The magnitude of brain tissue micromotion relative to stationary implants and its impact on the viability function surrounding due mechanical stresses is poorly understood. central goal this study characterize surface in somatosensory cortex against cylindrical implants. We used a differential variable reluctance transducer (DVRT) adult rats (n = 6) monitor normal surface. Experiments were performed both presence absence dura mater displacement measurements made at three different locations...

Objective. Brain tissue undergoes dramatic molecular and cellular remodeling at the implant–tissue interface that evolves over a period of weeks after implantation. The biomechanical impact such on remains unknown. In this study, we aim to assess changes in mechanical properties brain–electrode chronic implantation microelectrode. Approach. Microelectrodes were implanted rodent cortex depth 1 mm for different durations—1 day (n = 4), 10–14 days 4 4) 6–8 7). After initial duration...

Objective. The objective of this research is to characterize the mechanical interactions (1) soft, compliant and (2) non-compliant implants with surrounding brain tissue in a rodent brain. Understanding such will enable engineering novel materials that improve stability reliability implants. Approach. Acute force measurements were made using load cell n = 3 live rats, each 4 craniotomies. Using an indentation method, was tested for changes established protocols. A total non-compliant, bare...

Abstract Conventional electrodes and associated positioning systems for intracellular recording from single neurons in vitro vivo are large bulky, which has largely limited their scalability. Further, acquiring successful recordings is very tedious, requiring a high degree of skill not readily achieved typical laboratory. We report here robotic, MEMS-based system to overcome the above limitations with form factor, scalability, highly skilled tedious manual operations required recordings....

The objective of this study was to test the hypothesis that neural implants with reduced cross-sectional areas will have less glial scarring associated implantation injury in long-term experiments. In study, we implanted nine adult rats two different 12 µm (n = 6), and 25 6) diameters (cross-sectional 68 µm2, 232 µm2 respectively) expression fibrilliary acidic protein (GFAP) assessed after 2 weeks 4 implantation. order facilitate implantation, diameter were coated poly-glycolic acid (PGA), a...

Burst suppression patterns in electroencephalograms (EEG's) have been observed a variety of situations including recovery subject from traumatic brain injury. They are associated with grave prognostic outcomes neonates. We study power spectral parameters and bispectral the EEG at baseline, during early an asphyxic arrest (EEG burst patterns) late after evolves into more continuous activity. The bicoherence indexes, which indicate degree phase coupling between two frequency components signal,...

Microelectrode arrays used for monitoring single and multineuronal action potentials often fail to record from the same population of neurons over a period time likely due micromotion away microelectrode, gliosis around recording site also brain movement behavior. We report here novel electrostatic microactuated microelectrodes that will enable precise repositioning within tissue. Electrostatic comb-drive microactuators associated are fabricated using SUMMiT V/spl trade/ (Sandia's...

Arrays of microelectrodes used for monitoring single- and multi-neuronal action potentials often fail to record from the same population neurons over a period time several technical biological reasons. We report here novel Neural Probe chip with 3-channel microactuated microelectrode array that will enable precise repositioning individual within brain tissue after implantation. Thermal microactuators associated in are microfabricated using Sandia's Ultraplanar Multi-level MEMS Technology...

The football helmet is used to help mitigate the occurrence of impact-related traumatic (TBI) and minor brain injuries (mTBI) in game American football. While current design methodology may be adequate for reducing linear acceleration head minimizing TBI, it however has had less effect mTBI. objectives this study are (a) develop validate a coupled finite element (FE) model human body, (b) assess responses different regions two impact conditions - frontal oblique crown conditions. FE was...

Abstract INTRODUCTION: Cerebral anoxia is fundamental to morbidity and mortality after resuscitation from cardiac arrest. With no proven effective primary therapy for post‐anoxic brain injury, the goal of neurologic care are supportive, provide prognosis prevention further complications. multifaceted approach using electroencephalography (EEG), somatosensory evoked potentials (SEP), multiunit recordings, behavioral histologic assessment, we investigated hyperacute recovery period arrest in a...

Transfection of siRNA and plasmid nucleic molecules to animal, microbial plant cell cultures is a critical process in various research areas, including drug discovery, functional genomics basic life science research. Till recent times, transfection these exogenous have been global nature i.e. targeting all the cells culture lacking capability spatially confine small populations within single culture. However, emerging areas like high-throughput screening large molecule libraries, there need...

We report here a novel approach called MEMS microflex interconnect (MMFI) technology for packaging new generation of Bio-MEMS devices that involve movable microelectrodes implanted in brain tissue. MMFI addresses the need (i) operating space parts and (ii) flexible interconnects mechanical isolation. fabricated thin polyimide substrate with embedded bond-pads, vias, conducting traces backside dry etch, so can act as thin-film cap package. A double gold stud bump rivet bonding mechanism was...

Repositioning microelectrodes post-implantation is emerging as a promising approach to achieve long-term reliability in single neuronal recordings. The main goal of this study was (a) assess glial reaction response movement the brain and (b) determine an optimal window time when within would result minimal reaction. Eleven Sprague-Dawley rats were implanted with two each that could be moved vivo post-implantation. Three cohorts investigated: (1) microelectrode at day 2 (n = 4 animals), (2)...

This paper presents a new actuation scheme for in-plane bidirectional translation of polysilicon microelectrodes. The Chevron-peg uses micro-electromechanical systems (MEMS) based electrothermal microactuators to move microelectrodes brain implant applications. design changes were motivated by specific needs identified the in vivo testing an earlier generation MEMS that actuated Chevron-latch type mechanism. mechanism discussed here show improved performance following key areas: higher force...

The objective of this study was to design and evaluate a methodology for estimating the depth anesthesia in canine model that integrates electroencephalogram (EEG)-derived autoregressive (AR) parameters, hemodynamic alveolar anesthetic concentration. Using parametric approach, two separate AR models order ten were derived EEG, one from third-order cumulant sequence other autocorrelation lags EEG. Since dose versus curve is highly nonlinear, neural network (NN) chosen as basic estimator...

A piezoelectric immunosensor for sensing the low molecular weight neurotransmitter γ-aminobutyric acid (GABA), one of two major inhibitory neurotransmitters in central nervous system, is described. The interface consists a dextran layer covalently attached to self-assembled monolayer thiolamine compound on surface gold electrodes crystals. further modified with GABA molecules act as biosensing layer. affinity binding monoclonal anti-GABA antibody crystals studied real time without any...

The aim of this study was to carefully assess the level modulation in electrical excitability single neurons with application high frequency ultrasound. High tone bursts ultrasound have been shown dramatically increase spike primary hippocampal culture. In addition, these ultrasonic also induce silent or still developing fire. Results indicate that is largely mediated by mechanical effects and not thermal Future studies on culture models exposed varying protocols may provide insight into...

Implantable microelectrodes that are currently used to monitor neuronal activity in the brain vivo have serious limitations both acute and chronic experiments. Movable adapt their position maximize quality of recording been suggested tried as a potential solution overcome challenges with current fixed implantable microelectrodes. While results so far suggest movable improve stability recordings from vivo, bulky nature technologies involved making these limits throughput (number neurons can...

The viability of a new biophotonic alternative to conventional prescription‐drug‐based treatments is explored for inflammatory disease and mental health disorders using non‐invasive drug‐free optogenetics‐based therapy treat patients by optically stimulating selected afferent branches the auricular vagus nerve transcutaneously via outer ear high‐resolution, addressable array organic light emitting diodes (OLED) manufactured on flexible plastic substrate. Preliminary analysis optical...