Stretchable microelectrode array: Difference between revisions

Revision as of 22:22, 10 November 2024

Revision as of 22:42, 10 November 2024

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==History==

The first time the term stretchable multielectrode array (sMEA) [[File:Manually Stretching Microelectrode Array.jpg|thumb|left|Manually stretching sMEA]] Understanding how cells convert [[stimulus (physiology) | mechanical stimuli]] appeared in the literature was in a conference proceeding in 2002 from the Lawrence Livermore National Laboratory.<ref>{{cite book |doi=10.1109/MMB.2002.1002269 |chapter=Stretchable micro-electrode array &#91;for retinal prosthesis&#93; |title=2nd Annual International IEEE-EMBS Special Topic Conference on Microtechnologies in Medicine and Biology. Proceedings (Cat. No.02EX578) |date=2002 |last1=Maghribi |first1=M. |last2=Hamilton |first2=J. |last3=Polla |first3=D. |last4=Rose |first4=K. |last5=Wilson |first5=T. |last6=Krulevitch |first6=P. |pages=80–83 |isbn=0-7803-7480-0 }}</ref> This paper described the [[fabrication]] of an sMEA for a retinal [[prosthesis]], but no biological material was used, i.e., functionality to record or stimulate [[neural activity]] was not attempted. The first description of sMEAs being used to record [[neural activity]] in biological samples was in 2006 when the research group of Barclay Morrison at Columbia University and Sigurd Wagner at Princeton University reported recording of spontaneous activity in organotypic [[hippocampal]] tissue slices.<ref>{{cite book |doi=10.1109/IEMBS.2006.260933 |chapter=Stretchable microelectrode arrays a tool for discovering mechanisms of functional deficits underlying traumatic brain injury and interfacing neurons with neuroprosthetics |title=2006 International Conference of the IEEE Engineering in Medicine and Biology Society |date=2006 |last1=Yu |first1=Zhe |last2=Tsay |first2=Candice |last3=Lacour |first3=Stephanie P. |last4=Wagner |first4=Sigurd |last5=Morrison |first5=Barclay |volume=Suppl |pages=6732–6735 |pmid=17959498 |isbn=1-4244-0032-5 }}</ref> Neither the electrodes nor the tissue appears to have been stretched in these experiments. In 2008, a paper from the [[Georgia Institute of Technology]] and [[Emory University]] described the use of sMEAs in stimulating a [[explant]] of a rat [[spinal cord]].<ref>{{cite journal |last1=Meacham |first1=Kathleen W. |last2=Giuly |first2=Richard J. |last3=Guo |first3=Liang |last4=Hochman |first4=Shawn |last5=DeWeerth |first5=Stephen P. |title=A lithographically-patterned, elastic multi-electrode array for surface stimulation of the spinal cord |journal=Biomedical Microdevices |date=April 2008 |volume=10 |issue=2 |pages=259–269 |doi=10.1007/s10544-007-9132-9 |pmid=17914674 |pmc=2573864 }}</ref> The sMEA was wrapped around the spinal cord, but not stretched, and the cells were electrically stimulated but not used in recording electrophysiological activity. In 2009, another paper of the Morrison/Wagner groups described for the first time the use of an sMEA with a biological sample being stretched as well as [[electrical stimulation]] and recording of [[electrophysiological]] activity being carried out before and after stretching.<ref>{{cite journal |last1=Yu |first1=Zhe |last2=Graudejus |first2=Oliver |last3=Tsay |first3=Candice |last4=Lacour |first4=Stéphanie P. |last5=Wagner |first5=Sigurd |last6=Morrison |first6=Barclay |title=Monitoring Hippocampus Electrical Activity In Vitro on an Elastically Deformable Microelectrode Array |journal=Journal of Neurotrauma |date=July 2009 |volume=26 |issue=7 |pages=1135–1145 |doi=10.1089/neu.2008.0810 |pmid=19594385 |pmc=2848944 }}</ref> sMEAs for in vitro application are commercially available from BioMedical Sustainable Elastic Electronic Devices.{{fact|date=November 2024}}

In subsequent years, the number of research papers that describes different approaches to fabricating sMEAs and their use for [[in vitro]] and [[in vivo]] research has increased immensely.

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* '''Spacing between microelectrodes''': The spacing between microelectrodes (center-to-center) is typically larger than 300μm for sMEAs and 200 μm for glass MEAs. but can be less than 20μm in CMOS MEAs.

The reason for these differences is that sMEAs are fabricated using soft elastomeric materials such as [[PDMS]] as substrate and [[encapsulation]] which have a much higher coefficient of thermal expansion and lower Young’s Modulus than rigid MEAs that are built on glass, plastic or silicon (CMOS) substrates. These properties make it more challenging to align and bond small features. In addition, the maximum [[Strain (mechanics)|strain]] that the electrodes can tolerate decreases for narrower electrodes, which is why the electrodes leads are often wide, thus limiting the number electrodes.<ref>{{cite journal |last1=Graudejus |first1=O. |last2=Jia |first2=Zheng |last3=Li |first3=Teng |last4=Wagner |first4=S. |title=Size-dependent rupture strain of elastically stretchable metal conductors |journal=Scripta Materialia |date=June 2012 |volume=66 |issue=11 |pages=919–922 |doi=10.1016/j.scriptamat.2012.02.034 |pmid=22773917 |pmc=3388513 }}</ref> sMEAs for in vitro applications are only available commercially from BioMedical Elastic Electronic Devices.{{fact|date=November 2024}}

====Advantages====

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====Disadvantage====

The main disadvantage of sMEAs compared to rigid MEAs are related to the different technologies that are used to manufacture these devices. sMEAs have usually up to 60 electrodes with diameters of between 50μm and 100μm where rigid CMOS based MEAs{{fact|date=November 2024}} can have thousands of electrodes with diameters of 10μm. This means that sMEAs are not suitable for studying [[sub-cellular]] structures.

===In vivo stretchable MEAs===