A study of intra-cochlear electrodes and tissue interface by electrochemical impedance methods in vivo

Biomaterials ◽  
2004 ◽  
Vol 25 (17) ◽  
pp. 3813-3828 ◽  
Author(s):  
Y.Y. Duan ◽  
G.M. Clark ◽  
R.S.C. Cowan
Keyword(s):  
Electrochemical Impedance ◽  
Tissue Interface

scholarly journals Characterizing Longitudinal Changes in the Impedance Spectra of In-Vivo Peripheral Nerve Electrodes

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 587 ◽  
Author(s):  
Malgorzata Straka ◽  
Benjamin Shafer ◽  
Srikanth Vasudevan ◽  
Cristin Welle ◽  
Loren Rieth
Keyword(s):  
Electrochemical Impedance ◽  
Iridium Oxide ◽  
Support Vector ◽  
Impedance Spectra ◽  
Computationally Efficient ◽  
Wide Range ◽  
Tissue Interface ◽  
Computationally Efficient Algorithms ◽  
Physical Changes

Characterizing the aging processes of electrodes in vivo is essential in order to elucidate the changes of the electrode–tissue interface and the device. However, commonly used impedance measurements at 1 kHz are insufficient for determining electrode viability, with measurements being prone to false positives. We implanted cohorts of five iridium oxide (IrOx) and six platinum (Pt) Utah arrays into the sciatic nerve of rats, and collected the electrochemical impedance spectroscopy (EIS) up to 12 weeks or until array failure. We developed a method to classify the shapes of the magnitude and phase spectra, and correlated the classifications to circuit models and electrochemical processes at the interface likely responsible. We found categories of EIS characteristic of iridium oxide tip metallization, platinum tip metallization, tip metal degradation, encapsulation degradation, and wire breakage in the lead. We also fitted the impedance spectra as features to a fine-Gaussian support vector machine (SVM) algorithm for both IrOx and Pt tipped arrays, with a prediction accuracy for categories of 95% and 99%, respectively. Together, this suggests that these simple and computationally efficient algorithms are sufficient to explain the majority of variance across a wide range of EIS data describing Utah arrays. These categories were assessed over time, providing insights into the degradation and failure mechanisms for both the electrode–tissue interface and wire bundle. Methods developed in this study will allow for a better understanding of how EIS can characterize the physical changes to electrodes in vivo.

scholarly journals Wafer-Scale Fabrication and Assembly Method of Multichannel Microelectrode Arrays for ECoG Application

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 316
Author(s):  
Cong Wang ◽  
Yu-Chen Wei ◽  
Ho-Kun Sung ◽  
Alok Kumar ◽  
Zhong-Liang Zhou ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Electrochemical Impedance ◽  
Microelectrode Arrays ◽  
Absence Seizure ◽  
Curing Conditions ◽  
Wafer Scale ◽  
In Vivo Test ◽  
Assembly Method ◽  
Signal Recording

High density electrocorticography (ECoG)-based microelectrode arrays (MEAs) are fabricated to timely record the neural activities to provide the fundamental understanding in neuroscience and biomedical engineering. This paper aims to introduce a device-based concept and wafer-scale fabrication process for MEAs. Flexible and biocompatible polyimide is applied on MEAs to bear all possible stress and strain. Detailed fabrication key techniques, including surface treatment, polyimide stability measurement, evaporation process, and curing conditions, have been discussed thoroughly. Moreover, the fabricated polyimide-based MEAs are surface-mounted on well-packaged printed circuit boards (PCBs) via a slot-type connector without any additional wire bonding to make the signal recording process easier. An absence seizure was recorded during the in vivo test, which shows the availability of signal recording based on the presented MEAs. The proposed MEAs could be remained at the skull, while the connector and PCBs can be disassembled apart. Therefore, the testing sample will get less suffering. To verify the robustness of the fabricated MEAs, the impedance properties were characterized using electrochemical impedance spectroscopy. The measured results indicate an average impedance of 12.3 ± 0.675 kΩ at 1 kHz. In total, 10 groups of MEAs were sample tested, and over 90% of the total 60 channels per 1-MEAs operated efficiently.

What can we Predict Before it's Implanted?

1985 ◽  
Vol 55 ◽  
Author(s):  
Donald F. Gibbons
Keyword(s):  
Biological Response ◽  
High Sensitivity ◽  
Biological Pathways ◽  
Surface Topology ◽  
Dystrophic Calcification ◽  
Vitro Assay ◽  
In Vivo Assays ◽  
Tissue Interface

ABSTRACTThe material factors which relate to the degradation and/or leaching of ions or molecules are described and the possible biological pathways which they may activate are described, i.e. cytotoxic, immune, tumor and nonspecific inflammatory response. Cytotoxicity is the only biological response which may be measured with high sensitivity by an in vitro assay prior to implantation. All other biological pathways require some degree of in vivo involvement. Three examples of biological response to material factors associated with devices which require evaluation by in vivo assays are discussed, namely: surface topology (texture), mechanically induced factors at the device/tissue interface caused by differences in compliance, and dystrophic calcification in connective tissue and vascular devices.

A Direct Comparison of Glassy Carbon and PEDOT-PSS Electrodes for High Charge Injection and Low Impedance Neural Interfaces

2016 ◽  
Vol 102 ◽  
pp. 68-76 ◽  
Author(s):  
Maria Vomero ◽  
Elisa Castagnola ◽  
Emma Maggiolini ◽  
Francesca Ciarpella ◽  
Irene Rembado ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Glassy Carbon ◽  
Cultured Cells ◽  
Electrochemical Impedance ◽  
Neural Interfaces ◽  
Somatosensory Stimulation ◽  
Brain Surface ◽  
First Time

For neural applications, materials able to interface with the brain without harming it while recording high-fidelity signals over long-term implants are still sought after. Glassy Carbon (GC) and Poly (3,4-ethylenedioxythiophene)-poly (styrenesulfonate) (PEDOT-PSS) have proved to be promising materials for neural interfaces as they show – compared to conventional metal electrodes - higher conductivity, better electrochemical stability, very good mechanical properties and therefore seem to be very promising for in vivo applications. We present here, for the first time, a direct comparison between GC and PEDOT-PSS microelectrodes in terms of biocompatibility, electrical and electrochemical properties as well as in vivo recording capabilities, using electrocorticography microelectrode arrays located on flexible polyimide substrate. The GC microelectrodes were fabricated using a traditional negative lithography processes followed by pyrolysis. PEDOT-PSS was selectively electrodeposited on the desired electrodes. Electrochemical performance of the two materials was evaluated through electrochemical impedance spectroscopy and cyclic voltammetry. Biocompatibility was assessed through in-vitro studies evaluating cultured cells viability. The in vivo performance of the GC and PEDOT-PSS electrodes was directly compared by simultaneously recording neuronal activity during somatosensory stimulation in Long-Evans rats. We found that both GC and PEDOT-PSS electrodes outperform metals in terms of electrochemical performance and allow to obtain excellent recordings of somatosensory evoked potentials from the rat brain surface. Furthermore, we found that both GC and PEDOT-PSS substrates are highly biocompatible, confirming that they are safe for neural interface applications.

scholarly journals Influence of Biocompatible Coating on Titanium Surface Characteristics

2020 ◽  
Author(s):  
Željka Petrović ◽  
Jozefina Katić ◽  
Ankica Šarić ◽  
Ines Despotović ◽  
Nives Matijaković ◽  
...  
Keyword(s):  
Self Assembly ◽  
Titanium Surface ◽  
Electrochemical Impedance ◽  
Calcium Phosphates ◽  
Artificial Saliva ◽  
Surface Characteristics ◽  
Corrosion Stability ◽  
Assembly Method

Background: Nowadays investigations in the field of dental implants engineering are focused on bioactivity and osseointegration properties.Objective: In this study, the oxide-covered titanium was functionalized by vitamin D3 molecules via a simple self-assembly method with the aim to design more corrosion resistant and at the same time more bioactive surface.Methods: Surface properties of the D3-coated titanium were examined by scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and contact angle measurements, while a long-term corrosion stability during immersion in an artificial saliva solution was investigated in situ by electrochemical impedance spectroscopy.Results: Results of all techniques confirmed a successful formation of the D3 vitamin layer on the oxide-covered titanium. Besides very good corrosion resistivity (~5 MΩcm2 ) the D3-modified titanium surface induced spontaneous formation of biocompatible bone-like calcium phosphates (CaP).Conclusion: Observed in vitro CaP-forming ability as a result of D3-modified titanium/artificial saliva interactions could serve as a promising predictor of in vivo bioactivity of implant materials.

scholarly journals Influence of Biocompatible Coating on Titanium Surface Characteristics

2020 ◽  
Vol 10 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Željka Petrović ◽  
Jozefina Katić ◽  
Ankica Šarić ◽  
Ines Despotović ◽  
Nives Matijaković ◽  
...  
Keyword(s):  
Vitamin D3 ◽  
Titanium Surface ◽  
Electrochemical Impedance ◽  
Calcium Phosphates ◽  
Artificial Saliva ◽  
Surface Characteristics ◽  
Corrosion Stability ◽  
Assembly Method

Background: Nowadays investigations in the field of dental implants engineering are focused on bioactivity and osseointegration properties. Objective: In this study, the oxide-covered titanium was functionalized by vitamin D3 molecules via a simple self-assembly method with the aim to design more corrosion-resistant and at the same time more bioactive surface. Methods: Surface properties of the D3-coated titanium were examined by scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and contact angle measurements, while long-term corrosion stability during immersion in an artificial saliva solution was investigated in situ by electrochemical impedance spectroscopy. Results: Results of all techniques confirmed a successful formation of the vitamin D3 layer on the oxide-covered titanium. Besides very good corrosion resistivity (~5 MΩ cm2), the D3-modified titanium surface induced spontaneous formation of biocompatible bone-like calcium phosphates (CaP). Conclusion: Observed in vitro CaP-forming ability as a result of D3-modified titanium/artificial saliva interactions could serve as a promising predictor of in vivo bioactivity of implant materials.

In vivo analysis of bone-tissue interface in medical grade titanium and porous titanium with and without cenosphere as space holder

Materialia ◽  
2020 ◽  
Vol 9 ◽  
pp. 100623 ◽  
Author(s):  
D. Dutta Majumdar ◽  
V. Kumar ◽  
A. Roychowdhury ◽  
D.P. Mondal ◽  
M. Ghosh ◽  
...  
Keyword(s):  
Bone Tissue ◽  
Porous Titanium ◽  
Space Holder ◽  
In Vivo Analysis ◽  
Tissue Interface ◽  
Medical Grade

In vivo electrochemical impedance measurement on single cell membrane

2011 ◽  
Vol 88 (10) ◽  
pp. 3094-3100 ◽  
Author(s):  
Seoung-Jai Bai ◽  
Fritz B. Prinz
Keyword(s):  
Cell Membrane ◽  
Single Cell ◽  
Electrochemical Impedance ◽  
Impedance Measurement

Morphology of the Interface “Silicon Wire - Nerve Fiber"

2016 ◽  
Vol 39 ◽  
pp. 214-220 ◽  
Author(s):  
A. Klimovskaya ◽  
N. Vysotskaya ◽  
Yu. Chaikovsky ◽  
A. Korsak ◽  
V. Lichodievskiy ◽  
...  
Keyword(s):  
Nerve Fiber ◽  
Silicon Surface ◽  
Point Of View ◽  
Nerve Tissue ◽  
Interface Morphology ◽  
Physicochemical State ◽  
Tissue Interface ◽  
Potential Use ◽  
Mechanisms Of Adhesion

Recently study of the “silicon wire - nerve tissue’ interface has been in the focus of attention due to its potential use in recovering nervous system damage caused by injuries or diseases. The key objective of this research was to test the physicochemical state of the interface and to study its properties. Although much research has been done in this field, the process of interface formation was not thoroughly described from the surface physics point of view. In the current research specimens of the “silicon wire - nerve fiber" interface were made. Experiments were carried out in vivo. The interface morphology and mechanisms of adhesion were examined in more detail and a physical model of intermolecular interaction of silicon surface and nerve fiber was proposed.

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