Multifunctional flexible parylene-based intracortical microelectrodes.

Department of Biomedical Engineering, University of Michigan, MI, USA.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 02/2005; 5:5272-5. DOI: 10.1109/IEMBS.2005.1615669
Source: PubMed

ABSTRACT Delivering drugs directly to the brain tissue opens new approaches to disease treatment and improving neural interfaces. Several approaches using neural prostheses have been made to deliver drugs directly with bypassing the blood-brain barrier (BBB) [1, 2]. In this paper, we propose a new polymer-based flexible microelectrode with drug delivery capability. The probe was fabricated and tested for electrical and fluidic functionality in early stage design. In vivo chronic recording experiments succeeded in demonstrating the in vivo reliability of the probe. Successful in vivo experiments confirm the suitability of the probes as implantable chronic recording devices with robust fluid delivery function.

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    ABSTRACT: While the signal quality of recording neural electrodes is observed to degrade over time, the degradation mechanisms are complex and less easily observable. Recording microelectrodes failures are attributed to different biological factors such as tissue encapsulation, immune response, and disruption of blood-brain barrier (BBB) and non-biological factors such as strain due to micromotion, insulation delamination, corrosion, and surface roughness on the recording site (1-4). Strain due to brain micromotion is considered to be one of the important abiotic factors contributing to the failure of the neural implants. To reduce the forces exerted by the electrode on the brain, a high compliance 2D serpentine shaped electrode cable was designed, simulated, and measured using polyimide as the substrate material. Serpentine electrode cables were fabricated using MEMS microfabrication techniques, and the prototypes were subjected to load tests to experimentally measure the compliance. The compliance of the serpentine cable was numerically modeled and quantitatively measured to be up to 10 times higher than the compliance of a straight cable of same dimensions and material.
    Frontiers in Neurology 01/2013; 4:124.
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    ABSTRACT: We present here a microfabricated, multi-functional neural interface with the ability to selectively apply electrical and chemical stimuli, while simultaneously monitoring both electrical and chemical activity in the brain. Such a comprehensive approach is required to understand and treat neuropsychiatric disorders, such as major depressive disorder (MDD), and to understand the mechanisms underlying treatments, such as pharmaceutical therapies and deep brain stimulation (DBS). The polymer-based, multi-functional neural interface is capable of electrical stimulation and recording, targeted drug delivery, and electrochemical sensing. A variety of different electrode and fluidic channel arrangements are possible with this fabrication process. Preliminary testing has shown the suitability of these neural interfaces for in vivo electrical stimulation and recording, as well as in vitro chemical sensing. Testing of the in vitro drug delivery and combined in vivo functionalities this neural interface are currently underway.
    Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 07/2013; 2013:5159-5162.
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    ABSTRACT: Abstract Intracortical microprobes allow the precise monitoring of electrical and chemical signaling and are widely used in neuroscience. Microelectromechanical system (MEMS) technologies have greatly enhanced the integration of multifunctional probes by facilitating the combination of multiple recording electrodes and drug delivery channels in a single probe. Depending on the neuroscientific application, various assembly strategies are required in addition to the microprobe fabrication itself. This paper summarizes recent advances in the fabrication and assembly of micromachined silicon probes for drug delivery achieved within the EU-funded research project NeuroProbes. The described fabrication process combines a two-wafer silicon bonding process with deep reactive ion etching, wafer grinding, and thin film patterning and offers a maximum in design flexibility. By applying this process, three general comb-like microprobe designs featuring up to four 8-mm-long shafts, cross sections from 150×200 to 250×250 µm², and different electrode and fluidic channel configurations are realized. Furthermore, we discuss the development and application of different probe assemblies for acute, semichronic, and chronic applications, including comb and array assemblies, floating microprobe arrays, as well as the complete drug delivery system NeuroMedicator for small animal research.
    Biomedizinische Technik/Biomedical Engineering 10/2013; · 1.16 Impact Factor


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