scholarly journals Microfluidic Technology for the Production of Well-Ordered Porous Polymer Scaffolds

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1863
Author(s):  
Pei Zhao ◽  
Jianchun Wang ◽  
Yan Li ◽  
Xueying Wang ◽  
Chengmin Chen ◽  
...  
Keyword(s):  
Pore Size ◽  
Porous Scaffold ◽  
Short Review ◽  
Porous Polymer ◽  
Morphological Properties ◽  
High Porosity ◽  
Polymer Scaffolds ◽  
Pore Interconnectivity ◽  
Microfluidic Technology ◽  
Ordered Porous

Advances in tissue engineering (TE) have revealed that porosity architectures, such as pore shape, pore size and pore interconnectivity are the key morphological properties of scaffolds. Well-ordered porous polymer scaffolds, which have uniform pore size, regular geometric shape, high porosity and good pore interconnectivity, facilitate the loading and distribution of active biomolecules, as well as cell adhesion, proliferation and migration. However, these are difficult to prepare by traditional methods and the existing well-ordered porous scaffold preparation methods require expensive experimental equipment or cumbersome preparation steps. Generally, droplet-based microfluidics, which generates and manipulates discrete droplets through immiscible multiphase flows inside microchannels, has emerged as a versatile tool for generation of well-ordered porous materials. This short review details this novel method and the latest developments in well-ordered porous scaffold preparation via microfluidic technology. The pore structure and properties of microfluidic scaffolds are discussed in depth, laying the foundation for further research and application in TE. Furthermore, we outline the bottlenecks and future developments in this particular field, and a brief outlook on the future development of microfluidic technique for scaffold fabrication is presented.

Pore Morphology Effects on the Fibrovascular Tissue Growth in Porous Polymer Substrates

1994 ◽  
Vol 3 (4) ◽  
pp. 339-343 ◽  
Author(s):  
M. Conley Wake ◽  
Charles W. Patrick ◽  
Antonios G. Mikos
Keyword(s):  
Lactic Acid ◽  
Pore Size ◽  
Pore Diameter ◽  
Tissue Growth ◽  
Porous Polymer ◽  
Pore Morphology ◽  
Cell Seeding ◽  
Polymer Scaffolds ◽  
Polymer Substrates ◽  
Fibrovascular Tissue

The feasibility of developing biodegradable polymer scaffolds to engineer tissues was investigated by studying the effects of pore size on the dynamics of fibrovascular tissue ingrowth. Tissue advanced into amorphous poly(l-lactic acid) porous substrates faster as the pore diameter increased. Porous cylindrical devices of 13.5 mm diameter, 5 mm thickness, and approximately 500 μm pore size were filled completely by tissue 5 days postimplantation. Although prevascularized devices possessed minimal void volume for cell seeding to regenerate metabolic organs, they hold promise in the regeneration of tubular tissues by relying on the epithelization of prevascularized grafts.

scholarly journals Large Optical Nonlinearity of the Activated Carbon Nanoparticles Prepared by Laser Ablation

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 737
Author(s):  
Yasin Orooji ◽  
Hamed Ghanbari Gol ◽  
Babak Jaleh ◽  
Mohammad Reza Rashidian Vaziri ◽  
Mahtab Eslamipanah
Keyword(s):  
Electron Microscopy ◽  
Activated Carbon ◽  
Laser Ablation ◽  
Carbon Nanoparticles ◽  
Morphological Properties ◽  
Excitation Wavelength ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
High Porosity ◽  
Nlo Properties

Carbon nanoparticles (CNPs) with high porosity and great optical features can be used as a luminescent material. One year later, the same group investigated the NLO properties CNPs and boron-doped CNPs by 532 nm and 1064 nm laser excitations to uncover the underlying physical mechanisms in their NLO response. Hence, a facile approach, laser ablation technique, was employed for carbon nanoparticles (CNPs) synthesis from suspended activated carbon (AC). Morphological properties of the prepared CNPs were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). UV-Vis and fluorescence (FL) spectra were used to optical properties investigation of CNPs. The size distribution of nanoparticles was evaluated using dynamic light scattering (DLS). The nonlinear optical (NLO) coefficients of the synthesized CNPs were determined by the Z-scan method. As a result, strong reverse saturable absorption and self-defocusing effects were observed at the excitation wavelength of 442 nm laser irradiation. These effects were ascribed to the presence of delocalized π-electrons in AC CNPs. To the best of our knowledge, this is the first study investigating the NLO properties of the AC CNPs.

Preparation of Nano-Fibrous Poly(L-lactic acid) Scaffold with Hierarchical Pores

2011 ◽  
Vol 418-420 ◽  
pp. 303-306
Author(s):  
Xue Jun Wang ◽  
Tao Lou ◽  
Guo Jun Song
Keyword(s):  
Tissue Engineering ◽  
Lactic Acid ◽  
Pore Size ◽  
Composite Scaffold ◽  
Compressive Modulus ◽  
High Porosity ◽  
Nano Composite ◽  
Hierarchical Pores ◽  
Fiber Size ◽  
Hierarchical Pore

In this study, a nano-fibrous PLLA scaffold with hierarchical pore was sucessfully fabricated using combined TIPS and particle leaching method.The scaffold had a nano-fibrous PLLA matrix (fiber size 100-800 nm), an interconnective hierarchical pores (1.0- 425 μm), high porosity (>96%). The compressive modulus of scaffold with different pore size was between 0.16 MPa to 0.2 Mpa and it decreased with the increased salt size embedded in. The new nano composite scaffold is potentially a very promising scaffold for tissue engineering.

Development of Scaffold Building Units and Assembly for Tissue Engineering Using Fused Deposition Modelling

2009 ◽  
Vol 83-86 ◽  
pp. 269-274 ◽  
Author(s):  
Syed H. Masood ◽  
Kadhim Alamara
Keyword(s):  
Tissue Engineering ◽  
Pore Size ◽  
Fused Deposition Modeling ◽  
Porous Scaffold ◽  
Cell Structure ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
Unit Cells

In tissue engineering (TE), a porous scaffold structure of biodegradable material is required as a template to guide the proliferation, growth and development of cells appropriately in three dimensions. The scaffold must meet design requirements of appropriate porosity, pore size and interconnected structure to allow cell proliferation and adhesion. This paper presents a methodology for design and manufacture of TE scaffolds with varying porosity by employing open structure building units and Fused Deposition Modeling (FDM) rapid prototyping technique. A computer modeling approach for constructing and assembly of three-dimensional unit cell structure is presented to provide a solution of scaffolds design that can potentially meet the diverse requirements of TE applications. A parametric set of open polyhedral unit cells is used to assist the user in designing the required micro-architecture of the scaffold with required porosity and pore size and then the Boolean operation is used to create the scaffold of a given CAD model from the designed microstructure. The procedure is verified by fabrication of physical scaffolds using the commercial FDM system.

Effect of Alkaline Activators Concentration to the Strength and Morphological Properties of Wastepaper-Based Geopolymer Mortars

2014 ◽  
Vol 803 ◽  
pp. 88-92 ◽  
Author(s):  
A.R.M. Ridzuan ◽  
A.A. Khairulniza ◽  
M.A. Fadzil ◽  
J. Nurliza
Keyword(s):  
Compressive Strength ◽  
Ambient Temperature ◽  
Waste Paper ◽  
Morphological Properties ◽  
Composition Analysis ◽  
Paper Sludge ◽  
High Porosity ◽  
X Ray ◽  
Paper Sludge Ash ◽  
Sludge Ash

Waste paper sludge ash (WPSA) is a byproduct that has potential to replace Ordinary Portland Cement (OPC) as a building material. The purpose of this study is to investigate the effect of NaOH concentration on the strength of Waste Paper Sludge Ash (WPSA)-based geopolymer mortar. Initially, the WPSA samples were been analyzed using X-ray Fluorescence (XRF) to determine the chemical composition. From the XRF analysis, the by-product WPSA containing higher amount of calcium, silica and alumina. Alkaline solution are from soluble sodium-based used in geopolymerization are combination of Sodium Hydroxide (NaOH) and Sodium Silicate (Na2SiO3). The mortars samples were cast with various concentration of NaOH and ratio of Na2SiO3 /NaOH which is 2.5. The specimens were carried out on size 50x50x50 mm cube and fresh mortar were been cured at 70 ̊c oven temperature and ambient temperature. The compressive strength tests were conducted after aging the specimen at 3, 7, 14, and 28 days. The results revealed that as the concentration of NaOH increased, the compressive strength of geopolymer mortar increases. However, the optimum NaOH concentration of geopolymer mortar is at 12M. More than 12M concentrations of NaOH were produced high porosity and decreasing the strength. Moreover, curing of fresh geopolymer mortar is performed mostly at an oven temperature compared to ambient temperature due to heat being a reaction accelerator. This paper also present on the morphology, and Energy dispersive x-Ray (EDX) composition analysis of WPSA based geopolymer mortar.

scholarly journals Minimizing Drying Shrinkage and Enhancing Impermeability of Foam Concrete Modified with Epoxy Resin

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jianqing Gong ◽  
Ke Li
Keyword(s):  
Surface Energy ◽  
Pore Size ◽  
Epoxy Resin ◽  
Average Pore Size ◽  
Drying Shrinkage ◽  
Maximum Level ◽  
High Porosity ◽  
Foam Concrete ◽  
Average Pore ◽  
Internal Pore Structure

Relatively high drying shrinkage and permeability were two of the major challenges associated with foam concrete (FC), primarily due to its high porosity nature. This study was aimed at reducing the drying shrinkage and improving the impermeability of FC by blending and modifying it with epoxy resin (EP). Extensive laboratory testing yielded an optimum content of 4.0% EP, corresponding to a minimum drying shrinkage rate of 1.47 mm/m, which was 48% lower than that of the unmodified FC. At this optimum dosage of 4.0% EP, the permeability pressure was at a maximum level of 1.4 MPa, whereas the permeability coefficient was at its lowest value of 0.75 × 10−9  mm/h. Internal pore structure and EP distribution were characterized using the scanning electron microscopy and indicated that a microgrid structure of the FC was formed internally, featuring an increase in the number of pores, a reduction in the average pore size, and a uniform pore size distribution. Similarly, surface energy measurements using the tensiometry method yielded maximum surface energy values at 4.0% EP content, which could be used to explain the reduced drying shrinkage and the enhanced impermeability characteristics of the modified FC.

scholarly journals Rapid Fabrication of Anatomically-Shaped Bone Scaffolds Using Indirect 3D Printing and Perfusion Techniques

2020 ◽  
Vol 21 (1) ◽  
pp. 315 ◽  
Author(s):  
Brian E. Grottkau ◽  
Zhixin Hui ◽  
Yang Yao ◽  
Yonggang Pang
Keyword(s):  
3D Printing ◽  
Time Course ◽  
Porous Scaffold ◽  
High Surface ◽  
Water Soluble ◽  
Calcium Deposition ◽  
Patient Specific ◽  
Residual Water ◽  
High Porosity ◽  
Surface Detail

Fused deposit modeling (FDM) 3D printing technology cannot generate scaffolds with high porosity while maintaining good integrity, anatomical-surface detail, or high surface area-to-volume ratio (S/V). Solvent casting and particulate leaching (SCPL) technique generates scaffolds with high porosity and high S/V. However, it is challenging to generate complex-shaped scaffolds; and solvent, particle and residual water removal are time consuming. Here we report techniques surmounting these problems, successfully generating a highly porous scaffold with the anatomical-shape characteristics of a human femur by polylactic acid polymer (PLA) and PLA-hydroxyapatite (HA) casting and salt leaching. The mold is water soluble and is easily removable. By perfusing with ethanol, water, and dry air sequentially, the solvent, salt, and residual water were removed 20 fold faster than utilizing conventional methods. The porosities are uniform throughout the femoral shaped scaffold generated with PLA or PLA-HA. Both scaffolds demonstrated good biocompatibility with the pre-osteoblasts (MC3T3-E1) fully attaching to the scaffold within 8 h. The cells demonstrated high viability and proliferation throughout the entire time course. The HA-incorporated scaffolds demonstrated significantly higher compressive strength, modulus and osteoinductivity as evidenced by higher levels of alkaline-phosphatase activity and calcium deposition. When 3D printing a 3D model at 95% porosity or above, our technology preserves integrity and surface detail when compared with FDM-generated scaffolds. Our technology can also generate scaffolds with a 31 fold larger S/V than FDM. We have developed a technology that is a versatile tool in creating personalized, patient-specific bone graft scaffolds efficiently with high porosity, good scaffold integrity, high anatomical-shaped surface detail and large S/V.

scholarly journals Robocasting of Single and Multi-Functional Calcium Phosphate Scaffolds and Its Hybridization with Conventional Techniques: Design, Fabrication and Characterization

2020 ◽  
Vol 10 (23) ◽  
pp. 8677
Author(s):  
Mehdi Mohammadi ◽  
Patricia Pascaud-Mathieu ◽  
Valeria Allizond ◽  
Jean-Marc Tulliani ◽  
Bartolomeo Coppola ◽  
...  
Keyword(s):  
Surrounding Medium ◽  
Silver Ions ◽  
Octacalcium Phosphate ◽  
Hybrid Structure ◽  
Functionally Graded ◽  
Porous Polymer ◽  
Polymer Layer ◽  
Polymer Scaffolds ◽  
Salt Leaching ◽  
Porous Part

In this work, dense, porous, and, for the first time, functionally-graded bi-layer scaffolds with a cylindrical geometry were produced from a commercially available hydroxyapatite powder using the robocasting technique. The bi-layer scaffolds were made of a dense core part attached to a surrounding porous part. Subsequently, these bi-layer robocast scaffolds were joined with an outer shell of an antibacterial porous polymer layer fabricated by solvent casting/salt leaching techniques, leading to hybrid ceramic-polymer scaffolds. The antibacterial functionality was achieved through the addition of silver ions to the polymer layer. All the robocast samples, including the bi-layer ones, were first characterized through scanning electron microscopy observations, mechanical characterization in compression and preliminary bioactivity tests. Then, the hybrid bi-layer ceramic-polymer scaffolds were characterized through antimicrobial tests. After sintering at 1300 °C for 3 h, the compressive strengths of the structures were found to be equal to 29 ± 4 MPa for dense samples and 7 ± 4 MPa for lattice structures with a porosity of 34.1%. Bioactivity tests performed at 37 °C for 4 weeks showed that the precipitated layer on the robocast samples contained octacalcium phosphate. Finally, it was evidenced that the hybrid structure was effective in releasing antibacterial Ag+ ions to the surrounding medium showing its potential efficiency in limiting Staphylococcus aureus proliferation during surgery.

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