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The opportunity to create magneto‐responsive soft materials (MSMs) with in‐process tailorable and locally controllable magnetic properties is highly desirable across many technological and biomedical applications. In this paper, this capability is demonstrated for the first time using computer‐controlled dual‐material aerosol jet printing (DMAJP) technology. This approach allows controlled variation of composition between the aerosols of a magnetic nanoparticles (MNPs) ink and a photocurable polymer during the printing process. The mixing ratio of the two aerosols determines the MNPs loading in the nanocomposite, which can be used to locally control the magnetic properties of the printed structures. The printing process is structured in a layer‐by‐layer fashion in combination with a sacrificial layer approach for building fully freestanding MSM structures that combine magnetoactive and non‐magnetoactive elements in a single process multi‐material printing method with no further assembly requirements. Using this method, the direct manufacturing of small‐scale multi‐material soft objects with complex shapes and programmable functions whose movements can be controlled by the application of an external magnetic field is demonstrated. [ABSTRACT FROM AUTHOR]

Endothelial cells (ECs) line the inner walls of blood vessels, respond to shear stress by elongating in the direction of flow. Engineering aligned ECs in vitro is essential for modeling human vascular diseases and for drug testing. Current microfluidic approaches mainly rely on unidirectional laminar flow, uniform coating of surfaces to improve cellular adhesion or alteration of the surface topography. Challenges persist due to shear stress‐induced changes in cellular behavior, especially in complex multicellular environments and the time needed for the cells to align and polarize inside the microfluidic conduits. Generally, protein coating processes and physical treatments are also not compatible with the steps required for the assembly of microfluidic devices. This approach employs aerosol jet printing (AJP) to precisely pattern poly(3,4‐ethylenedioxythiophene) polystyrene sulphonate (PEDOT:PSS) within microfluidic chambers in a single step. It is shown that the PEDOT:PSS is biocompatible and facilitates EC adhesion, patterning, elongation, and alignment. Under capillary flow, the cells retain their pattern‐induced morphology over 7 d, confirming the efficacy of the approach in promoting cellular organization, eliminating the need for external pumps. Furthermore, it is demonstrated that the PEDOT:PSS pattern retains structural integrity and electrical stability following oxygen plasma treatment, required for assembling of fully enclosed microfluidic devices. [ABSTRACT FROM AUTHOR]

The field of soft robotics is rapidly progressing toward applications including; wearable electronics, prosthetics, and biomedical devices. This is leading to demand for flexible, embedded high‐performance strain sensors to deliver real‐time feedback on the static configurations and dynamic motions of these robotic devices, to ultimately enable the levels of autonomous control and structural monitoring required for intelligent manipulation. Herein, aerosol jet printing (AJP) technology is utilized to generate arbitrary piezoresistive strain sensor layouts on fibrous paper suitable for direct integration into elastomeric soft robots. A custom graphene nanoplatelet ink with a viscosity of around 2.70 cP has been formulated for optimized atomization and patterning of conductive traces via AJP. Single and multilayer printing onto different paper substrates are explored; with the nominal resistance of the printed tracks varying from 272 to 4900 kΩ depending on paper type and number of layers. Maximum gauge factors of 24.2 ± 1.8 and 56.5 ± 4.5 are determined for sensor surfaces under tensile and compression modes, respectively. To demonstrate the possibility for direct integration of this approach for soft robotics, strain sensors are directly printed onto the strain‐limiting layer of a pneumatic soft robotic gripper, to provide continuous feedback of the gripper over curvatures up to 80 m−1. [ABSTRACT FROM AUTHOR]

Supersonic cluster beam implantation of Ag nanoparticles is proposed for the fabrication of stretchable and compliant electrodes for dielectric elastomer actuators (DEAs) with reduced thickness. Thanks to the low-energy and finely tunable implantation process, a nanocomposite Ag/polydimethylsiloxane electrode layer is produced with a moderate stiffening effect for the DEA in contrast with a common deposition strategy for electrodes. Thin DEAs with an overall thickness of 17 μm were fabricated and tested under different preloading conditions, demonstrating a max uniaxial actuation strain of 2.5% at an actuation voltage of 765 V, lower than the typical voltage values of DEAs. The electrodes remained conductive up to 40% strain, and they fully recovered the original resistance after 70% stretching. Our results represent a significant step towards the development of DEAs operating at reduced actuation voltages, by stacking of micrometer-thick elastomer films, paving the way to novel applications in soft robotics. [ABSTRACT FROM AUTHOR]

The electrical signals in plant's physiological processes are of great interest in biology, biohybrid robotics, and sensors for interfacing the living organisms with an electronic readout and control. This paper reports on the application of conformable, self‐adhering surface electrodes for the measurement and bidirectional stimulation of electrical signals in plants. The inkjet‐printed poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate based electrodes are <3 µm thick, light‐weight, soft and flexible, and can be easily and non‐invasively transferred onto plant's outer organs for surface potential recordings due to their realization on tattoo transfer paper. The devices prove to be extremely versatile for analyzing electrical signals in Dionaea muscipula, Arabidopsis thaliana, and Codariocalyx motorius and for stimulating mechanical responses in D. muscipula. A benefit over traditional electrodes is the van der Waals self‐adherence of the thin electrodes, their intrinsic flexibility and adaptation also on small leaves while providing excellent readout. The same electrode allows long‐term multicycle measurements over at least 10 days and, moreover, straightforward recordings on fast‐moving organs such as snapping fly traps and endogenously oscillating leaflets. The results confirm that self‐adhering soft organic electronics are particularly suitable for plant electrical signal analysis when easy‐application, self‐adaptation, and long‐term performance are required in plant science, biohybrid robotics, and biohybrid sensors. [ABSTRACT FROM AUTHOR]

Polymeric free-standing nanofilms are emerging as appealing materials for many applications, including biomedical ones. This communication describes a new and versatile method to obtain self-supported plasma-deposited coatings. Coupling a soluble sacrificial layer with low or atmospheric pressure plasma processes, free-standing films have been prepared. Vancomycin-embedded bio-composite coatings have been deposited at atmospheric pressure with an aerosol-assisted plasma process, while PolyEthylene Oxide-like (antifouling and cross-linked) coatings and silver-containing (antibacterial) nanocomposite coatings have been plasma-deposited at low pressure. The described approach can certainly be extended to many possible free-standing nanofilms of different nature that can be synthesized by means of customized plasma processes, and it is a valid alternative to conventional wet methods to nanofilm synthesis. [ABSTRACT FROM AUTHOR]

Organic Electronics: Ultraconformable, Self-Adhering Surface Electrodes for Measuring Electrical Signals in Plants (Adv. Biohybrid robotics and sensors, electrophysiology, organic electronics, plant's electrical signals, soft electronics Utilizable to record and bidirectionally stimulate electrophysiological signals in different plant species, the devices are relevant for plant science and plant-hybrid robotics and -sensors. [Extracted from the article]

The development of dry, ultra-conformable and unperceivable temporary tattoo electrodes (TTEs), based on the ink-jet printing of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) on top of commercially available temporary tattoo paper, has gained increasing attention as a new and promising technology for electrophysiological recordings on skin. In this work, we present a TTEs epidermal sensor for real time monitoring of respiration through transthoracic impedance measurements, exploiting a new design, based on the application of soft screen printed Ag ink and magnetic interlink, that guarantees a repositionable, long-term stable and robust interconnection of TTEs with external "docking" devices. The efficiency of the TTE and the proposed interconnection strategy under stretching (up to 10%) and over time (up to 96 h) has been verified on a dedicated experimental setup and on humans, fulfilling the proposed specific application of transthoracic impedance measurements. The proposed approach makes this technology suitable for large-scale production and suitable not only for the specific use case presented, but also for real time monitoring of different bio-electric signals, as demonstrated through specific proof of concept demonstrators. [ABSTRACT FROM AUTHOR]

Back Cover: PE‐CVD allows a versatile approach to the fabrication of free‐standing nanofilms (NFs). Here, different plasma‐deposited NFs are presented, of possible biomedical applications: with non fouling properties, or embedding an antibiotic molecule or silver nanoparticles. Plasma‐deposited NFs could be easily released free‐standing after immersion in water and recollected on any target substrate in a conformal way. SEM and optical microscope images in the cover show the conformal adhesion of the plasma‐deposited NFs to a nylon mesh. Further details can be found in the article by Daniela Pignatelli et al. on page 1224. [ABSTRACT FROM AUTHOR]