scholarly journals Synthesis and 3D Printing of Conducting Alginate–Polypyrrole Ionomers

Gels ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 13 ◽  
Author(s):  
Cassandra J. Wright ◽  
Binbin Zhang Molino ◽  
Johnson H. Y. Chung ◽  
Jonathan T. Pannell ◽  
Melissa Kuester ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Tissue Engineering ◽  
Phase Separation ◽  
Ir Spectroscopy ◽  
Large Scale ◽  
Polymerization Reaction ◽  
Conductivity Measurements ◽  
Tissue Engineering Scaffolds ◽  
Extrusion Printing

Hydrogels composed of calcium cross-linked alginate are under investigation as bioinks for tissue engineering scaffolds due to their variable viscoelasticity, biocompatibility, and erodibility. Here, pyrrole was oxidatively polymerized in the presence of sodium alginate solutions to form ionomeric composites of various compositions. The IR spectroscopy shows that mild base is required to prevent the oxidant from attacking the alginate during the polymerization reaction. The resulting composites were isolated as dried thin films or cross-linked hydrogels and aerogels. The products were characterized by elemental analysis to determine polypyrrole incorporation, electrical conductivity measurements, and by SEM to determine changes in morphology or large-scale phase separation. Polypyrrole incorporation of up to twice the alginate (monomer versus monomer) provided materials amenable to 3D extrusion printing. The PC12 neuronal cells adhered and proliferated on the composites, demonstrating their biocompatibility and potential for tissue engineering applications.

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.

Structure and Conductivity of Iodine-Doped C60 Thin Films

1994 ◽  
Vol 359 ◽  
Author(s):  
Jun Chen ◽  
Haiyan Zhang ◽  
Baoqiong Chen ◽  
Shaoqi Peng ◽  
Ning Ke ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Room Temperature ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
X Ray ◽  
Thermally Activated ◽  
Order Of Magnitude

ABSTRACTWe report here the results of our study on the properties of iodine-doped C60 thin films by IR and optical absorption, X-ray diffraction, and electrical conductivity measurements. The results show that there is no apparent structural change in the iodine-doped samples at room temperature in comparison with that of the undoped films. However, in the electrical conductivity measurements, an increase of more that one order of magnitude in the room temperature conductivity has been observed in the iodine-doped samples. In addition, while the conductivity of the undoped films shows thermally activated temperature dependence, the conductivity of the iodine-doped films was found to be constant over a fairly wide temperature range (from 20°C to 70°C) exhibiting a metallic feature.

Characterisation of ‘wet’ polymer surfaces for tissue engineering applications: Are flat surfaces a suitable model for complex structures?

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Laleh Safinia ◽  
Jonny J. Blaker ◽  
Véronique Maquet ◽  
Aldo R. Boccaccini ◽  
Athanassios Mantalaris ◽  
...  
Keyword(s):  
Thin Films ◽  
Tissue Engineering ◽  
Pore Wall ◽  
Polymer Surfaces ◽  
Suitable Model ◽  
Tissue Engineering Scaffolds ◽  
3D Structures ◽  
Flat Surfaces ◽  
Point Test ◽  
Highly Porous

AbstractTissue engineering scaffolds are 3D constructs that simulate the growth environment in vivo. The present work aims to address the question of whether thin films, i.e., flat surfaces, are a suitable model for more complex 3D structures? With this in mind a complete study of the morphology and surface chemistry of poly(D,Llactide) (PDLLA) substrates, fabricated into two different structures, is presented. The polymer structures studied include a 3D, porous, foam-like scaffold prepared by the thermally induced phase separation (TIPS) method and flat polymer thin films made by solvent casting. Based on the maximum bubble point test, a new method to assess the wettability of wet pore wall surfaces inside highly porous 3D structures was developed and tested. The maximum pore diameter determined using the maximum bubble point test for the total wetting liquids was confirmed through image analysis of scanning electron micrographs. The method allows the determination of the contact angle between the wet pore wall and a contacting liquid. The captive bubble method was employed to characterise the wettability of flat polymer films in contact with water. Both structures were further characterised using zeta- (ζ-) potential measurements to assess the surface chemistry of the polymer. The results demonstrate that PDLLA contains acidic functional groups and is hydrophobic. In order to evaluate the sensitivity of the test methods, the polymer surfaces were modified by protein adsorption using fibronectin and collagen. ζ-Potential and wettability measurements show that proteins indeed adsorb on virgin PDLLA surfaces. Protein adsorption causes the wettability of the PDLLA for water to improve. Our results strongly indicate that flat surfaces are not a suitable model for surfaces in complex 3D structures such as highly porous tissue engineering scaffolds. Such scaffolds must be characterised as a 3D system.

Transport Properties of Polyelectrolyte Solutions. Effect of Confinement in Thin Liquid Films

2015 ◽  
Vol 229 (7-8) ◽  
Author(s):  
Jérôme Delacotte ◽  
Dominique Langevin
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Transport Properties ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Conductivity Measurements ◽  
Polyelectrolyte Solutions

AbstractThe role of condensed counterions in transport properties, such as electrical conductivity and viscosity, has been investigated with solutions of a flexible polyelectrolyte. Comparisons with existing theories are proposed. Viscosity is strongly affected by confinement in thin films, depending whether polyelectrolyte chains are adsorbed or not at the film surfaces. The role of counterion mobility is however difficult to assess because the measurements are not accurate enough. It is proposed that this role could be tested by electrical conductivity measurements.

Electrical conductivity measurements in evaporated tin sulphide thin films

1994 ◽  
Vol 76 (5) ◽  
pp. 917-922 ◽  
Author(s):  
K. DERAMAN ◽  
S. SAKRANI ◽  
B. B. ISMATL ◽  
Y. WAHAB ◽  
R. D. GOULD
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Conductivity Measurements

scholarly journals Preparation and Characterization ofSb2Te3Thin Films by Coevaporation

2010 ◽  
Vol 2010 ◽  
pp. 1-4 ◽  
Author(s):  
Bin Lv ◽  
Songbai Hu ◽  
Wei Li ◽  
Xia Di ◽  
Lianghuan Feng ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Photoelectron Spectroscopy ◽  
Electrical Transport ◽  
Film Surface ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Conductivity Measurements ◽  
X Ray ◽  
Thin Film Surface

Deposition ofSb2Te3thin films on soda-lime glass substrates by coevaporation of Sb and Te is described in this paper.Sb2Te3thin films were characterized by x-ray diffraction (XRD), x-ray fluorescence (XRF), atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), electrical conductivity measurements, and Hall measurements. The abnormal electrical transport behavior occurred fromin situelectrical conductivity measurements. The results indicate that as-grownSb2Te3thin films are amorphous and undergo an amorphous-crystalline transition after annealing, and the posttreatment can effectively promote the formation of Sb-Te bond and prevent oxidation of thin film surface.

Effect of Boron and Phosphorus Ion Implantation on a-SixC1-x:H Thin Films

1992 ◽  
Vol 258 ◽  
Author(s):  
F. Demichelis ◽  
R. Galloni ◽  
C. F. Pirri ◽  
R. Rizzolid ◽  
C. Summonte ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Ir Spectroscopy ◽  
Ion Implantation ◽  
Gas Phase ◽  
Vapor Deposition ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Vacuum Plasma

ABSTRACTIon implantation of boron and phosphorus in device quality a-SixC1-x:H films deposited by Ultra High Vacuum Plasma Enhanced Chemical Vapor Deposition (UHV PECVD) has been performed. The effects of damage and of damage recovering after annealing were investigated by optical absorption, electrical conductivity and infrared (IR) spectroscopy measurements. It is found that samples doped by phosphorus implantation can have dark conductivities as high as those obtained on samples doped with boron, either by ion implantation or gas phase.

scholarly journals Recent Progress on Biodegradable Tissue Engineering Scaffolds Prepared by Thermally-Induced Phase Separation (TIPS)

2021 ◽  
Vol 22 (7) ◽  
pp. 3504
Author(s):  
Reza Zeinali ◽  
Luis J. del Valle ◽  
Joan Torras ◽  
Jordi Puiggalí
Keyword(s):  
Tissue Engineering ◽  
Phase Separation ◽  
Material Selection ◽  
Three Dimensional ◽  
Target Cells ◽  
Porous Scaffolds ◽  
Thermally Induced Phase Separation ◽  
Tissue Engineering Scaffolds ◽  
Thermally Induced ◽  
Biodegradable Scaffolds

Porous biodegradable scaffolds provide a physical substrate for cells allowing them to attach, proliferate and guide the formation of new tissues. A variety of techniques have been developed to fabricate tissue engineering (TE) scaffolds, among them the most relevant is the thermally-induced phase separation (TIPS). This technique has been widely used in recent years to fabricate three-dimensional (3D) TE scaffolds. Low production cost, simple experimental procedure and easy processability together with the capability to produce highly porous scaffolds with controllable architecture justify the popularity of TIPS. This paper provides a general overview of the TIPS methodology applied for the preparation of 3D porous TE scaffolds. The recent advances in the fabrication of porous scaffolds through this technique, in terms of technology and material selection, have been reviewed. In addition, how properties can be effectively modified to serve as ideal substrates for specific target cells has been specifically addressed. Additionally, examples are offered with respect to changes of TIPS procedure parameters, the combination of TIPS with other techniques and innovations in polymer or filler selection.

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