Jing Zhang

Nature Photonics, Published online: 14 June 2024; doi:10.1038/s41566-024-01462-7

Super-resolved photonic force microscopy employs the fluorescence of lanthanide-doped nanoparticles as a force probe, enabling the measurement of sub-femtonewton forces with a sensitivity of 1.8 fN Hz–1/2, approaching the thermal limit.

Nature Communications, Published online: 14 June 2024; doi:10.1038/s41467-024-49398-4

Magnetic anisotropy in mixed rare earth iron garnet films is shown to originate from the atomic ordering of the rare earth cations during growth of the film. Cation ordering on inequivalent sites provides a powerful strategy to engineer the magnetic properties of complex oxides.

Cell membrane perforation is a promising technique with diverse applications, including assisting intracellular delivery, eliminating diseased or cancerous cells, and bringing about other benefits. In this review, the patterns of cell membrane perforation based on the mechanisms and the functions are introduced, aiming to shed light on its broad applications in biomedical science.

Abstract

Cell membrane is crucial for the cellular activities, and any disruption to it may affect the cells. It is demonstrated that cell membrane perforation is associated with some biological processes like programmed cell death (PCD) and infection of pathogens. Specific developments make it a promising technique to perforate the cell membrane controllably and precisely. The pores on the cell membrane provide direct pathways for the entry and exit of substances, and can also cause cell death, which means reasonable utilization of cell membrane perforation is able to assist intracellular delivery, eliminate diseased or cancerous cells, and bring about other benefits. This review classifies the patterns of cell membrane perforation based on the mechanisms into 1) physical patterns, 2) biological patterns, and 3) chemical patterns, introduces the characterization methods and then summarizes the functions according to the characteristics of reversible and irreversible pores, with the aim of providing a comprehensive summary of the knowledge related to cell membrane perforation and enlightening broad applications in biomedical science.

Smart Contact Lens

In article number 2309785, Weihua Pei, Kai Jiang, La Li, Guozhen Shen, and co-workers present a Ti₃C₂T _x MXene-based contact lens sensor with an extremely high sensitivity of 7.483 mV mmHg⁻¹, which is then integrated with the wireless module and achieve real-time intraocular pressure monitoring and warning via mobile phones. This work provides a new material platform and new thoughts for future multifunctional implantable microelectronics.

End-to-end fabrication of microgels, including uniform dispersion, homogeneous gelation, and continuous extraction, is realized in a gravity-oriented microfluidic device. Microgels extraction is achieved by buoyancy guidance and pseudosurfactant-induced acceleration, which is applicable to microgels down to 15 µm in diameter and of varying stiffness. This method maintains excellent cell viability with minimal variations, enhancing the practicality of microfluidics-based cell encapsulation.

Abstract

Droplet microfluidics are extensively utilized to generate monodisperse cell-laden microgels in biomedical applications. However, maintaining cell viability is still challenging due to overexposure to harsh conditions in subsequent procedures that recover the microgels from the oil phase. Here, a gravity-oriented microfluidic device for end-to-end fabrication of cell-laden microgels is reported, which integrates dispersion, gelation, and extraction into a continuous workflow. This innovative on-chip extraction, driven by native buoyancy and kinetically facilitated by pseudosurfactant, exhibits 100% retrieval efficiency for microgels with a wide range of sizes and stiffnesses. The viability of encapsulated cells is perfectly maintained at ≈98% with minimal variations within and between batches. The end-to-end fabrication remarkably enhances the biocompatibility and practicality of microfluidics-based cell encapsulation and is promising to be compatible with various applications ranging from single-cell analysis to clinical therapy.

Nature Communications, Published online: 11 June 2024; doi:10.1038/s41467-024-49186-0

Activated B cells and T cells accumulate within joints of patients with rheumatoid arthritis. Here, the authors use single-cell transcriptome and repertoire profiling to identify clonally expanded synovial B cells and T cells and define their phenotypes and predicted cell-cell interactions.

Active optical waveguide materials based on luminescent liquid crystals are designed and synthesized. The integrated properties of long-range order structure, diverse phases, dynamic reconfiguration capabilities, and response to external fields place luminescent liquid crystals in a unique position to create ideal organic active optical waveguide materials.

Abstract

Organic optical waveguide materials have attracted considerable attention for their promising applications in photonic and optoelectronic devices. However, for most materials, excellent light-loss properties at high temperature cannot be obtained due to many factors. Consequently, realizing efficient optical waveguide materials that perform well at elevated temperatures remains a significant challenge. In this study, relying on the luminescent properties and self-assembly properties of luminescent liquid crystals (LLCs), successfully fabricated materials are present for highly efficient active optical waveguides. A systematically synthesized set of LLCs with different structures is named according to the substituent type and the position of the cyano group, namely α-DECN, α-DEEOCN, β-DECN, and β-DEEOCN. Notably, α-DECN and β-DECN reveal hexagonal columnar phase, while α-DEEOCN and β-DEEOCN exhibit smectic phase. Optical waveguide experiments have revealed that the obtained LLCs showed highly efficient optical waveguide behavior, where the lowest light loss reached 0.15 dB mm⁻¹ at room temperature. Remarkably, these LLCs show even lower light loss at high temperatures, with the light loss reaching 0.11 dB mm⁻¹ as the lowest point. Further experimental results indicate that this phenomenon is attributed to the change in the dipole moment of these molecules. This research forms a significant groundwork for advanced exploration in optical waveguide material.

The work demonstrates the shift of absorbance from UV-B to UV-A and the generation of white light emission using CCTC NCs.

Abstract

Recently, lanthanide-based 0D metal halides have garnered considerable attention owing to their applications in light–emitting diodes (LEDs), X-ray imaging, and photodetectors. Among these materials, 0D Cs₃TbCl₆ (CTC) nanocrystals (NCs) have demonstrated promising performance in X-ray imaging and light-emitting diodes. However, a considerable drawback of CTC NCs is their limited absorption coefficient in the UV-A region (315–380 nm). To address this limitation and enhance the absorption coefficient in the UV-A region, Ce³⁺ is incorporated into CTC NCs—advantageous owing to the high absorption coefficient of Ce³⁺ in the UV-A region, attributed to—4f-5d orbital coupling. In addition, Ce³⁺ ions sensitize the luminescence of CTC NCs and enhance the photoluminescence quantum yield from 75% to 87%. Energy transfer from Ce³⁺ to Tb³⁺ is investigated at different dopant ratios. Furthermore, Cs₃CeTbCl₆ (CCTC) NCs have been utilized in white LED devices. Understanding such competitive energy transfer in lanthanide-based perovskite-inspired metal halides will facilitate the development of novel luminescent metal halides for lighting applications.

A pyramid-shaped perovskite single crystal is successfully synthesized with an asymmetrically spatial confinement induced crystallization method. The photodetector, constructed by the as-grown crystal, exhibits enhanced optoelectronic properties, including high responsivity 9.4 A W^-1, insensitivity to the incident photon direction, and flexibility under bending condition.

Abstract

To boost the power conversion efficiency of silicon/perovskite tandem solar cells, pyramid-textured structures have been investigated and introduced into devices. However, high-quality pyramid-shaped single crystal preparation is an obstacle in tandem device development. Perovskite crystals obtained using general methods are cubic because of their structural symmetry and rapid growth rate. In this study, based on mass transfer boundary layer theory, a pyramid-shaped perovskite single crystal is successfully obtained using an asymmetrically spatial confinement-induced crystallization method. The synthesized pyramid crystals exhibited high crystallinity and enhanced optical absorption. A photodetector constructed using the as-grown crystal exhibited high-performance properties, including a responsivity of 9.4 A W⁻¹, photo-to-dark current ratio of 2.3 × 10⁴, and detectivity of 2.1 × 10¹¹ Jones. Its unique insensitivity to the incident photon direction is also characterized. The flexible photodetector also exhibited excellent responsivity under different bending curvature radii. Additionally, the light-trapping effect and absorption superiority of pyramid crystals over cuboid crystals are well established based on a semi-empirical analytical model. This breakthrough in pyramid-shaped perovskite crystal preparation provides a promising approach for the development of novel tandem solar cells and other optoelectronic devices.

Gold nanoprisms act as optical switchers inside the tissue of Hydra vulgaris. Following NIR illumination the heat locally delivered modulates several molecular pathways, promoting stem cell self-renewal, proliferation and differentiation of head tissue. The final outcome is the enhancement of the regeneration efficiency.

Abstract

The possibility to remotely manipulate intracellular pathways in single cells is among the current goals of regenerative medicine, demanding new strategies to enhance tissue repair and reprogram stem cell activity. Plasmonic nanomaterials are addressing this need, due to improvements in the controlled synthesis allowing convenient regulation and precise thermal positioning. Leveraging on the thermal properties of gold nanoprisms (AuNPs) and on the unparalleled regenerating capabilities of the small invertebrate Hydra vulgaris, here the possibility to activate the molecular machinery underlying the animal regeneration by using AuNPs and applying regular pulses of near infrared irradiation (NIR) is shown. The efficiency of the head regeneration, reproductive capability, and stem cell proliferation rate are boosted by the AuNP photostimulation, indicating NIR triggered hyperthermia as new tool to enhance tissue regeneration. By transcriptional profiling of key developmental genes in animals exposed to external heat or irradiated an estimation of the heat developed in vivo by intracellular nanoheaters is obtained, revealing Hydra as a living thermometer to test performance of plasmonic materials. These results shed light on a novel function of heat emitting nanoparticles to control cell stemness through the activation of molecular pathways that can be targeted for regenerative medicine or wound healing strategies.

The liquid metal nanoreactor strategy is proposed for realizing high-entropy alloy arrays. The coalescence nature endowed by the tendency to decrease surface energy constructed the basis of the nanoreactor to provide a confined reaction environment for the nucleation and growth of multiple elements, thus forming a single particle within each patterned feature.

Abstract

High-entropy alloy (HEA) nanostructures arranged into well-defined configurations hold great potential for accelerating the development of electronics, photonics, catalysis, and device integration. However, the random nucleation induced by the disparity in physicochemical properties of multiple elements makes it challenging to achieve single-particle synthesis at the patterned preset sites in the high-entropy scenario. Herein, the liquid metal nanoreactor strategy is proposed to realize the construction of HEA arrays. The coalescence of the liquid metal driven by the tendency to decrease surface energy provides a restricted environment for the nucleation and growth to form single HEA particles at the preset locations, which can be regarded as a self-confinement reaction. Liquid metal endowing a low diffusion energy barrier on the substrate and a high diffusivity of the alloy system can dynamically promote the aggregation process. As a result, the HEA array is prepared with elements up to eleven and possesses uniform periodicity, which exhibits excellent holography response in a broad spectrum. This work injects new vitality into the construction of HEA nanopatterns and provides an excellent platform for propelling their fundamental research and applications.

Nature Photonics, Published online: 10 June 2024; doi:10.1038/s41566-024-01454-7

A fully hybrid integrated erbium-doped photonic integrated waveguide laser with wide tuning of 40 nm, side-mode suppression ratio of >70 dB and output power up to 17 mW is demonstrated, achieving not only footprint reduction but also the long-anticipated fibre-laser coherence.

This research unveils a facile technique for creating intricate patterns in multi-material combinations. The technique uses a cross-flow concept-driven nozzle design, enhancing multi-material 3D printing. The interaction between liquid metal and polymer generates versatile patterns. These patterns increase capacitance in dielectric polymers, enabling the development of affordable yet sensitive pressure sensors and accurate motion detection in wearable devices.

Abstract

This paper presents a scalable and straightforward technique for the immediate patterning of liquid metal/polymer composites via multiphase 3D printing. Capitalizing on the polymer's capacity to confine liquid metal (LM) into diverse patterns. The interplay between distinctive fluidic properties of liquid metal and its self-passivating oxide layer within an oxidative environment ensures a resilient interface with the polymer matrix. This study introduces an inventive approach for achieving versatile patterns in eutectic gallium indium (EGaIn), a gallium alloy. The efficacy of pattern formation hinges on nozzle's design and internal geometry, which govern multiphase interaction. The interplay between EGaIn and polymer within the nozzle channels, regulated by variables such as traverse speed and material flow pressure, leads to periodic patterns. These patterns, when encapsulated within a dielectric polymer polyvinyl alcohol (PVA), exhibit an augmented inherent capacitance in capacitor assemblies. This discovery not only unveils the potential for cost-effective and highly sensitive capacitive pressure sensors but also underscores prospective applications of these novel patterns in precise motion detection, including heart rate monitoring, and comprehensive analysis of gait profiles. The amalgamation of advanced materials and intricate patterning techniques presents a transformative prospect in the domains of wearable sensing and comprehensive human motion analysis.

Non-adsorbed polymer chains result in island formation during layer-by-layer (LbL) deposition, impacting morphology, roughness, surface chemistry, and mechanical properties of LbL nanofilms. These properties can be used to tune cell behavior, including morphology and cell proliferation. These insights emphasize the potential of LbL techniques for precise manipulation of cell behavior and the design of tailored cellular microenvironments.

Abstract

This study provides a detailed molecular mechanism of the layer-by-layer (LbL) film formation process involving BB polymers. The roles of adsorbed and non-adsorbed chain segments during the layer buildup are revealed by employing surface force apparatus (SFA) and atomic force microscopy (AFM) to probe critical aspects such as surface coverage, polymer conformation at the surface, adhesive properties, and morphology after each layer deposition. The results show that the thickness, nanomechanical properties, and surface chemistry of the nanofilms are significantly influenced by the number of layers. All these cues have an important impact on cell behavior when employed as coatings for culture substrates. The evidence is shown that cells respond very differently to these cues and exhibit behavior that goes from superproliferation down to accelerated death.

A novel, electrically-driven variable-stiffness fiber transitions from a flat to curved cross-section, providing a rigid structure when powered and flexibility otherwise. This actively-rigid, passively-soft fiber enables the creation of sturdy legs for thin, fabric-based machines while retaining flexibility when unpowered. Paired with a compatible actuator, this fiber enables a first-of-its-kind, fully untethered locomoting robotic fabric.

Abstract

A robot that uses fabrics as its core body material can be lightweight, compact, and highly flexible. Ideally, the robot's actuation, sensing, and structural support are provided by fiber-based components, designed to integrate with the fabric's soft and conformable nature while preserving its fiber architecture. Typically, variable stiffness fibers are used for the structural elements, functioning as “bones” that can be turned on and off as needed. However, many variable stiffness fibers are passively-rigid, only allowing the fabric to become soft when powered, while some require bulky external air or power supplies, making them untenable for untethered robotics. In this work, an electrically-driven variable stiffness fiber is presented that performs a flat-to-curved geometry transition, providing a rigid load-bearing structure when powered but remaining flexible otherwise. Design principles for pairing the actively-rigid variable stiffness fiber with a materially compatible fiber-based actuator are presented, and the actuator performance in different configurations is characterized. The variable stiffness fiber can be arranged into sturdy legs, stable enough for a robotic fabric to lift and hold its own battery pack and onboard electronics. This capability is demonstrated with a first-of-its-kind fully-untethered locomoting robotic fabric using two different quadruped gaits.

(Me₂NH₂)₄MCl₆·Cl (M = Sb, In) exhibits the superior temperature/component-dependent luminescence behaviors resulting from the competition transition between the triplet-states (T_n-S₀) STEs of inorganic units and the singlet-state (S₁-S₀) of organic cations, which is manipulated by the optical activity levels of [SbCl₆]³⁻ and [InCl₆]³⁻. This work sheds light on the different electron-transition mechanisms, as well as explores the optical-functional applications such as temperature sensors and anti-counterfeiting.

Abstract

Hybrid metal halides (HMHs) have emerged as a promising platform for optically functional crystalline materials, but it is extremely challenging to thoroughly elucidate the electron transition coupled to additional ligand emission. Herein, to discover sequences of lead-free HMHs with distinct optically active metal cations are aimed, that is, Sb³⁺ (5s²) with the lone-pair electron configuration and In³⁺ (4d¹⁰) with the fully-filled electron configuration. (Me₂NH₂)₄ MCl₆·Cl (Me = −CH₃, M = Sb, In) exhibits the superior temperature/component-dependent luminescence behaviors resulting from the competition transition between triplet-states (T_n-S₀) self-trapped excitons (STEs) of inorganic units and singlet-state (S₁-S₀) of organic cations, which is manipulated by the optical activity levels of [SbCl₆]³⁻ and [InCl₆]³⁻. The bonding differences between Sb³⁺/In³⁺ and Cl⁻ in terms of electronic excitation and hybridization are emphasized, and the different electron-transition mechanisms are established according to the PL spectra at the extreme temperature of 5 to 305 K and theoretical calculations. By fine-tuning the B-site Sb³⁺/In³⁺ alloying, the photoluminescence quantum yield (PLQY = 81.5%) and stability are optimized at 20% alloying of Sb³⁺. This research sheds light on the rules governing PL behaviors of HMHs, as well as exploring the optical-functional application of aviation temperature sensors and access-control systems.

Half-Heusler systems normally exhibit topological features in a semimetallic state and trivial ones in an insulating state. For TmPdSb, a “band inversion” in the conductance band and a metallic surface state spreading all over the Brillouin zone are found. Additionally, the linear contribution in the magnetoresistance at low temperature also hints to the presence of metallic surface states.

Abstract

Theoretical and experimental results exploring a half-Heusler compound TmPdSb with unusual band order and metallic surface states are presented. Typically, the half-Heusler systems exhibit topological features in a semimetallic state, and trivial ones in an insulating state. Topological properties of the most of half-Heusler systems are related to the band inversion around the Fermi level, similar to this observed in CdTe/HgTe systems. In the case of TmPdSb, the gapped electronic band structure with “band inversion” in the conductance band is observed, while the slab-like system realized metallic surface states. The bulk insulating nature of the compound is corroborated by means of electrical transport measurements. The experimental data reveal several features due to the presence of metallic surface states, such as linear magnetoresistance and weak-antilocalization effect, characterized by enhanced coherence length and a very large number of surface conductive channels. The findings reveal new features of the rare-earth bearing half-Heusler.

Giant iontronic flexoelectricity of soft hydrogels is reported induced by the ion polarization of cations and anions with different transfer rates under bending deformations, achieving flexoelectric coefficient much higher than state-of-the-art flexoelectric materials.

Abstract

Flexoelectricity features the strain gradient-induced mechanoelectric conversion using materials not limited by their crystalline symmetry, but state-of-the-art flexoelectric materials exhibit very small flexoelectric coefficients and are too brittle to withstand large deformations. Here, inspired by the ion polarization in living organisms, this paper reports the giant iontronic flexoelectricity of soft hydrogels where the ion polarization is attributed to the different transfer rates of cations and anions under bending deformations. The flexoelectricity is found to be easily regulated by the types of anion–cation pairs and polymer networks in the hydrogel. A polyacrylamide hydrogel with 1 m NaCl achieves a record-high flexoelectric coefficient of ≈1160 µC m⁻¹, which can even be improved to ≈2340 µC m⁻¹ by synergizing with the effects of ion pairs and extra polycation chains. Furthermore, the hydrogel as flexoelectric materials can withstand larger bending deformations to obtain higher polarization charges owing to its intrinsic low modulus and high elasticity. A soft flexoelectric sensor is then demonstrated for object recognition by robotic hands. The findings greatly broaden the flexoelectricity to soft, biomimetic, and biocompatible materials and applications.

When carbon nanomaterials are functionalized by photochromic molecules, the resultant hybrids exhibit either new or improved properties and functions that are attractive for diverse device applications. This review summarizes the fabrication methods, properties, and various applications of photochromic carbon nanomaterials.

Abstract

Photochromic molecules have remarkable potential in memory and optical devices, as well as in driving and manipulating molecular motors or actuators and many other systems using light. When photochromic molecules are introduced into carbon nanomaterials (CNMs), the resulting hybrids provide unique advantages and create new functions that can be employed in specific applications and devices. This review highlights the recent developments in diverse photochromic CNMs. Photochromic molecules and CNMs are also introduced. The fundamentals of different photochromic CNMs are discussed, including design principles and the types of interactions between CNMs and photochromic molecules via covalent interactions and non-covalent bonding such as π−π stacking, amphiphilic, electrostatic, and hydrogen bonding. Then the properties of photochromic CNMs, e.g., in photopatterning, fluorescence modulation, actuation, and photoinduced surface-relief gratings, and their applications in energy storage (solar thermal fuels, photothermal batteries, and supercapacitors), nanoelectronics (transistors, molecular junctions, photo-switchable conductance, and photoinduced electron transfer), sensors, and bioimaging are highlighted. Finally, an outlook on the challenges and opportunities in the future of photochromic CNMs is presented. This review discusses a vibrant interdisciplinary research field and is expected to stimulate further developments in nanoscience, advanced nanotechnology, intelligently responsive materials, and devices.

The work reports the synthesis of the superconducting freestanding La_0.8Sr_0.2NiO₂ membranes (Tczero=10.6K${T}_{\mathrm{c}}^{\mathrm{zero}}\ =\ 10.6\mathrm{K}$), emphasizing the crucial roles of the interface engineering in the precursor phase film growth and the quick transfer process in achieving superconductivity. This work offers a new versatile platform for investigating superconductivity in nickelates, such as the pairing symmetry via constructing Josephson tunneling junctions and higher T _c values via high-pressure experiments.

Abstract

The observation of superconductivity in infinite-layer nickelates has attracted significant attention due to its potential as a new platform for exploring high-T _c superconductivity. However, thus far, superconductivity has only been observed in epitaxial thin films, which limits the manipulation capabilities and modulation methods compared to two-dimensional exfoliated materials. Given the exceptionally giant strain tunability and stacking capability of freestanding membranes, separating superconducting nickelates from the as-grown substrate is a novel way to engineer the superconductivity and uncover the underlying physics. Herein, this work reports the synthesis of the superconducting freestanding La_0.8Sr_0.2NiO₂ membranes (Tczero=10.6K${T}_{\mathrm{c}}^{\mathrm{zero}}\ =\ 10.6\ \mathrm{K}$), emphasizing the crucial roles of the interface engineering in the precursor phase film growth and the quick transfer process in achieving superconductivity. This work offers a new versatile platform for investigating superconductivity in nickelates, such as the pairing symmetry via constructing Josephson tunneling junctions and higher T _c values via high-pressure experiments.

This review delves into high-performance thermal interface materials (TIMs) based on 2D materials like graphene/boron nitride, pivotal for heat management in advanced electronics. Focusing on their structural attributes, properties, and applications, it differentiates from other reviews by emphasizing their developmental history, addressing critical challenges, and proposing solutions. Additionally, it introduces other 2D materials-based TIMs, providing insights for future advancements.

Abstract

The challenges associated with heat dissipation in high-power electronic devices used in communication, new energy, and aerospace equipment have spurred an urgent need for high-performance thermal interface materials (TIMs) to establish efficient heat transfer pathways from the heater (chip) to heat sinks. Recently, emerging 2D materials, such as graphene and boron nitride, renowned for their ultrahigh basal-plane thermal conductivity and the capacity to facilitate cross-scale, multi-morphic structural design, have found widespread use as thermal fillers in the production of high-performance TIMs. To deepen the understanding of 2D material-based TIMs, this review focuses primarily on graphene and boron nitride-based TIMs, exploring their structures, properties, and applications. Building on this foundation, the developmental history of these TIMs is emphasized and a detailed analysis of critical challenges and potential solutions is provided. Additionally, the preparation and application of some other novel 2D materials-based TIMs are briefly introduced, aiming to offer constructive guidance for the future development of high-performance TIMs.

Hardware Security

In article number 2400661, Akshay Wali, Harikrishnan Ravichandran, and Saptarshi Das present a novel hardware security authentication system that employs programmable integrated circuits (ICs) crafted from atomically thin monolayers of molybdenum disulfide (MoS₂), a two-dimensional material. It capitalizes on the inherent randomness of charge trapping and de-trapping in 2D memtransistors to generate cryptographic keys. Additionally, it utilizes the properties of a NOR gate to establish a secure one-way hash function.

A novel microfluidic device based on optoelectronic tweezers (OETs) is introduced, which comprises a large array of micro-wells integrated with a photo-conductive plate. This method enables the parallel forming cell arrays in a continuous flow, reliable dynamic cell sorting, and target cell retrieval.

Abstract

Single-cell arrays have emerged as a versatile method for executing single-cell manipulations across an array of biological applications. In this paper, an innovative microfluidic platform is unveiled that utilizes optoelectronic tweezers (OETs) to array and sort individual cells at a flow rate of 20 µL min⁻¹. This platform is also adept at executing dielectrophoresis (DEP)-based, light-guided single-cell retrievals from designated micro-wells. This presents a compelling non-contact method for the rapid and straightforward sorting of cells that are hard to distinguish. Within this system, cells are individually confined to micro-wells, achieving an impressive high single-cell capture rate exceeding 91.9%. The roles of illuminating patterns, flow velocities, and applied electrical voltages are delved into in enhancing the single-cell capture rate. By integrating the OET system with the micro-well arrays, the device showcases adaptability and a plethora of functions. It can concurrently trap and segregate specific cells, guided by their dielectric signatures. Experimental results, derived from a mixed sample of HepG2 and L-O2 cells, reveal a sorting accuracy for L-O2 cells surpassing 91%. Fluorescence markers allow for the identification of sequestered, fluorescence-tagged HepG2 cells, which can subsequently be selectively released within the chip. This platform's rapidity in capturing and releasing individual cells augments its potential for future biological research and applications.

Nature Photonics, Published online: 06 June 2024; doi:10.1038/s41566-024-01453-8

Nanofabricated strained photonic crystals in silicon platforms enable the formation of photonic Landau levels at telecommunication wavelengths, with broad potential applications for enhanced light–matter interactions on-chip.

Nature Physics, Published online: 06 June 2024; doi:10.1038/s41567-024-02515-y

Some features resembling superconductivity at high temperature have been seen under pressure in La3Ni2O7, but a transition to a zero-resistance state has not been observed. Now transport studies demonstrate this transition, along with strange metallicity.

This research introduces a previously unmentioned synesthesia-like complex image and sound recognition system based on photo/acoustic-thermal-electric effects. It successfully discriminates monochromatic RGB and color coverage, showcasing its proficiency in distinguishing ten digital paintings. Additionally, the system achieves time-domain identification of four classical music compositions. It holds promise in quantifying emotional responses to images and sound.

Abstract

Inherent in humans is the capacity to perceive music and art, engaging both the visual and auditory senses, with profound effects on physiological and psychological states. Sound and light possess the remarkable ability to transform into thermal energy and, ultimately, electrical signals, playing a crucial role in human sensory perception. This research introduces a previously unmentioned synesthesia-inspired image and sound recognition system, diverging from conventional image/sound acquisition techniques based on photo/mechanical-electrical conversion. Leveraging the photo/acoustic-thermal-electric effects, the system utilizes micro-/commercial thermoelectric devices as a conduit for energy conversion. It successfully discriminates monochromatic red, green, blue (RGB) and color coverage, showcasing its proficiency in distinguishing ten digital paintings. Additionally, by probing fiber responses to varied sound frequencies and loudness levels, the system achieves time-domain identification of four classical music compositions. The device exhibits high sensitivity to detecting input energy and its inputting rate power, offering a novel approach to image and sound recognition through thermal signals. Potential applications span from bionic image sensors and time-domain thermal monitoring of audio. With further exploration, this thermoelectric-based system holds promise in quantifying emotional responses to images and sound.

Nature Nanotechnology, Published online: 06 June 2024; doi:10.1038/s41565-024-01686-2

Combining single-molecule Förster resonance energy transfer (FRET) and fluorescence lifetime information inside an anti-Brownian electrokinetic (ABEL) trap makes it possible to distinguish dozens of biomolecules in a sample mixture. This method enables extensive barcoding of biomolecules with a minimal set of chemical components and opens up a path toward biomolecule quantification in complex mixtures.

By harnessing the unique property changes induced by photothermal effects in 2D graphene oxide (GO) films, three novel functionalities beyond the capability of photonic integrated circuits are demonstrated, including all-optical control and tuning, optical power limiting, and nonreciprocal light transmission. The experimental results are theoretically analyzed, reflecting intriguing insights into the physics of 2D GO films.

Abstract

On-chip integration of 2D materials with unique structures and properties endow integrated devices with new functionalities and improved performance. With high flexibility in ways to modify its properties and compatibility with integrated platforms, graphene oxide (GO) is an exceptionally attractive 2D material for hybrid integrated photonic chips. Here, by harnessing unique property changes induced by photothermal effects in 2D GO films, novel functionalities beyond the capability of photonic integrated circuits are demonstrated. These include all-optical control and tuning, optical power limiting, and nonreciprocal light transmission. The 2D layered GO films are integrated onto photonic chips with precise control of their thickness and size. Benefitting from the broadband optical response of 2D GO films, all three functionalities feature a very wide operational optical bandwidth. By fitting the experimental results with theory, the changes in GO film properties induced by the photothermal effects are analyzed, revealing interesting insights about the physics of 2D GO films. These results highlight the versatility of 2D GO films in implementing new functions for integrated photonic devices for a wide range of applications.