bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variable Stiffness Actuators with Covalently Attached Nanofragments that Induce Mineralization
Authors: Cao Danfeng , Martinez Jose G. , Hara Emilio Satoshi , Jager Edwin W. H. 
Published: January 2023

AbstractSoft robotics has attracted great attention owing to their immense potential especially in human–robot interfaces. However, the compliant property of soft robotics alone, without stiff elements, restricts their applications under load‐bearing conditions. Herein, biohybrid soft actuators, that create their own bone‐like rigid layer and thus alter their stiffness from soft to hard, are designed. Fabrication of the actuators is based on polydimethylsiloxane (PDMS) with an Au film to make a soft substrate onto which polypyrrole (PPy) doped with poly(4‐styrenesulfonic‐co‐maleic acid) sodium salt (PSA) is electropolymerized. The PDMS/Au/PPy(PSA) actuator is then functionalized, chemically and physically, with plasma membrane nanofragments (PMNFs) that induce bone formation within 3 days, without using cells. The resulting stiffness change decreases the actuator displacement; yet a thin stiff layer cannot completely stop the actuator's movement, while a relatively thick segment can, but results in partial delamination the actuator. To overcome the delamination, an additional rough Au layer is electroplated to improve the adhesion of the PPy onto the substrate. Finally, an alginate gel functionalized with PMNFs is used to create a thicker mineral layer mimicking the collagen‐apatite bone structure, which completely suppresses the actuator movement without causing any structural damage.
A 3D Nanomaterials‐Printed Wearable, Battery‐Free, Biocompatible, Flexible, and Wireless pH Sensor System for Real‐Time Health Monitoring
Authors: NajafiKhoshnoo Sahar , Kim Taeil , Tavares‐Negrete Jorge A , Pei Xiaochang , Das Prativa , Lee Sang Won , Rajendran Jerome , Esfandyarpour Rahim 
Published: January 2023

AbstractThe pH sensing devices can provide important health information with applications in infection detection, disease diagnosis, and personalized medicine. However, these devices are often expensive with modest flexibility and require bulky readout instruments, thus inappropriate for wearable, remote, and continuous health monitoring applications. Herein, an integrated, miniaturized, modular, wearable, battery‐free, biocompatible, flexible, 3D‐printed (WB2F3D) sensor system for on‐demand, continuous, wireless, and real‐time pH monitoring is proposed, developed, and fully characterized. The 3D‐printing of nanomaterials on skin‐like flexible substrates is innovatively applied to enable multimaterial and multilayer printing of the sensors, reusable electronic/communication circuity, and antennas in a tailorable, low‐cost, and time‐efficient manner. The battery‐free and flexible readout system is designed to enable wireless and on‐demand energy and data transmission for continuous and real‐time pH monitoring. This sensor system exhibits high sensitivity (≈|51.76| mV pH−1), specificity, repeatability, reproducibility toward various pH ranges (3.0–10.0), excellent mechanical flexibility, and outstanding biocompatibility (cell viability > = 90%). It successfully demonstrates the pH change monitoring in an ex situ hydrogel‐based wound model. The WB2F3D sensor system is envisioned to provide an integrated platform for accurate, on‐demand, battery‐free, wireless, and real‐time human health monitoring, and another step toward personalized medicine.
Localization of Multiple Hydrogels with MultiCUBE Platform Spatially Guides 3D Tissue Morphogenesis In Vitro
Authors: Suthiwanich Kasinan , Hagiwara Masaya 
Published: January 2023

AbstractLocalization of multiple hydrogels is expected to develop the structure of 3D tissue models in a location‐specific manner. Here, 3D tissue morphogenesis is spatially guided by localizing different hydrogel conditions at different parts of a tissue. To achieve the localization, a unit‐based scaffold is developed with a unique frame design to trap hydrogel solutions inside their designated units. An optimal range of unit dimensions and surface wettabilities enables a solution trapping up to several cubic millimeters without any need for chemical additives. This capability allows spatial organization of biomolecular compositions and physical conditions of hydrogels, as well as the relative position of biological samples (cells, spheroids, and reconstituted tissues) within the scaffold. Successful localization of branching development on reconstituted human epithelial tissues is achieved by localizing growth factors or cross‐linked matrix proteins within hydrogels, demonstrating a direct dependence on local hydrogel conditions. Unlike 3D‐bioprinting or microfluidic techniques, this scaffold‐based localization of hydrogels requires only a manual pipetting and no specialized tools, making it ready‐to‐use for researchers from any field. This localization technique provides a new promising route to spatially control morphogenesis, differentiation, and other developmental processes within 3D organoids or tissue models for practical biomedical applications in the future.
Flexible Vitrimers for Self‐healable Triboelectric Nanogenerators
Authors: Ye Chongnan , Li Wenjian , Voet Vincent S.D. , Folkersma Rudy , Pei Yutao , Loos Katja 
Published: January 2023

AbstractDespite rapid advancements in the development of triboelectric nanogenerators (TENG), mechanical defects generated during their working condition limit the service lifetime of these devices. Polyester‐based vitrimers can offer a solution to solve this issue via their dynamic bond exchange reactions. However, they often require high temperatures and a long time to crosslink, rendering them not useful for large‐scale TENG fabrication. To solve these issues, a self‐healable vitrimer‐based triboelectric nanogenerator (VITENG) is developed based on diacrylate poly(dimethylsiloxane) (AA‐PDMS) via a fast thiol‐Michael reaction. By including 2,3‐dihydroxypropyl methacrylate (DHPMA), hydroxy end dangling side chains are generated in the matrix, which increase the PDMS network's flexibility and transesterification efficiency. Efficient transesterification occurs on the abundant dynamic β‐hydroxy ester bonds in the PDMS network, resulting in 100% efficient mechanical damage repair. The VITENG demonstrates a good performance with an output voltage of 135 V under a load of 10 N, demonstrating the potential for mechanical energy harvesters with long lifetimes and high design flexibility.
Room‐Temperature NH3 Sensor Based on SnO2 Quantum Dots Functionalized SnS2 Nanosheets
Authors: Bai Jinzhou , Shen Yanbai , Zhao Sikai , Li Ang , Kang Zhangke , Cui Baoyu , Wei Dezhou , Yuan Zhenyu , Meng Fanli 
Published: January 2023

AbstractTraditional metal oxide semiconductor gas sensors are facing significant challenges for portable devices and integration due to large power consumption caused by high working temperature. 2D nanomaterials with large specific surface areas, rich active sites, and tunable electrical properties are proved to be promising candidates for room‐temperature gas sensors. However, several disadvantages including weak response, sluggish response/recovery kinetics, and poor selectivity still need to be overcome for high‐performance gas sensors. Herein, SnO2 quantum dots (QDs) with a diameter of ≈3 nm functionalized SnS2 nanosheets with a thickness of ≈17 nm are synthesized via a two‐step solvothermal method, which exhibits a high response of 11.1 to 100 ppm NH3 at room temperature of 25 °C with fast response speed and good repeatability, high selectivity, and long‐term stability. The sensing mechanism is mainly ascribed to 0D/2D heterostructure, synergistic effect, and n‐n heterojunction constructed across the interfaces between SnO2 QDs and SnS2 nanosheets. The as‐prepared nanomaterials may contribute to the reasonable design of heterostructure between 0D QDs and 2D nanomaterials, and offer a promising candidate for room‐temperature NH3 detection.
Sustainable Additive Manufacturing of Polyelectrolyte Photopolymer Complexes
Authors: Kolibaba Thomas J. , Higgins Callie I. , Crawford Nathan C. , Samaniuk Joseph R. , Killgore Jason P. 
Published: January 2023

AbstractPolyelectrolyte complexes (PECs), assemblies of oppositely charged polymers with powerful properties and wide‐ranging applications, are currently not melt‐processable via any conventional means and have been limited commercially to applications only as coatings. Herein, a unique strategy of pairing a polycation with an oppositely charged photopolymerizable monomer is employed. Vat photopolymerization of this mixture yields 3D spatial control over PECs for the first time. The properties of these 3D‐printed PECs are evaluated and are found to be similar to conventionally studied PEC materials. The water sensitivity of the PEC parts is adjustable through the incorporation of a small amount of a hydrophilic covalent crosslinker, highlighting potential future applications of these materials in 4D printing. Finally, the upcyclability of the additively manufactured PECs is demonstrated through the dissolution of a printed part and its incorporation into virgin resin to yield a part composed of partially recycled material. This chemistry has the potential to dramatically expand the application space of PEC materials and is a step towards a more circular economy for the field of additive manufacturing.
Pattern Transformation Inspired Multifunctional Cylindrical Vessels with Programmable Stoma‐Shaped Biomimetic Openings
Authors: Sun Jiabin , Zhou Zhenhuan , Cao Xueqing , Zhang Qifeng , Zhang Qilin , Jia Ziguang , Sun Wei , Tong Zhenzhen , Xu Xinsheng , Lim C.W. 
Published: January 2023

AbstractPattern transformation in a periodic porous structure has inspired multifarious mechanical metamaterials/metastructures due to the induced unusual negative Poisson's ratio behavior of macroscopic materials. Recently, it has been leveraged to architect a variety of designable and multifunctional structural members. Inspired by this design methodology, a novel porous cylindrical shell, which is perforated by a large number of staggered openings, is constructed and investigated meticulously. A stable, anti‐disturbed, and controllable waisted deformation of the architected cylindrical shell will be triggered under an axial compression. A stoma‐shaped biomimetic hole and graded distribution of initial openings are proposed to ensure that the holes distributed throughout the shell can be closed up concurrently while the closed states of holes can be flexibly programmed. To explore the applications of such shells, a handy cylindrical vessel is elaborately designed and its multiple functions including reagent release, underwater sampling, and flow control are exhibited by experiments. The results reflect that the designed vessel can be facilitated with many advantages such as uniform release, quick action, easy actuation, and repeated usage. Moreover, it also may open a new avenue for metamaterials in the fields of biomedical engineering, underwater detection, fluid machinery, etc.
Air‐Permeable Textile Bioelectronics for Wearable Energy Harvesting and Active Sensing
Authors: Zhao Xun , Chang Austin , Li Justin , Xu Jing , Hollister John , Che Ziyuan , Wan Xiao , Yin Junyi , Wang Shaolei , Lee Shinyoung , Kavehpour Pirouz , Chen Jun 
Published: January 2023

AbstractAdvances in wearable bioelectronics enable the possibility of transforming the currently reactive and disease‐centric healthcare system to one focused on disease prevention and health promotion. Converting biomechanical activities into electrical signals could be a unique way to develop wearable bioelectronics for personalized healthcare. In this work, an air‐permeable textile (APT) bioelectronics is developed. It is formed with a liquid metal electrode treated with Nickel (Ni‐EGaIn) encapsulated between two layers of electrospun Polycaprolactone textile. With a size of 4 cm by 4 cm, the APT bioelectronics produces an open‐circuit voltage of 12 V and a short‐circuit current of 0.12 mA, ultimately outputting a power density of 7.975 W m−2. The APT bioelectronics demonstrates an ability to produce electrical output under varying degrees of deformation with stable performance over 6000 cycles. In addition, the APT bioelectronics holds a drying rate of 5.07% min−1 compared to conventional fabrics such as polyester with a drying rate of 3.93% min−1. This keeps the ATP dry and cool for decent wearing comfort. With a collection of compelling features, the air‐permeable textile bioelectronics represents a promising approach for human body centered energy and sensing applications.
An Anisotropic Dielectric Elastomer Actuator with an Oriented Electrospun Nanofiber Composite Film
Authors: Zhang Yang , Chen Zhiwen , Xu Feng , Lin Jiawei , Zhu Bin , Xu Zhenjin , Zhou Gang , Zhang Shaohua , Chen Qinnan , Wang Lingyun , Wu Dezhi 
Published: January 2023

AbstractAnisotropic actuation, a universal phenomenon in nature, may be inspiring for the development of intelligent soft robotics in the future. For dielectric elastomers (DEs), important investigations have been done to decrease the voltage and increase the actuation strain. However, mechanical isotropy of synthetic DEs shows in‐plane uniform deformation, lacking the controllability of the actuation direction. Herein, an anisotropic DE (denoted as ADE) is constructed by casting Ecoflex/BaTiO3 solution onto oriented TPU nanofibrous membranes fabricated via drum electrospinning. The resulting ADE with a seamless three‐layer structure features mechanical anisotropy in the elastic modulus, with the maximum ratio between x and y directions of the plane being 11. A prototype ADE‐based actuator demonstrates a high electroactuation anisotropy of 3.95, a large unidirectional length strain of 15%, and a high energy density of 0.014 MJ m−3 at an electric field of 40 V µm−1. Two potential applications, a flow divider valve simulating the Transwell test in the medical field and a mechanical stimulus component mimicking the maturation of cardiomyocytes, are successfully demonstrated. Thus, this work offers a versatile yet simple approach for fabricating anisotropic electroactive elastomer actuators in the future.
Controlling the Inkjet Printing Process for Electrochemical (Bio)Sensors
Authors: Pradela‐Filho Lauro A. , Gongoni Juliana L. M. , Arantes Iana V. S. , De Farias Davi M. , Paixão Thiago R. L. C. 
Published: January 2023

AbstractInkjet printing is a popular technique for depositing high‐precision ink lines. This study reports the printing parameters’ influence on the electrical properties of the sensing devices. The electrochemical sensors are fabricated with a commercial piezoelectric printer and silver ink. Different substrates are evaluated in the printing process, including paper, polyimide, and polyvinyl chloride (PVC) tapes. Ink depositions’ temperature, ink drop spacing, length, and the number of the ink layer are also evaluated in this study. Higher temperatures (40 °C) make the substrate surface smoother, improving the printing quality. Controlling the ink drop spacing produces narrow continuous ink lines. The number of ink layers changes the film thickness, altering their electroactive surface area. The best printing parameters are PVC tape at 40 °C, 17 µm drop spacing, one layer, and 13 mm length. Under optimized conditions, three‐electrode electrochemical systems are fully printed with silver ink, showing batch‐to‐batch reproducibility (RSD = 3%). Their analytical performance is evaluated for picric acid, hydrogen peroxide, and glucose quantification. The sensors are modified with glucose oxidase to quantify glucose in artificial saliva, confirming their analytical applicability. Therefore, this work reports fundamental aspects of inkjet printing, bringing valuable findings to guide new research involving inkjet‐printed electrochemical biosensors/sensors ((bio)sensors).
Nitrogen‐Doped Multilayer Graphene Microtubes for High‐Density Recording of Occipital EEG Signals
Authors: Zhang Chengcheng , Li Mingji , Xuan Xiuwei , Zhou Baozeng , Li Penghai , Li Hongji 
Published: January 2023

AbstractGraphene microelectrodes exhibit potential in recording high‐density electroencephalography (EEG) signals from various brain regions. In this study, microtubes composed of nitrogen‐doped graphene (NG) nanosheets are synthesized by chemical vapor deposition to record high‐density EEG signals. The N‐content of the NG samples ranges from 1.35 to 2.22 at.%. One of the fabricated microtubes with an N‐content of 2.22% exhibits low scalp‐contact resistance and high signal‐to‐noise ratio (SNR) of EEG signals. The NG‐microtube has the advantages of high water‐retention, scalp affinity, water absorption, salt interception, and low resistance; these advantages reduce the scalp‐contact resistance and improve the response of EEG signals. Furthermore, an occipital 24‐lead EEG sensor with 72 optimized NG microtubes is assembled to record spontaneous and visually evoked EEG signals. Untrained volunteers are asked to wear the NG‐EEG sensor, and thus, spontaneous EEG with a high SNR and visually evoked EEG signals with an interval of 0.1 Hz are obtained easily. The occipital NG‐based EEG sensor is convenient to wear and can identify high‐density EEG signals. Therefore, the EEG sensor is not only suitable for the peripheral fine control of motion imagination but also used in the clinical diagnosis of functional disorders in various brain regions, promoting the development of healthcare electronics.
Optimizing Surface Composition and Structure of FeWO4 Photoanodes for Enhanced Water Photooxidation
Authors: Ta Xuan Minh Chau , Nguyen Thi Kim Anh , Bui Anh Dinh , Nguyen Hieu T. , Daiyan Rahman , Amal Rose , Tran‐Phu Thanh , Tricoli Antonio 
Published: January 2023

AbstractPhotoelectrochemical water splitting is a promising approach to produce green hydrogen using solar energy. A primary bottleneck remains the lack of efficient photoanodes to catalyze the sluggish water photooxidation reaction. Engineering photoabsorbers with a narrow bandgap and suitable band edge can boost the photoelectrochemical performance. Herein, nanostructured iron tungstate (FeWO4) photoanodes are engineered directly on a fluorine doped tin oxide glass substrate via a scalable and ultra‐fast flame synthesis route in 13 seconds. Physiochemical, optoelectronic, and electrochemical properties of these photoanodes are systematically investigated. The key roles of charge transport, transfer, and dissolution of W and Fe ions from the FeWO4 matrix within long‐term performance are revealed. Optimal FeWO4 photoanode with a bandgap of 1.82 eV and a FeOOH/NiOOH co‐catalyst coating shows an improved water photooxidation performance, reaching a photocurrent density of 0.23 mA cm−2 at 1.4 V versus reversible hydrogen electrode in 1 m potassium hydroxide. It further demonstrates relatively good photostability, maintaining ≈96% of photocurrent density after 1‐hour continuous photooxidation, albeit some trace of Fe, W and Ni elements dissolution. Insights on the photooxidation performance of nanostructured FeWO4 provide promising directions for the engineering of small band‐gap catalysts for a variety of photoelectrochemical applications.
Ultrastretchable Triboelectric Nanogenerators Based on Ecoflex/Porous Carbon for Self‐Powered Gesture Recognition
Authors: Zhao Jiang , Xiao Yu , Yang Wei , Zhang Shaochun , Wang Huining , Wang Qiang , Sun Zhaoyang , Li Wenjie , Gao Min , Wang Zefeng , Xu Yun , Chen Huamin , Wang Jun 
Published: January 2023

AbstractStretchable triboelectric nanogenerator (STENG) has become the research hotspots in flexible power supply, which is indispensable in intelligent wearable electronics. In this work, an ultrastretchable Ecoflex/porous carbon‐based STENG (EP‐STENG) is presented for gesture recognition application. Due to the ultrahigh stretchability of Ecoflex (570%) and high conductivity of porous carbon, the EP thin film acts as an excellent stretchable electrode under various deformations. In addition, the output performance of the EP‐STENG can be enhanced by adjusting the concentration of porous carbon. At a mass fraction of 0.28 wt%, the EP‐STENG reaches the optimal output performance. This is due to the appropriate conductive networks and strong trapping effect. Surprisingly, the performance of the EP‐STENG still remains 70% at a stretching strain of 177%, which makes it a promising wearable sensor for human–machine interaction. Finally, the EP‐STENG‐based stretchable sensor array can acquire gesture signal of the fingers, which can control the mechanical hand to make corresponding actions. The proposed ultrastretchable EP‐STENG can promote the development of intelligent wearable system and flexible electronics.
Molecular Copper Phthalocyanine and FeOOH Modified BiVO4 Photoanodes for Enhanced Photoelectrochemical Water Oxidation
Authors: Fan Mengmeng , Tao Ziyang , Zhao Qiang , Li Jinping , Liu Guang , Zhao Chuan 
Published: January 2023

AbstractThe limited performance of BiVO4 for photoelectrochemical (PEC) water splitting is currently restricted to limited light absorption and rapid carrier recombination. Herein, molecular copper phthalocyanine (CuPc) and FeOOH co‐integrated BiVO4 photoanode are prepared by a simple dipping method and demonstrate significantly improved PEC water oxidation activities. The optimized BiVO4/CuPc/FeOOH photoanode attains a photocurrent density of 3.67 mA cm−2 at 1.23 VRHE and maintains the PEC performance without significant decay over a long period of time. In addition, significant increase of charge separation efficiency and decrease of charge transfer resistance of the BiVO4/CuPc/FeOOH photoanode also demonstrate that the hole–electron transfer and water oxidation reaction are promoted. It is found that CuPc has a similar structure to photosensitized chlorophyll, which can broaden the absorption range of BiVO4 in the visible region and improve the photo‐generated carriers transfer in the semiconductor. Whereas the FeOOH layer can rapidly transfer the photo‐generated holes into the electrolyte to participate in the water oxidation reaction as oxygen evolution cocatalyst. This work provides a feasible pathway to improve the PEC water splitting performance of BiVO4 by increasing light absorption and accelerating carrier transfer.
Accelerated Multi‐Stage Synthesis of Indium Phosphide Quantum Dots in Modular Flow Reactors
Authors: Epps Robert W. , Delgado‐Licona Fernando , Yang Hyeyeon , Kim Taekhoon , Volk Amanda A. , Han Suyong , Jun Shinae , Abolhasani Milad 
Published: January 2023

AbstractDevelopment and scalable nanomanufacturing of high‐quality heavy metal‐free quantum dots (QDs) with high‐dimensional experimental design spaces still remain a challenge. In this work, a universal flow chemistry framework for accelerated fundamental and applied studies of heavy metal‐free QDs with multi‐stage chemistries is presented. By introducing flexible time‐ and temperature‐to‐distance transformation using modular fluidic blocks, an in‐flow synthetic route of InP QDs with the highest reported first excitonic absorption peak to valley ratio is unveiled with a reaction time one order of magnitude faster than batch reactors. The flexible time‐ and temperature‐to‐distance transformation as an enabling factor for generalization of flow reactors toward the accelerated discovery, development, and nanomanufacturing of high‐quality emerging nanomaterials for next‐generation energy, display, and chemical technologies is discussed.