Influence of pore sizes in 3D-scaffolds on mechanical properties of scaffolds and survival, distribution, and proliferation of human chondrocytes

2021 ◽  
pp. 1-12
Author(s):  
Zahra Abpeikar ◽  
Peiman Brouki Milan ◽  
Lida Moradi ◽  
Maryam Anjomshoa ◽  
Shiva Asadpour
Keyword(s):  
Mechanical Properties ◽  
Human Chondrocytes ◽  
3D Scaffolds ◽  
Survival Distribution ◽  
Pore Sizes

scholarly journals Controlling the crystallinity and solubility of functional PCL with efficient post-polymerisation modification

2021 ◽  
Author(s):  
Cinzia Clamor ◽  
Beatrice Cattoz ◽  
Peter Wright ◽  
Rachel K. O'Reilly ◽  
Andrew P Dove
Keyword(s):  
Mechanical Properties ◽  
3D Scaffolds ◽  
Biocompatible Polymer

Poly(ε-caprolactone) is a semi-crystalline biocompatible polymer with good mechanical properties. Its crystallinity also uniquely enables poly(ε-caprolactone) to be used in different applications, from the development of 3D scaffolds for tissue...

Silk fibroin–keratin based 3D scaffolds as a dermal substitute for skin tissue engineering

2015 ◽  
Vol 7 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Nandana Bhardwaj ◽  
Wan Ting Sow ◽  
Dipali Devi ◽  
Kee Woei Ng ◽  
Biman B. Mandal ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Silk Fibroin ◽  
Skin Tissue ◽  
Dermal Substitute ◽  
Skin Substitutes ◽  
3D Scaffolds ◽  
Skin Tissue Engineering ◽  
Dermal Tissue ◽  
Engineered Skin Substitutes

Development of highly vascular dermal tissue-engineered skin substitutes with appropriate mechanical properties and cellular cues is in need for significant advancement in the field of dermal reconstruction.

Mechanical properties of ferroelastic La0.6Sr0.4Co0.2Fe0.8O3−δ with various porosities and pore sizes

2019 ◽  
Vol 54 (7) ◽  
pp. 5256-5265 ◽  
Author(s):  
Md. Nurul Islam ◽  
Wakako Araki ◽  
Yoshio Arai
Keyword(s):  
Mechanical Properties ◽  
Pore Sizes

Near-Field Electrospinning and Characterization of Biodegradable Small Diameter Vascular Grafts

2021 ◽  
Author(s):  
◽  
William King, III ◽  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Pore Size ◽  
Vascular Graft ◽  
Fiber Diameter ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Pore Sizes ◽  
Small Diameter Vascular Grafts

The ideal “off the shelf” tissue engineering, small-diameter (< 6 mm inner diameter (ID)) vascular graft hinges on designing a template that facilitates transmural ingrowth of capillaries to regenerate an endothelized neointimal surface. Previous traditionally electrospun (TES) approaches to create bioresorbable vascular grafts lack the pore sizes required to facilitate transmural capillary ingrowth required for successful in situ neovascular regeneration. Therefore, the ability to create scaffolds with program-specific architectures independent of fiber diameter via the relatively recent sub-technique of near-field electrospinning (NFES) represents a promising solution to create tissue engineering vascular grafts. These programmed large pore sizes are anticipated to promote in situ regeneration and improve the outcomes as well as the quality of life of patients with arterial disease. In this dissertation, we manufactured via NFES as well as characterized biodegradable polydioxanone (PDO) small-diameter vascular grafts. Chapter 1 introduces the need for off-the-shelf, small-diameter vascular grafts to facilitate in situ regeneration, the process and pore size limitations of TES vascular grafts, and the promising use of NFES to develop precisely tailored PDO vascular grafts. Chapter 2 describes the process of NFES and details the current progress in NFES of biomedical polymers as well as the major limitations that exist in the field. Chapters 3, 4, and 5 contain primary research exploring the creation of an NFES vascular graft scaffold and characterizing the mechanical as well as biological response of these scaffolds. Specifically, in Chapter 3 we demonstrate a NFES apparatus designed around a commercial 3D printer to write PDO microfibers. The processing parameters of air gap, polymer concentration, translational velocity, needle gauge, and applied voltage were characterized for their effects on PDO fiber diameter. The processing parameters of polymer concentration and translational fiber deposition velocity were further characterized for their effects on fiber crystallinity and individual fiber uniformity. The precision of fiber stacking via a 3D printer was qualitatively evaluated to inform the creation of 3D scaffolds to guide the alignment of human gingival fibroblasts. It was found that fiber diameters correlate positively with polymer concentration, applied voltage, and needle gauge and inversely correlate with translational velocity and air gap distance. Individual fiber diameter variability decreases, and crystallinity increases with increasing translational fiber deposition velocity. These data resulted in the creation of tailored PDO 3D scaffolds which guided the alignment of primary human fibroblast cells. Together, these results suggest that NFES of PDO can be scaled to create precise geometries with tailored fiber diameters for vascular graft scaffolds. In Chapter 4, we demonstrated a NFES device to semi-stably write PDO microfibers. The polymer spinneret was programmed to translate in a stacking grid pattern, which resulted in a scaffold with highly aligned grid fibers that were intercalated with low density, random fibers. As a consequence of this random switching process, increasing the grid dimensions resulted in both a lower density of fibers in the center of each grid in the scaffold as well as a lower density of “rebar-like” stacked fibers per unit area. These hybrid architecture scaffolds resulted in tailorable as well as greater surface pore sizes as given by scanning electron micrographs and effective object permeability as indicated by fluorescent microsphere filtration compared to TES scaffolds of the same fiber diameter. Furthermore, these programmable scaffolds resulted in tailorability in the characterized mechanical properties ultimate tensile strength, percent elongation, yield stress, yield elongation, and Young’s modulus independent of fiber diameter compared to the static TES scaffold characterization. Lastly, the innate immune response of neutrophil extracellular traps (NETs) was further attenuated on NFES scaffolds compared to TES scaffolds. These results suggest that this novel NFES scaffold architecture of PDO can be highly tailored as a function of programming for small diameter vascular graft scaffolds. In Chapter 5, we created two types of NFES PDO architectures, as small-diameter vascular graft scaffolds. The first architecture type consisted of a 200 x 200 µm and 500 x 500 µm grid geometry with random fiber infill produced from one set of processing parameters, while the second architecture consisted of aligned fibers written in a 45°/45° and 20°/70° offset from the long axis, both on a 4 mm diameter cylindrical mandrel. These vascular graft scaffolds were characterized for their effective object transit pore size, mechanical properties, and platelet-material interactions compared to TES scaffolds and Gore-Tex® vascular grafts. It was found that effective pore size, given by 9.9 and 97 µm microsphere filtration through the scaffold wall for NFES grafts, was significantly more permeable compared to TES grafts and Gore-Tex® vascular grafts. Furthermore, the characterized mechanical properties of ultimate tensile strength, percent elongation, suture retention, burst pressure, and Young’s modulus were all tailorable for NFES grafts, independent of fiber diameter, compared to TES graft characterization. Lastly, platelet adhesion was attenuated on large pore size NFES grafts compared to the TES grafts which approximated the low level of platelet adhesion measured on Gore-Tex® grafts, with all grafts showing minimal platelet activation given by P-selectin surface expression. Together, these results suggest a highly tailorable process for the creation of the next generation of small-diameter vascular grafts. Lastly, Chapter 6 expounds future considerations for continuing research in NFES technology, NFES for general tissue engineering, and NFES for vascular tissue engineering as well as gives final conclusions. Together, the finding of this dissertation indicated that NFES vascular grafts result in seamless, small diameter tubular scaffolds with programmable pore sizes on the magnitude anticipated to facilitate transmural endothelialization as well as programmable mechanical properties that approximate native values. Thus, this work represents the next step in developing bioinstructive designed scaffolds to facilitate in situ vascular regeneration to improve the outcomes as well as the quality of life of patients with arterial vascular disease.

Effect of Pore Size on Mechanical Properties of Titanium Foams

2010 ◽  
Vol 654-656 ◽  
pp. 827-830 ◽  
Author(s):  
Yang An ◽  
Chun Hui Yang ◽  
Peter D. Hodgson ◽  
Cui E Wen
Keyword(s):  
Mechanical Properties ◽  
Pore Size ◽  
Size Effects ◽  
Cell Walls ◽  
Deformation Behaviour ◽  
Pore Sizes ◽  
Geometrical Characteristics ◽  
Titanium Foam ◽  
Scanning Electron ◽  
Compressive Tests

In the study, both experimental work and numerical modeling are performed to investigate the pore size effects on the mechanical properties and deformation behaviours of titanium foams. Cylindrical titanium foam samples with different pore sizes are fabricated through powder metallurgy. Scanning electron microscope (SEM) is used to determine the pore size, pore distribution and the ratios of the length to width of pores. Compressive tests are carried out to determine the mechanical properties of the titanium foams with different pore sizes. Finally, finite element modeling is attempted to simulate the deformation behaviour and the mechanical properties of the titanium foams. Results indicate that titanium foams with different pore sizes have different geometrical characteristics, which lead to different deformation behaviours of cell walls during compression, resulting in different mechanical properties of titanium foams.

scholarly journals Nickel Wick by Continuous Freeze-Casting: Influences of the Particle Size on the Capillarity and Mechanical Properties

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4340
Author(s):  
Pedro Javier Lloreda-Jurado ◽  
Laura Chicote ◽  
Ernesto Chicardi ◽  
Ranier Sepúlveda
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Size Range ◽  
Casting Process ◽  
Freeze Casting ◽  
Particle Size Range ◽  
Particle Sedimentation ◽  
Average Pore ◽  
Pore Sizes ◽  
Interconnected Pore

The aim of this work was to study the effect of the particle size range, the freeze casting temperature and sintering temperature on the capillarity performance and mechanical properties of Ni wicks manufactured by freeze-casting. The use of Ni/camphene-polystyrene suspensions creates wicks with an open porosity above 80% and average pore sizes of 38 μm to 17 μm by tailoring the particle size ranges and freezing temperatures employed. The incorporation of PS and the use of a continuous freeze-casting process reduces the particle sedimentation and generates a highly interconnected pore structure with regular pore sizes across the sample. The capillarity performances exhibit a fast and complete water adsorption, especially in Ni wicks freeze-casted at 10 °C and sintered at 800 °C, but only when the smaller particle size range is used do Ni wicks achieve sufficient mechanical strength.

scholarly journals MECHANICAL PROPERTIES OF 3D SCAFFOLDS FOR BONE REGENERATION / 3D KARKASŲ, SKIRTŲ KAULŲ REGENERACIJAI, MECHANINIŲ SAVYBIŲ TYRIMAS

2017 ◽  
Vol 8 (6) ◽  
pp. 587-591
Author(s):  
Deividas Mizeras ◽  
Andžela Šešok ◽  
Algirdas Vaclovas Valiulis ◽  
Justinas Gargasas ◽  
Irmantas Gedzevičius
Keyword(s):  
Mechanical Properties ◽  
Testing Machine ◽  
Bone Substitutes ◽  
Point Of View ◽  
Bone Tissue Regeneration ◽  
3D Scaffolds ◽  
Bending Tests ◽  
Ethical Point ◽  
Additional Surgery ◽  
3D Printed

One of the biggest challenges in modern tissue engineering is a creation 3D scaffolds for bone tissue regeneration. Until now, in order to restore bone defects are used various bone substitutes (autologous and allogeneic), however, their usage is limited because is required additional surgery, possible complications, also limited their use is associated with ethical point of view. In this work we aim to determine the mechanical properties of 3D printed PLA objects having various orientation woodpile microarchitectures. In this work we chose three different 3D microarchitectures: woodpile BCC (each layer consists of parallel logs which are rotated 90 deg every next layer), woodpile FCC (every layer is additionally shifted half of the period in respect to the previous parallel log layer) and a rotating woodpile 60 deg (each layer is rotated 60 deg in respect to the previous one). Compressive and bending tests were carried out with TIRAtest2300 universal testing machine. We found that 60 deg rotating woodpile geometry had the highest mechanical values which were approximately about 3 times higher than the BCC or FCC microstructures. Vienas didžiausių šiuolaikinės audinių inžinerijos iššūkių yra 3D karkasų, skirtų kaulinio audinio regeneracijai, sukūrimas. Iki šiol, norint atstatyti kaulo defektus, naudojami įvairūs kaulo pakaitalai (autogeniniai ir alogeniniai), kurių naudojimo galimybės jau nebeatitinka poreikių, nes reikalinga papildoma operacija, galimos komplikacijos, taip pat ribotas jų naudojimas, susijęs su etinėmis pažiūromis. Šiame darbe lyginamos 3D spausdintuvu suformuotų mikrodarinių, skirtų kaulinio audinio defektui atkurti, mechaninės savybės. Darbe pasirinktos trys skirtingos 3D karkasų mikrostruktūros: woodpile BCC (kiekvienas sluoksnis susideda iš lygiagrečių rąstų, kurie keičiami 90 laipsnių kampu prieš tai esančio sluoksnio atžvilgiu), woodpile FCC (kiekvienas sluoksnis papildomai keičiasi per pusę periodo sluoksnio, esančio prieš tai, atžvilgiu) ir woodpile 60 deg (besisukanti rąstų rietuvė, kiekvienas tokios gardelės sluoksnis yra pasuktas 60 laipsnių prieš tai esančios atžvilgiu). Gniuždymo ir lenkimo bandymai buvo atlikti TIRAtest 2300 universalia bandymų mašina. Buvo nustatyta, kad, taikant 60 laipsnių kampu besikeičiančią woodpile geometriją, galima pasiekti didžiausias mechanines vertes, kurios buvo maždaug tris kartus didesnės nei woodfile BCC arba woodfile FCCmikrostruktūros.

scholarly journals Biocomposites conductive scaffold based on PEDOT:PSS/nHA/chitosan/PCL: Fabrication and characterization

2019 ◽  
Vol 15 (2) ◽  
pp. 146-149
Author(s):  
Alireza Lari ◽  
Naznin Sultana ◽  
Chin Fhong Soon
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Composite Scaffold ◽  
Biological Evaluation ◽  
Sem Analysis ◽  
Human Skin Fibroblast ◽  
Fabrication Technique ◽  
Pore Sizes ◽  
Material Component

Biomaterial-based scaffolds with suitable characteristics are highly desired in tissue engineering (TE) application. Biocomposites based on polymer and ceramics increase the chance for modulating the properties of scaffold. In recent years, researchers have considered conductive polymers to be used in TE application, due to their conductivity. This property has a good impact on tissue regeneration. A suitable design for bone substitute that consists of considerations such as material component, fabrication technique and mechanical properties. The previous studies on PEDOT:PSS/nHA/CS showed high wettability rate but low mechanical properties. Polycaprolactone (PCL) is a biodegradable and biocompatible polymer with a low wettability. The incorporation of PCL inside biocomposite can lead to the decrement in wettability and increment in mechanical property. In addition, this paper would examine the feasibility of blending of PCL and chitosan to fabricate PEDOT:PSS/nHA/CS composite scaffold. The fabrication technique of freezing/ lyophilization was used in this study. The scaffolds were characterized morphologically using scanning electron microscopy (SEM). Wettability was studied using a contact angle instrument. The attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) spectra interpreted the presence of polymeric ingredients within composite scaffold. Conductivity of the scaffolds was measured using a Digital Multimeter. In-vitro biological evaluation of the scaffolds was studied using human skin Fibroblast (HSF) cell line. The morphological study of biocomposite PEDOT:PSS/nHA/CS/PCL scaffold revealed random pore sizes and 66% porosity. Contact angle of the scaffold was increased and the swelling property and pore sizes were decreased after blending of PCL polymer. The viability of HSF cells on biocomposite PEDOT:PSS/nHA/CS/PCL scaffold was 85%. After 7 days, SEM analysis revealed the presence of cells on the surface of scaffold. In conclusion, the results suggested that PEDOT:PSS/nHA/CS/PCL biocomposite scaffold was non-toxic to cells and has suitable properties.

Nanotubes and nanoparticles based 3D scaffolds for the construction of high performance Biosensors

2014 ◽  
Vol 1700 ◽  
pp. 97-102
Author(s):  
Meenakshi Singh ◽  
Michael Holzinger ◽  
Maryam Tabrizian ◽  
Serge Cosnier
Keyword(s):  
Carbon Nanotubes ◽  
Glucose Oxidase ◽  
Current Density ◽  
High Performance ◽  
Single Walled Carbon Nanotubes ◽  
3D Scaffolds ◽  
Pore Sizes ◽  
Enzyme Sensors ◽  
The One ◽  
Walled Carbon Nanotubes

ABSTRACT3D scaffolds with different pore sizes, using single-walled carbon nanotubes (SWCNTs) and nanoparticles of different size were constructed. Biotinylated glucose oxidase (GOX-B) and anti-cholera toxin (anti-CT) were immobilized onto the one and two level nanoscaffolds, functionalized with pyrene-β-cyclodextrin for the construction of glucose based enzyme sensors and immunosensors, respectively. For enzyme sensors, highest current density and sensitivity (41.72 μA cm-2, 3 mA M-1 cm-2) were obtained with two level scaffolds made with 100 nm nanoparticles. In contrast to this, for immunosensors, highest current density and sensitivity (11.71 μA cm-2, 116.2 μA M-1 cm-2) were obtained with two level scaffolds made with 500 nm nanoparticles, indicating that the pore sizes can be adjusted using different size of nanoparticles for the respective applications.

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