Integration of TMR Sensors in Silicon Microneedles for Magnetic Measurements of Neurons

Abstract. Ultrasensitive magnetic field sensors envisaged for applications on biomedical imaging require the detection of low-intensity and low-frequency signals. Therefore linear magnetic sensors with enhanced sensitivity low noise levels and improved field detection at low operating frequencies are necessary. Suitable devices can be designed using magnetoresistive sensors, with room temperature operation, adjustable detected field range, CMOS compatibility and cost-effective production. The advent of spintronics set the path to the technological revolution boosted by the storage industry, in particular by the development of read heads using magnetoresistive devices. New multilayered structures were engineered to yield devices with linear output. We present a detailed study of the key factors influencing MR sensor performance (materials, geometries and layout strategies) with focus on different linearization strategies available. Furthermore strategies to improve sensor detection levels are also addressed with best reported values of ∼40 pT/ √ Hz at 30 Hz, representing a step forward the low field detection at room temperature.

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“…Some major breakthroughs have already been achieved, leading the way to portable neural activity sensing [22][23][24].…”

Section: -P1mentioning

confidence: 99%

Linearization strategies for high sensitivity magnetoresistive sensors

Silva

Leitao

Valadeiro

et al. 2015

Eur. Phys. J. Appl. Phys.

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“…To provide accessible equipment for this purpose inside the small laboratories, the spintronics can be helped. It is shown that the magnetic field of the brain of mice can be measured with MR elements [25][26][27][28]. A few measurement series were successfully carried out, for example, in-vitro actuation and recognition of magnetic field of the small slice of mice's Hippocampus located on a MR stack, as shown schematically in Figure 2 [25,29].…”

Section: Mini Reviewmentioning

confidence: 99%

“…Finally, it has to be mentioned that neural field detection was carried out with a pulse field actuation and the neurons relaxation amplitude and time were recorded [25][26][27][28][29]. Such techniques require more attention for future measurements and analyses from clinical points of view.…”

Section: Mini Reviewmentioning

confidence: 99%

Spintronics as a Neurotechnique

Mohseni¹

2015

JNMR

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Understanding the brain as a complex system is the current problem and challenge in multi-disciplinary science. To this end, finding new techniques to touch many un-known mechanisms inside the brain via observations and measurements are circumventing different neurotechniques today. One possible technique toward this purpose is based on sensing the magnetic field of neurons with spintronics devices, given that neurons are sources of magnetic fields. Additionally, correlation of individual neuron's magnetic field to the magnetic field of many neurons is not very clear. In this paper, we shortly review the application of spintronics as one branch of nanotechnology for neural magnetic field detection. The major spintronics elements that can be implemented for the neural field detection nominated the magneto resistance (MR) will be introduced. Electronic properties of such a device will be reviewed and its technical issues such as magnetic coupling between layers and their materials and thickness dependence toward achieving high sensitive elements will be shortly addressed. Such elements can be implemented to measure the magnetic field of small neuron population down to individual neuron. Potential applications of spintronics elements for neural magnetic field detection toward the completion of the neuroscience will be addressed.

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“…Neural probes like multi-electrode arrays (MEAs) and micro-devices are used for recording the activity of large neuronal assemblies (Wise 2007;Chang-Hsiao et al 2010;Amaral et al 2013) and to stimulate nerve cells for various clinical applications (Wise 2007). MEAs are produced for various applications in electrophysiology, chemical sensing, neurostimulation and optogenetics (Du et al 2011;Tye and Deisseroth 2012;Alivisatos et al 2013;Opris et al 2013).…”

Section: Nanotechnologymentioning

confidence: 99%

“…MEAs add real-time versatility to long-term recording of neurophysiological activity in the extra-cellular micro-environment along with biochemical fluctuations, while being minimally invasive (Wise 2007;Chang-Hsiao et al 2010;Amaral et al 2013). The micro-anatomy of a neural ensemble and its synaptic interconnectivity, excitability, and plasticity may be better monitored by MEAs.…”

Section: Multi-electrode Array Technologies For Brain Circuitsmentioning

confidence: 99%

Uncovering Cortical Modularity by Nanotechnology

Enăchescu

Vidu

Opriş

2015

Recent Advances on the Modular Organization of the Cortex

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Cortical modularity and nanotechnology might look like a strange pair of concepts taken together, but nevertheless they seem very much suited for each other. Indeed, cortical modularity is a fundamental microanatomic feature of the brain while nanotechnology with its nanometric precision provides nanoscale structures, namely nanowires and carbon nanotubes capable of interacting with the brain at the genetic, molecular, and microcircuit level. Research in neuroscience is essentially a combination of many interdisciplinary sciences where nanoscience and nanotechnology plays a pivotal role. In this chapter we examine carbon nanotubes (CNTs) and nanowires (NWs), and their potential to uncover the function of cortical microcircuits, as well as novel applications for diagnosis and treatment of brain diseases. For example, the simultaneous recording from cortical minicolumns with multi-electrode arrays (MEAs) consisting of CNTs or NWs is emerging for developing cognitive prostheses for a broad range of neurological and psychiatric dysfunctions.

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Integration of TMR Sensors in Silicon Microneedles for Magnetic Measurements of Neurons

Cited by 35 publications

References 13 publications

Linearization strategies for high sensitivity magnetoresistive sensors

Linearization strategies for high sensitivity magnetoresistive sensors

Spintronics as a Neurotechnique

Uncovering Cortical Modularity by Nanotechnology

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