Public Regulatory Databases as a Source of Insight for Neuromodulation Devices Stimulation Parameters.

Objective: The Shannon model is often used to define an expected boundary between non-damaging and damaging modes of electrical neurostimulation. Numerous preclinical studies have been performed by manufacturers of neuromodulation devices using different animal models and a broad range of stimulation parameters while developing devices for clinical use. These studies are mostly absent from peer-reviewed literature, which may lead to this information being overlooked by the scientific community.

Engagement of the medical-technology sector with society.

The medical-technology sector must educate society in an unbiased rational way about the successes and benefits of biotechnology innovation.

High-throughput in vitro assay to evaluate the cytotoxicity of liberated platinum compounds for stimulating neural electrodes.

Background: It is currently unclear how the platinum (Pt) species released from platinum-containing stimulating electrodes may affect the health of the surrounding tissue. This study develops an effective system to assess the cytotoxicity of any electrode-liberated Pt over a short duration, to screen systems before future in vivo testing.

New Method: A platinum electrode was stimulated for two hours under physiologically relevant conditions to induce the liberation of Pt species.

Electrical neurostimulation with imbalanced waveform mitigates dissolution of platinum electrodes.

Objective: Electrical neurostimulation has traditionally been limited to the use of charge-balanced waveforms. Charge-imbalanced and monophasic waveforms are not used to deliver clinical therapy, because it is believed that these stimulation paradigms may generate noxious electrochemical species that cause tissue damage.

Approach: In this study, we investigated the dissolution of platinum as one of such irreversible reactions over a range of charge densities up to 160 μC cm with current-controlled first phase, capacitive discharge second phase waveforms of both cathodic-first and anodic-first polarity.

Electron transfer processes occurring on platinum neural stimulating electrodes: a tutorial on the i(V e) profile.

The aim of this tutorial is to encourage members of the neuroprosthesis community to incorporate electron transfer processes into their thinking and provide them with the tools to do so when they design and work with neurostimulating devices. The focus of this article is on platinum because it is the most used electrode metal for devices in commercial use. The i(V e) profile or cyclic voltammogram contains information about electron transfer processes that can occur when the electrode-electrolyte interface, V e, is at a specific potential, and assumed to be near steady-state conditions.

Abrasion and fatigue resistance of PDMS containing multiblock polyurethanes after accelerated water exposure at elevated temperature.

Segmented polyurethane multiblock polymers containing polydimethylsiloxane and polyether soft segments form tough and easily processed thermoplastic elastomers (PDMS-urethanes). Two commercially available examples, PurSil 35 (denoted as P35) and Elast-Eon E2A (denoted as E2A), were evaluated for abrasion and fatigue resistance after immersion in 85 °C buffered water for up to 80 weeks. We previously reported that water exposure in these experiments resulted in a molar mass reduction, where the kinetics of the hydrolysis reaction is supported by a straight forward Arrhenius analysis over a range of accelerated temperatures (37-85 °C).

Degradability of polymers for implantable biomedical devices.

Many key components of implantable medical devices are made from polymeric materials. The functions of these materials include structural support, electrical insulation, protection of other materials from the environment of the body, and biocompatibility, as well as other things such as delivery of a therapeutic drug. In such roles, the stability and integrity of the polymer, over what can be a very long period of time, is very important.

Maximum conductivity of packed nanoparticles and their polymer composites.

Adding conductive fillers to nonconductive polymers is a common way to make soft conductive materials such as conductive adhesives. An important issue is how to achieve high volume conductivity with acceptable mechanical performance. Two questions pertaining to this issue were studied in this paper.

In vitro biostability evaluation of polyurethane composites in acidic, basic, oxidative, and neutral solutions.

New and improved properties can often be achieved by compounding two or more different but compatible materials. But, can failure possibility also be increased by such a compounding strategy? In this article, we compared the in vitro biostability of composites with that of the pure polymer. We tested three model composites in oxidative, acidic, basic, and neutral solutions.

Kinetics and time-temperature equivalence of polymer degradation.

We studied the hydrolysis kinetics of amorphous polylactide. It was found the hydrolysis rate had a slow-to-fast transition at a certain molecular weight (Mn). This transition was not correlated with the mass loss and water uptake of samples, nor the pH values of testing media.