 10 wt% PCL with 10 and 20 wt% chitosan showed significantly increased viscoelastic properties compared to 15 wt% PCL scaffolds with 0 and 10 wt% chitosan. Thus, 10 wt% PCL scaffolds with 0 wt% and 10 wt% chitosan are potential scaffolds for cartilage regeneration.

Properties of Hydrophilic Chitosan/Polysulfone Nanofibrous Filtration Membrane

2014 ◽  
Vol 9 (1) ◽  
pp. 155892501400900 ◽  
Author(s):  
Leigen Liu ◽  
Zhijuan Pan
Keyword(s):  
Mechanical Properties ◽  
Pore Size ◽  
Average Pore Size ◽  
High Surface ◽  
Chitosan Solution ◽  
Water Filtration ◽  
Average Pore ◽  
Filtration Membrane ◽  
Crosslinked Chitosan ◽  
Nanofibrous Membranes

Electrospun nanofibrous membranes are useful water filtration materials due to their high interconnected porosity and tunable pore sizes, which cause very high permeability and selectivity. However, poor mechanical properties and easy fouling due to their extremely high surface area limit their applications. Therefore, it is desirable to enhance the mechanical properties and the hydrophilicity of such electrospun nanofibrous membranes. In this paper, electrospun polysulfone (PSF) nanofibrous membranes were treated with plasma. Crosslinked chitosan solution was then employed to pad the membranes. We studied the influence of the chitosan concentration and the volume of glutaraldehyde on the morphology, porosity structure, mechanical properties and hydrophilicity of electrospun polysulfone nanofibrous membranes. The results showed that the average pore size decreased from 4.5 μm to 2.68 μm, the breaking stress increased from 6.01±0.44 MPa to 9.25±0.45 MPa, and the water contact angle decreased from 130.8° to 0° in 30 s when chitosan was applied to the membranes. These changes occurred by padding due to the crosslinked chitosan solution. The results indicate that a significant improvement occurred in the mechanical properties; the highly hydrophobic PSF membrane was changed to a superhydrophilic one and the pore size was reduced. These results encouraged us to propose this material as a water filtration membrane with longer life span, lower fouling and higher rejection efficiency.

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