Miniaturized probe on polymer SU-8 with array of individually addressable microelectrodes for electrochemical analysis in neural and other biological tissues

Marchoubeh, Mahsa Lotfi; Cobb, Samuel J.; Tello, Miguel Abrego; Hu, Mengjia; Jaquins-Gerstl, Andrea; Robbins, Elaine; Macpherson, Julie V.; Michael, Adrian C.; Fritsch, Ingrid

doi:10.1007/s00216-021-03327-2

Cited by 13 publications

(21 citation statements)

References 53 publications

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“…Since SU-8 is proven to be biocompatible and chemically stable, it is used as a material of microfluidics for life science applications. Recently, SU-8 has also been used for the substrate or insulation of microelectrode arrays [42][43][44]. Even though the biocompatibility of SU-8 is proven, a subtle change of the culture environment can dramatically affect the viability of cultured neurons and the long-term stability cannot be guaranteed in the harsh culture environment.…”

Section: Discussionmentioning

confidence: 99%

Fabrication of Planar Microelectrode Array Using Laser-Patterned ITO and SU-8

Jeong

Hwang

Min³

et al. 2021

Micromachines

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For several decades, microelectrode array (MEA) has been a powerful tool for in vitro neural electrophysiology because it provides a unique approach for monitoring the activity of a number of neurons over time. Due to the various applications of MEAs with different types of cells and tissues, there is an increasing need to customize the electrode designs. However, the fabrication of conventional MEAs requires several microfabrication procedures of deposition, etching, and photolithography. In this study, we proposed a simple fabrication method with a laser-patterned indium tin oxide (ITO) conductor and SU-8 photoresist insulation. Unlike in a conventional metal patterning process, only the outlines of ITO conductors are ablated by laser without removing background ITO. Insulation is achieved simply via SU-8 photolithography. The electrode sites are electroplated with iridium oxide (IrOX) to improve the electrochemical properties. The fabricated MEAs are electrochemically characterized and the stability of insulation is also confirmed by impedance monitoring for three weeks. Dissociated neurons of rat hippocampi are cultured on MEAs to verify the biocompatibility and the capacity for extracellular neural recording. The electrochemical and electrophysiological results with the fabricated MEAs are similar to those from conventional SiNX-insulated MEAs. Therefore, the proposed MEA with laser-patterned ITO and SU-8 is cost-effective and equivalently feasible compared with the conventional MEAs fabricated using thin-film microfabrication techniques.

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Section: Discussionmentioning

confidence: 99%

Fabrication of Planar Microelectrode Array Using Laser-Patterned ITO and SU-8

Jeong

Hwang

Min³

et al. 2021

Micromachines

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“…While flexible probes can move with the tissue during micromotions and improve device-tissue integration (20,(28)(29)(30), insertion of these flexible devices into the tissue becomes more difficult (31)(32)(33) . Flexible materials often are too soft to penetrate tissue on their own, so shuttle systems are common to aid insertion (20,27,34,35).…”

Section: Optimization Of the Spinal Cord Insertion Proceduresmentioning

confidence: 99%

Real-time in vivo thoracic spinal glutamate sensing reveals spinal hyperactivity during myocardial ischemia

Salavatian

Robbins

Kuwabara

et al. 2023

Preprint

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Myocardial ischemia-reperfusion (IR)-induced ventricular arrhythmias are the leading cause of death. The spinal cord neural network plays a critical role in triggering ventricular arrhythmias. Assessing the spinal neural signaling during IR is essential to develop neuromodulation therapies that target the spinal neural network. In this study, we have developed a flexible glutamate-sensing multielectrode array to evaluate the spinal cord network activity in a large animal model using amperometry. IR injury was induced by ligating the left anterior descending artery for 1 hour and releasing the ligation suture. A glutamate sensing probe was inserted into the dorsal horn of the thoracic spinal cord at the T2-T3 level which processes the neural information that is generated by the cardiac sensory neurons and provides sympathoexcitatory feedback to the heart. Using the glutamate sensing probe, we have shown that the spinal neural network is excited during the IR, particularly after 15 mins of the onset of the ischemia and it is elevated even during the reperfusion. The glutamate release signal is correlated with the reduction in the cardiac myocyte activation recovery interval which is a surrogate for the action potential duration, as well as dispersion of the repolarization which is a marker for increased risk of arrhythmias. This study illustrates a new technique that is capable of measuring the spinal glutamate at different levels of the spinal cord as a surrogate for the spinal neural network activity during cardiac interventions that engage the cardio-spinal neural pathway.

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“…SU-8 as a versatile photoresist has allowed for innovative designs in neural probe devices. Marchoubeh et al reported an SU-8-based neural probe for electrochemical analysis in neural regions [69]. The fabricated device was shown to detect potassium and dopamine in potassium chloride electrolyte and artificial cerebral spinal fluid, respectively.…”

Section: Su-8 Neural Probesmentioning

confidence: 99%

Biocompatibility of SU-8 and Its Biomedical Device Applications

Chen

Lee

2021

Micromachines

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SU-8 is an epoxy-based, negative-tone photoresist that has been extensively utilized to fabricate myriads of devices including biomedical devices in the recent years. This paper first reviews the biocompatibility of SU-8 for in vitro and in vivo applications. Surface modification techniques as well as various biomedical applications based on SU-8 are also discussed. Although SU-8 might not be completely biocompatible, existing surface modification techniques, such as O2 plasma treatment or grafting of biocompatible polymers, might be sufficient to minimize biofouling caused by SU-8. As a result, a great deal of effort has been directed to the development of SU-8-based functional devices for biomedical applications. This review includes biomedical applications such as platforms for cell culture and cell encapsulation, immunosensing, neural probes, and implantable pressure sensors. Proper treatments of SU-8 and slight modification of surfaces have enabled the SU-8 as one of the unique choices of materials in the fabrication of biomedical devices. Due to the versatility of SU-8 and comparative advantages in terms of improved Young’s modulus and yield strength, we believe that SU-8-based biomedical devices would gain wider proliferation among the biomedical community in the future.

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Miniaturized probe on polymer SU-8 with array of individually addressable microelectrodes for electrochemical analysis in neural and other biological tissues

Cited by 13 publications

References 53 publications

Fabrication of Planar Microelectrode Array Using Laser-Patterned ITO and SU-8

Fabrication of Planar Microelectrode Array Using Laser-Patterned ITO and SU-8

Real-time in vivo thoracic spinal glutamate sensing reveals spinal hyperactivity during myocardial ischemia

Biocompatibility of SU-8 and Its Biomedical Device Applications

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