scholarly journals Characterization of the Neuroinflammatory Response to Thiol-ene Shape Memory Polymer Coated Intracortical Microelectrodes

Micromachines ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 486 ◽  
Author(s):  
Andrew Shoffstall ◽  
Melanie Ecker ◽  
Vindhya Danda ◽  
Alexandra Joshi-Imre ◽  
Allison Stiller ◽  
...  
Keyword(s):  
Shape Memory ◽  
Room Temperature ◽  
Shape Memory Polymer ◽  
Biological Response ◽  
Material Surface ◽  
Neuroinflammatory Response ◽  
Precise Control ◽  
Silicon Devices ◽  
The Brain

Thiol-ene based shape memory polymers (SMPs) have been developed for use as intracortical microelectrode substrates. The unique chemistry provides precise control over the mechanical and thermal glass-transition properties. As a result, SMP substrates are stiff at room temperature, allowing for insertion into the brain without buckling and subsequently soften in response to body temperatures, reducing the mechanical mismatch between device and tissue. Since the surface chemistry of the materials can contribute significantly to the ultimate biocompatibility, as a first step in the characterization of our SMPs, we sought to isolate the biological response to the implanted material surface without regards to the softening mechanics. To accomplish this, we tightly controlled for bulk stiffness by comparing bare silicon ‘dummy’ devices to thickness-matched silicon devices dip-coated with SMP. The neuroinflammatory response was evaluated after devices were implanted in the rat cortex for 2 or 16 weeks. We observed no differences in the markers tested at either time point, except that astrocytic scarring was significantly reduced for the dip-coated implants at 16 weeks. The surface properties of non-softening thiol-ene SMP substrates appeared to be equally-tolerated and just as suitable as silicon for neural implant substrates for applications such as intracortical microelectrodes, laying the groundwork for future softer devices to improve upon the prototype device performance presented here.

Characristics of Shape Memory Composites Combined with Shape Memory Alloy and Shape Memory Polymer

2013 ◽  
Vol 705 ◽  
pp. 169-172
Author(s):  
Xue Feng ◽  
Li Min Zhao ◽  
Xu Jun Mi
Keyword(s):  
Shape Memory ◽  
Room Temperature ◽  
Shape Recovery ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Young Modulus ◽  
Thermomechanical Properties ◽  
The Matrix ◽  
Shape Memory Composites ◽  
Shape Fixity

In order to develop high functionality of shape memory materials, the shape memory composites combined with TiNi wire and shape memory epoxy were prepared, and the mechanical and thermomechanical properties were studied. The results showed the addition of TiNi wire increased the Young modulus and breaking strength both at room temperature and at elevated temperature. The composites maintained the rates of shape fixity and shape recovery close to 100%. The maximum recovery stress increased with increasing TiNi wire volume fraction, and obtained almost 3 times of the matrix by adding 1vol% TiNi wire.

Synthesis and characterization of a novel biodegradable thermoplastic shape memory polymer

2009 ◽  
Vol 63 (3-4) ◽  
pp. 347-349 ◽  
Author(s):  
Yuanliang Wang ◽  
Yonggang Li ◽  
Yanfeng Luo ◽  
Meina Huang ◽  
Zhiqing Liang
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Synthesis And Characterization

scholarly journals Mechanically Robust, Softening Shape Memory Polymer Probes for Intracortical Recording

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 619 ◽  
Author(s):  
Allison Stiller ◽  
Joshua Usoro ◽  
Jennifer Lawson ◽  
Betsiti Araya ◽  
María González-González ◽  
...  
Keyword(s):  
Shape Memory ◽  
Room Temperature ◽  
Shape Memory Polymer ◽  
Microelectrode Arrays ◽  
Device Fabrication ◽  
High Modulus ◽  
Mechanical Instability ◽  
Rat Cortex ◽  
Clinical Scenarios ◽  
Stiff Material

While intracortical microelectrode arrays (MEAs) may be useful in a variety of basic and clinical scenarios, their implementation is hindered by a variety of factors, many of which are related to the stiff material composition of the device. MEAs are often fabricated from high modulus materials such as silicon, leaving devices vulnerable to brittle fracture and thus complicating device fabrication and handling. For this reason, polymer-based devices are being heavily investigated; however, their implementation is often difficult due to mechanical instability that requires insertion aids during implantation. In this study, we design and fabricate intracortical MEAs from a shape memory polymer (SMP) substrate that remains stiff at room temperature but softens to 20 MPa after implantation, therefore allowing the device to be implanted without aids. We demonstrate chronic recordings and electrochemical measurements for 16 weeks in rat cortex and show that the devices are robust to physical deformation, therefore making them advantageous for surgical implementation.

Design of variable stiffness fixture for computerized embroidery machine based on shape memory polymer

2022 ◽  
pp. 1045389X2110721
Author(s):  
Yawen Yang ◽  
Lei Tian ◽  
Xi Chen ◽  
Jiayuan Wang ◽  
Yongyan Zhang ◽  
...  
Keyword(s):  
Shape Memory ◽  
Material Properties ◽  
Room Temperature ◽  
Working Condition ◽  
Raw Materials ◽  
Shape Memory Polymer ◽  
Variable Stiffness ◽  
Fixture Design ◽  
Stiffness Characteristic ◽  
The Relationship

It is a challenge to handle the metal fixture used for cloth clamping in a computerized embroidery machine because of its fixed stiffness. Herein, a prototype that acts as a fixture to provide variable stiffness property is explored by discussing the potential of a thermal-sensitive epoxy resin-based shape memory polymer (SMP). The general model of fixture design is obtained after analyzing the working condition of the metal fixture. The structure of the SMP fixture is designed by discussing the material properties and working requirements of SMP, and a theoretical model is established to deduce the relationship between thickness and stiffness of the fixture. Six SMP fixtures that memorized clamping and opening state were manufactured with different proportions of raw materials. The results show that the designed fixtures have a lighter weight but higher clamping force than the metal fixture at room temperature (RT). It is the first work that demonstrates the potential of the SMP fixture to replace the metal fixture in the computerized embroidery machine and provides inspiration for product design with variable stiffness characteristic in engineering.

scholarly journals Preparation and characterization of shape memory polymer scaffolds via solvent casting/particulate leaching

2012 ◽  
Vol 2 (10) ◽  
pp. 119-126 ◽  
Author(s):  
Luigi De Nardo ◽  
Serena Bertoldi ◽  
Alberto Cigada ◽  
Maria Cristina Tanzi ◽  
Håvard Jostein Haugen ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Solvent Casting ◽  
Polymer Scaffolds ◽  
Particulate Leaching

Synthesis and Characterization of Radiopaque Shape Memory Polymers

2017 ◽  
Author(s):  
Kendal Ezell ◽  
Landon Nash ◽  
Sonya Gordon ◽  
Duncan Maitland
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
The United States ◽  
Endovascular Embolization ◽  
Polymer Foam ◽  
X Ray ◽  
Unruptured Cerebral Aneurysm ◽  
Composite Foams ◽  
Function Impairment

An estimated 6 million people in the United States have an unruptured cerebral aneurysm [1]. If left untreated, these aneurysms can rupture and to lead to severe brain function impairment or even death. Shape memory polymer (SMP) foams have been proposed for use to optimize endovascular embolization in place of current embolization devices [2,3]. SMPs are capable of actuating from a programmed secondary geometry to their expanded primary geometry in response to a stimulus, such as body temperature [4]. The expanded foam geometry provides an interface for embolization of the aneurysm to occur, however, treatment with these devices has limited visibility under fluoroscopy. Previous work by Hasan et al. increased radiopacity through the incorporation of tungsten (W) nanoparticles. These composite foams showed successful x-ray visibility, but aggregate disruption of the SMP matrix led to decreased mechanical properties [5]. This work addresses limitations of composite SMP foams, namely toughness, by chemically incorporating x-ray visible monomers, such as the triodobenzene containing monomer, 5-Amino-2,4,6-triiodoisophthalic acid (AT), into the material composition. These materials enable contrast agent loading without disrupting the polymer matrix. This polymer foam system was characterized to determine the clinical relevance of the improved radiopaque SMP foam for occlusion devices.

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