scholarly journals A Customizable, Low-Cost Perfusion System for Sustaining Tissue Constructs

2018 ◽  
Vol 23 (6) ◽  
pp. 592-598
Author(s):  
Brian J. O’Grady ◽  
Jason X. Wang ◽  
Shannon L. Faley ◽  
Daniel A. Balikov ◽  
Ethan S. Lippmann ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Cell Viability ◽  
Large Scale ◽  
Low Cost ◽  
Three Dimensional ◽  
Tissue Scaffolds ◽  
Perfusion System ◽  
Pump System ◽  
Tissue Constructs ◽  
Engineered Tissue

The fabrication of engineered vascularized tissues and organs requiring sustained, controlled perfusion has been facilitated by the development of several pump systems. Currently, researchers in the field of tissue engineering require the use of pump systems that are in general large, expensive, and generically designed. Overall, these pumps often fail to meet the unique demands of perfusing clinically useful tissue constructs. Here, we describe a pumping platform that overcomes these limitations and enables scalable perfusion of large, three-dimensional hydrogels. We demonstrate the ability to perfuse multiple separate channels inside hydrogel slabs using a preprogrammed schedule that dictates pumping speed and time. The use of this pump system to perfuse channels in large-scale engineered tissue scaffolds sustained cell viability over several weeks.

scholarly journals Microvascular Guidance: A Challenge to Support the Development of Vascularised Tissue Engineering Construct

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Irza Sukmana
Keyword(s):  
Tissue Engineering ◽  
Three Dimensional ◽  
Artificial Organ ◽  
Vascular Networks ◽  
Tissue Constructs ◽  
Future Challenges ◽  
Engineered Tissue ◽  
And Function ◽  
Tissue Construct

The guidance of endothelial cell organization into a capillary network has been a long-standing challenge in tissue engineering. Some research efforts have been made to develop methods to promote capillary networks inside engineered tissue constructs. Capillary and vascular networks that would mimic blood microvessel function can be used to subsequently facilitate oxygen and nutrient transfer as well as waste removal. Vascularization of engineering tissue construct is one of the most favorable strategies to overpass nutrient and oxygen supply limitation, which is often the major hurdle in developing thick and complex tissue and artificial organ. This paper addresses recent advances and future challenges in developing three-dimensional culture systems to promote tissue construct vascularization allowing mimicking blood microvessel development and function encounteredin vivo. Bioreactors systems that have been used to create fully vascularized functional tissue constructs will also be outlined.

scholarly journals GEOREFERENCING AND REPROJECTION ERROR INVESTIGATION ON IMAGE BASED 3D DIGITIZATION AND MAPPING OF HISTORICAL BUILDINGS

2019 ◽  
Vol XLII-2/W11 ◽  
pp. 71-75
Author(s):  
C. Altuntas
Keyword(s):  
Point Cloud ◽  
Large Scale ◽  
Cloud Model ◽  
Low Cost ◽  
Three Dimensional ◽  
Control Points ◽  
Historical Buildings ◽  
Reprojection Error ◽  
Dense Point ◽  
Point Cloud Model

<p><strong>Abstract.</strong> Image based dense point cloud creation is easy and low-cost application for three dimensional digitization of small and large scale objects and surfaces. It is especially attractive method for cultural heritage documentation. Reprojection error on conjugate keypoints indicates accuracy of the model and keypoint localisation in this method. In addition, sequential registration of the images from large scale historical buildings creates big cumulative registration error. Thus, accuracy of the model should be increased with the control points or loop close imaging. The registration of point point cloud model into the georeference system is performed using control points. In this study historical Sultan Selim Mosque that was built in sixteen century by Great Architect Sinan was modelled via photogrammetric dense point cloud. The reprojection error and number of keypoints were evaluated for different base/length ratio. In addition, georeferencing accuracy was evaluated with many configuration of control points with loop and without loop closure imaging.</p>

scholarly journals Brown Coal in Victoria, Australia and Maddingley Brown Coal Open Cut Mine Batter Stability

2020 ◽  
Vol 9 (3) ◽  
pp. 109-118
Author(s):  
Lei Zhao ◽  
Greg You
Keyword(s):  
Coal Seam ◽  
Brown Coal ◽  
Large Scale ◽  
Low Cost ◽  
Three Dimensional ◽  
Open Pit ◽  
Open Pit Mining ◽  
Mining Operations ◽  
Power Generators ◽  
Three Dimensional Finite Element

Brown coal is young, shallowly deposited, and widely distributed in the world. It is a fuel commonly used to generate electricity. This paper first reviews the resources and characteristics of brown coal in Victoria, Australia, and its exploitation and contribution to the economy or power supply in Victoria. Due to the shallow depth of the brown coal seam, e.g. very favorable stripping ratio, open pit mining is the only mining method used to extract the coal at low cost for power generators. With the large-scale mining operations, cases of batter failure were not rare in the area. From the comprehensive review of past failures, overburden batter tends to fail by circular sliding, coal batter tends to fail by block sliding after the overburden is stripped due to a weak water-bearing layer underneath the coal seam and tension cracks developed at the rear of the batter, and batter failure is typically coincided with peak raining seasons. Secondly, the paper reviews the case study of Maddingley Brown Coal (MBC) Open Cut Mine batter stability, including geology, hydrogeology, and hydro-mechanically coupled numerical modelling. The modelling employs three-dimensional finite element method to simulate the MBC northern batter where cracks were observed in November 2013. The comprehensive simulation covers an overburden batter, a brown coal batter, two rainfall models, and a buttressed batter. The simulated results agree well with observed data, and it is found that the rainfall at the intensity of 21mm substantially lowered the factor of safety of the coal batter.

scholarly journals Computer modelling and simulation of a novel printing head for complex tissue engineering constructs

2020 ◽  
Vol 318 ◽  
pp. 01045
Author(s):  
Gokhan Ates
Keyword(s):  
Tissue Engineering ◽  
Computer Modelling ◽  
Three Dimensional ◽  
Biological Tissues ◽  
Biological Properties ◽  
Functionally Graded ◽  
Mixing Efficiency ◽  
Tissue Constructs ◽  
Multiple Materials ◽  
Graded Structures

In tissue engineering, three-dimensional functional scaffolds with tailored biological properties are needed to be able to mimic the hierarchical structure of biological tissues. Recent developments in additive biomanufacturing allow to extrude multiple materials enabling the fabrication of more sophisticated tissue constructs. These multi-material biomanufacturing systems comprise multiple printing heads through which individual materials are sequentially printed. Nevertheless, as more printing heads are added the fabrication process significantly decreases, since it requires mechanical switching among the physically separated printheads to enable printing multiple materials. In addition, this approach is not able to create biomimetic tissue constructs with property gradients. To address these limitations, this paper presents a novel static mixing extrusion printing head to enable the fabrication of multi-material, functionally graded structures using a single nozzle. Computational fluid dynamics (CFD) was used to numerically analyze the influence of Reynolds number on the flow pattern of biomaterials and mixing efficiency considering different miscible materials.

Three-Dimensional MoS2/Graphene Hybrid Aerogel as Free-Standing, High-Performance Electrode for Supercapacitor

NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050062
Author(s):  
Zhaolei Meng ◽  
Xiaojian He ◽  
Song Han ◽  
Zijian Hu
Keyword(s):  
Porous Structure ◽  
Surface Area ◽  
High Performance ◽  
Large Scale ◽  
Low Cost ◽  
Hydrothermal Process ◽  
Three Dimensional ◽  
Rate Capability ◽  
Free Standing ◽  
Hybrid Aerogel

Carbon materials are generally employed as supercapacitor electrodes due to their low- cost, high-chemical stability and environmental friendliness. However, the design of carbon structures with large surface area and controllable porous structure remains a daunt challenge. In this work, a three-dimensional (3D) hybrid aerogel with different contents of MoS2 nanosheets in 3D graphene aerogel (MoS2-GA) was synthesized through a facial hydrothermal process. The influences of MoS2 content on microstructure and subsequently on electrochemical properties of MoS2-GA are systematically investigated and an optimized mass ratio with MoS2: GA of 1:2 is chosen to achieve high mechanical robustness and outstanding electrochemical performance in the hybrid structure. Due to the large specific surface area, porous structure and continuous charge transfer network, such MoS2-GA electrodes exhibit high specific capacitance, good rate capability and excellent cyclic stability, showing great potential in large-scale and low-cost fabrication of high-performance supercapacitors.

Design and additive manufacturing of porous titanium scaffolds for optimum cell viability in bone tissue engineering

2020 ◽  
pp. 095440542093756
Author(s):  
Bingbing Li ◽  
Bani Davod Hesar ◽  
Yiwen Zhao ◽  
Li Ding
Keyword(s):  
Tissue Engineering ◽  
Cell Viability ◽  
Bone Tissue Engineering ◽  
Pore Size ◽  
Bone Tissue ◽  
Structural Strength ◽  
Three Dimensional ◽  
Porous Titanium ◽  
Nih3t3 Cells ◽  
Pore Sizes

Pore size, external shape, and internal complexity of additively manufactured porous titanium scaffolds are three primary determinants of cell viability and structural strength of scaffolds in bone tissue engineering. To obtain an optimal design with the combination of all three determinants, four scaffolds each with a unique topology (external geometry and internal structure) were designed and varied the pore sizes of each scaffold 3 times. For each topology, scaffolds with pore sizes of 300, 400, and 500 µm were designed. All designed scaffolds were additively manufactured in material Ti6Al4V by the direct metal laser melting machine. Compression test was conducted on the scaffolds to assure meeting minimum compressive strength of human bone. The effects of pore size and topology on the cell viability of the scaffolds were analyzed. The 12 scaffolds were ultrasonically cleaned and seeded with NIH3T3 cells. Each scaffold was seeded with 1 million cells. After 32 days of culturing, the cells were fixed for their three-dimensional architecture preservation and to obtain scanning electron microscope images.

scholarly journals Green and facile synthesis of cerium doped Ni3Fe electrocatalyst for efficient oxygen evolution reaction

2020 ◽  
Vol 34 (2) ◽  
pp. 353-363
Author(s):  
F. Kanwal ◽  
A. Batool ◽  
R. Akbar ◽  
S. Asim ◽  
M. Saleem
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Large Scale ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Three Dimensional ◽  
Alkaline Electrolyte ◽  
Hydrogen Electrode ◽  
Molar Ratios

Electrochemical water splitting is the most promising pathway to produce high-purity hydrogen to alleviate global energy crisis. This reaction demands inexpensive, efficient and robust electrocatalyst for its commercial use. Herein, we demonstrate an effective, facile and scalable method for the synthesis of cerium doped Ni3Fe nanostructures as an electrocatalyst for oxygen evolution reaction (OER) by following simple chemical bath deposition route. The different molar ratios (3, 6 and 12 mM) of cerium in the chemical bath were used to study its effect on the structural and the electrochemical properties of the Ni3Fe nanostructured films. Doping of cerium contents induced variations in the morphology of deposited Ni3Fe nanostructures. The optimized electrocatalyst Ni3Fe/Ce-6 yielded high surface area catalyst nanosheets uniformly deposited on three-dimensional conductive scaffold to ensure increase in the exposure of doped Ni3Fe catalytic sites with high electrical conductivity. As a result, this earth-abundant electrocatalyst affords high OER performance with a small overpotential of 310 mV versus reversible hydrogen electrode (RHE) at 10 mA cm-2 and retains good stability up to ~ 10 h in alkaline electrolyte. This scalable strategy has great potential in future advancement of efficient and low-cost electrocatalysts for their large-scale application in energy conversion systems.                     KEY WORDS: Oxygen evolution, Electrocatalyst, Ni3Fe nanostructures, Cerium, Alkaline electrolyte   Bull. Chem. Soc. Ethiop. 2020, 34(2), 353-363 DOI: https://dx.doi.org/10.4314/bcse.v34i2.12

scholarly journals A Thin Layer of Activated Carbon Deposited on Polyurethane Cube Leads to New Conductive Bioanode for (Plant) Microbial Fuel Cell

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 574
Author(s):  
Emilius Sudirjo ◽  
Paola Y. Constantino Diaz ◽  
Matteo Cociancich ◽  
Rens Lisman ◽  
Christian Snik ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Activated Carbon ◽  
Field Test ◽  
Microbial Fuel Cells ◽  
Large Scale ◽  
Electrode Materials ◽  
Low Cost ◽  
Three Dimensional ◽  
Polyurethane Foams ◽  
Electrochemically Active

Large-scale implementation of (plant) microbial fuel cells is greatly limited by high electrode costs. In this work, the potential of exploiting electrochemically active self-assembled biofilms in fabricating three-dimensional bioelectrodes for (plant) microbial fuel cells with minimum use of electrode materials was studied. Three-dimensional robust bioanodes were successfully developed with inexpensive polyurethane foams (PU) and activated carbon (AC). The PU/AC electrode bases were fabricated via a water-based sorption of AC particles on the surface of the PU cubes. The electrical current was enhanced by growth of bacteria on the PU/AC bioanode while sole current collectors produced minor current. Growth and electrochemical activity of the biofilm were shown with SEM imaging and DNA sequencing of the microbial community. The electric conductivity of the PU/AC electrode enhanced over time during bioanode development. The maximum current and power density of an acetate fed MFC reached 3 mA·m−2 projected surface area of anode compartment and 22 mW·m−3 anode compartment. The field test of the Plant-MFC reached a maximum performance of 0.9 mW·m−2 plant growth area (PGA) at a current density of 5.6 mA·m−2 PGA. A paddy field test showed that the PU/AC electrode was suitable as an anode material in combination with a graphite felt cathode. Finally, this study offers insights on the role of electrochemically active biofilms as natural enhancers of the conductivity of electrodes and as transformers of inert low-cost electrode materials into living electron acceptors.

Fiber Filled Hybrid Hydrogel for Bio-Manufacturing

2020 ◽  
pp. 1-38
Author(s):  
MD Habib ◽  
Bashir Khoda
Keyword(s):  
Cell Viability ◽  
Large Scale ◽  
Three Dimensional ◽  
High Water ◽  
Solid Content ◽  
Design Stage ◽  
High Water Content ◽  
Cellulose Derivatives ◽  
Hybrid Hydrogel ◽  
Low Cytotoxicity

Abstract The extrusion based three-dimensional (3D) bio-printing deposits cell-laden bio-ink with high spatial resolution and may offer living tissue regeneration. Due to the biocompatibility, very low cytotoxicity, and high-water content, natural hydrogels are commonly considered as the cell-laden bio-ink for scaffold fabrication. However, due to the low mechanical integrity, a large-scale scaffold (&gt; 10 layers) with intricate architecture is a challenge. In this paper, we developed and characterize a novel bio-ink consisting of alginate, CMC, and TO-NFC for bio-printing applications. The potential of cellulose derivatives in terms of rheological property to satisfy scaffold architecture and cell viability is explored with a relatively small amount of solid content (&lt;5%). By combining alginate, CMC, and TO-NFC as a hybrid hydrogel, we design to overcome their individual challenges as bio-ink. At the design stage, we have considered two main characteristics, printability and shape fidelity with quantitative indices. We studied the rheological characteristics for determining the suitable composition for extrusion bio-printing. Our investigation suggests an optimal material composition that can print 42 layers and a 9 mm tall scaffold structure. The proposed hybrid hydrogel is used to prepare bio-ink encapsulating cells and cell viability is measured as 90% after 10 days of incubation.

Spatiotemporal Intracellular Deformation of Cells During Freezing-Induced Cell-Fluid-Matrix Interactions

2013 ◽  
Author(s):  
Soham Ghosh ◽  
J. Craig Dutton ◽  
Bumsoo Han
Keyword(s):  
Tissue Engineering ◽  
Cell Viability ◽  
Three Dimensional ◽  
Tissue Type ◽  
Major Constituent ◽  
Tissue Banks ◽  
Chemical Additives ◽  
Cryoprotective Agents ◽  
Cell Tissue ◽  
The Status

Freezing of biomaterials is emerging as one of the key biotechnologies in cell/tissue engineering, medicine and biology. Its applications include — 1) preservation of cell/tissue engineering products, 2) quality control of biospecimens cryopreserved in tissue banks and repositories, and 3) synthesis procedures of biomaterials such as decellularization of native tissues to create acellular (i.e., cell-free) complex three-dimensional extracellular matrices (ECMs). Traditionally, research efforts have focused on determining optimal freeze/thaw (F/T) protocols with chemical additives, so called cryoprotective agents, for a given cell/tissue-type by comparing the outcomes of F/T protocols, which are mainly gauged by cell viability. Although cell viability is the major constituent, it has recently been recognized that other features beyond viability are also critical to the functionality of biomaterials, including the microstructure of the ECM, the status of cell-matrix adhesion, and the cytoskeletal structure and organization [1, 2, 3].

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