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Electronic textiles (E-textiles) are made using various materials including carbon nanotubes, graphene, and graphene oxide. Among the materials here, e-textiles are fabricated with reduced graphene oxide (rGO) coating on commercial textiles. rGO-based yarns are prepared for e-textiles by a simple dip coating method with subsequent non-toxic reduction. To enhance the conductivity, the rGO yarns are coated with poly(3,4-ethylene dioxythiophene): poly(styrenesulfonic acid) (PEDOT) followed by electrochemical polymerization of polypyrrole (PPy) as the electromechanically active layer, resulting in textile actuators. The rGO-based yarn actuators are characterized in terms of both isotonic displacement and isometric developed forces, as well as electron microscopy and resistance measurements. Furthermore, it is demonstrated that both viscose rotor spun (VR) and viscose multifilament (VM) yarns can be used for yarn actuators. The resulting VM-based yarn actuators exhibit high strain (0.58%) in NaDBS electrolytes. These conducting yarns can also be integrated into textiles and fabrics of various forms to create smart e-textiles and wearable devices.

Smart textiles combine the features of conventional textiles with promising properties of smart materials such as electromechanically active polymers, resulting in textile actuators. Textile actuators comprise of individual yarn actuators, so understanding their electro-chemo-mechanical behavior is of great importance. Herein, this study investigates the effect of inherent structural and mechanical properties of commercial yarns, that form the core of the yarn actuators, on the linear actuation of the conducting-polymer-based yarn actuators. Commercial yarns were coated with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) to make them conductive. Then polypyrrole (PPy) that provides the electromechanical actuation is electropolymerized on the yarn surface under controlled conditions. The linear actuation of the yarn actuators is investigated in aqueous electrolyte under isotonic and isometric conditions. The yarn actuators generated an isotonic strain up to 0.99% and isometric force of 95 mN. The isometric strain achieved in this work is more than tenfold and threefold greater than the previously reported yarn actuators. The isometric actuation force shows an increase of nearly 11-fold over our previous results. Finally, a qualitative mechanical model is introduced to describe the actuation behavior of yarn actuators. The strain and force created by the yarn actuators make them promising candidates for wearable actuator technologies. © 2023 The Authors. Advanced Materials Technologies published by Wiley-VCH GmbH.

Here we present a new class of variable stiffness actuators for soft robotics based on biohybrid materials that change their state from soft-to-hard by creating their own bones. The biohybrid variable stiffness soft actuators were fabricated by combining the electromechanically active polymer polypyrrole (PPy) with a soft substrate of polydimethylsiloxane or alginate gel. These actuators were functionalized with cell-derived plasma membrane nanofragments (PMNFs), which promote rapid mineralization within 2 days. These actuators were used in robotic devices, and PMNF mineralization resulted in the robotic devices to achieve a soft to stiff state change and thereby a decreased or stopped actuation. Moreover, perpendicularly and diagonally patterned actuators were prepared. The patterned actuators showed programmed directional actuation motion and could be fixated in this programmed state. Finally, patterned actuators that combined soft and rigid parts in one actuator showed more complex actuation motion. Together, these variable stiffness actuators could expand the range of applications of morphing robotics with more complex structures and functions., Funding: Japanese Society of the Promotion of Science (JSPS) Bridge Fellowship program [BR170502]; KAKENHI [JP20H04534]; JSPS [JPJSBP 120 209 923]; STINT; Swedish Research Council [VR2014-3079]; China Scholarship Council [201808330454]

With the rise of ion-based devices using soft ionic conductors, ionotronics show the importance of matching electronic and biological interfaces. Since textiles are conformal, an essential property for matching interfaces, light-weight and comfortable, they present as an ideal candidate for a new generation of ionotronics, i-textiles. As fibers are the building blocks of textiles, ionically conductive fibers, named ionofibers, are needed. However, ionofibers are not yet demonstrated to fulfill the fabric manufacturing requirements such as mechanical robustness and upscaled production. Considering that ionogels are known to be conformal films with high ionic conductivity, ionofibers are produced from commercial core yarns with specifically designed ionogel precursor solution via a continuous dip-coating process. These ionofibers are to be regarded as composites, which keep the morphology and improve the mechanical properties from the core yarns while adding the (ionic) conductive function. They keep their conductivity also after their integration into conformal fabrics; thus, an upscaled production is a likely outlook. The findings offer promising perspectives for i-textiles with enhanced textile properties and in-air electrochemical applications., WEAFING

Commercially available yarns are promising precursor for artificial muscles for smart fabric-based textile wearables. Electrochemically driven conductive polymer (CP) coated yarns have already shown their potential to be used in smart fabrics. Unfortunately, the practical application of these yarns is still hindered due to their slow ion exchange properties and low strain. Here, a method is demonstrated to morph poly-3,4-ethylenedioxythiophene:poly-styrenesulfonate (PEDOT:PSS) coated multifilament textile yarns in highly twisted and coiled structures, providing >1% linear actuation in <1 s at a potential of +0.6 V. A potential window of +0.6 V and -1.2 V triggers the fully reversible actuation of a coiled yarn providing >1.62% strain. Compared to the untwisted, regular yarns, the twisted and coiled yarns produce >9x and >20x higher strain, respectively. The strain and speed are significantly higher than the maximum reported results from other electrochemically operated CP yarns. The yarn’s actuation is explained by reversible oxidation/reduction reactions occurring at CPs. However, the helical opening/closing of the twisted or coiled yarns due to the torsional yarn untwisting/retwisting assists the rapid and large linear actuation. These PEDOT:PSS coated yarn actuators are of great interest to drive smart textile exoskeletons.

Ions are prevalent within bioelectronics, as they are the main charge carriers in living systems. In contrast to electronic systems, ionic ones are closer to what can be found in our body; in muscles, neurons and nerves. Textiles are a much-used biomedical material, both in vivo and in vitro due to its membrane character, highly efficient area, softness, biocompatibility and biodegradability. Modifying the physicochemical properties of the core or the surface of textile has been reported a countless number of times, but still, its use in a bioelectrical context is limited. Fibres are the building blocks of textiles and what make textiles an architected class of material. Then ionically conductive fibres are of great interest. Here, we show the preparation of iono-conductive textile fibres through the (semi-)continuous dip-coating of ionogel on the cellulose-based viscose. Ionogels are composed of salts in liquid state and a 3-dimensional solid network, in our case an ionic liquid (IL), 1-Ethyl-3-methylimidazolium trifluoromethanesulfonate, commonly named EMIm OTf or EMIm Triflate, and a thiol acrylate network, allowing the mobility of the ions within or in/out of the gel. This specific combination is a first effort towards the development of ionic textile fibres and ionic smart textiles, as a variety of ILs with different cations and anions exists, potentially allowing a large number of different combinations. We investigate how the coating of this ionogel affects the mechanical properties as well as the conductivity in AC or DC arrangement and their relation to temperature and humidity. Also, the thermal stability and sensitivity of degradation of the fibre system is studied. Moreover, we introduce different textile structures, and potential applications directed to bioelectronics.

Hematopoietic stem cells are used in transplantations for patients with hematologic malignancies. Scarce sources require efficient strategies of expansion, including polymeric biomaterials mimicking architectures of bone marrow tissue. Tissue microenvironment and mode of cytokine presentation strongly influence cell fate. Although several cytokines with different functions as soluble or membrane-bound mediators have already been identified, their precise roles have not yet been clarified. A need exists for in vitro systems that mimic the in vivo situation to enable such studies. One way is to establish surfaces mimicking physiological presentation using protein-immobilization onto polymer films. However these films merely provide a static presentation of the immobilized proteins. It would be advantageous to also dynamically change protein presentation and functionality to better reflect the in vivo conditions. The electroactive polymer polypyrrole shows excellent biocompatibility and electrochemically alters its surface properties, becoming an interesting choice for such setups. Here, we present an in vitro system for switchable presentation of membrane-bound cytokines. We use interleukin IL-3, known to affect hematopoiesis, and show that when immobilized on polypyrrole films, IL-3 is bioavailable for the bone marrow-derived FDC-P1 progenitor cell line. Moreover, IL-3 presentation can be successfully altered by changing the redox state of the film, in turn influencing FDC-P1 cell viability. This novel in vitro system provides a valuable tool for stimuli-responsive switchable protein presentation allowing the dissection of relevant mediators in stem and progenitor cell behavior.

There is a need for soft actuators in various biomedical applications in order to manipulate delicate objects such as cells and tissues. Soft actuators are able to adapt to any shape and limit the stress applied to delicate objects. Conjugated polymer actuators, especially in the so-called trilayer configuration, are interesting candidates for driving such micromanipulators. However, challenges involved in patterning the electrodes in a trilayer with individual contact have prevented further development of soft micromanipulators based on conjugated polymer actuators. To allow such patterning, two printing-based patterning techniques have been developed. First an oxidant layer is printed using either syringe-based printing or micro-contact printing, followed by vapor phase polymerization of the conjugated polymer. Sub-millimeter patterns with electronic conductivities of 800 Scm-1 are obtained. Next, laser ablation is used to cleanly cut the final device structures including the printed patterns, resulting in fingers with individually controllable digits and miniaturized hands. The methods presented in this paper will enable integration of patterned electrically active conjugated polymer layers in many types of complex 3-D structures., Funding agencies:This study was financially supported by Linköping University, COST Action MP1003 ESNAM (European Scientific Network for Artificial Muscles), the Swedish Research Council (VR – 2010-6672, 2014-3079, 2015-03298), the Knut & Alice Wallenberg Stiftelse (LiU-2010-00318 & LiU-2012- 01361), and the EU FP7 Marie Curie action IEF (625923 POLYACT)

The capacity to store urine and initiate voiding is a valued characteristic of the human urinary bladder. To maintain this feature, it is necessary that the bladder can sense when it is full and when it is time to void. The bladder has a specialized epithelium called urothelium that is believed to be important for its sensory function. It has been suggested that autocrine ATP signalling contributes to this sensory function of the urothelium. There is well‐established evidence that ATP is released via vesicular exocytosis as well as by pannexin hemichannels upon mechanical stimulation. However, there are still many details that need elucidation and therefore there is a need for the development of new tools to further explore this fascinating field. In this work, we use new microphysiological systems to study mechanostimulation at a cellular level: a mechanostimulation microchip and a silicone‐based cell stretcher. Using these tools, we show that ATP is released upon cell stretching and that extracellular ATP contributes to a major part of Ca2+ signalling induced by stretching in T24 cells. These results contribute to the increasing body of evidence for ATP signalling as an important component for the sensory function of urothelial cells. This encourages the development of drugs targeting P2 receptors to relieve suffering from overactive bladder disorder and incontinence.