A Conformal, Bio-Interfaced Class of Silicon Electronics for Mapping Cardiac Electrophysiology

Abstract

The sophistication and resolution of current implantable medical devices are limited by the need connect each sensor separately to data acquisition systems. The ability of these devices to sample and modulate tissues is further limited by the rigid, planar nature of the electronics and the electrode-tissue interface. Here, we report the development of a class of mechanically flexible silicon electronics for measuring signals in an intimate, conformal integrated mode on the dynamic, three dimensional surfaces of soft tissues in the human body. We illustrate this technology in sensor systems composed of 2016 silicon nanomembrane transistors configured to record electrical activity directly from the curved, wet surface of a beating heart in vivo. The devices sample with simultaneous sub-millimeter and sub-millisecond resolution through 288 amplified and multiplexed channels. We use these systems to map the spread of spontaneous and paced ventricular depolarization in real time, at high resolution, on the epicardial surface in a porcine animal model. This clinical-scale demonstration represents one example of many possible uses of this technology in minimally invasive medical devices.[Conformal electronics and sensors intimately integrated with living tissues enable a new generation of implantable devices capable of addressing important problems in human health.]

In‐Plane Deformation Mechanics for Highly Stretchable Electronics

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Stretchable electronics represents a relatively recent class of technology [1,2] of interest partly due to its potential for applications in sensory robotic skins, [3,4] conformal photovoltaic modules, [5,6] wearable communication devices, [7,8] skin-mounted monitors of physiological health, [9][10][11] advanced, soft surgical and clinical diagnostic tools, [11,12] and bioinspired digital cameras. [13,14] A key challenge in each of these systems is in the development of strategies in mechanics that simultaneously allow large levels of elastic stretchability and high areal coverages of active devices built with materials that are themselves not stretchable (e.g., conventional metals) and are, in some cases, highly brittle (e.g., inorganic semiconductors).

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Cephalopod-inspired design of electro-mechano-chemically responsive elastomers for on-demand fluorescent patterning

“…The activation of EMCR elastomer and fluorescent patterning are reversible and repeatable over multiple cycles, in contrast to the irreversible plastic deformation or fracture required for activating most existing mechanoresponsive polymers 21,[26][27][28][29][30][31][32][33][34] . By integrating diverse fluorescent patterns, remote control by voltages and reversibility over multiple cycles, the new cephalopod-inspired EMCR elastomers open promising avenues for creating flexible devices that combine deformation, colorimetric and fluorescent response with topological and chemical changes that might eventually be useful in a variety of applications in soft/wet environments, including flexible displays [3][4][5][6][7][8][9]11 , optoelectronics 1,8,9 , biomedical luminescent devices 2,4 and dynamic camouflage coatings 10,17 .…”

“…The selection of chromatophores to be activated is usually controlled by the cephalopod's nervous system in response to environmental stimuli. This natural display strategy, if successfully implemented in engineering devices, would greatly benefit and advance various fields such as flexible electronics, photonics, dynamic camouflage and biomedical luminescent devices [1][2][3][4][5][6][7][8][9][10] . Despite its potential, both the development of new materials for chromatophores and the design of remote-control mechanisms for chromatophore devices are challenging tasks in materials science and technology 17,19 .…”

“…S oft material systems that are flexible, remotely controllable and capable of emitting fluorescence and light are playing critical roles in nontraditional displays for applications as diverse as stretchable electronics, foldable lighting devices, flexible and biocompatible luminescent recourses for clinical therapy, and dynamic camouflage [1][2][3][4][5][6][7][8][9][10] . To design these responsive soft material systems, various strategies have been exploited, such as embedding rigid light-emitting diodes into elastomeric substrates [3][4][5][6][7] , employing stretchable electro-luminescent polymers 1,8,9,11 and designing microfluidic networks filled with controlled pigment fluids 10,[12][13][14][15] .…”

Injectable electronics as a modern day ‘ship in a bottle’

“…2 However, one key challenge in this field is designing devices that are minimally invasive, with researchers constantly pushing to overcome the challenges associated with incorporating hard planar semiconductors with soft pliable biological tissues. 3 Among these concerns, flexibility, size and cytotoxicity all play a crucial role in determining how successful a device is.…”