scholarly journals Modeling and Simulation of a Selective Laser Foaming Process for Fabrication of Microliter Tissue Engineering Scaffolds

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
JinGyu Ock ◽  
Wei Li
Keyword(s):  
Tissue Engineering ◽  
Laser Power ◽  
Biomedical Applications ◽  
Processing Parameters ◽  
Tissue Engineering Scaffolds ◽  
Element Analysis ◽  
Laser Absorption ◽  
Fea Model ◽  
Foaming Process ◽  
And Control

Selective laser foaming is a novel process that combines solid-state foaming and laser ablation to fabricate an array of microliter tissue engineering scaffolds on a polymeric chip for biomedical applications. In this study, a finite element analysis (FEA) model is developed to investigate the effect of laser processing parameters. Experimental results with biodegradable polylactic acid (PLA) were used for validation. It is found that foaming always occurs before ablation, and once it occurs, the temperature increases dramatically due to an enhanced laser absorption effect of the porous structure. The geometry of the fabricated scaffolds can be controlled by laser parameters. While the depth of scaffolds can be controlled by laser power and lasing time, the diameter is more effectively controlled by the laser power. The model developed in this study can be used to optimize and control the selective foaming process.

scholarly journals GAKTpore: Stereological Characterisation Methods for Porous Foams in Biomedical Applications

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1269
Author(s):  
Gareth Sheppard ◽  
Karl Tassenberg ◽  
Bogdan Nenchev ◽  
Joel Strickland ◽  
Ramy Mesalam ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Biomedical Applications ◽  
Large Scale ◽  
Collagen Scaffold ◽  
Porous Structures ◽  
Tissue Engineering Scaffolds ◽  
Biological Responses ◽  
Sem Micrograph ◽  
Cell Adhesion And Proliferation ◽  
Characterisation Methods

In tissue engineering, scaffolds are a key component that possess a highly elaborate pore structure. Careful characterisation of such porous structures enables the prediction of a variety of large-scale biological responses. In this work, a rapid, efficient, and accurate methodology for 2D bulk porous structure analysis is proposed. The algorithm, “GAKTpore”, creates a morphology map allowing quantification and visualisation of spatial feature variation. The software achieves 99.6% and 99.1% mean accuracy for pore diameter and shape factor identification, respectively. There are two main algorithm novelties within this work: (1) feature-dependant homogeneity map; (2) a new waviness function providing insights into the convexity/concavity of pores, important for understanding the influence on cell adhesion and proliferation. The algorithm is applied to foam structures, providing a full characterisation of a 10 mm diameter SEM micrograph (14,784 × 14,915 px) with 190,249 pores in ~9 min and has elucidated new insights into collagen scaffold formation by relating microstructural formation to the bulk formation environment. This novel porosity characterisation algorithm demonstrates its versatility, where accuracy, repeatability, and time are paramount. Thus, GAKTpore offers enormous potential to optimise and enhance scaffolds within tissue engineering.

scholarly journals Development of 3D Bioactive Nanocomposite Scaffolds Made from Gelatin and Nano Bioactive Glass for Biomedical Applications

2010 ◽  
Vol 19 (2) ◽  
pp. 096369351001900 ◽  
Author(s):  
M. Mozafari ◽  
F. Moztarzadeh ◽  
M. Rabiee ◽  
M. Azami ◽  
N. Nezafati ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bioactive Glass ◽  
Biomedical Applications ◽  
Cell Attachment ◽  
Tissue Engineering Scaffolds ◽  
Study Results ◽  
Nanocomposite Scaffold ◽  
Nanocomposite Scaffolds ◽  
First Time

In this research, macroporous, mechanically competent and bioactive nanocomposite scaffolds have been fabricated from cross-linked gelatine (Gel) and nano bioactive glass (nBG) through layer solvent casting combined with freeze-drying and lamination techniques. This study has developed a new composition to produce a new bioactive nanocomposite which is porous with interconnected microstructure, pore sizes are 200-500 μm, porosity are 72%-86%. Also, we have reported formation of chemical bonds between nBG and Gel for the first time. Finally, the in vitro cytocompatability of the scaffolds was assessed using MTT assay and cell attachment study. Results indicated no sign of toxicity and cells found to be attached to the pore walls offered by the scaffolds. These results suggested that the developed nanocomposite scaffold possess the prerequisites for bone tissue engineering scaffolds and it can be used for tissue engineering applications.

Novel Fabrication Technique for 3-Dimensional Electrospun Poly(DL-Lactide-Co-Glycolide) Acid Scaffolds

2010 ◽  
Author(s):  
Linus H. Leung ◽  
Elmira Khatounabad ◽  
Hani E. Naguib
Keyword(s):  
Tissue Engineering ◽  
Saturation Pressure ◽  
Processing Parameters ◽  
Fibrous Structure ◽  
Fabrication Technique ◽  
Mechanical Pressure ◽  
Tissue Engineering Scaffolds ◽  
Adhesion Properties ◽  
Fibrous Scaffolds ◽  
Optimal Processing

Current tissue engineering scaffolds created by electrospinning techniques are mostly limited to a 2D membrane. In this study, a novel method to fabricate 3D fibrous scaffolds is presented, and a parametric study to identify the optimal processing parameters was performed. The fabrication technique uses a batch foaming setup to saturate the fibrous scaffolds with CO2 to lower the glass transition temperature of PLGA to allow for the sintering of the fibers. When a mechanical pressure was applied to multiple layers of the thin films in the presence of gas, the layers of PLGA scaffolds sinter to form a thick 3D fibrous structure. This study was divided into three parts. First, the effect of gas saturation on the scaffolds was examined. Three saturation pressures of 200, 300, and 400 psi and multiple saturation times of 1, 3, 5, 30, 60, and 120 minutes were used. At the lowest pressure of 200 psi, the morphology and mechanical properties of the scaffolds were not affected. As saturation pressure and time were increased, the fibers sintered, and eventually the fibrous structure was lost because the polymer was over-sintered. The second part of the study was to determine the adhesion properties of the scaffolds using gas pressure. The same processing pressures and times were used for this set of experiments, and a higher pressure was found to better adhere the layers of PLGA films together. From the first two parts of this study, the optimal combination of processing parameters was determined to be saturating the samples under 400 psi of pressure for three minutes. This set of parameters was then used in the third part of the study to fabricate 3D fibrous scaffolds. The demonstration of this ability to fabricate 3D scaffolds improves on current electrospinning techniques while maintaining a desirable fibrous structure for tissue engineering.

scholarly journals Antibacterial cellulose-based aerogels for wound healing application: A review

2020 ◽  
Vol 7 (10) ◽  
pp. 4032-4040
Author(s):  
Esam Bashir Yahya ◽  
Marwa Mohammed Alzalouk ◽  
Khalifa A. Alfallous ◽  
Abdullah F. Abogmaza
Keyword(s):  
Drug Delivery ◽  
Tissue Engineering ◽  
Wound Healing ◽  
Wound Dressing ◽  
Biomedical Applications ◽  
Inorganic Materials ◽  
Medical Applications ◽  
Tissue Engineering Scaffolds

Aerogels have been steadily developed since its first invention to become one of the most promising materials for various medical and non-medical applications. It has been prepared from organic and inorganic materials, in pure forms or composites. Cellulose-based aerogels are considered one of the promising materials in biomedical applications due to their availability, degradability, biocompatibility and non-cytotoxicity compared to conventional silica or metal-based aerogels. The unique properties of such materials permit their utilization in drug delivery, biosensing, tissue engineering scaffolds, and wound dressing. This review presents a summary of aerogel development as well as the properties and applications of aerogels. Herein, we further discuss the recent works pertaining to utilization of cellulose-based aerogels for antibacterial delivery.

Solvent Free Fabrication of Biodegradable Porous Polymers

2004 ◽  
Author(s):  
Xiaoxi Wang ◽  
Wei Li ◽  
Vipin Kumar
Keyword(s):  
Tissue Engineering ◽  
Polymer System ◽  
Solvent Free ◽  
Porous Polymers ◽  
Tissue Engineering Scaffolds ◽  
Co2 Gas ◽  
Biochemical Sensors ◽  
Foaming Process ◽  
Cell Structures ◽  
Chemical Blowing Agents

Biodegradable porous polymers with interconnected pores of sub-micrometers to a few hundred micrometers find many applications in emerging technology areas such as tissue engineering, controlled drug delivery, and biochemical sensors. However, most of the current fabrication processes involve organic solvents and chemical blowing agents that may cause environmental concerns and leave residues harmful to biological cells. This paper presents a solvent free fabrication approach for biodegradable porous polymers. Ultrasound cavitation is introduced after the solid state foaming process to produce open cell structures. The material used in this study is polylactic acid (PLA). It belongs to a family of biodegradable polymers that can be used for tissue engineering scaffolds. In order to identify suitable conditions to apply ultrasound, a saturation and foaming study is conducted for the PLA-CO2 gas polymer system. The effects of various process variables are discussed.

Thermal Processing of Tissue Engineering Scaffolds

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Alisa Morss Clyne
Keyword(s):  
Tissue Engineering ◽  
Thermal Processing ◽  
Three Dimensional ◽  
Processing Parameters ◽  
High Pressure Processing ◽  
Porous Scaffolds ◽  
Tissue Engineering Scaffolds ◽  
Thermally Induced ◽  
Advantages And Disadvantages ◽  
Particulate Leaching

Tissue engineering requires complex three-dimensional scaffolds that mimic natural extracellular matrix function. A wide variety of techniques have been developed to create both fibrous and porous scaffolds out of polymers, ceramics, metals, and composite materials. Existing techniques include fiber bonding, electrospinning, emulsion freeze drying, solvent casting/particulate leaching, gas foaming/particulate leaching, high pressure processing, and thermally induced phase separation. Critical scaffold properties, including pore size, porosity, pore interconnectivity, and mechanical integrity, are determined by thermal processing parameters in many of these techniques. In this review, each tissue engineering scaffold preparation method is discussed, including recent advancements as well as advantages and disadvantages of the technique, with a particular emphasis placed on thermal parameters. Improvements on these existing techniques, as well as new thermal processing methods for tissue engineering scaffolds, will be needed to provide tissue engineers with finer control over tissue and organ development.

Prediction of Processing Parameters of Laser Clad TiC/NiCrBSiC Coatings on Ti6Al4V by Finite Element Analysis

2011 ◽  
Vol 189-193 ◽  
pp. 1547-1550
Author(s):  
Yi Wen Lei ◽  
Wei Niu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Laser Power ◽  
Processing Parameters ◽  
Processing Parameter ◽  
Element Analysis ◽  
Scanning Velocity ◽  
Temperature Distributions ◽  
Parameter Prediction ◽  
Good Agreement

This work deals with the processing parameter prediction of laser clad TiC/NiCrBSiC coatings on Ti6Al4V alloys by Finite Element Method. Temperature distribution and dilution rate were obtained. The temperature distributions were sparse and enlarged when laser power increased. With increasing of scanning velocity, the temperature distributions were compressed and lengthened at the front and at the end of the laser beam, respectively. Under laser power P=2.5 kW, scanning velocity V=5 mm/s, the calculated and experimental dilution rates are 6.25% and 8.3%, respectively. There is a good agreement between the results.

Controlling Pore Size of Tissue Engineering Scaffolds Fabricated by Electrospinning and Phase Separation

2015 ◽  
Vol 815 ◽  
pp. 379-384 ◽  
Author(s):  
Yu Zhou ◽  
Qi Long Zhao ◽  
Min Wang
Keyword(s):  
Tissue Engineering ◽  
Phase Separation ◽  
Pore Size ◽  
Hybrid Technique ◽  
Tissue Engineering Scaffolds ◽  
Water Ice ◽  
Nanofibrous Scaffolds ◽  
Small Pore ◽  
And Control ◽  
Ice Water

Electrospinning is a versatile and efficient technique for fabricating nanofibrous tissue engineering scaffolds. However, problems such as small pore size of electrospun scaffolds have limited their applications for tissue regeneration. It is important to modify/improve existing electrospinning techniques for fully realizing the potential of both the electrospinning technology and electrospun nanofibrous scaffolds. To increase the pore size of scaffolds prepared by conventional electrospinning technology, in the present study, a hybrid fabrication technique by combining electrospinning with phase separation is utilized. Polymer solutions were made using mixed solvent of (a) DCM and DMF or (b) chloroform and DMF and electrospun fibers were deposited in ice water, ice methanol or liquid nitrogen. It was shown that for poly (ε-caprolactone) (PCL) scaffolds, the hybrid technique could maintain the nanofibrous structure for scaffolds and control the pore size in scaffolds. As compared with pore sizes in PCL scaffolds made by conventional electrospinning, pores were larger in PCL scaffolds produced by the hybrid technique.

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