scholarly journals SURFACE MODIFICATION OF BIOMATERIAL FABRIC USING SUPERCRITICAL N2 JET

2019 ◽  
Vol 2019 ◽  
pp. 166-169
Author(s):  
Foued KHOFFI ◽  
Yosri KHALSI ◽  
Abdel TAZIBT ◽  
Slah MSAHLI ◽  
Frédéric HEIM
Keyword(s):  
Static Pressure ◽  
Foreign Body Reaction ◽  
Standoff Distance ◽  
Material Surface ◽  
Crater Diameter ◽  
Textile Materials ◽  
Pet Fabric ◽  
Novel Technique ◽  
Micro Particles

Textile biomaterials have been largely used over the last decades as vascular grafts, hernia meshes and heart valve leaflet [1-2]. Once implanted in vivo, the natural porosity of textile materials tends to induce exaggerated tissue ingrowth, which may prevent the implants from remaining flexible [3]. One hypothesized way to limit the foreign body reaction process is to increase the material surface roughness [4]. Supercritical N2 jet particle projection is a novel technique to provide enough velocity to micro particles to induce plastic deformation on the textile impacted surface. The aim of this study is to investigate the influence of micro particles laden supercritical N2 jet projection parameters like jet static pressure, standoff distance and particle size on the roughness of PET fabric surfaces. Results bring out that particles projected by the jet N2 SC generate craters on the surface of monofilament as well as multifilament fabric, allowing topographical modifications at the yarn scale. We found that larger particles induce larger crater diameters. Moreover, increasing the static jet pressure from 300 to 1000 bars further allows increase in the crater diameter. For a pressure of 500 bar, the standoff distance must be greater than 300 mm in order to obtain significant roughness values without breaking the PET monofilament fabrics. Thus, this treatment increased the roughness of the monofilament fabric from 0.78 μm to 1.22 μm. The results obtained in this work show that it is possible to create a roughness on a PET fabric using the N2 jet technology.

The Influence of Bioactive Glass Particles on Osteolysis

2007 ◽  
Vol 330-332 ◽  
pp. 193-196
Author(s):  
Duck Hyun Kim ◽  
Kang Sik Lee ◽  
Jung Hwa Kim ◽  
Jae Suk Chang ◽  
Yung Tae Kim
Keyword(s):  
Foreign Body ◽  
Bioactive Glass ◽  
Foreign Body Reaction ◽  
Statistical Significance ◽  
Giant Cells ◽  
In Vivo Test ◽  
Micro Particles ◽  
Rat Calvaria ◽  
Replacement Arthroplasty

We observed the cytotoxicity of human bone marrow stromal cells(hBMSCs) by microparticles of bioactive glass with four particle groups(same chemical composition-45S5 but produced by two different manufacturer and two different size groups). In vivo test using rat calvaria were also carried out. The apoptosis rates of all small particle groups(10-20 ㎛) were increased than large(500-700 ㎛ or 200-900 ㎛) particle groups in any culture time and any amount of particles with statistical significance. In vivo study we observed pathologic signs such as macrophages and foreign-body giant cells in rat calvaria by micro-particles of bioglass. Small(10- 20 ㎛) sized particles induced foreign body reaction and bone resorption. There was proliferation of macrophages and cells in large number. But in large particle groups, only fibroblasts were surrounding the particles. The micro-particles of bioglass induced apoptosis of hBMSC and foreign body reaction in calvaria of rat, therefore micro-particles of bioglass may cause osteolysis if used in replacement arthroplasty.

scholarly journals Development of a gel dedicated to gel immersion endoscopy

2021 ◽  
Vol 09 (06) ◽  
pp. E918-E924
Author(s):  
Tomonori Yano ◽  
Atsushi Ohata ◽  
Yuji Hiraki ◽  
Makoto Tanaka ◽  
Satoshi Shinozaki ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Porcine Model ◽  
Ex Vivo ◽  
In Vitro Experiments ◽  
Efficacy And Safety ◽  
Coagulative Necrosis ◽  
Novel Technique ◽  
In Vivo Experiments

Abstract Backgrounds and study aims Gel immersion endoscopy is a novel technique to secure the visual field during endoscopy. The aim of this study was to develop a dedicated gel for this technique. Methods To identify appropriate viscoelasticity and electrical conductivity, various gels were examined. Based on these results, the dedicated gel “OPF-203” was developed. Efficacy and safety of OPF-203 were evaluated in a porcine model. Results  In vitro experiments showed that a viscosity of 230 to 1900 mPa·s, loss tangent (tanδ) ≤ 0.6, and hardness of 240 to 540 N/cm2 were suitable. Ex vivo experiments showed electrical conductivity ≤ 220 μS/cm is appropriate. In vivo experiments using gastrointestinal bleeding showed that OPF-203 provided clear visualization compared to water. After electrocoagulation of gastric mucosa in OPF-203, severe coagulative necrosis was not observed in the muscularis but limited to the mucosa. Conclusions OPF-203 is useful for gel immersion endoscopy.

scholarly journals Titanium oral implants: surface characteristics, interface biology and clinical outcome

2010 ◽  
Vol 7 (suppl_5) ◽  
Author(s):  
Anders Palmquist ◽  
Omar M. Omar ◽  
Marco Esposito ◽  
Jukka Lausmaa ◽  
Peter Thomsen
Keyword(s):  
Surface Properties ◽  
Cellular Response ◽  
Randomized Clinical Trials ◽  
Three Dimensional ◽  
Cell Communication ◽  
Surface Characteristics ◽  
Titanium Implants ◽  
Material Surface ◽  
Oral Implants

Bone-anchored titanium implants have revolutionized oral healthcare. Surface properties of oral titanium implants play decisive roles for molecular interactions, cellular response and bone regeneration. Nevertheless, the role of specific surface properties, such as chemical and phase composition and nanoscale features, for the biological in vivo performance remains to be established. Partly, this is due to limited transfer of state-of-the-art preparation techniques to complex three-dimensional geometries, analytical tools and access to minute, intact interfacial layers. As judged by the available results of a few randomized clinical trials, there is no evidence that any particular type of oral implant has superior long-term success. Important insights into the recruitment of mesenchymal stem cells, cell–cell communication at the interface and high-resolution imaging of the interface between the surface oxide and the biological host are prerequisites for the understanding of the mechanisms of osseointegration. Strategies for development of the next generation of material surface modifications for compromised tissue are likely to include time and functionally programmed properties, pharmacological modulation and incorporation of cellular components.

scholarly journals Inducible transgene expression in PDX models in vivo identifies KLF4 as therapeutic target for B-ALL

2019 ◽  
Author(s):  
Wen-Hsin Liu ◽  
Paulina Mrozek-Gorska ◽  
Tobias Herold ◽  
Larissa Schwarzkopf ◽  
Dagmar Pich ◽  
...  
Keyword(s):  
Residual Disease ◽  
Therapeutic Option ◽  
Lymphoblastic Leukemia ◽  
Clinical Model ◽  
Novel Technique ◽  
Pdx Model ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Disease Stages ◽  
Pdx Models

Clinic-close methods are not available that prioritize and validate potential therapeutic targets in individual tumors from the vast bulk of descriptive expression data. We developed a novel technique to express transgenes in established patient-derived xenograft (PDX) models in vivo to fill this gap. With this technique at hand, we analyzed the role of transcription factor Krüppel-like factor 4 (KLF4) in B-cell acute lymphoblastic leukemia (B-ALL) PDX models at different disease stages. In competitive pre-clinical in vivo trials, we found that re-expression of wild type KLF4 reduced leukemia load in PDX models of B-ALL, with strongest effects after conventional chemotherapy at minimal residual disease (MRD). A non-functional KLF4 mutant had no effect in this model. Re-expressing KLF4 sensitized tumor cells in the PDX model towards systemic chemotherapy in vivo. Of major translational relevance, Azacitidine upregulated KLF4 levels in the PDX model and a KLF4 knockout reduced Azacitidine-induced cell death, suggesting that Azacitidine can regulate KLF4 re-expression. These results support applying Azacitidine in patients with B-ALL to regulated KLF4 as a therapeutic option. Taken together, our novel technique allows studying the function of dysregulated genes in a highly clinic-related, translational context and testing clinically applicable drugs in a relevant pre-clinical model.

scholarly journals Large Animal Studies to Reduce the Foreign Body Reaction in Brain–Computer Interfaces: A Systematic Review

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 275
Author(s):  
Shan Yasin Mian ◽  
Jonathan Roy Honey ◽  
Alejandro Carnicer-Lombarte ◽  
Damiano Giuseppe Barone
Keyword(s):  
Foreign Body ◽  
Animal Studies ◽  
Foreign Body Reaction ◽  
Inflammatory Cells ◽  
Anatomical Location ◽  
Large Animal ◽  
Brain Computer Interfaces ◽  
Computer Interfaces ◽  
Electrode Insertion

Brain–computer interfaces (BCI) are reliant on the interface between electrodes and neurons to function. The foreign body reaction (FBR) that occurs in response to electrodes in the brain alters this interface and may pollute detected signals, ultimately impeding BCI function. The size of the FBR is influenced by several key factors explored in this review; namely, (a) the size of the animal tested, (b) anatomical location of the BCI, (c) the electrode morphology and coating, (d) the mechanics of electrode insertion, and (e) pharmacological modification (e.g., drug eluting electrodes). Trialing methods to reduce FBR in vivo, particularly in large models, is important to enable further translation in humans, and we systematically reviewed the literature to this effect. The OVID, MEDLINE, EMBASE, SCOPUS and Scholar databases were searched. Compiled results were analysed qualitatively. Out of 8388 yielded articles, 13 were included for analysis, with most excluded studies experimenting on murine models. Cats, rabbits, and a variety of breeds of minipig/marmoset were trialed. On average, over 30% reduction in inflammatory cells of FBR on post mortem histology was noted across intervention groups. Similar strategies to those used in rodent models, including tip modification and flexible and sinusoidal electrode configurations, all produced good effects in histology; however, a notable absence of trials examining the effect on BCI end-function was noted. Future studies should assess whether the reduction in FBR correlates to an improvement in the functional effect of the intended BCI.

Modern Strategies in the Prevention of Implant-Associated Infections

2005 ◽  
Vol 28 (11) ◽  
pp. 1146-1156 ◽  
Author(s):  
C. Von Eiff ◽  
W. Kohnen ◽  
K. Becker ◽  
B. Jansen
Keyword(s):  
Medical Devices ◽  
Fungal Infections ◽  
Material Surface ◽  
Strict Adherence ◽  
Antimicrobial Substances ◽  
Substantial Risk ◽  
Considerable Impact ◽  
Almost All ◽  
Microbial Adherence

The application of medical devices either for temporary or permanent use has become an indispensible part of almost all fields of medicine. However, foreign bodies are associated with a substantial risk of bacterial and fungal infections. Implant-associated infections significantly contribute to the still increasing problem of nosocomial infections. To reduce the incidence of such infections, specific guidelines providing evidence-based recommendations and comprising both technological and nontechnological strategies for prevention have been established. Strict adherence to hygienic rules during insertion or implantation of the device are aspects of particular importance. Besides such basic and indispensable aspects, the development of new materials which could withstand microbial adherence and colonization has become a major topic in recent years. Modification of surface by primarily physico-chemical methods may lead to a change in specific and unspecific interactions with microorganisms and, thus, to a reduction in microbial adherence. Medical devices made out of a material that would be ideally antiadhesive or at least colonization-resistant would be the most suitable candidates to avoid colonization and subsequent infection. However, it appears impossible to create a surface with an absolute “zero”-adherence due to thermodynamical reasons and due to the fact that a modified material surface is in vivo rapidly covered by plasma and connective tissue proteins. Therefore, another concept for the prevention of implant-associated infections involves the impregnation of devices with various antimicrobial substances such as antibiotics, antiseptics, and/or metals. In fact, already commercially available materials for clinical use such as antimicrobial catheters have been introduced, in part with considerable impact on subsequent infections. However, future studies are warranted to translate the knowledge on the pathogenesis of device-associated infections into applicable prevention strategies.

scholarly journals An Implanted Magnetic Microfluidic Pump for In Vivo Bone Remodeling Applications

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 300 ◽  
Author(s):  
Ziyu Chen ◽  
Sunggi Noh ◽  
Rhonda D. Prisby ◽  
Jeong-Bong Lee
Keyword(s):  
Bone Growth ◽  
Static Pressure ◽  
Dynamic Pressure ◽  
The Body ◽  
In Vivo Studies ◽  
Fischer 344 ◽  
Fischer 344 Rat ◽  
Pressure Modulation

Modulations of fluid flow inside the bone intramedullary cavity has been found to stimulate bone cellular activities and augment bone growth. However, study on the efficacy of the fluid modulation has been limited to external syringe pumps connected to the bone intramedullary cavity through the skin tubing. We report an implantable magnetic microfluidic pump which is suitable for in vivo studies in rodents. A compact microfluidic pump (22 mm diameter, 5 mm in thickness) with NdFeB magnets was fabricated in polydimethylsiloxane (PDMS) using a set of stainless-steel molds. An external actuator with a larger magnet was used to wirelessly actuate the magnetic microfluidic pump. The characterization of the static pressure of the microfluidic pump as a function of size of magnets was assessed. The dynamic pressure of the pump was also characterized to estimate the output of the pump. The magnetic microfluidic pump was implanted into the back of a Fischer-344 rat and connected to the intramedullary cavity of the femur using a tube. On-demand wireless magnetic operation using an actuator outside of the body was found to induce pressure modulation of up to 38 mmHg inside the femoral intramedullary cavity of the rat.

scholarly journals Measurement of Retinal Microvascular Blood Velocity Using Erythrocyte Mediated Velocimetry

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Breanna M. Tracey ◽  
Lakyn N. Mayo ◽  
Christopher T. Le ◽  
Victoria Y. Chen ◽  
Julian Weichsel ◽  
...  
Keyword(s):  
Average Diameter ◽  
Retinal Blood Flow ◽  
Direct Visualization ◽  
Ocular Diseases ◽  
Novel Technique ◽  
Retinal Microvasculature ◽  
The Mean ◽  
Pharmacologic Agents

AbstractChanges in retinal blood flow may be involved in the pathogenesis of glaucoma and other ocular diseases. Erythrocyte mediated velocimetry (EMV) is a novel technique where indocyanine green (ICG) dye is sequestered in erythrocyte ghosts and autologously re-injected to allow direct visualization of erythrocytes for in vivo measurement of speed. The purpose of this study is to determine the mean erythrocyte speed in the retinal microvasculature, as well as the intravisit and intervisit variability of EMV. Data from 23 EMV sessions from control, glaucoma suspect, and glaucoma patients were included in this study. In arteries with an average diameter of 43.11 µm ± 6.62 µm, the mean speed was 7.17 mm/s ± 2.35 mm/s. In veins with an average diameter of 45.87 µm ± 12.04 µm, the mean speed was 6.05 mm/s ± 1.96 mm/s. Intravisit variability, as measured by the mean coefficient of variation, was 3.57% (range 0.44–9.68%). Intervisit variability was 4.85% (range 0.15–8.43%). EMV may represent reliable method for determination of retinal blood speed, potentially allowing insights into the effects of pharmacologic agents or pathogenesis of ocular diseases.

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