Multifunctional Materials Strategies for Enhanced Safety of Wireless, Skin-Interfaced Bioelectronic Devices

Abstract

Many recently developed classes of wireless, skin-interfaced bioelectronic devices rely on conventional thermoset silicone elastomer materials, such as poly(dimethylsiloxane) (PDMS), as soft encapsulating structures around collections of electronic components, radio frequency antennas and, commonly, rechargeable batteries. In optimized layouts and device designs, these materials provide attractive features, most prominently in their gentle, noninvasive interfaces to the skin even at regions of high curvature and large natural deformations. Past work, however, overlooks opportunities for developing variants of these materials for multimodal means to enhance the safety of the devices against failure modes that range from mechanical damage to thermal runaway. This paper presents a self-healing PDMS dynamic covalent matrix embedded with chemistries that provide thermochromism, mechanochromism, strain-adaptive stiffening, and thermal insulation, as a collection of attributes relevant to safety. Demonstrations of this materials system and associated encapsulation strategy involve a wireless, skin-interfaced device that captures mechanoacoustic signatures of health status. The concepts introduced here can apply immediately to many other related bioelectronic devices.

3-Pyridylvinyl benzoxazole-derived multifunctional organic materials—from solid-state photoreactivity to photophysical and electrochemical properties

“…The crystal structures were determined and data were collected on a Bruker D8 Quest single-crystal X-ray diffractometer (SCXRD). 1 H and 13 C NMR spectra were recorded on a 500-MHz Bruker spectrometer with TMS as an internal reference in both CDCl 3 and DMSO-d 6 solution. FT-IR spectra were collected using an IR Tracer 100 Shimadzu instrument in ATR-IR mode.…”

“…[39][40][41][42] Single crystals of the dimer, i.e., 1,3-bis(benzoxazole)-2,4-bis(3-pyridyl)cyclobutane (PBOCB) were obtained by slowly evaporating a solution in methanol. 1 H NMR (500 MHz, CDCl 3 ), d H : 8.54 (s, 2H), 8.26 (d, J = 5 Hz, 2H), 7.58-7.54 (m, 4H), 7.28-7.26 (m, 2H), 7.20-7.14 (m, 6H), 7.0 (dd, J = 8 Hz, 5 Hz, 2H), 5.01 (dd, J = 10 Hz, 7 Hz, 2H), 4.83 (dd, J = 10 Hz, 7 Hz, 2H). 13…”

“…S3 in the ESI †). Accordingly, crystals of 3-PVBO exhibited a solid-state photocycloaddition reaction, leading to formation of the dimer PBOCB, when irradiated under UV light, as identified by 1 H NMR spectroscopy (vide supra). Crystals of PBOCB were isolated by fractional crystallization, and its structure was characterized by spectroscopic means (vide supra) and elucidated by crystallographic means (vide infra).…”

“…Research on developing multifunctional materials has drawn immense interest in the past few decades as such materials can offer low cost and simplicity of manufacture as well as enhanced environmental sustainability. [1][2][3] Functional organic compounds have also been shown to offer multifaceted materials applications, just as purely inorganic, inorganic-organic hybrid, or composite materials do. [1][2][3] In combination with suitable donor (D) and acceptor (A) groups, different classes of organic compounds (e.g., D-p, A-p, D-p-D, A-p-A, D-p-A, etc.)…”

“…[1][2][3] Functional organic compounds have also been shown to offer multifaceted materials applications, just as purely inorganic, inorganic-organic hybrid, or composite materials do. [1][2][3] In combination with suitable donor (D) and acceptor (A) groups, different classes of organic compounds (e.g., D-p, A-p, D-p-D, A-p-A, D-p-A, etc.) containing a polyaromatic hydrocarbon (e.g., anthracene, pyrene, polyphenylene, etc.…”