Ink‐based processes, which enable scalable fabrication of flexible devices based on nanomaterials, are one of the practical approaches for the production of wearable electronics. However, carbon nanotubes (CNTs), which possess great potential for flexible electronics, are facing challenges for use in inks due to their low dispersity in most solvents and suspicious cytotoxicity. Here, a stable and biocompatible CNT ink, which is stabilized by sustainable silk sericin and free from any artificial chemicals, is reported. The ink shows stability up to months, which can be attributed to the formation of sericin–CNT (SSCNT) hybrid through non‐covalent interactions. It is demonstrated that the SSCNT ink can be used for fabricating versatile circuits on textile, paper, and plastic films through various techniques. As proofs of concept, electrocardiogram electrodes, breath sensors, and electrochemical sensors for monitoring human health and activity are fabricated, demonstrating the great potential of the SSCNT ink for smart wearables.
Achieving integrated systems with comfortability and durability comparable to traditional textiles is one of the ultimate pursuits of smart wearables. This work reports a hydrophilic, breathable, biocompatible, and washable graphene-decorated electronic textile that is achieved with the assistance of silk sericin and enables the fabrication of comfortable and integrated multisensing textiles. The graphene-decorated textile is prepared by dyeing commercial textile with an aqueous graphene ink, which contains natural silk sericin-coated graphene and is free of any artificial chemicals. The conformally coated hydrophilic sericin-graphene flakes and the well-reserved knitted structure endow the textile with good conductivity, excellent hydrophilicity, biocompatibility, breathability, and flexibility, ensuring its electronic performance and wearing-comfort. Moreover, the obtained textile is washable after processed with a cross-linking agent. Based on the obtained textile, an integrated multisensing textile that can simultaneously collect and analyze myoelectrical and mechanical signals is developed, enabling the recognition and distinguishment of complex human motions. With the combined features of hydrophilicity, breathability, biocompatibility, washability, and versatility, this strategy of fabricating electronic textiles based on conventional textiles and an aqueous sericin-graphene ink provides a scalable and sustainable way to construct smart wearables.
Tumor cells respond actively to the extracellular microenvironment
via biomechanical and biochemical stimulation. Microchips provide
a flexible platform to integrate multiple factors for cell research.
In this work, we developed a subtle microfluidic chip that can generate
a controllable stiffness gradient and orthogonal chemical stimulation
to study the behaviors of glioma cells. Fibronectin-conjugated polyacrylamide
(PAA) hydrogel with a longitudinal stiffness gradient ranging from
about 1 kPa to 40 kPa is integrated within the cell culture chamber
while lateral diffusion-based chemical stimulation is generated through
circumambient microchannel arrays. The synergistic effect of epidermal
growth factor (EGF) stimulation and hydrogel stiffness gradient on
U87-MG cell migration was studied. By tracing cell migration, we discovered
that hydrogel stiffness can promote cell chemotaxis, while the EGF
gradient can accelerate cell migration. In addition, cell morphology
showed typical cell spreading, increased aspect ratios, and decreased
circularity in response to a stiffer substrate and plateaued at a
certain stiffness level. Meanwhile, the content of intracellular reactive
oxygen species (ROS) on the hydrogel soft end is enhanced by approximately
2 fold compared with that on the hydrogel stiff end. The enhancement
of substrate stiffness on cell chemotaxis is very significant for
in vitro model simulation and tissue engineering.
We report an open-space microfluidic chip with fluid walls, integrating functions of cell culture and online detection of secreted proteins controlled by the interfacial tension value.
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