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The 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 are currently lacking 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 comprehensive information on the evolving heart status. 

Direct laser scribing of molybdenum dioxide is enabled on soft elastomers to build Janus wearables and reshapable devices. 

Repairing large tissue defects often represents a great challenge in clinics due to issues regarding lack of donors, mismatched sizes, irregular shapes, and immune rejection. 3D printed scaffolds are attractive for growing cells and producing tissue constructs because of the intricate control over pore size, porosity, and geometric shape, but the lack of biomimetic surface nanotopography and limited biomolecule presenting capacity render them less efficacious in regulating cell responses. Herein, a facile method for coating 3D printed scaffolds with electrospun nanofiber segments is reported. The surface morphology of modified 3D scaffolds changes dramatically, displaying a biomimetic nanofibrous structure, while the bulk mechanical property, pore size, and porosity are not significantly compromised. The short nanofibers‐decorated 3D printed scaffolds significantly promote adhesion and proliferation of pre‐osteoblasts and bone marrow mesenchymal stem cells (BMSCs). Further immobilization of bone morphogenetic protein‐2 mimicking peptides to nanofiber segments‐decorated 3D printed scaffolds show enhanced mRNA expressions of osteogenic markers Runx2, Alp, OCN, and BSP in BMSCs, indicating the enhancement of BMSCs osteogenic differentiation. Together, the combination of 3D printing and electrospinning is a promising approach to greatly expand the functions of 3D printed scaffolds and enhance the efficacy of 3D printed scaffolds for tissue engineering.

 

A new approach is described for fabricating 3D poly(ε‐caprolactone) (PCL)/gelatin (1:1) nanofiber aerogels with patterned macrochannels and anisotropic microchannels by freeze‐casting with 3D‐printed sacrificial templates. Single layer or multiple layers of macrochannels are formed through an inverse replica of 3D‐printed templates. Aligned microchannels formed by partially anisotropic freezing act as interconnected pores between templated macrochannels. The resulting macro‐/microchannels within nanofiber aerogels significantly increase preosteoblast infiltration in vitro. The conjugation of vascular endothelial growth factor (VEGF)‐mimicking QK peptide to PCL/gelatin/gelatin methacryloyl (1:0.5:0.5) nanofiber aerogels with patterned macrochannels promotes the formation of a microvascular network of seeded human microvascular endothelial cells. Moreover, nanofiber aerogels with patterned macrochannels and anisotropic microchannels show significantly enhanced cellular infiltration rates and host tissue integration compared to aerogels without macrochannels following subcutaneous implantation in rats. Taken together, this novel class of nanofiber aerogels holds great potential in biomedical applications including tissue repair and regeneration, wound healing, and 3D tissue/disease modeling.

 

Mechanically guided, 3D assembly has attracted broad interests, owing to its compatibility with planar fabrication techniques and applicability to a diversity of geometries and length scales. Its further development requires the capability of on‐demand reversible shape reconfigurations, desirable for many emerging applications (e.g., responsive metamaterials, soft robotics). Here, the design, fabrication, and modeling of soft electrothermal actuators based on laser‐induced graphene (LIG) are reported and their applications in mechanically guided 3D assembly and human–soft actuators interaction are explored. Over 20 complex 3D architectures are fabricated, including reconfigurable structures that can reshape among three distinct geometries. Also, the structures capable of maintaining 3D shapes at room temperature without the need for any actuation are realized by fabricating LIG actuators at an elevated temperature. Finite element analysis can quantitatively capture key aspects that govern electrothermally controlled shape transformations, thereby providing a reliable tool for rapid design optimization. Furthermore, their applications are explored in human–soft actuators interaction, including elastic metamaterials with human gesture‐controlled bandgap behaviors and soft robotic fingers which can measure electrocardiogram from humans in an on‐demand fashion. Other demonstrations include artificial muscles, which can lift masses that are about 110 times of their weights and biomimetic frog tongues which can prey insects.