scholarly journals Glassy Carbon Electrocorticography Electrodes on Ultra-Thin and Finger-Like Polyimide Substrate: Performance Evaluation Based on Different Electrode Diameters

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2486 ◽  
Author(s):  
Maria Vomero ◽  
Elena Zucchini ◽  
Emanuela Delfino ◽  
Calogero Gueli ◽  
Norma Mondragon ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Photoelectron Spectroscopy ◽  
Implantable Devices ◽  
Signal Source ◽  
Electrode Diameter ◽  
Low Frequencies ◽  
High Frequencies ◽  
X Ray ◽  
Polyimide Substrate

Glassy carbon (GC) has high potential to serve as a biomaterial in neural applications because it is biocompatible, electrochemically inert and can be incorporated in polyimide-based implantable devices. Miniaturization and applicability of GC is, however, thought to be partially limited by its electrical conductivity. For this study, ultra-conformable polyimide-based electrocorticography (ECoG) devices with different-diameter GC electrodes were fabricated and tested in vitro and in rat models. For achieving conformability to the rat brain, polyimide was patterned in a finger-like shape and its thickness was set to 8 µm. To investigate different electrode sizes, each ECoG device was assigned electrodes with diameters of 50, 100, 200 and 300 µm. They were electrochemically characterized and subjected to 10 million biphasic pulses—for achieving a steady-state—and to X-ray photoelectron spectroscopy, for examining their elemental composition. The electrodes were then implanted epidurally to evaluate the ability of each diameter to detect neural activity. Results show that their performance at low frequencies (up to 300 Hz) depends on the distance from the signal source rather than on the electrode diameter, while at high frequencies (above 200 Hz) small electrodes have higher background noises than large ones, unless they are coated with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS).

scholarly journals Synthesis, characterization and in vitro cytotoxicity study of Co and Ni ferrite nanoparticles prepared by sol-gel method

2021 ◽  
Vol 3 (7) ◽  
Author(s):  
Alexandre Pancotti ◽  
Dener Pereira Santos ◽  
Dielly Oliveira Morais ◽  
Mauro Vinícius de Barros Souza ◽  
Débora R. Lima ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Test Sample ◽  
In Vitro Cytotoxicity ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Transmission Electron ◽  
Crystallite Sizes

AbstractIn this study, we report the synthesis and characterization of NiFe2O4 and CoFe2O4 nanoparticles (NPs) which are widely used in the biomedical area. There is still limited knowledge how the properties of these materials are influenced by different chemical routes. In this work, we investigated the effect of heat treatment over cytotoxicity of cobalt and niquel ferrites NPs synthesized by sol-gel method. Then the samples were studied using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), Fourier Transform Infrared Spectroscopy Analysis (FTIR), and X-ray fluorescence (XRF). The average crystallite sizes of the particles were found to be in the range of 20–35 nm. The hemocompatibility (erythrocytes and leukocytes) was checked. Cytotoxicity results were similar to those of the control test sample, therefore suggesting hemocompatibility of the tested materials.

scholarly journals Lactoferrin/Calcium Phosphate-Modified Porous Ti by Biomimetic Mineralization: Effective Infection Prevention and Excellent Osteoinduction

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 992
Author(s):  
Song Chen ◽  
Yuanli He ◽  
Linna Zhong ◽  
Wenjia Xie ◽  
Yiyuan Xue ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Photoelectron Spectroscopy ◽  
Antibacterial Properties ◽  
Biomimetic Mineralization ◽  
Matrix Mineralization ◽  
X Ray ◽  
Porous Ti ◽  
Potential Applications ◽  
Modification Of Titanium

The surface modification of titanium (Ti) can enhance the osseointegration and antibacterial properties of implants. In this study, we modified porous Ti discs with calcium phosphate (CaP) and different concentrations of Lactoferrin (LF) by biomimetic mineralization and examined their antibacterial effects and osteogenic bioactivity. Firstly, scanning electron microscopy (SEM), the fluorescent tracing method, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and the releasing kinetics of LF were utilized to characterize the modified Ti surface. Then, the antibacterial properties against S. sanguis and S. aureus were investigated. Finally, in vitro cytological examination was performed, including evaluations of cell adhesion, cell differentiation, extracellular matrix mineralization, and cytotoxicity. The results showed that the porous Ti discs were successfully modified with CaP and LF, and that the LF-M group (200 μg/mL LF in simulated body fluid) could mildly release LF under control. Further, the LF-M group could effectively inhibit the adhesion and proliferation of S. sanguis and S. aureus and enhance the osteogenic differentiation in vitro with a good biocompatibility. Consequently, LF-M-modified Ti may have potential applications in the field of dental implants to promote osseointegration and prevent the occurrence of peri-implantitis.

scholarly journals Surface Characteristics and Cell Adhesion Behaviors of the Anodized Biomedical Stainless Steel

2020 ◽  
Vol 10 (18) ◽  
pp. 6275
Author(s):  
Heng-Jui Hsu ◽  
Chia-Yu Wu ◽  
Bai-Hung Huang ◽  
Chi-Hsun Tsai ◽  
Takashi Saito ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Culture ◽  
Stainless Steel ◽  
Cell Adhesion ◽  
Oxide Layer ◽  
Photoelectron Spectroscopy ◽  
X Ray ◽  
In Vitro Cell Culture ◽  
Cell Culture Assay

In this study, an electrochemical anodizing method was applied as surface modification of the 316L biomedical stainless steel (BSS). The surface properties, microstructural characteristics, and biocompatibility responses of the anodized 316L BSS specimens were elucidated through scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffractometry, transmission electron microscopy, and in vitro cell culture assay. Analytical results revealed that the oxide layer of dichromium trioxide (Cr2O3) was formed on the modified 316L BSS specimens after the different anodization modifications. Moreover, a dual porous (micro/nanoporous) topography can also be discovered on the surface of the modified 316L BSS specimens. The microstructure of the anodized oxide layer was composed of amorphous austenite phase and nano-Cr2O3. Furthermore, in vitro cell culture assay also demonstrated that the osteoblast-like cells (MG-63) on the anodized 316L BSS specimens were completely adhered and covered as compared with the unmodified 316L BSS specimen. As a result, the anodized 316L BSS with a dual porous (micro/nanoporous) oxide layer has great potential to induce cell adhesion and promote bone formation.

scholarly journals Gradient Chitosan Hydrogels Modified with Graphene Derivatives and Hydroxyapatite: Physiochemical Properties and Initial Cytocompatibility Evaluation

2020 ◽  
Vol 21 (14) ◽  
pp. 4888
Author(s):  
Karolina Kosowska ◽  
Patrycja Domalik-Pyzik ◽  
Małgorzata Sekuła-Stryjewska ◽  
Sylwia Noga ◽  
Joanna Jagiełło ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Mechanical Analysis ◽  
Biological Properties ◽  
Human Umbilical Cord ◽  
Tissue Engineering Scaffolds ◽  
X Ray ◽  
Chitosan Matrix ◽  
Graphene Derivatives

In this study, we investigated preparation of gradient chitosan-matrix hydrogels through a novel freezing–gelling–thawing method. The influence of three types of graphene family materials (GFM), i.e., graphene oxide (GO), reduced graphene oxide (rGO), and poly(ethylene glycol) grafted graphene oxide (GO-PEG), as well as hydroxyapatite (HAp) on the physicochemical and biological properties of the composite hydrogels was examined in view of their potential applicability as tissue engineering scaffolds. The substrates and the hydrogel samples were thoroughly characterized by X-ray photoelectron spectroscopy, X-ray diffractometry, infrared spectroscopy, digital and scanning electron microscopy, rheological and mechanical analysis, in vitro chemical stability and bioactivity assays, as well as initial cytocompatibility evaluation with human umbilical cord Wharton’s jelly mesenchymal stem cells (hUC-MSCs). We followed the green-chemistry approach and avoided toxic cross-linking agents, using instead specific interactions of our polymer matrix with tannic acid, non-toxic physical cross-linker, and graphene derivatives. It was shown that the most promising are the gradient hydrogels modified with GO-PEG and HAp.

scholarly journals Alkyl-group grafting onto glassy carbon cathodes by reduction of primary monohaloalkanes: electrochemistry and X-ray photoelectron spectroscopy studies

2020 ◽  
Vol 856 ◽  
pp. 113531 ◽  
Author(s):  
J. Tyler Barnes ◽  
Kent J. Griffith ◽  
Joshua A. Beeler ◽  
Benjamin H.R. Gerroll ◽  
Ana G. Couto Petro ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Photoelectron Spectroscopy ◽  
Alkyl Group ◽  
X Ray ◽  
Spectroscopy Studies ◽  
Grafting Onto

Growth of Calcium Phosphate on Poled Piezoelectric Poly-L-lactic Acid Membrane by a Biomimetic Method

2007 ◽  
Vol 330-332 ◽  
pp. 703-706
Author(s):  
Chun Peng Huang ◽  
Dong Hua Guan ◽  
Kun Tian ◽  
Xin Min Chen ◽  
Lin Niu ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Electric Field ◽  
Photoelectron Spectroscopy ◽  
Charged Surface ◽  
X Ray ◽  
Charged Surfaces ◽  
Before And After ◽  
Dc Electric Field ◽  
Biomimetic Method

The bioactivity of poled piezoelectric PLLA membrane was investigated by studying the calcium phosphate formation in vitro using a biomimetic method. Samples (φ10mm) were poled under DC electric field of 8~l0kV/cm at 70°C for 30 min followed by cooling under the electric field. Surface chemistry of the samples before and after poling treatment was studied by X-ray photoelectron spectroscopy (XPS). Poled/unpoled samples were immersed in supersaturated calcification solution (SCS) for periods up to 24 h (36.5°C). The surface morphology and composition of the soaked samples were evaluated by using scanning electron microscope (SEM) and X-ray diffraction analysis (XRD). Poled samples showed two different charged surfaces, negatively-charged surface (N-PLLA) and positively-charged surface (P-PLLA). On the N-PLLA surfaces, SEM together with XRD showed a gradually formed calcium phosphate (Ca-P), while no obvious Ca-P on either P-PLLA or unpoled samples was observed. This study demonstrated that poled piezoelectric PLLA substrates induce substantially higher level of Ca-P formation than electrically neutral substrates and only N-PLLA, however, can improve Ca-P formation after immersion in SCS.

CONTROL OF SURFACE MODIFIED LAYER ON METALLIC BIOMATERIALS BY AN ADVANCED ELID GRINDING SYSTEM (EG-X)

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3605-3610 ◽  
Author(s):  
MASAYOSHI MIZUTANI ◽  
JUN KOMOTORI ◽  
KAZUTOSHI KATAHIRA ◽  
HITOSHI OHMORI
Keyword(s):  
Oxide Layer ◽  
Surface Properties ◽  
Photoelectron Spectroscopy ◽  
Titanium Implants ◽  
X Ray ◽  
Elid Grinding ◽  
Modified Layer ◽  
Surface Modified ◽  
Grinding System

The biocompatibility of titanium implants with different surface properties is investigated. We prepared three types of specimens, one ground by the newly developed ELID grinding system, another ground by conventional ELID grinding, and the other polished by SiO 2 powder. These surfaces were characterized and, the number of cell and cytotoxicity in in-vitro were measured. Energy Dispersive X-ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscope (TEM) revealed that the modified ELID system can create a significantly thick oxide layer and a diffused oxide layer, and also can control the thickness of a modified layer. The results of cell number and cytotoxicity showed that the sample ground by the modified system had the highest biocompatibility. This may have been caused by improvement of chemical properties due to a surface modified layer. The above results suggest that this newly developed ELID grinding system can create the desirable surface properties. Consequently, this system appears to offer significant future promise for use in biomaterials and other engineering components.

scholarly journals The Surface Characterisation of Fused Filament Fabricated (FFF) 3D Printed PEEK/Hydroxyapatite Composites

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3117
Author(s):  
Krzysztof Rodzeń ◽  
Mary Josephine McIvor ◽  
Preetam K. Sharma ◽  
Jonathan G. Acheson ◽  
Alistair McIlhagger ◽  
...  
Keyword(s):  
3D Printing ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Secondary Ion Mass Spectrometry ◽  
Fused Filament Fabrication ◽  
Surface Characterisation ◽  
X Ray ◽  
3D Printed

Polyetheretherketone (PEEK) is a high-performance thermoplastic polymer which has found increasing application in orthopaedics and has shown a lot of promise for ‘made-to-measure’ implants via additive manufacturing approaches. However, PEEK is bioinert and needs to undergo surface modification to make it at least osteoconductive to ensure a more rapid, improved, and stable fixation that will last longer in vivo. One approach to solving this issue is to modify PEEK with bioactive agents such as hydroxyapatite (HA). The work reported in this study demonstrates the direct 3D printing of PEEK/HA composites of up to 30 weight percent (wt%) HA using a Fused Filament Fabrication (FFF) approach. The surface characteristics and in vitro properties of the composite materials were investigated. X-ray diffraction revealed the samples to be semi-crystalline in nature, with X-ray Photoelectron Spectroscopy and Time-of-Flight Secondary Ion Mass Spectrometry revealing HA materials were available in the uppermost surface of all the 3D printed samples. In vitro testing of the samples at 7 days demonstrated that the PEEK/HA composite surfaces supported the adherence and growth of viable U-2 OS osteoblast like cells. These results demonstrate that FFF can deliver bioactive HA on the surface of PEEK bio-composites in a one-step 3D printing process.

scholarly journals Preparation and Application of Keggin Silicomolybdic acid Modified Electrode

2020 ◽  
Author(s):  
Miao Liu ◽  
Mingxuan Jia ◽  
Dong Hui Li
Keyword(s):  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Photoelectron Spectroscopy ◽  
Limit Of Detection ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
X Ray ◽  
Linear Relationships

Abstract An innovative method for the determination of isoniazid tablets is studied through electrochemical method for the modification of glassy carbon electrode (GCE). Polyoxomolybdate, with stable structures, has not been widely used for the determination of substance. In this study, the mentioned polyoxomolybdate was characterized by Fourier transform infrared spectroscopy (FT-IR), UV-vis, X-ray diffraction (XRD), Atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS), and used to modify the glassy carbon electrode. The electrochemical performance of the polyoxomolybdate@GCE was investigated with cyclic voltammetry (CV) and differential pulse voltammetry (DPV), compared with the unmodified electrode, the proposed polyoxomolybdate modified electrode exhibited strong electro-catalytic activities towards isoniazid (INH). Under the optimized conditions, there was linear relationships between the DPV peak currents and the concentrations in the range of 1 × 10 -7 g/L to 3 × 10 -7 g/L for INH (R 2 = 0.9979), with the limit of detection (LOD) of 0.024 μg/L (based on S/N = 3). The modified electrode has proper reproducibility (RSD < 5%), stability, response time (< 3 min) and lifetime (up to 6 days).

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