Skin‐Inspired Porous Mesh Bioelectronics with Built‐In Multifunctionality for Concurrently Monitoring Heart Electrical and Mechanical Functions

Abstract

Skin exhibits nonlinear mechanics, which is initially soft and stiffens rapidly as being stretched to prevent large deformation‐induced injuries. Developing skin‐interfaced bioelectronics with skin‐inspired nonlinear mechanical behavior, together with multiple other desired features (breathable, antibacterial, and sticky), is desirable yet challenging. Herein, this study reports the design, fabrication, and biomedical application of porous mesh bioelectronics that can simultaneously achieve these features. On the one hand, porous serpentine meshes of polyimide (PI) are designed and fabricated under the guidance of theoretical simulations to provide skin‐like nonlinear mechanics and high breathability. On the other hand, ultrasoft, sticky, and antibacterial polydimethylsiloxane (PDMS) is developed through epsilon polylysine (ε‐PL) modifications, which currently lacks in the field. Here, ε‐PL‐modified PDMS is spray‐coated on PI meshes to form the core–shell structures without blocking their pores to offer ultrasoft, sticky, and antibacterial skin interfaces. And rationally designed porous hybrid meshes can not only retain skin‐like nonlinear mechanical properties but also enable the integration of both soft and hard bioelectronic components for various healthcare applications. As the exemplar example, this study integrates soft silver nanowires (AgNWs) based electrophysiological sensors and rigid commercial accelerometers on multifunctional porous meshes for concurrently monitoring heart electrical and mechanical functions to provide the comprehensive information of the evolving heart status.

Recent Advances in Stretchable and Permeable Electrodes for Epidermal Electronics

“…Structural engineering strategies such as wrinkle, wavy, serpentine, kirigami, mesh shapes, knitted design have been extensively applied to enable or enhance the stretchability of permeable electrodes. [107][108][109][110][111][112][113] As a typical example, a strain-insensitive and permeable conductor with a wrinkled structure was developed by sputtering gold on shrinkable electrospun fluorine rubber fiber mats. [108] This approach used the pre-stretching effect of the fibers during electrospinning that caused their area shrinkage by 35-40% after releasing from the substrate.…”

“…PI meshes interfaced with the skin (Figure 11d). [111] This bimodal system records both ECG and SCG signals simultaneously (Figure 11e,f), providing vital information about the evolving condition of the heart.…”

“…(d-f) Reproduced with permission. [111] Copyright 2023, John Wiley & Sons, Ltd. the skin. [18,21,[59][60][61][62][63] Xu et al created a permeable electrode in a trilayer architecture consisting of an active Au layer, a hydrophobic TPU nanofiber mat, and a hydrophilic cellulose nanofiber mat (see Figure 12a,b).…”

“…f) ECG (top) and SCG (bottom) measured simultaneously using porous mesh bioelectronics. (d-f) Reproduced with permission [111]. Copyright 2023, John Wiley & Sons, Ltd.…”

Structural Engineering in Piezoresistive Micropressure Sensors: A Focused Review

“…Hybrid integration is expedient for realizing device flexibility, in which the MEMS sensor can be integrated onto the flexible substrate to realize macro flexibility. For example, a hybrid sensor system for concurrently monitoring heart electrical and mechanical functions was reported [ 109 ]. A solid accelerometer is adhered onto the polymer substrate, and the stretchable serpentine metal wires on the substrate guarantee electrical connection when the whole system is compliantly attached onto the largely curved surface for specific measuring tasks.…”