Conductive elastomer composites for fully polymeric, flexible bioelectronics

Cuttaz, Estelle A.; Goding, Josef; Vallejo-Giraldo, Catalina; Aregueta‐Robles, Ulises A.; Lovell, Nigel H.; Ghezzi, Diego; Green, Rylie A.

doi:10.1039/c8bm01235k

Cited by 70 publications

(73 citation statements)

References 64 publications

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“…Over the past decade, there has been a renewed interest in the use of thin films and other “soft” electrode materials to create high‐channel, yet low geometric area electrodes with a Young's modulus closer to native tissue to minimize initial surgical trauma and the chronic immune response . These electrode development strategies include the use of PDMS substrates with conductive traces and electrode contacts to develop stretchable multicontact electrode arrays for stimulation and recording . Additionally, shape memory polymer (SMP) or other “shuttles” have been used to create a stiff carrier to facilitate implantation of electrodes into the brain, yet leave a soft electrode chronically to minimize the immune response of tissue .…”

Section: Resultsmentioning

confidence: 99%

An Injectable Neural Stimulation Electrode Made from an In‐Body Curing Polymer/Metal Composite

Trevathan

Baumgart

Nicolai

et al. 2019

Adv Healthcare Materials

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Implanted neural stimulation and recording devices hold vast potential to treat a variety of neurological conditions, but the invasiveness, complexity, and cost of the implantation procedure greatly reduce access to an otherwise promising therapeutic approach. To address this need, a novel electrode that begins as an uncured, flowable prepolymer that can be injected around a neuroanatomical target to minimize surgical manipulation is developed. Referred to as the Injectrode, the electrode conforms to target structures forming an electrically conductive interface which is orders of magnitude less stiff than conventional neuromodulation electrodes. To validate the Injectrode, detailed electrochemical and microscopy characterization of its material properties is performed and the feasibility of using it to stimulate the nervous system electrically in rats and swine is validated. The silicone-metal-particle composite performs very similarly to pure wire of the same metal (silver) in all measures, including exhibiting a favorable cathodic charge storage capacity (CSC C ) and charge injection limits compared to the clinical LivaNova stimulation electrode and silver wire electrodes. By virtue of its simplicity, the Injectrode has the potential to be less invasive, more robust, and more cost-effective than traditional electrode designs, which could increase the adoption of neuromodulation therapies for existing and new indications.

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Section: Resultsmentioning

confidence: 99%

An Injectable Neural Stimulation Electrode Made from an In‐Body Curing Polymer/Metal Composite

Trevathan

Baumgart

Nicolai

et al. 2019

Adv Healthcare Materials

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“…A pair of silver-silver chloride electrodes spaced 2 mm apart are used in the oil partition for recording through a differential low noise amplifier (SR560, Stanford Research Systems). In the saline partition an 800 µm inner diameter conformal nerve cuff (Cortec) and an 800 µm inner diameter custom-made conductive elastomer nerve cuff[36] were implanted for stimulation and block of the nerve respectively. For current return a large 2 cm side square sheet of platinum is used and connected to stimulator ground.…”

Section: Acute Ex-vivo Experimentation Resultsmentioning

confidence: 99%

A Block-Capable and Module-Extendable 4-Channel Stimulator for Acute Neurophysiology

Rapeaux

Constandinou

2020

Preprint

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1Objective: This paper describes the design, testing and use of a novel multichannel 2 block-capable stimulator for acute neurophysiology experiments to study highly 3 selective neural interfacing techniques. This paper demonstrates the stimulator's 4 ability to excite and inhibit nerve activity in the rat sciatic nerve model concurrently 5 using monophasic and biphasic nerve stimulation as well as high-frequency alternating 6 current (HFAC). 7 Approach: The proposed stimulator uses a Howland Current Pump circuit as 8 the main analogue stimulator element. 4 current output channels with a common 9 return path were implemented on printed circuit board using Commercial Off-The-10 Shelf components. Programmable operation is carried out by an ARM Cortex-M4 11 Microcontroller on the Freescale freedom development platform (K64F). 12 Main Results: This stimulator design achieves ±10 mA of output current with 13 ±15 V of compliance and less than 6 µA of resolution using a quad-channel 12-bit 14 external DAC, for four independently driven channels. This allows the stimulator 15 to carry out both excitatory and inhibitory (HFAC block) stimulation. DC Output 16 impedance is above 1 MΩ. Overall cost is less than USD 450 or GBP 350 and device 17 size is approximately 9 cm × 6 cm × 5 cm. 18 Significance: Experimental neurophysiology often requires significant investment 19 in bulky equipment for specific stimulation requirements, especially when using HFAC 20 block. Different stimulators have limited means of communicating with each other, 21 making protocols more complicated. This device provides an effective solution for 22 multi-channel stimulation and block of nerves, enabling studies on selective neural 23 interfacing in acute scenarios with an affordable, portable and space-saving design for 24 the laboratory. The stimulator can be further upgraded with additional modules to 25 extend functionality while maintaining straightforward programming and integration 26 of functions with one controller.

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“…Pure conjugated polymer films can be brittle, tearing or cracking under strain. [ 26 ] Improving the mechanical properties of conjugated polymer systems has focused on developing either intrinsically stretchable polymers, [ 213–215 ] composites, [ 43,216–218 ] or conjugated polymer hydrogels. [ 39,219 ] Patterning materials with designs that compensate for motion are another approach, as developed for flexible thin film metal electrodes.…”

Section: Methodsmentioning

confidence: 99%

Organic Bioelectronics: Using Highly Conjugated Polymers to Interface with Biomolecules, Cells, and Tissues in the Human Body

Higgins

Fiego

Patrick

et al. 2020

Adv Materials Technologies

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Conjugated polymers exhibit interesting material and optoelectronic properties that make them well‐suited to the development of biointerfaces. Their biologically relevant mechanical characteristics, ability to be chemically modified, and mixed electronic and ionic charge transport are captured within the diverse field of organic bioelectronics. Conjugated polymers are used in a wide range of device architectures, and cell and tissue scaffolds. These devices enable biosensing of many biomolecules, such as metabolites, nucleic acids, and more. Devices can be used to both stimulate and sense the behavior of cells and tissues. Similarly, tissue interfaces permit interaction with complex organs, aiding both fundamental biological understanding and providing new opportunities for stimulating regenerative behaviors and bioelectronic based therapeutics. Applications of these materials are broad, and much continues to be uncovered about their fundamental properties. This report covers the current understanding of the fundamentals of conjugated polymer biointerfaces and their interactions with biomolecules, cells, and tissues in the human body. An overview of current materials and devices is presented, along with highlighted major in vivo and in vitro applications. Finally, open research questions and opportunities are discussed.

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Conductive elastomer composites for fully polymeric, flexible bioelectronics

Abstract: Soft, flexible and stretchable conductive elastomers made of polyurethane and PEDOT:PSS blends were fabricated into fully polymeric implantable bioelectrode arrays.

Cited by 70 publications

References 64 publications

An Injectable Neural Stimulation Electrode Made from an In‐Body Curing Polymer/Metal Composite

An Injectable Neural Stimulation Electrode Made from an In‐Body Curing Polymer/Metal Composite

A Block-Capable and Module-Extendable 4-Channel Stimulator for Acute Neurophysiology

Organic Bioelectronics: Using Highly Conjugated Polymers to Interface with Biomolecules, Cells, and Tissues in the Human Body

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