Jing Zhang

In this work, by altering the doping concentration of Eu³⁺, a color-tunable ML compound has been prepared. A stress-temperature dual-mode imaging system is constructed by utilizing the different responses of Tb³⁺ and Eu³⁺ ions to stress and temperature. Calculating I_R (I_Tb /I_Eu) and observing the corresponding color provide a solution for accurately obtaining real-time stress and temperature data. It has potential application prospects in human-computer interaction, structural safety detection, and multi-modal information storage.

Abstract

Mechanoluminescence (ML) refers to the luminescence phenomenon that occurs when a material is under external mechanical stimuli. However, relying solely on stress information to obtain ML signals is prone to test errors in complex test conditions. In this work, a Tb³⁺/Eu³⁺-doped Lu₃Al₂Ga₃O₁₂ multicolor ML material is reported, in which the ML color can be adjusted from white to red (CIE color coordinates: from (x = 0.313, y = 0.3293) to (x = 0.6183, y = 0.379)) by changing the Eu³⁺ concentration. In addition, LAGO: 0.25% Tb³⁺ and LAGO: 1.5% Eu³⁺ are physically mixed at different mass ratios, and the varied stimuli-responsed emission characteristics of Tb³⁺ and Eu³⁺ ions are used to develop a stress and temperature dual sensing device. Stress and temperature information can be further reflected simultaneously through the blue/red emission ratio I_R (I_Tb/I_Eu). As the temperature increases, the color changes from white to red (CIE color coordinates: from (x = 0.3259, y = 0.306) to (x = 0.4707, y = 0.3625)), and the relative temperature sensitivity (Sr) is as high as 1.209% K⁻¹ at 298 K. This sensing device provides a new idea for potential structural safety monitoring, multi-modal anti-counterfeiting technology, etc.

This work demonstrates the odd-even layer-dependence of out-of-plane ferroelectricity in ε-InSe. The device based on the ε-InSe achieves an on/off ratio of 10⁴ in ferroelectric tunneling junction and ultrafast bulk photovoltaic response in photodetector in the near-infrared band. Moreover, the photoresponse in ε-InSe can even exceed graphene in the same conditions, confirming the possibility of application in multifunctional devices.

Abstract

2D sliding ferroelectric semiconductors have greatly expanded the ferroelectrics family with the flexibility of bandgap and material properties, which hold great promise for ultrathin device applications that combine ferroelectrics with optoelectronics. Besides the induced different resistance states for non-volatile memories, the switchable ferroelectric polarizations can also modulate the photogenerated carriers for potentially ultrafast optoelectronic devices. Here, it is demonstrated that the room temperature sliding ferroelectricity can be used for ultrafast switchable photovoltaic response in ε-InSe layers. By first-principles calculations and experimental characterizations, it is revealed that the ferroelectricity with out-of-plane (OOP) polarization only exists in even layer ε-InSe. The ferroelectricity is also demonstrated in ε-InSe-based vertical devices, which exhibit high on-off ratios (≈10⁴) and non-volatile storage capabilities. Moreover, the OOP ferroelectricity enables an ultrafast (≈3 ps) bulk photovoltaic response in the near-infrared band, rendering it a promising material for self-powered reconfigurable and ultrafast photodetector. This work reveals the essential role of ferroelectric polarization on the photogenerated carrier dynamics and paves the way for hybrid multifunctional ferroelectric and optoelectronic devices.

As an emerging p-type van der Waals semiconductor, tellurium (Te) exhibits great potential in advancing future electronics and optoelectronics. This review provides a comprehensive overview of the fundamental properties and synthesis strategies of Te nanostructures, followed by a detailed discussion of the state-of-the-art progress in their application across various advanced devices, including electronics, optoelectronics, sensors, and large-scale circuits.

Abstract

As a true 1D system, group-VIA tellurium (Te) is composed of van der Waals bonded molecular chains within a triangular crystal lattice. This unique crystal structure endows Te with many intriguing properties, including electronic, optoelectronic, thermoelectric, piezoelectric, chirality, and topological properties. In addition, the bandgap of Te exhibits thickness dependence, ranging from 0.31 eV in bulk to 1.04 eV in the monolayer limit. These diverse properties make Te suitable for a wide range of applications, addressing both established and emerging challenges. This review begins with an elaboration of the crystal structures and fundamental properties of Te, followed by a detailed discussion of its various synthesis methods, which primarily include solution phase, and chemical and physical vapor deposition technologies. These methods form the foundation for designing Te-centered devices. Then the device applications enabled by Te nanostructures are introduced, with an emphasis on electronics, optoelectronics, sensors, and large-scale circuits. Additionally, performance optimization strategies are discussed for Te-based field-effect transistors. Finally, insights into future research directions and the challenges that lie ahead in this field are shared.

Silica nanozigzags (NZs) facilitate the in vitro maturation of dendritic cells (DCs) via mechanoactivation of focal adhesion kinase. The NZ-maturated DCs in vitro prime the cytotoxic T-lymphocytes (CTLs) into the programmed cell death protein-1 (PD-1)^lowCD44^high effector memory CTLs, and in vivo suppress the growth of tumors, indicating a promising new strategy for cancer immunotherapy.

Abstract

The efficacy of dendritic cell (DC)-based cancer vaccines is critically determined by the functionalities of in vitro maturated DCs. The maturation of DCs typically relies on chemicals that are cytotoxic or hinder the ability of DCs to efficiently activate the antigen-specific cytotoxic T-lymphocytes (CTLs) against tumors. Herein, the maturation chemicals are replaced with extracellular silica nanomatrices, fabricated by glancing angle deposition, to promote in vitro maturation of murine bone marrow-derived DCs (mBMDCs). The extracellular nanomatrices composed of silica nanozigzags (NZs) enable the generation of mature mBMDCs with upregulated levels of co-stimulatory molecules, C-C chemokine receptor type-7, X-C motif chemokine recetpor-1, DC-specific ICAM-3 grabbing nonintegrin, and enhanced endocytic capacity. The in vitro maturation is partially governed by focal adhesion kinase (FAK) that is mechanically activated in the curved cell adhesions formed at the DC-NZ interfaces. The NZ-maturated mBMDCs can prime the antigen-specific CTLs into programmed cell death protein-1 (PD-1)^lowCD44^high memory phenotypes in vitro and suppress the growth of tumors in vivo. Meanwhile, the NZ-mediated beneficial effects are also observed in human monocyte-derived DCs. This work demonstrates that the silica NZs promote the anti-tumor capacity of in vitro maturated DCs via the mechanoactivation of FAK, supporting the potential of silica NZs being a promising biomaterial for cancer immunotherapy.

Material systems with direction-asymmetric transport properties are scientifically intrguing with various potential applications. This study presents optical bi-layer metasurfaces that achieve generalized asymmetric transmission for any input polarization. Experimental results demonstrate polarization-direction-multiplexed vectorial holograms, enabling advanced optical encryption and paving the way for future applications in optical computation, sensing, and imaging.

Abstract

The field of optical systems with asymmetric responses has grown significantly due to their various potential applications. Janus metasurfaces are noteworthy for their ability to control light asymmetrically at the pixel level within thin films. However, previous demonstrations are restricted to the partial control of asymmetric transmission for a limited set of input polarizations, focusing primarily on scalar functionalities. Here, optical bi-layer metasurfaces that achieve a fully generalized form of asymmetric transmission for any input polarization are presented. The designs owe much to the theoretical model of asymmetric transmission in reciprocal systems, which elucidates the relationship between front- and back-side Jones matrices in general cases. This model reveals a fundamental correlation between the polarization-direction channels of opposing sides. To circumvent this constraint, partitioning the transmission space is utilized to realize four distinct vector functionalities within the target volume. As a proof of concept, polarization-direction-multiplexed Janus vectorial holograms generating four vectorial holographic images are experimentally demonstrated. When integrated with computational vector polarizer arrays, this approach enables optical encryption with a high level of obscurity. The proposed mathematical framework and novel material systems for generalized asymmetric transmission may pave the way for applications such as optical computation, sensing, and imaging.

The monolithic photolithograph integration of sub-5 µm perovskite quantum-dot (PeQD) pixels is achieved on 0.39-inch blue-backlight micro-LED screens. This integration demonstrates full-color image and video display capabilities, with remarkable features including brightness exceeding 400 000 nits, an ultra-high resolution of 3300 PPI, and a wide color gamut of 130.4% NTSC.

Abstract

Monolithic integration of color-conversion materials onto blue-backlight micro-light-emitting-diodes (micro-LEDs) has emerged as a promising strategy for achieving full-color microdisplay devices. However, this approach still encounters challenges such as the blue-backlight leakage and the poor fabrication yield rate due to unsatisfied quantum dot (QD) material and fabrication process. Here, the monolithic integration of 0.39-inch micro-display screens displaying colorful pictures and videos are demonstrated, which are enabled by creating interfacial chemical bonds for wafer-scale adhesion of sub-5 µm QD-pixels on blue-backlight micro-LED wafer. The ligand molecule with chlorosulfonyl and silane groups is selected as the synthesis ligand and surface treatment material, facilitating the preparation of high-efficiency QD photoresist and the formation of robust chemical bonds for pixel integration. This is a leading record in micro-display devices achieving the highest brightness larger than 400 thousand nits, the ultrahigh resolution of 3300 PPI, the wide color gamut of 130.4% NTSC, and the ultimate performance of service life exceeding 1000 h. These results extend the mature integrated circuit technique into the manufacture of micro-display device, which also lead the road of industrialization process of full-color micro-LEDs.

A facile method of gradient polymerization induced by a small molecule of itaconic acylhydrazine (IAH) is presented to prepare Janus-structured polymer skin patches with congeneric, robust adhesive, and high SNR to capture high-quality ECG signals under a variety of interferences, demonstrating its potential for future healthcare applications.

Abstract

Epidermal patches utilized for the transduction of biopotentials and biomechanical signals are pivotal in wearable health monitoring. However, the shortcomings, such as inferior conformal ability, deficient adhesion, and motion artifacts, severely impede the bioelectrodes from perceiving stable and superior-quality physiological signals. Herein, a polymer epidermal patch possessing a spontaneous Janus structure is facilely prepared through itaconic acylhydrazine (IAH) induced gradient polymerization. The solubility discrepancy of the monomers in IAH authorized the Janus structure with distinct adhesion properties on each side. Moreover, the hydrogen bond network constructed by IAH confers the polymer with a high degree of skin compliance, enabling dynamic and stable mechanical properties to withstand complex monitoring environments. By integrating skin-like softness (Young's modulus ≈0.16 MPa), robust adhesion (35 kPa), and high signal-to-noise ratio (32 dB), this epidermal patch displays exceptional elasticity within the physiological activity spectrum, provides swift electrical and mechanical self-recovery capabilities, and resists interference in dynamic signal monitoring (deformation, compression, humidity, etc.). By demonstrating multifaceted applications for Electrocardiogram recording under diverse disturbances, the epidermal patch profiles a promising noninvasive, enduring wearable bioelectronic interface with immunity to interference.

This study leverages the preferential recognition of red and green by human eye cone cells, selecting transition metal Mn²⁺ ions and rare earth Tb³⁺ ions as the emission centers for mechanoluminescence (ML). Through various mechanisms, it achieves visual ratiometric ML dynamic pressure sensing under conditions of uniform stretching and pressure deformation.

Abstract

Optical sensing technology based on mechanoluminescent (ML) materials offers advantages such as rapid response, real-time monitoring, visual signal output, and multi-functional sensing, making it promising for various applications. However, traditional sensing techniques based on the absolute intensity of ML suffer from issues of low accuracy and large errors, which have a significant impact on the reliability and visual effectiveness of the sensor. To address these problems, this study employs a ratiometric ML pressure sensing method. By utilizing the primary color recognition of human cone cells, transition metal ion Mn²⁺ and rare earth ion Tb³⁺ are selected as luminescent centers. The rich intermediate colors ensure a wide range of colors that are easily distinguishable by the human eye. Through studies involving mechanical stimulation and similar high-energy radiation, it is confirmed that the differences in sensitivity between rare earth ions and transition metal ions, as well as the contributions of shallow trap states, are the reasons for the dynamic changes in the ratiometric ML intensity. Finally, a conceptual application of pressure sensing is realized by combining homogeneous gas compression with pipeline monitoring for dynamic visualization, self-referencing, and high-precision mechanical sensing.

Nature, Published online: 11 September 2024; doi:10.1038/d41586-024-02862-z

Tiny cellular tubes between neurons and brain cells called microglia serve as conduits for the export of toxic protein aggregates from neurons and the import of healthy organelles, keeping neurodegeneration at bay.

Nature, Published online: 11 September 2024; doi:10.1038/s41586-024-07925-9

A molecular aggregate formed in a two-dimensional organic–inorganic hybrid perovskite superlattice with a near-equilibrium distance is shown to have a near-unity photoluminescence quantum yield like that of single molecules, despite being in an aggregated state.

Nature Physics, Published online: 12 September 2024; doi:10.1038/s41567-024-02626-6

How cells manage the internal energetic budget to drive mechanical and chemical dynamics is still an open question. Now it is shown that the allocation of energy depends on the distance from thermodynamic equilibrium.

Nature Materials, Published online: 11 September 2024; doi:10.1038/s41563-024-02007-7

Shape transformations in microrobots less than 1 mm in size remain challenging. Here the authors present an electronically configurable metasheet microrobot with reprogrammable shapes and locomotory gaits in an electrolytic solution.

Nature Photonics, Published online: 13 September 2024; doi:10.1038/s41566-024-01517-9

Cr3+-sensitized lanthanide-doped nanoparticles afford high-brightness luminescence in the near-infrared region for applications in in vivo non-invasive bioimaging.

A hybrid material combining molybdenum disulfide (MoS₂) and spiropyran for humidity and light responsiveness is developed. Ultraviolete (UV) irradiation tunes the wettability of MoS₂ decorated by spiropyran, enhancing the humidity sensitivity. Water adsorption and photochromic doping significantly alter the optoelectronic properties of MoS₂ flakes, greatly improving device performance.

Abstract

The optically tuneable nature of hybrid organic/inorganic heterostructures tailored by interfacing photochromic molecules with 2D semiconductors (2DSs) can be exploited to endow multi-responsiveness to the exceptional physical properties of 2DSs. In this study, a spiropyran-molybdenum disulfide (MoS₂) light-switchable bi-functional field-effect transistor is realized. The spiropyran-merocyanine reversible photo-isomerization has been employed to remotely control both the electron transport and wettability of the hybrid structure. This manipulation is instrumental for tuning the sensitivity in humidity sensing. The hybrid organic/inorganic heterostructure is subjected to humidity testing, demonstrating its ability to accurately monitor relative humidity (RH) across a range of 10%–75%. The electrical output shows good sensitivity of 1.0% · (%) RH⁻¹. The light-controlled modulation of the sensitivity in chemical sensors can significantly improve their selectivity, versatility, and overall performance in chemical sensing.

Small (sub-20 nm) lanthanide-doped nanoparticles are successfully utilized in electron microscopy to label biological structures and contextualize them in the cell's ultrastructure. Leveraging unique energy-dispersive X-ray signatures, the nanoparticles' location and doping-identity is easily and fast retrieved, demonstrating the methods' potential to (co)-localize labels while supplying a holistic impression of the underlying processes, as entire cells can be mapped.

Abstract

Understanding the localization and the interactions of biomolecules at the nanoscale and in the cellular context remains challenging. Electron microscopy (EM), unlike light-based microscopy, gives access to the cellular ultrastructure yet results in grey-scale images and averts unambiguous (co-)localization of biomolecules. Multimodal nanoparticle-based protein labels for correlative cathodoluminescence electron microscopy (CCLEM) and energy-dispersive X-ray spectromicroscopy (EDX-SM) are presented. The single-particle STEM-cathodoluminescence (CL) and characteristic X-ray emissivity of sub-20 nm lanthanide-doped nanoparticles are exploited as unique spectral fingerprints for precise label localization and identification. To maximize the nanoparticle brightness, lanthanides are incorporated in a low-phonon host lattice and separated from the environment using a passivating shell. The core/shell nanoparticles are then functionalized with either folic (terbium-doped) or caffeic acid (europium-doped). Their potential for (protein-)labeling is successfully demonstrated using HeLa cells expressing different surface receptors that bind to folic or caffeic acid, respectively. Both particle populations show single-particle CL emission along with a distinctive energy-dispersive X-ray signal, with the latter enabling color-based localization of receptors within swift imaging times well below 2 min per μm$\umu\text{m}$² while offering high resolution with a pixel size of 2.78 nm. Taken together, these results open a route to multi-color labeling based on electron spectromicroscopy.

A range of inkjet-printable 2D material inks is prepared for the fabrication of inkjet-printed, ultra-flexible and machine-washable 2D material heterostructure-based textile micro-supercapacitors. Such micro-supercapacitors demonstrate higher energy (≈18.06 µWh cm^‒2) and power densities (≈4333.33 µW cm^‒2), as well as ≈82.48% higher areal capacitance with excellent capacitance retention (≈95% after 1000 cycles).

Abstract

Wearable electronic textiles (e-textiles) have emerged as promising healthcare solutions, offering point-of-care diagnostics while maintaining breathability, comfort, durability, and environmental stability with strong mechanical performance. However, the lack of thin and flexible power supplies hinders their practical adoption. In this regard, textile-based micro-energy storage devices present an appealing solution. Inkjet printing offers the capability to produce high-quality prints with sharp details and versatile substrate compatibility, making it an ideal choice for a wide array of printing applications. Here, the preparation of a range of inkjet-printable 2D material inks is reported for the fabrication of ultra-flexible and machine-washable textile micro-supercapacitors. Then 2D material heterostructures are proposed to enhance the performance of textile supercapacitors. This study reveals that a unique combination of highly conductive graphene with an insulator hexagonal boron nitride (h-BN) can enhance the areal capacitance of graphene-based textile supercapacitors by ≈82.48%. The heterostructure-based supercapacitors also demonstrate higher energy (≈18.06 µWh cm⁻²) and power densities (≈4333.33 µW cm⁻²) with excellent capacitance retention (≈95% after 1000 cycles). These findings on inkjet-printed heterostructure-based supercapacitors may herald a new era for the future application of high-performance micro-supercapacitors within textile-based wearable technology.

A pair of amino-borane isomers are synthesized in order to investigate the impact of the charge transfer channel on phosphorescence emission. Interestingly, they exhibit multi-substrate multicolor luminescence, phosphorescent energy transfer, multi-level data encryption, and textile information encryption behaviors, which opens a new way for the design and application of organic room-temperature phosphorescent materials.

Abstract

Significant advances are made in understanding the structure-property relationship in room-temperature phosphorescence (RTP) materials. For example, intramolecular charge transfer (ICT) structural molecules based on electron donors(D) and electron acceptors(A) are an efficient method to achieve RTP. However, the ability to precisely regulate the singlet-triplet energy gap (ΔE _ST) through molecular design to control RTP emissions remains constrained. Herein, a group of 4BN-NP and 5BN-NP isomers is reported with D and A position isomerization, where 4BN-NP exhibits a photo-induced orange afterglow phenomenon in PMMA. Calculations show that the spin-orbit coupling (SOC) value of 4BN-NP is greater compared to 5BN-NP and the intersystem crossing (ISC) channel is more efficient, resulting in a smaller ΔE _ST value for 4BN-NP. This indicates that the short ICT channel is more conducive to inducing phosphorescence emission. In addition, compound 4BN-NP co-doped with red fluorescent dyes (RhB, Rh6G, and RBNN) in PMMA produces phosphorescence resonance energy transfer (PRET), inducing red afterglow emission. Surprisingly, light-activated yellow RTP can be obtained by attaching 4BN-NP with polymethyl methacrylate (PMMA) to nylon filaments, and its phosphorescence intensity does not diminish even when it is immersed in water containing detergent solution, thus expanding the prospects of its application in textile encryption.

The study develops a nanopore-in-a-tube (NIAT) device that precisely regulates molecule translocation in a funnel-shaped nanopore by controlling the inertial angle and centrifugation speed in a centrifuge. This ensures stable signal readout with a high signal-to-noise ratio, enabling nanoscale sensing of single molecules.

Abstract

Nanopore is commonly used for high-resolution, label-free sensing, and analysis of single molecules. However, controlling the speed and trajectory of molecular translocation in nanopores remains challenging, hampering sensing accuracy. Here, the study proposes a nanopore-in-a-tube (NIAT) device that enables decoupling of the current signal detection from molecular translocation and provides precise angular inertia-kinetic translocation of single molecules through a nanopore, thus ensuring stable signal readout with high signal-to-noise ratio (SNR). Specifically, the funnel-shaped silicon nanopore, fabricated at a 10-nm resolution, is placed into a centrifugal tube. A light-induced photovoltaic effect is utilized to achieve a counter-balanced state of electrokinetic effects in the nanopore. By controlling the inertial angle and centrifugation speed, the angular inertial force is harnessed effectively for regulating the translocation process with high precision. Consequently, the speed and trajectory of the molecules are able to be adjusted in and around the nanopore, enabling controllable and high SNR current signals. Numerical simulation reveals the decisive role of inertial angle in achieving uniform translocation trajectories and enhancing analyte-nanopore interactions. The performance of the device is validated by discriminating rigid Au nanoparticles with a 1.6-nm size difference and differentiating a 1.3-nm size difference and subtle stiffness variations in flexible polyethylene glycol molecules.

A novel electro–microfluidic assembly colloidal particle droplet array platform is developed, featuring large-scale, rapidly reversible assemblies. This platform encodes precise information within individual droplets via addressable electrodes beneath them. Moreover, it can create dynamic informative droplet arrays and offer significant potential for anti-counterfeiting applications as an advanced electronic token.

Abstract

The assembly of colloidal particles into micro-patterns is essential in optics, informatics, and microelectronics. However, it is still a challenge to achieve quick, reversible, and precise assembly patterns within micro-scale spaces like droplets. Hereby, a method is presented that utilizes in-plane dielectrophoresis to precisely manipulate particle assemblies within microscale droplets. The electro–microfluidic particle assembly platform, equipped with ingenious electrode designs, enables the formation of diverse micro-patterns within a droplet array. The tunability, similarity, stability, and reversibility of this platform are demonstrated. The ability to assemble letters, numbers, and Morse code patterns within the droplet array underscores its potential for information encoding. Furthermore, using an example with four addressing electrodes beneath a droplet, 16 distinct pieces of information through electrical stimuli is successfully encoded. This unique capability facilitates the construction of a dynamic electronic token, indicating promising applications in anti-counterfeiting technologies.

Anomalous Hall effect is observed in quasi-1D Dirac Material La₃MgBi₅. The obtained anomalous Hall conductivity is the largest one in the current anomalous Hall effect systems. Especially, the absence of magnetic elements makes La₃MgBi₅ one of the few non-magnetic materials that can exhibit anomalous Hall effect.

Abstract

Anomalous Hall effect (AHE), one of the most important electronic transport phenomena, generally appears in ferromagnetic materials but is rare in materials without magnetic elements. Here, a study of La₃MgBi₅ is presented, whose band structure carries multitype Dirac fermions. Although magnetic elements are absent in La₃MgBi₅, the signals of AHE can be observed. In particular, the anomalous Hall conductivity is extremely large, reaching 42,356 Ω⁻¹ cm⁻¹ with an anomalous Hall angle of 8.8%, the largest one that has been observed in the current AHE systems. The AHE is suggested to originate from the combination of skew scattering and Berry curvature. Another unique property discovered in La₃MgBi₅ is the axial diamagnetism. The diamagnetism is significantly enhanced and dominates the magnetization in the axial directions, which is the result of the restricted motion of the Dirac fermion at the Fermi level. These findings not only establish La₃MgBi₅ as a suitable platform to study AHE and quantum transport but also indicate the great potential of 315-type Bi-based materials for exploring novel physical properties.

The formation process of nano-patterned biologically-formed silica is investigated using in situ electron microscopy that allows for 3D visualization at the nanometer scale. The data show a two-step process that yields a hexagonal lattice based on the sequential formation of parallel rods, followed by their connection via evenly spaced bridges.

Abstract

Organisms are able to control material patterning down to the nanometer scale. This is exemplified by the intricate geometrical patterns of the silica cell wall of diatoms, a group of unicellular algae. Theoretical and modeling studies propose putative physical and chemical mechanisms to explain morphogenesis of diatom silica. Nevertheless, direct investigations of the underlying formation process are challenging because this process occurs within the confines of the living cell. Here, a method is developed for in situ 3D visualization of silica development in the diatom Stephanopyxis turris, using electron microscopy slice-and-view techniques. The formation of an isotropic hexagonal pattern made of nanoscale pores is documented. Surprisingly, these data reveal a directional process that starts with elongation of silica rods along one of the three equivalent orientations of the hexagonal lattice. Only as a secondary step, these rods are connected by crisscrossing bridges that give rise to the complete hexagonal pattern. These in situ observations combine two known properties of diatom silica, close packing of pores and branching of rods, to a unified process that yields isotropic patterns from an anisotropic background. Future research into diatom morphogenesis should focus on rod elongation and branching as the key for pattern formation.

Nature Communications, Published online: 06 September 2024; doi:10.1038/s41467-024-51987-2

No method exists for real-time evaluation of the status of spinal implants. Here, the authors developed a bio-adhesive metal detector array (BioMDA) that provides a wearable, non-invasive solution for positional analyses of osseous implants within the spine.

SIP-nanoFTIR is a new single-cell spectroscopic technique capable of simultaneous metabolic quantitation and high-resolution imaging. It is employed here, capturing environmentally induced variations in protein synthesis and morphology, and unique spectroscopic features linked to specific cellular growth phases. As such, SIP-nanoFTIR provides a connection from subcellular translational processes, to single-cell heterogeneity, to broader population-wide changes.

Abstract

This study utilizes nanoscale Fourier transform infrared spectroscopy (nanoFTIR) to perform stable isotope probing (SIP) on individual bacteria cells cultured in the presence of ¹³C-labelled glucose. SIP-nanoFTIR simultaneously quantifies single-cell metabolism through infrared spectroscopy and acquires cellular morphological information via atomic force microscopy. The redshift of the amide I peak corresponds to the isotopic enrichment of newly synthesized proteins. These observations of single-cell translational activity are comparable to those of conventional methods, examining bulk cell numbers. Observing cells cultured under conditions of limited carbon, SIP- nanoFTIR is used to identify environmentally-induced changes in metabolic heterogeneity and cellular morphology. Individuals outcompeting their neighboring cells will likely play a disproportionately large role in shaping population dynamics during adverse conditions or environmental fluctuations. Additionally, SIP-nanoFTIR enables the spectroscopic differentiation of specific cellular growth phases. During cellular replication, subcellular isotope distribution becomes more homogenous, which is reflected in the spectroscopic features dependent on the extent of ¹³C-¹³C mode coupling or to specific isotopic symmetries within protein secondary structures. As SIP-nanoFTIR captures single-cell metabolism, environmentally-induced cellular processes, and subcellular isotope localization, this technique offers widespread applications across a variety of disciplines including microbial ecology, biophysics, biopharmaceuticals, medicinal science, and cancer research.

Electronic charge transport through multilayers of the protein bacteriorhodopsin (bR) shows an intriguing, mono-exponential conductance attenuation with layer thickness up to ≈16 nm. A measured small attenuation coefficient β ≈ 0.8 nm⁻¹ indicates efficient long-range transport, which is mostly limited by charge injection at the interfaces.

Abstract

The remarkable ability of natural proteins to conduct electricity in the dry state over long distances remains largely inexplicable despite intensive research. In some cases, a (weakly) exponential length-attenuation, as in off-resonant tunneling transport, extends to thicknesses even beyond 10 nm. This report deals with such charge transport characteristics observed in self-assembled multilayers of the protein bacteriorhodopsin (bR). ≈7.5 to 15.5 nm thick bR layers are prepared on conductive titanium nitride (TiN) substrates using aminohexylphosphonic acid and poly-diallyl-dimethylammonium electrostatic linkers. Using conical eutectic gallium-indium top contacts, an intriguing, mono-exponential conductance attenuation as a function of the bR layer thickness with a small attenuation coefficient β ≈ 0.8 nm⁻¹ is measured at zero bias. Variable-temperature measurements using evaporated Ti/Au top contacts yield effective energy barriers of ≈100 meV from fitting the data to tunneling, hopping, and carrier cascade transport models. The observed temperature-dependence is assigned to the protein-electrode interfaces. The transport length and temperature dependence of the current densities are consistent with tunneling through the protein–protein, and protein-electrode interfaces, respectively. Importantly, the results call for new theoretical approaches to find the microscopic mechanism behind the remarkably efficient, long-range electron transport within bR.

A novel laser thermal printing technique toward the fabrication of all-in-one flexible intelligent devices is proposed, and a multifunctional intelligent cobweb structure is synthesized for demonstration. The printed intelligent cobweb seamlessly incorporates multifunctional sensing, stimulus response, and actuation, indicating that the proposed technique has great potential in efficiently fabricating miniaturized and multifunctional flexible intelligent devices.

Abstract

A novel laser thermal printing technique toward the fabrication of all-in-one flexible intelligent devices is presented in this work, addressing the existing challenges in their scalable manufacturing and multifunctional performance. The first-ever application of this technique for the synthesis of a multifunctional intelligent cobweb structure is presented. The resultant cobweb integrates a conductive network of multi-walled carbon nanotubes (MWCNTs) and NdFeB magnetic microparticles within a polydimethylsiloxane (PDMS) matrix, enabling seamless incorporation of sensing, stimulus response, and actuation functionalities. The cobweb exhibits multifunctional sensing characteristics, including a 2.37 strain gauge factor and a 0.312%·mT⁻¹ magnetic field sensitivity, excellent stability exceeding 3500 cycles. Furthermore, the cobweb achieves accurate capture of a beetle on the basis of real-time sensing of the beetle, verifying its rapid stimulus response characteristics. Meanwhile, the cobweb exhibits an electromagnetic ejection performance with an ejection height of over 33.5 times the size of the projectile, verifying its powerful actuating ability. These results demonstrate the successful integration of multifunctional sensing, stimulus response, and actuation within the cobweb structure, facilitated by the innovative laser thermal printing process. The laser thermal printing technique marks a significant advancement in the efficient fabrication of miniaturized and multifunctional flexible intelligent devices based on thermosetting materials.

Nature Reviews Materials, Published online: 23 August 2024; doi:10.1038/s41578-024-00718-6

An article in Science Robotics presents a high-energy-density, picolitre-sized battery.