Engineering

  • Article | | open

    Defect tolerance is important in order to ensure the mechanical integrity of synthetic materials and biological tissues. Here the authors demonstrate that toughening mechanisms provide soft collagenous tissues with high defect tolerance, with important implications for biomedical applications.

    • Kevin Bircher
    • , Manuel Zündel
    • , Marco Pensalfini
    • , Alexander E. Ehret
    •  & Edoardo Mazza
  • Article | | open

    Processes for efficient production of primary, secondary or ternary aminated compounds are constant challenges for chemical and pharmaceutical industries. Here, the authors develop selective and sustainable amination chemistry widely applicable to chemical substrates via formic acid.

    • Hu Li
    • , Haixin Guo
    • , Yaqiong Su
    • , Yuya Hiraga
    • , Zhen Fang
    • , Emiel J. M. Hensen
    • , Masaru Watanabe
    •  & Richard Lee Smith Jr.
  • Article | | open

    Heart grafts need good vascularization to survive. Here, the authors engineer perfusable constructs of human embryonic stem cell-derived endothelial cells seeded in collagen matrix in patterned microchannels that form anastomosed vessels in vitro and have increased coronary vascular perfusion on transplantation in rats.

    • Meredith A. Redd
    • , Nicole Zeinstra
    • , Wan Qin
    • , Wei Wei
    • , Amy Martinson
    • , Yuliang Wang
    • , Ruikang K. Wang
    • , Charles E. Murry
    •  & Ying Zheng
  • Article | | open

    Mass fabrication of supraparticles is essential for their applications, but it is not easy. Tan et al. produce porous supraparticles with tunable shapes by drying colloidal particles in water-ethanol-oil ternary drops, where the pining effect at drop edges is alleviated by the formation of oil rings.

    • Huanshu Tan
    • , Sanghyuk Wooh
    • , Hans-Jürgen Butt
    • , Xuehua Zhang
    •  & Detlef Lohse
  • Article | | open

    Plant-inspired osmotic actuation has been proposed as a competitive actuation strategy yet reversibility is still an open issue hampering its implementation in soft robotics. Here the authors show a low input voltage reversible osmotic actuation strategy based on the electrosorption of ions on flexible electrodes.

    • Indrek Must
    • , Edoardo Sinibaldi
    •  & Barbara Mazzolai
  • Article | | open

    Designing mechanical metamaterials is challenging because of the large number of non-periodic constituent elements. Here, the authors develop an approach to design arbitrarily shaped metamaterials that is more computationally efficient by six orders of magnitude compared to other approaches.

    • Lucas A. Shaw
    • , Frederick Sun
    • , Carlos M. Portela
    • , Rodolfo I. Barranco
    • , Julia R. Greer
    •  & Jonathan B. Hopkins
  • Article | | open

    The integration and release of reagents in portable diagnostic devices is critical for the good functioning of such devices. Here the authors propose a device with a reservoir for long-term storage of reagents with integrated, pressure operated, normally closed, passive check-valve for dispensing.

    • Amin Kazemzadeh
    • , Anders Eriksson
    • , Marc Madou
    •  & Aman Russom
  • Article | | open

    Electric fields can produce strains in soft elastomers but a generalizable method for changing the Gaussian curvature has not been devised. Here the authors demonstrate voltage-tunable shape morphing using a spatially inhomogeneous electric field generated by electrodes incorporated between elastomer layers.

    • Ehsan Hajiesmaili
    •  & David R. Clarke
  • Article | | open

    Understanding how forces orchestrate tissue formation requires technologies to map internal tissue stress at cellular length scales. Here, authors develop ultrasoft sensors that visibly deform under cell-generated stress to capture patterns of internal stress development during multicellular spheroid formation.

    • Wontae Lee
    • , Nikita Kalashnikov
    • , Stephanie Mok
    • , Ruba Halaoui
    • , Elena Kuzmin
    • , Andrew J. Putnam
    • , Shuichi Takayama
    • , Morag Park
    • , Luke McCaffrey
    • , Ruogang Zhao
    • , Richard L. Leask
    •  & Christopher Moraes
  • Article | | open

    The mechanism underlying the superlubricity of tetrahedral amorphous carbon coatings lubricated with organic friction modifiers is still under debate. Here the authors combine experiments and simulations to reveal that superlubricious layers form due the mechano-chemical decomposition of friction modifiers.

    • Takuya Kuwahara
    • , Pedro A. Romero
    • , Stefan Makowski
    • , Volker Weihnacht
    • , Gianpietro Moras
    •  & Michael Moseler
  • Article | | open

    The demonstration of nature-inspired embodied control logic in simple autonomous material systems is of significant interest in applications such as soft robots and drug delivery. Here, the authors demonstrate 3D printed self-actuating structures with control logic in response to suitable stimuli.

    • Yijie Jiang
    • , Lucia M. Korpas
    •  & Jordan R. Raney
  • Article | | open

    There is significant interest in providing real-world applications for metamaterials. Here, the authors design an Advanced Short Backfire Antenna, augmented with anisotropic metamaterial surfaces to achieve high aperture efficiency across two frequency bands, making the antenna ideal for spaceborne applications.

    • J. Daniel Binion
    • , Erik Lier
    • , Thomas H. Hand
    • , Zhi Hao Jiang
    •  & Douglas H. Werner
  • Article | | open

    Resistive random-access memory is operated based on the formation and disruption of nanoscale conductive filaments, but a mechanistic understanding of this process remains unclear. Here, Wang et al. develop a surface-diffusion model to describe lifetime of filaments ranging from microseconds to years.

    • Wei Wang
    • , Ming Wang
    • , Elia Ambrosi
    • , Alessandro Bricalli
    • , Mario Laudato
    • , Zhong Sun
    • , Xiaodong Chen
    •  & Daniele Ielmini
  • Article | | open

    The scalability of printable integrated circuits is lagging far behind that of conventional silicon-based technologies. Here, Kwon et al. show a three-dimensional integration approach by stacking printeddual-gate organic transistors on plastic foils with a density of 60 transistors per centimeter square.

    • Jimin Kwon
    • , Yasunori Takeda
    • , Rei Shiwaku
    • , Shizuo Tokito
    • , Kilwon Cho
    •  & Sungjune Jung
  • Article | | open

    Replacing the toxic lead in the state-of-the-art halide perovskite solar cells is highly desired but the device performance and stability are usually compromised. Here Chen et al. develop inorganic cesium tin and germanium mixed-cation perovskites that show high operational stability and efficiency over 7%.

    • Min Chen
    • , Ming-Gang Ju
    • , Hector F. Garces
    • , Alexander D. Carl
    • , Luis K. Ono
    • , Zafer Hawash
    • , Yi Zhang
    • , Tianyi Shen
    • , Yabing Qi
    • , Ronald L. Grimm
    • , Domenico Pacifici
    • , Xiao Cheng Zeng
    • , Yuanyuan Zhou
    •  & Nitin P. Padture
  • Article | | open

    Atomically-clean interfaces are required in heterostructures. Here, authors report a method for fast and parallel removal of contaminants from fully-formed heterostructures, including sample intentionally exposed to polymers and solvent, achieving room temperature mobility over 180,000 cm2/Vs for graphene.

    • D. G. Purdie
    • , N. M. Pugno
    • , T. Taniguchi
    • , K. Watanabe
    • , A. C. Ferrari
    •  & A. Lombardo
  • Article | | open

    Vertical charge transport through homogeneous WSe2 layers can be effectively tuned by the layer number and contacting metals deposited. Here, the authors report WSe2 vertical diodes with superior device performance characteristics based on variable WSe2 thickness and gadolinium and platinum contact metals.

    • Ghazanfar Nazir
    • , Hakseong Kim
    • , Jihwan Kim
    • , Kyoung Soo Kim
    • , Dong Hoon Shin
    • , Muhammad Farooq Khan
    • , Dong Su Lee
    • , Jun Yeon Hwang
    • , Chanyong Hwang
    • , Junho Suh
    • , Jonghwa Eom
    •  & Suyong Jung
  • Article | | open

    The methylammonium lead halide perovskites have shown excellent optoelectronic properties but the field-effect transistors are much less studied. Here Yu et al. synthesize micrometer-thin crystals of perovskites with low surface contamination and make ambipolar transistor devices with high mobilities.

    • Weili Yu
    • , Feng Li
    • , Liyang Yu
    • , Muhammad R. Niazi
    • , Yuting Zou
    • , Daniel Corzo
    • , Aniruddha Basu
    • , Chun Ma
    • , Sukumar Dey
    • , Max L. Tietze
    • , Ulrich Buttner
    • , Xianbin Wang
    • , Zhihong Wang
    • , Mohamed N. Hedhili
    • , Chunlei Guo
    • , Tom Wu
    •  & Aram Amassian
  • Article | | open

    Power dissipation is usually unavoidable in transistor channels due to the inelastic scattering of electrons. Here, Firdaus et al. propose a nanoscaled silicon electron-aspirator to remove this constraint, which shows enhanced current output by 3 times at 8 K without additional power supply.

    • Himma Firdaus
    • , Tokinobu Watanabe
    • , Masahiro Hori
    • , Daniel Moraru
    • , Yasuo Takahashi
    • , Akira Fujiwara
    •  & Yukinori Ono
  • Article | | open

    Hardware implementation of spiking neural networks holds promise for high energy efficient brain-inspired computing. Here, Prezioso et al. realize the detection of synchrony in a demo circuit composed of 20 metal-oxide memristor synapses connected to a leaky-integrate-and-fire silicon neuron.

    • M. Prezioso
    • , M. R. Mahmoodi
    • , F. Merrikh Bayat
    • , H. Nili
    • , H. Kim
    • , A. Vincent
    •  & D. B. Strukov
  • Article | | open

    To realize the potential of resistive RAM crossbar arrays as platforms for neuromorphic computing, reduced network-level energy consumption must be achieved. Here, the authors use a hardware/software co-design approach to realize reduced energy consumption during network training for the network.

    • Yuhan Shi
    • , Leon Nguyen
    • , Sangheon Oh
    • , Xin Liu
    • , Foroozan Koushan
    • , John R. Jameson
    •  & Duygu Kuzum
  • Article | | open

    Methods to silence broadband noise and shield large volumes are lacking. Here, the authors show theoretically and experimentally that acoustic bianisotropic materials, with non-zero strain to momentum coupling, lead to effective sound barriers with excellent efficiency in terms of attenuation, bandwidth, and shielded volume.

    • Bogdan-Ioan Popa
    • , Yuxin Zhai
    •  & Hyung-Suk Kwon
  • Article | | open

    Human skin constructs hold potential for regenerative medicine, but the incorporation of hair follicles into such constructs is a challenge. Here, the authors use 3D printed molds to pattern hair follicle cell types in a physiological organization, and achieve human hair growth on the back of a mouse.

    • Hasan Erbil Abaci
    • , Abigail Coffman
    • , Yanne Doucet
    • , James Chen
    • , Joanna Jacków
    • , Etienne Wang
    • , Zongyou Guo
    • , Jung U. Shin
    • , Colin A. Jahoda
    •  & Angela M. Christiano
  • Article | | open

    Optogenetics is a promising alternative approach for restoration of neuromuscular function. Here the authors establish a closed-loop functional optogenetic stimulation for the control of limb joint angle in murine models, which demonstrates improved control and less fatigue than electrical stimulation systems.

    • Shriya S. Srinivasan
    • , Benjamin E. Maimon
    • , Maurizio Diaz
    • , Hyungeun Song
    •  & Hugh M. Herr
  • Article | | open

    The toughening of layered composite materials during cyclic loading remains poorly understood. Here, the authors introduce an interfacial nanolayer to a polymer-metal-ceramic stack to triple the fracture energy during cyclic loading via nanolayer-induced interfacial bond strengthening and load transfer to the polymer layer.

    • Matthew Kwan
    • , Muriel Braccini
    • , Michael W. Lane
    •  & Ganpati Ramanath
  • Article | | open

    Printed conductive inks show promise for future electronic device applications. Here, the authors report synthesis of graphene inks with conductivity of 7.13 × 10^4 S/m by Cyrene assisted liquid phase exfoliation, and their applications in data communication and RF energy harvesting.

    • Kewen Pan
    • , Yangyang Fan
    • , Ting Leng
    • , Jiashen Li
    • , Zhiying Xin
    • , Jiawei Zhang
    • , Ling Hao
    • , John Gallop
    • , Kostya S. Novoselov
    •  & Zhirun Hu
  • Article | | open

    The potential of electromechanical sensors has been limited by low volumetric density in sensing sites. Here, the authors demonstrate ultrasensitive pressure and strain sensors using ZnO microparticles that have high-aspect ratio and high-density nanostructured spines mimicking bristles in insects.

    • Bing Yin
    • , Xiaomeng Liu
    • , Hongyan Gao
    • , Tianda Fu
    •  & Jun Yao
  • Article | | open

    Minimizing contact effects in organic semiconductor-based devices is a key step toward the development of a low-cost technology for next-generation electronics. Here, the authors reduce contact resistance in organic devices by engineering electrodes with high work function surface domains.

    • Zachary A. Lamport
    • , Katrina J. Barth
    • , Hyunsu Lee
    • , Eliot Gann
    • , Sebastian Engmann
    • , Hu Chen
    • , Martin Guthold
    • , Iain McCulloch
    • , John E. Anthony
    • , Lee J. Richter
    • , Dean M. DeLongchamp
    •  & Oana D. Jurchescu
  • Article | | open

    Artificial neural networks can emulate the human vision because of their spike-based operation by employing memristors as synapses. Here, Seo et al. integrate synaptic and optical sensing functions in a single heterostructure, which enables accurate and energy-efficient recognition of colored patterns.

    • Seunghwan Seo
    • , Seo-Hyeon Jo
    • , Sungho Kim
    • , Jaewoo Shim
    • , Seyong Oh
    • , Jeong-Hoon Kim
    • , Keun Heo
    • , Jae-Woong Choi
    • , Changhwan Choi
    • , Saeroonter Oh
    • , Duygu Kuzum
    • , H.-S. Philip Wong
    •  & Jin-Hong Park
  • Review Article | | open

    Transcranial electrical stimulation techniques, such as tDCS and tACS, are popular tools for neuroscience and clinical therapy, but how low-intensity current might modulate brain activity remains unclear. In this review, the authors review the evidence on mechanisms of transcranial electrical stimulation.

    • Anli Liu
    • , Mihály Vöröslakos
    • , Greg Kronberg
    • , Simon Henin
    • , Matthew R. Krause
    • , Yu Huang
    • , Alexander Opitz
    • , Ashesh Mehta
    • , Christopher C. Pack
    • , Bart Krekelberg
    • , Antal Berényi
    • , Lucas C. Parra
    • , Lucia Melloni
    • , Orrin Devinsky
    •  & György Buzsáki
  • Review Article | | open

    Organic−inorganic metal halide perovskite solar cells possess high efficiency and low processing cost but suffer poor stability. Here Gao et al. review the recent progress on the 2D–3D mixed perovskites and suggest that greatly improved stability can be achieved without compromising the efficiency.

    • Peng Gao
    • , Abd Rashid Bin Mohd Yusoff
    •  & Mohammad Khaja Nazeeruddin
  • Article | | open

    Sample orientation is crucial to ensure optimal image quality in light microscopy. Here the authors enable multi-axis orientation of fixed mouse embryos and shrimp, and live zebrafish embryos and larvae by introducing magnetic beads and rotating the sample with a magnetic field in a microscope.

    • Frederic Berndt
    • , Gopi Shah
    • , Rory M. Power
    • , Jan Brugués
    •  & Jan Huisken
  • Article | | open

    Passive daytime radiative cooling presents a promising low-cost refrigeration solution but has thus far relied on specialized nanophotonic structures. Here Bhatia et al. show a directional approach that decouples solar reflectance and infrared emission to achieve superior cooling performance.

    • Bikram Bhatia
    • , Arny Leroy
    • , Yichen Shen
    • , Lin Zhao
    • , Melissa Gianello
    • , Duanhui Li
    • , Tian Gu
    • , Juejun Hu
    • , Marin Soljačić
    •  & Evelyn N. Wang
  • Article | | open

    Voltage tunable inductors (VTIs) with high working frequency and tunability are desired for new design of energy efficient electronics. Here the authors demonstrate magnetoelectric VTIs operating up to 10 MHz with tunability over 750% via strain mediated magnetoelectric effect and magnetocrystalline anisotropy cancellation strategy.

    • Yongke Yan
    • , Liwei D. Geng
    • , Yaohua Tan
    • , Jianhua Ma
    • , Lujie Zhang
    • , Mohan Sanghadasa
    • , Khai Ngo
    • , Avik W. Ghosh
    • , Yu U. Wang
    •  & Shashank Priya
  • Article | | open

    LiCoO2 is a cathode material widely used in lithium-ion batteries but suffers from solubilization of cobalt and structural disorder when the voltage is increased to release more capacity. Here the authors show a ternary Li, Al and F-modified LiCoO2 and battery cells with stable cycling behavior over 4.55 V.

    • Jiawei Qian
    • , Lei Liu
    • , Jixiang Yang
    • , Siyuan Li
    • , Xiao Wang
    • , Houlong L. Zhuang
    •  & Yingying Lu
  • Article | | open

    In vitro chemotactic assays are often 2D, low-throughput and lack fine gradient control. Here the authors present a hydrogel-based microfluidic platform for high-throughput 3D chemotactic assays, and use it to study neuronal sensitivity to guidance molecule gradient steepness.

    • Zhen Xu
    • , Peilin Fang
    • , Bingzhe Xu
    • , Yufeng Lu
    • , Jinghui Xiong
    • , Feng Gao
    • , Xin Wang
    • , Jun Fan
    •  & Peng Shi
  • Article | | open

    Chromium and arsenic are prevalent water pollutants, but their removal is currently limited by low selectivity. Here, the authors use redox-active metallopolymer electrodes based on poly(vinyl)ferrocene to selectively remove the two heavy metal oxyanions at concentrations as low as 100 ppb.

    • Xiao Su
    • , Akihiro Kushima
    • , Cameron Halliday
    • , Jian Zhou
    • , Ju Li
    •  & T. Alan Hatton
  • Article | | open

    The neuromorphic computing based on complementary metal-oxide-semiconductor transistors holds promise for artificial intelligence, but it suffers from the trade-off between scalability and biological fidelity. Yi et al. emulate 23 types of biological neuronal behaviors using scalable VO2 active memristors.

    • Wei Yi
    • , Kenneth K. Tsang
    • , Stephen K. Lam
    • , Xiwei Bai
    • , Jack A. Crowell
    •  & Elias A. Flores
  • Article | | open

    Both photonic topological structures and optical angular momentum have been investigated over the last few years. Here, the authors propose and demonstrate that a honeycomb LC circuit can support topological photonic states with band inversion between modes that carry orbital angular momentum.

    • Yuan Li
    • , Yong Sun
    • , Weiwei Zhu
    • , Zhiwei Guo
    • , Jun Jiang
    • , Toshikaze Kariyado
    • , Hong Chen
    •  & Xiao Hu
  • Article | | open

    The authors introduce a compliant rolling-contact architected material as a class of shape reconfigurable mechanical metamaterial. They also devise an approach that combines two photon stereolithography and scanning holographic optical tweezers, which allows them to fabricate these architected materials on the microscale.

    • Lucas A. Shaw
    • , Samira Chizari
    • , Matthew Dotson
    • , Yuanping Song
    •  & Jonathan B. Hopkins
  • Article | | open

    High-resolution imaging technologies call for photodetectors with high-gain and linear response over a large dynamic range. Chow et al. show a dual-gate structure that combines the operation of photodiodes and phototransistors to enable both amplified and linear response without external circuitry.

    • Philip C. Y. Chow
    • , Naoji Matsuhisa
    • , Peter Zalar
    • , Mari Koizumi
    • , Tomoyuki Yokota
    •  & Takao Someya
  • Article | | open

    Enhancing the catalytic activity of noble-metal alloys is frequently accompanied by side reactions. Here, the authors describe an approach to break the scaling relationship for propane dehydrogenation, by assembling single atom alloys, to achieve simultaneous enhancement of propylene selectivity and propane conversion.

    • Guodong Sun
    • , Zhi-Jian Zhao
    • , Rentao Mu
    • , Shenjun Zha
    • , Lulu Li
    • , Sai Chen
    • , Ketao Zang
    • , Jun Luo
    • , Zhenglong Li
    • , Stephen C. Purdy
    • , A. Jeremy Kropf
    • , Jeffrey T. Miller
    • , Liang Zeng
    •  & Jinlong Gong
  • Article | | open

    Interfacial instabilities can be damaging as they may lead to fabrication defects. Here the authors harness a fluid instability to their advantage to produce thin polymeric films with drop-shaped structures which have tailored geometrical properties.

    • J. Marthelot
    • , E. F. Strong
    • , P. M. Reis
    •  & P.-T. Brun
  • Article | | open

    Sandwich structures such as corrugated cardboard offer low weight and high bending stiffness, but they are difficult to produce at the nanoscale. Here, the authors combine webbing and perforation to produce alumina ‘nanocardboard’ with ultralow areal density that recovers without damage from extreme deformation.

    • Chen Lin
    • , Samuel M. Nicaise
    • , Drew E. Lilley
    • , Joan Cortes
    • , Pengcheng Jiao
    • , Jaspreet Singh
    • , Mohsen Azadi
    • , Gerald G. Lopez
    • , Meredith Metzler
    • , Prashant K. Purohit
    •  & Igor Bargatin
  • Article | | open

    Many aspects of concentrated macromolecular solutions, such as encountered in cytosol or in pharmaceutical formulations, are dependent on particle size distributions and weak intermolecular interactions. Here, the authors exploit hydrodynamic separation in the centrifugal field to measure both.

    • Sumit K. Chaturvedi
    • , Jia Ma
    • , Patrick H. Brown
    • , Huaying Zhao
    •  & P. Schuck
  • Article | | open

    Peripheral nerves have a complex physiology and it is therefore difficult to measure axonal activity in vitro. Here the authors make a nerve-on-a-chip platform to align peripheral nerves and permit measurement of conduction amplitude and velocity along several axons in a single experiment.

    • Sandra Gribi
    • , Sophie du Bois de Dunilac
    • , Diego Ghezzi
    •  & Stéphanie P. Lacour
  • Article | | open

    Current digital coding metasurfaces are only space-encoded. Here, the authors propose space-time modulated digital coding metasurfaces to obtain simultaneous manipulations of electromagnetic waves and present harmonic beam steering, beam shaping, and scattering-signature control as application examples.

    • Lei Zhang
    • , Xiao Qing Chen
    • , Shuo Liu
    • , Qian Zhang
    • , Jie Zhao
    • , Jun Yan Dai
    • , Guo Dong Bai
    • , Xiang Wan
    • , Qiang Cheng
    • , Giuseppe Castaldi
    • , Vincenzo Galdi
    •  & Tie Jun Cui
  • Article | | open

    Existing n-type colloidal quantum dot materials easily lose their doping polarity in air. Here Song et al. passivate the reactive covalent surface of indium arsenide quantum dots to gain the energy-level tunability and show p–n junction type solar cells with 7.92% certified efficiency.

    • Jung Hoon Song
    • , Hyekyoung Choi
    • , Hien Thu Pham
    •  & Sohee Jeong
  • Article | | open

    Despite the enormous potential of magnetically-guided soft robots for various applications, challenges related to inefficient locomotion in harsh environments hinder its development. Here, the authors demonstrate a multi-legged millirobot with excellent locomotion capability in harsh environments.

    • Haojian Lu
    • , Mei Zhang
    • , Yuanyuan Yang
    • , Qiang Huang
    • , Toshio Fukuda
    • , Zuankai Wang
    •  & Yajing Shen