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Neuromorphic bioelectronics aim to integrate electronics with biological systems yet encounter challenges in biocompatibility, operating voltages, power consumption, and stability. This study presents biocompatible neuromorphic devices fabricated from acellular dermal matrix (ADM) derived from porcine dermis using low-temperature supercritical CO 2 extraction. The ADM preserves the natural scaffold structure of collagen and minimizes immunogenicity by eliminating cells, fats, and noncollagenous impurities, ensuring excellent biocompatibility. The ADM-based devices emulate biological ion channels with biphasic membrane current modulation, exhibiting temperature dependency and pH sensitivity. It operates at an ultralow voltage of 1 mV and demonstrates reliable synaptic modulation exceeding 4 × 10 4 endurance cycles. The activation voltage can be theoretically as low as 59 μV, comparable to brainwave signals with a power of merely 7 aJ/event. Furthermore, a brain-like forgetting visualization algorithm is developed, leveraging the synaptic forgetting plasticity of ADM-based devices to achieve complex computing tasks in a highly energy-efficient manner. Neuromorphic devices based on ADM not only hold potential in implantable biointerfaces due to their exceptional biocompatibility, ultralow voltage, and power but also provide a feasible way for energy-efficient computing paradigms through a synergistic hardware-software approach.

The atomic substitution in two-dimensional (2D) materials is propitious to achieving compositionally engineered semiconductor heterostructures. However, elucidating the mechanism and developing methods to synthesize 2D heterostructures with atomic-scale precision are crucial. Here, we demonstrate the synthesis of monolayer WSe 2 -WS 2 heterostructures with a relatively sharp interface from monolayer WSe 2 using a chalcogen atom-exchange synthesis route at high temperatures for short periods. The substitution was initiated at the edges of monolayer WSe 2 and the lateral diffuse along the heterointerface, and the reaction can be controlled by the precise reaction time and temperature. The lateral heterostructure and substitution process are studied by Raman and photoluminescence (PL) spectroscopies, electron microscopy, and device characterization, revealing a possible mechanism of strain-induced transformation. Our findings demonstrate a highly controllable synthesis of 2D layered materials through atom substitutional chemistry and provide a simple route to control the atomic structure.

The low permeability and heterogeneous distribution of drugs (including nanomedicines) have limited their deep penetration into solid tumors. Herein we report the design of gold nanoparticles with virus-like spikes (AuNVs) to mimic viral shapes and facilitate tumor penetration. Mechanistic studies revealed that AuNVs mainly entered cells through macropinocytosis, then transported to the Golgi/endoplasmic reticulum system via Rab11-regulated pathway, and finally exocytosed through recycling endosomes, leading to high cellular uptake, effective transcytosis, and deep tumor penetration compared to gold nanospheres (AuNPs) and gold nanostars (AuNSs). The high tumor accumulation and deep tumor penetration of mitoxantrone (MTO) facilitated by AuNVs endowed effective chemophotothermal therapy when exposed to a near-infrared II laser, significantly reducing tumor sizes in a mouse model of colorectal cancer. This study reveals a potent mechanism of viral-like structures in tissue penetration and highlights their potential as effective drug delivery carriers.

Super-resolution fluorescence microscopy has emerged as a powerful tool for studying endoplasmic reticulum (ER) dynamics in living cells. However, the lack of high-brightness, high-photostability, and stable labeling probes makes long-term super-resolution imaging of the ER still challenging. Herein, we reported a surface-functionalized Halo-tag gold nanofluorescent probe (GNP-Atto565-fR8-CA) that exhibits excellent brightness, photostability, and biocompatibility. GNP-Atto565-fR8-CA can simultaneously load multiple Atto565 dye molecules, significantly improving its brightness. Modifying the cell-penetrating peptide fR8 enables GNP-Atto565-fR8-CA to be efficiently delivered into the cytoplasm, overcoming the challenge of their easy entrapment in vesicles. Fluorescent labeling of ER proteins via Halo tags enables high specificity and stable labeling of GNP-Atto565-fR8-CA to the ER. The SIM super-resolution imaging results showed that GNP-Atto565-fR8-CA can track and observe the long-term dynamic process of the ER, and can also be used for long-term super-resolution imaging of the dynamic interactions between the ER and other organelles. This work offers a practical tool to study live-cell ER ultrastructure and dynamics.

Precise synthesis of all-inorganic lead halide perovskite nanowire heterostructures and superlattices with designable modulation of chemical compositions is essential for tailoring their optoelectronic properties. Nevertheless, controllable synthesis of perovskite nanostructure heterostructures remains challenging and underexplored to date. Here, we report a rational strategy for wafer-scale synthesis of one-dimensional periodic CsPbCl 3 /CsPbI 3 superlattices. We show that the highly parallel array of halide perovskite nanowires can be prepared roughly as horizontally guided growth on an M -plane sapphire. A periodic patterning of the sapphire substrate enables position-selective ion exchange to obtain highly periodic CsPbCl 3 /CsPbI 3 nanowire superlattices. This patterning is further confirmed by micro-photoluminescence investigations, which show that two separate band-edge emission peaks appear at the interface of a CsPbCl 3 /CsPbI 3 heterojunction. Additionally, compared with the pure CsPbCl 3 nanowires, photodetectors fabricated using these periodic heterostructure nanowires exhibit superior photoelectric performance, namely, high I ON / I OFF ratio (10 4 ), higher responsivity (49 A/W), and higher detectivity (1.51 × 10 13 Jones). Moreover, a spatially resolved visible image sensor based on periodic nanowire superlattices is demonstrated with good imaging capability, suggesting promising application prospects in future photoelectronic imaging systems. All these results based on the periodic CsPbCl 3 /CsPbI 3 nanowire superlattices provides an attractive material platform for integrated perovskite devices and circuits.

Emerging 2D chromium-based dichalcogenides (CrX n (X = S, Se, Te; 0 < n ≤ 2)) have provoked enormous interests due to their abundant structures, intriguing electronic and magnetic properties, excellent environmental stability, and great application potentials in next generation electronics and spintronics devices. Achieving stoichiometry-controlled synthesis of 2D CrX n is of paramount significance for such envisioned investigations. Herein, we report the stoichiometry-controlled syntheses of 2D chromium selenide (Cr x Se y ) materials (rhombohedral Cr 2 Se 3 and monoclinic Cr 3 Se 4 ) via a Cr-self-intercalation route by designing two typical chemical vapor deposition (CVD) strategies. We have also clarified the different growth mechanisms, distinct chemical compositions, and crystal structures of the two type materials. Intriguingly, we reveal that the ultrathin Cr 2 Se 3 nanosheets exhibit a metallic feature, while the Cr 3 Se 4 nanosheets present a transition from p -type semiconductor to metal upon increasing the flake thickness. Moreover, we have also uncovered the ferromagnetic properties of 2D Cr 2 Se 3 and Cr 3 Se 4 below ∼70 K and ∼270 K, respectively. Briefly, this research should promote the stoichiometric-ratio controllable syntheses of 2D magnetic materials, and the property explorations toward next generation spintronics and magneto-optoelectronics related applications.

Real-time dynamic imaging of immunoactivation-related cytokines is crucial for evaluating the efficacy of immune checkpoint blockade therapy and optimizing the treatment regimen. We introduce herein a spatiotemporally controlled nanodevice that allows in situ photoactivated imaging of interferon-gamma (IFN-γ) secretion from T cells in vitro and in vivo . The nanodevice is constructed by rational engineering of an aptamer-embedded, UV-cleavable PC-DNA probe and further integration with upconversion nanoparticles- and CRISPR-Cas12a-enhanced fluorescence systems. Using human peripheral blood mononuclear cells (PBMC)-engrafted mouse models, this nanodevice allows for the quantitative imaging of endogenous IFN-γ and its intratumoral dynamics responding to antiprogrammed cell death receptor 1 (anti-PD-1) therapy. This study thus provides a toolbox for boosting the sensitivity and precision of cytokine imaging during immune checkpoint blockade therapy, enlightening research toward imaging-guided tumor therapy.

The discovery of high-entropy oxides (HEOs) in 2015 has provided a family of potential solid catalysts, due to their tunable components, abundant defects or lattice distorts, excellent thermal stability (Δ G ↓ = Δ H - T Δ S ↑), and so on. When facing the heterogeneous catalysis by HEOs, the micrometer bulky morphology and low surface areas (e.g., <10 m 2 g -1 ) by traditional synthesis methods obstructed their way. In this work, an electrospinning method to fabricate HEO nanofibers with diameters of 50-100 nm was demonstrated. The key point lay in the formation of one-dimensional filamentous precursors, during which the uniform dispersion of five metal species with disordered configuration would help to crystallize into single-phase HEOs at lower temperatures: inverse spinel (Cr 0.2 Mn 0.2 Co 0.2 Ni 0.2 Fe 0.2 ) 3 O 4 (400 °C), perovskite La(Mn 0.2 Cu 0.2 Co 0.2 Ni 0.2 Fe 0.2 )O 3 (500 °C), spinel Ni 0.2 Mg 0.2 Cu 0.2 Mn 0.2 Co 0.2 )Al 2 O 4 (550 °C), and cubic Ni 0.2 Mg 0.2 Cu 0.2 Zn 0.2 Co 0.2 O (750 °C). As a proof-of-concept, (Ni 3 MoCoZn)Al 12 O 24 nanofiber exhibited good activity (CH 4 Conv. > 96%, CO 2 Conv. > 99%, H 2 /CO ≈ 0.98), long-time stability (>100 h) for the dry reforming of methane (DRM) at 700 °C without coke deposition, better than control samples (Ni 3 MoCoZn)Al 12 O 24 -Coprecipitation-700 (CH 4 Conv. < 3%, CO 2 Conv. < 7%). The reaction mechanism of DRM was studied by in situ infrared spectroscopy, CO 2 -TPD, and CO 2 /CH 4 -TPSR. This electrospinning method provides a synthetic route for HEO nanofibers for target applications.

Low-temperature lithium metal batteries are of vital importance for cold-climate condition applications. Their realization, however, is plagued by the extremely sluggish Li + transport kinetics in the vicinity of Li metal anode at low temperatures. Different from the widely adopted electrolyte engineering, a functional interphase design concept is proposed in this work to efficiently improve the low-temperature electrochemical reaction kinetics of Li metal anodes. As a proof of concept, we design a hybrid polymer-alloy-fluoride (PAF) interphase featuring numerous gradient fluorinated solid-solution alloy composite nanoparticles embedded in a polymerized dioxolane matrix. Systematic experimental and theoretical investigations demonstrate that the hybrid PAF interphase not only exhibits superior lithiophilicity but also provides abundant ionic conductive pathways for homogeneous and fast Li + transport at the Li-electrolyte interface. With enhanced interfacial dynamics of Li-ion migration, the as-designed PAF-Li anode works stably for 720 h with low voltage hysteresis and dendrite-free electrode morphology in symmetric cell configurations at -40 °C. The full cells with PAF-Li anode display a commercial-grade capacity of 4.26 mAh cm -2 and high capacity retention of 74.7% after 150 cycles at -20 °C. The rational functional interphase design for accelerating ion-transfer kinetics sheds innovative insights for developing high-areal-capacity and long-lifespan lithium metal batteries at low temperatures.

Strain engineering has been proposed as a promising method to boost the carrier mobility of two-dimensional (2D) semiconductors. However, state-of-the-art straining approaches are largely based on putting 2D semiconductors on flexible substrates or rough substrate with nanostructures ( e.g ., nanoparticles, nanorods, ripples), where the observed mobility change is not only dependent on channel strain but could be impacted by the change of dielectric environment as well as rough interface scattering. Therefore, it remains an open question whether the pure lattice strain could improve the carrier mobilities of 2D semiconductors, limiting the achievement of high-performance 2D transistors. Here, we report a strain engineering approach to fabricate highly strained MoS 2 transistors on a flat substrate. By mechanically laminating a prefabricated MoS 2 transistor onto a custom-designed trench structure on flat substrate, well-controlled strain can be uniformly generated across the 2D channel. In the meantime, the substrate and the back-gate dielectric layer remain flat without any roughness-induced scattering effect or variation of the dielectric environment. Based on this technique, we demonstrate the MoS 2 electron mobility could be enhanced by tension strain and decreased by compression strain, consistent with theoretical predictions. The highest mobility enhancement is 152% for monolayer MoS 2 and 64% for bilayer MoS 2 transistors, comparable to that of a silicon device. Our method not only provides a compatible approach to uniformly strain the layered semiconductors on flat and solid substrate but also demonstrates an effective method to boost the carrier mobilities of 2D transistors.

Extensive macroscale two-dimensional (2-D) platinum (Pt) nanowire network (NWN) sheets are created through a hierarchical self-assembly process with the aid of biomolecular ligands. The Pt NWN sheet is assembled from the attachment growth of 1.9 nm-sized 0-D nanocrystals into 1-D nanowires featuring a high density of grain boundaries, which then interconnect to form monolayer network structures extending into centimeter-scale size. Further investigation into the formation mechanism reveals that the initial emergence of NWN sheets occurs at the gas/liquid interfaces of the bubbles produced by sodium borohydride (NaBH 4 ) during the synthesis process. Upon the rupture of these bubbles, an exocytosis-like process releases the Pt NWN sheets at the gas/liquid surface, which subsequently merge into a continuous monolayer Pt NWN sheet. The Pt NWN sheets exhibit outstanding oxygen reduction reaction (ORR) activities, with specific and mass activities 12.0 times and 21.2 times greater, respectively, than those of current state-of-the-art commercial Pt/C electrocatalysts.

Fine-tuning the geometric and electronic structure of catalytic metal centers via N-coordination engineering offers an effective design for the electrocatalytic transformation of O 2 to singlet oxygen ( 1 O 2 ). Herein, we develop a general coordination modulation strategy to synthesize fluidic single-atom electrodes for selective electrocatalytic activation of O 2 to 1 O 2 . Using a single Cr atom system as an example, >98% 1 O 2 selectivity can be achieved from electrocatalytic O 2 activation due to the subtle engineering of Cr-N 4 sites. Both theoretical simulations and experimental results determined that "end-on" adsorption of O 2 onto the Cr-N 4 sites lowers the overall activation energy barrier of O 2 and promotes the breakage of Cr-OOH bonds to form • OOH intermediates. In addition, the flow-through configuration ( k = 0.097 min -1 ) endowed convection-enhanced mass transport and improved charge transfer imparted by spatial confinement within the lamellar electrode structure compared to that of batch reactor ( k = 0.019 min -1 ). In a practical demonstration, the Cr-N 4 /MXene electrocatalytic system exhibits a high selectivity toward electron-rich micropollutants (e.g., sulfamethoxazole, bisphenol A, and sulfadimidine). The flow-through design of the fluidic electrode achieves a synergy with the molecular microenvironment that enables selective electrocatalytic 1 O 2 generation, which could be used in numerous ways, including the treatment of environmental pollution.

Nitric oxide (NO) exhibits a crucial role in various versatile and distinct physiological functions. Hence, its real-time sensing is highly important. Herein, we developed an integrated nanoelectronic system comprising a cobalt single-atom nanozyme (Co-SAE) chip array sensor and an electronic signal processing module (IND Co-SAE ) for both in vitro and in vivo multichannel qualifying of NO in normal and tumor-bearing mice. The high atomic utilization and catalytic activity of Co-SAE endowed an ultrawide linear range for NO varying from 36 to 4.1 × 10 5 nM with a low detection limit of 12 nM. Combining in situ attenuated total reflectance surface enhanced infrared spectroscopy (ATR-SEIRAS) measurements and density function calculation revealed the activating mechanism of Co-SAE toward NO. The NO adsorption on an active Co atom forms *NO, followed by the reaction between *NO and OH - , which could help design relevant nanozymes. Further, we investigated the NO-producing behaviors of various organs of both normal and tumor-bearing mice using the proposed device. We also evaluated the NO yield produced by the wounded mouse using the designed device and found it to be approximately 15 times that of the normal mouse. This study bridges the technical gap between a biosensor and an integrated system for molecular analysis in vitro and in vivo . The as-fabricated integrated wireless nanoelectronic system with multiple test channels significantly improved the detection efficiency, which can be widely used in designing other portable sensing devices with multiplexed analysis capability.

Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.

Two-dimensional (2D) materials have demonstrated promising potential for flexible electronics, owning to their atomic thin body thickness and dangling-bond-free surface. Here, we report a sliding contact device structure for efficient strain releasing. By fabricating a weakly coupled metal-2D junction with a van der Waals (vdW) gap in between, the applied strain could be effectively released through their interface sliding; hence minimized strain is transferred to the 2D lattice. Therefore, we observed stable device behavior with electrodes stretching over 110%, much higher than 2D devices using evaporated metal contacts. Furthermore, through multicycle straining-releasing measurements, we found the electrodes still form intimate contact with nearly constant contact resistance during sliding, confirming the optimization of device flexibility and electrical properties at the same time. Finally, we demonstrate this vdW sliding contact is a general device geometry and could be well-extended to various 2D or 3D bulk materials, leading to devices with much higher strain tolerance.

The limitation on the spintronic applications of van der Waals layered transition-metal dichalcogenide semiconductors is ascribed to the intrinsic nonmagnetic feature. Recent studies have proved that substitutional doping is an effective route to alter the magnetic properties of two-dimensional transition-metal dichalcogenides (TMDs). However, highly valid and repeatable substitutional doping of TMDs remains to be developed. Herein, we report group VIII magnetic transition metal-doped molybdenum diselenide (MoSe 2 ) single crystals via a one-pot mixed-salt-intermediated chemical vapor deposition method with high controllability and reproducibility. The high-angle annular dark-field scanning transmission electron microscopy studies further confirm that the sites of Fe are indeed substitutionally incorporated into the MoSe 2 monolayer. The Fe-doped MoSe 2 monolayer with a concentration from 0.93% to 6.10% could be obtained by controlling the ratios of FeCl 3 /Na 2 MoO 4 . Moreover, this strategy can be extended to create Co(Ni)-doped MoSe 2 monolayers. The magnetic hysteresis ( M-H ) measurements demonstrate that group VIII magnetic transition-metal-doped MoSe 2 samples exhibit room-temperature ferromagnetism. Additionally, the Fe-doped MoSe 2 field effect transistor shows n-type semiconductor characteristics, indicating the obtainment of a room-temperature dilute magnetic semiconductor. Our approach is universal in magnetic transition-metal substitutional doping of TMDs, and it inspires further research interest in the study of related spintronic and magnetoelectric applications.

Cell mechanical motion is a key physiological process that relies on the dynamics of actin filaments. Herein, a localized shear-force system based on gigahertz acoustic streaming (AS) is proposed, which can simultaneously realize intracellular delivery and cellular mechanical regulation. The results demonstrate that gold nanorods (AuNRs) can be delivered into the cytoplasm and even the nuclei of cancer and normal cells within a few minutes by AS stimulation. The delivery efficiency of AS stimulation is four times higher than that of endocytosis. Moreover, AS can effectively promote cytoskeleton assembly, regulate cell stiffness and change cell morphology. Since the inhibitory effect of AuNRs on cytoskeleton assembly, this AuNRs-AS system is able to inhibit or promote cell mechanical motion in a controlled manner by regulating the mechanical properties of cells. The bidirectional regulation of cell motion is further verified via scratch experiments, in which AuNRs-treated cells recover their motion ability through AS stimulation. In particular, the results of AuNRs-AS mechanical regulation on cell are related to the intrinsic properties of cell lines, revealing to more obvious effects on the cells with higher motor capacities. In summary, this acoustic technology has shown superiorities in controllable cell-motion manipulation, indicating its potential in building a multifunctional, integrated cytomechanics regulation platform.

Two-dimensional (2D) lateral heterostructures based on transition metal dichalcogenides (TMDCs) attract great interest due to their properties and potential applications in electronics and optoelectronics, such as p-n rectifying diodes, light-emitting diodes, photovoltaic devices, and bipolar junction transistors. However, the studies of 2D lateral heterostructures have mainly focused on monolayer nanosheets despite bilayer heterostructures exhibiting higher performance in many electronic and optoelectronic devices. It remains a great challenge to synthesize lateral heterostructures with few layers. Here, we report the growth of bilayer-bilayer (bl-bl), bilayer-bilayer-monolayer (bl-bl-mo), bilayer-monolayer (bl-mo), monolayer-bilayer (mo-bl), and monolayer-monolayer (mo-mo) tungsten disulfide (WS 2 ) and tungsten diselenide (WSe 2 ) lateral heterostructures. The selenium/tungsten (Se/W) ratio of WSe 2 precursor powders and the growth atmosphere can be changed with the extension of annealing time, which influences the layer number of the heterostructures. More bilayer WSe 2 epitaxially grows at the WS 2 edge with short annealing time (high Se/W ratio), and more monolayer WSe 2 grows at the WS 2 edge with long annealing time (low Se/W ratio). The density functional theory (DFT) calculations provide an in-depth understanding of the growth mechanism. This report expands the 2D material lateral heterostructure family, which gives impetus to their applications in electronics and optoelectronics.

Planar, thin-layered chiral plasmonic superstructures with complex two-dimensional (2D) patterns, namely, double-layered binary stars (bi-stars) and pinwheels, were realized through DNA programmable 2D supramolecular self-assembly of gold nanorods (AuNRs). The chirality of the chiral superstructures was defined by a finite number of AuNR pairs as enantiomeric motifs, and their sizes (∼240 nm) were precisely defined by the underlying DNA template. These planar, thin-layered chiral nanoparticle superstructures exhibited prescribed shapes and sizes at the dried state on the substrate surface and are characteristic of giant anisotropy of chiroptical responses, with enhanced g -factors from the axial incident excitation as compared to the in-plane excitation. This work will inspire possibilities for the construction of 2D chiral materials, for example, chiral metasurfaces, for the on-chip manipulation of chiral light-matter interactions via programmable self-assembly of nanoparticles.

Efforts to impart responsiveness to environmental stimuli in artificial hydrogel fibers are crucial to intelligent, shape-memory electronics and weavable soft robots. However, owing to the vulnerable mechanical property, poor processability, and the dearth of scalable assembly protocols, such functional hydrogel fibers are still far from practical usage. Herein, we demonstrate an approach toward the continuous fabrication of an electro-responsive hydrogel fiber by using the self-lubricated spinning (SLS) strategy. The polyelectrolyte inside the hydrogel fiber endows it with a fast electro-response property. After solvent exchange with triethylene glycol (TEG), the maximum tensile strength of the hydrogel fiber increases from 114 kPa to 5.6 MPa, far superior to those hydrogel fiber-based actuators reported previously. Consequently, the flexible and mechanical stable hydrogel fiber is knitted into various complex geometries on demand such as a crochet flower, triple knot, thread tube, pentagram, and hollow cage. Additionally, the electrochemical-responsive ionic hydrogel fiber is capable of acting as soft robots underwater to mimic biological motions, such as Mobula-like flapping, jellyfish-mimicking grabbing, sea worm-mimicking multi-degree of freedom movements, and human finger-like smart gesturing. This work not only demonstrates an example for the large-scale production of previous infeasible hydrogel fibers, but also provides a solution for the rational design and fabrication of hydrogel woven intelligent devices.

Monolayer two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted great interest in spintronics and valleytronics due to the spin-valley locking effect. To efficiently control and manipulate the valley pseudospin is of paramount importance for valley-based electronics and optoelectronics. A variety of strategies have been developed to address the valley pseudospin including optical, electrical, and magnetic methods; nonetheless, they involve either below liquid-nitrogen temperature or an external magnetic field, which increases the cost and complexity of the devices. Here, we report a straightforward way to manipulate valley polarization in monolayer TMDs via selective spin injection in chiral 2D perovskite/monolayer TMD ( e . g ., MoS 2 and WSe 2 ) van der Waals heterostructures without requiring an external magnetic field or specially designed device structures. We show the dangling-bond-free vdW interface can allow an impressive average spin injection efficiency of 78% to produce persistent valley polarization in monolayer MoS 2 (WSe 2 ) over 10% from liquid-nitrogen temperature to above 200 K. We attribute the valley polarization of monolayer MoS 2 (WSe 2 ) to selective spin injection from chiral 2D perovskites, which can effectively introduce population imbalance between valleys in monolayer MoS 2 (WSe 2 ). Our findings provide an alternative strategy to manipulate the valley polarization in TMDs without requiring circularly polarized light excitation, below liquid-nitrogen temperature, or external magnetic field, and thus would promote the development of perovskite-based spintronic and valleytronic devices.

Flexible pressure sensors that can robustly mimic the function of slow-adapting type I (SA-I) mechanoreceptors are essential for realizing human-like object manipulation in artificial intelligent (AI) robots or amputees. Here, we report a straightforward approach to highly sensitive and robust flexible pressure sensors with fast response time and low operating voltage based on conductive micropyramids made of polydimethylsiloxane/carbon nanotube composites. Both numerical simulations and experimental studies show that the pressure-sensing properties of the devices can be systematically tuned by the spatial arrangement of micropyramids. In particular, by tailoring the ratio between the spacing and the pyramidal base length, the optimal pressure sensors can be achieved with a combination of high sensitivity in both low-pressure (<10 kPa) and medium-pressure (10-100 kPa) regimes, rapid response, high mechanical robustness, low operating voltage, and low power consumption, along with linear response and low hysteresis in the medium-pressure regimes. The optimized pressure sensor is further used for constructing a wearable pressure-sensing system that can convert the amplitude of pressure to wirelessly transmittable frequency signals (spikes) with nearly linear response, closely mimicking SA-I mechanoreceptors. Furthermore, we demonstrate that the high uniformity and scalability of the pressure sensors enable large-area pressure-sensing arrays for spatially resolved pressure mapping.

Quartz fiber, a widely used reinforcer with high tensile strength and excellent heat resistance, can have more attractive electrical applications such as electromagnetic interference shielding, static dissipation, and strain sensing if it becomes conductive. Many attempts have been made to increase the electrical conductivity of quartz fiber by surface coating of conductive polymers or plating of metal films, but suffers from sacrificing flexibility and causing heavy metal pollution. Here we designed and massively produced a hybrid structure of graphene quartz fiber (GQF) by a forced-flow chemical vapor deposition (CVD) method, which combines the excellent conductivity of graphene and the extraordinary properties of quartz fiber. The as-fabricated flexible GQF exhibited high sensitivity, fast response (<0.5 s) and good durability (∼5000 cycles) to organic solvent vapor, suitable as a real-time biomimetic gas sensor. Furthermore, the massively produced GQFs can be knitted into meter-scale fabrics with tunable conductivity (sheet resistances of 0.2-10 kΩ/sq) and superior electrothermal conversion efficiency (up to 980 °C within a few seconds at 24 V), thus propelling its promising application in industrial electric heaters. We expect this hybrid GQF material will greatly expand the applications of traditional quartz fiber into an infusive multifunctional regime.

Developing a convenient and effective method to prepare single-atom catalysts at mild synthetic conditions remains a challenging task. Herein, a voltage-gauged electrofiltration method was demonstrated to synthesize single-atom site catalysts at room temperature. Under regulation of the graphene oxide membrane, a bulk Fe plate was directly converted into Fe single atoms, and the diffusion rate of Fe ions was greatly reduced, resulting in an ultralow concentration of Fe 2+ around the working electrode, which successfully prevented the growing of nuclei and aggregating of metal atoms. Monatomic Fe atoms are homogeneously anchored on the as-prepared nitrogen-doped carbon. Owing to the fast photoelectron injection from photosensitizers to atomically dispersed Fe sites through the highly conductive supported N-C, the Fe-SAs/N-C exhibits an outstanding photocatalytic activity toward CO 2 aqueous reduction into syngas with a tunable CO/H 2 ratio under visible light irradiation. The gas evolution rates for CO and H 2 are 4500 and 4950 μmol g -1 h -1 , respectively, and the tunable CO/H 2 ratio is from 0.3 to 8.8. This article presents an efficient strategy to develop the single-atom site catalysts and bridges the gap between heterogeneous and homogeneous catalysts toward photocatalytic CO 2 aqueous reduction into syngas.

An electronic "smart" contact lens device with high gas permeability and optical transparency, as well as mechanical compliance and robustness, offers daily wear capability in eye interfacing and can have broad applications ranging from ocular diagnosis to augmented reality. Most existing contact lens electronics utilize gas-impermeable substrates, electronic components, and interfacial adhesion layers, which impedes them from applications requiring continuous daily wear. Here we report on the design and fabrication of an eye interfacing device with a commercial ocular contact lens as the substrate, metal-coated nanofiber mesh as the conductor, and in situ electrochemically deposited poly(3,4-ethylenedioxythiophene) (PEDOT) /poly(styrene sulfonate) (PSS) as the adhesion material. This hydrogel contact lens device shows high gas permeability, wettability, and level of hydration, in addition to excellent optical transparency, mechanical compliance, and robustness. Using a rabbit model, we found that the animals wearing these hydrogel contact lens devices continuously for 12 hours showed a level of corneal fluorescein staining comparable to those wearing pure hydrogel contact lenses for same period of time, with no obvious corneal abrasion or irritation, indicating their high level of safety for continuous daily wear. Finally, full-field electroretinogram (ERG) recordings on rabbits were carried out to demonstrate the functionality of this device. We believe that the strategy of integrating nanofiber mesh-based electronic components demonstrated here can offer a general platform for hydrogel electronics with the advantages of preserving the physiological and mechanical properties of the hydrogel, thus enabling seamless integration with biological tissues and providing various wearable or implantable sensors with improved biocompatibility for health monitoring or medical treatment.

Expressed in macrophages and endothelial cells, the receptor for angiopoietin, tyrosine kinase with immunoglobulin and epidermal growth factor homology-2 (Tie2), is required for the reconstruction of blood vessels in tumor recurrence after chemotherapy. Thus, small therapeutic peptides that target and block Tie2 activity are promising as a therapeutic for the prevention of tumor relapse after chemotherapy. However, such small peptides often have low bioavailability, undergo rapid enzymatic degradation, and exhibit a short circulation half-life, making them ineffective in cancer therapy. Herein, we designed a dual-responsive amphiphilic peptide (mPEG 1000 -K(DEAP)-AAN-NLLMAAS) to modify the small peptide T4 (NLLMAAS) as a Tie2 inhibitor, endowing it with the ability to endure in circulation and specifically target tumor tissue. The ultimate nanoformulation (P-T4) releases T4 in response to the combination of the acidic tumor microenvironment and the presence of legumain, which is commonly overexpressed in tumor tissue. Compared with free T4, P-T4 decreases vessel density significantly (free T4: 2.44 ± 1.20%, P-T4: 0.90 ± 0.75%), delays tumor regrowth after chemotherapy (free T4: 43.2 ± 11.8%, P-T4: 63.6 ± 13.9%), and reduces distant metastasis formation (free T4: 4.50 ± 2.40%, P-T4: 0.67 ± 0.32%). These effects of P-T4 are produced by the local blockage of Tie2 signals in Tie2-positive macrophages and endothelial cells. In addition to describing a potential strategy to enhance circulation half-life and the accumulation of an active peptide at tumor sites, our approach exemplifies the successful targeting of multiple cell types that overexpress a key molecule in conditions associated with tumors.

With finite density of states and electrostatically tunable work function, graphene can function as a tunable contact for a semiconductor channel to enable vertical field-effect transistors (VFETs). However, the overall performance, especially the output current density, is still limited by the low conductance of the vertical semiconductor channel, as well as large series resistance of the graphene electrode. To overcome these limitations, we construct a VFET by using single-crystal InAs film as the high-conductance vertical channel and self-aligned metal contact as the source-drain electrodes, resulting in a record high current density over 45 000 A/cm 2 at a low bias voltage of 1 V. Furthermore, we construct a device-level VFET model using the resistor network method, and experimentally validate the impact of each geometry parameter on device performance. Importantly, we found the device performance is not only a function of the intrinsic channel material, but also greatly influenced by device geometries and footprint. Our study not only pushes the performance limit of graphene VFETs, but also sheds light on van der Waals integration between two-dimensional material and conventional bulk material for high-performance VFETs and circuits.

Control over plasmonic colors on the nanoscale is of great interest for high-resolution display, imaging, and information encryption applications. However, so far, very limited schemes have been attempted for dynamic plasmonic color generation. In this paper, we demonstrate a scanning plasmonic color generation scheme, in which subwavelength plasmonic pixels can be laterally switched on/off through directional hydrogenation/dehydrogenation of a magnesium screen. We show several dynamic plasmonic color displays with different scanning functions by varying the number and geometries of the palladium gates, where hydrogen enters the scanning screens. In particular, we employ the scanning effects to create a dynamic plasmonic quick response code. The information cannot be decrypted by varying the polarization states of light or by accessing the physical features. Rather, it can only be read out using hydrogen as a decoding key. Our work advances the established design concepts for plasmonic color printing and provides insights into the development of optical information storage and anticounterfeiting features.

Atomic substitution offers an important route to achieve compositionally engineered two-dimensional nanostructures and their heterostructures. Despite the recent research progress, the fundamental understanding of the reaction mechanism has still remained unclear. Here, we reveal the atomic substitution mechanism of two-dimensional atomic layered materials. We found that the atomic substitution process depends on the varying lattice constant (strain) in monolayer crystals, dominated by two strain-tuning (self-promoted and self-limited) mechanisms using density functional theory calculations. These mechanisms were experimentally confirmed by the controllable realization of a graded substitution ratio in the monolayers by controlling the substitution temperature and time and further theoretically verified by kinetic Monte Carlo simulations. The strain-tuning atomic substitution processes are of general importance to other two-dimensional layered materials, which offers an interesting route for tailoring electronic and optical properties of these materials.

Transition metal dichalcogenides (TMDs) have provided a fundamental stage to study light-matter interactions and optical applications at the atomic scale due to their ultrathin thickness and their appropriate band gap in the visible region. Here, we report the strong nonlinear optical effects, including second-harmonic generation (SHG) and third-harmonic generation (THG) in spiral WS 2 structures. SHG intensity quadratically increases with layer numbers, other than diminishing the oscillation of 2H stacking TMDs. The contrary SHG behavior is attributed to the broken symmetry from twisted screw structures, revealed by aberration-corrected transmission electronic microscope observation. Furthermore, the twist angle of the screw structure (5 degrees) was obtained by high-resolution transmission microscope measurements and confirmed by polarization tests of SHG output. Moreover, we roughly estimate the effective second-order nonlinear susceptibility. The discovery and understanding of the accumulation of nonlinear susceptibility of spiral structures with increasing thickness will extend the nonlinear applications of TMDs.

Two-dimensional layered materials (2DLMs) have attracted considerable recent interest for their layer-number-dependent physical and chemical properties, as well as potential technological opportunities. Here we report the synthesis of two-dimensional layered cadmium iodide (CdI 2 ) nanoplates using a vapor transport and deposition approach. Optical microscopy and scanning electron microscopy studies show that the resulting CdI 2 nanoplates predominantly adopt hexagonal and triangular morphologies with a lateral dimension of ∼2-10 μm. Atomic force microscopy studies show that the resulting nanoplates exhibit a thickness in the range of 5-220 nm with a relatively smooth surface. X-ray diffraction studies reveal highly crystalline CdI 2 in hexagonal phase, which is also confirmed by the characteristic Raman A g mode at 110 cm -1 . High-resolution transmission electron microscopy and selected area electron diffraction reveal that the resulting CdI 2 nanoplates are single crystals. Taking a step further, we show the CdI 2 nanoplates were readily grown on other 2DLMs (e.g., WS 2 , WSe 2 , MoS 2 ), forming diverse van der Waals heterostructures. Using prepatterned WS 2 monolayer square arrays as the nucleation and growth templates, we also show that regular arrays of CdI 2 /WS 2 vertical heterostructures can be prepared. The synthesis of the CdI 2 nanoplates, heterostructures, and heterostructure arrays offers a valuable material system for 2D materials science and technology.

Composition-controlled growth of two-dimensional layered semiconductor heterostructures is crucially important for their applications in multifunctional integrated photonics and optoelectronics devices. Here, we report the realization of composition completely modulated layered semiconductor MoS 2 -MoS 2(1-x) Se 2x (0 < x < 1) lateral heterostructures via the controlled layer-selected atomic substitution of pregrown stacking MoS 2 , with a bilayer located at the center of a monolayer. Through controlling the reaction time, S at the monolayer MoS 2 at the peripheral area can be selectively substituted by Se atoms at different levels, while the bilayer region at the center retains the original composition. Microstructure characterizations demonstrated the formation of lateral heterostructures with a sharp interface, with the composition at the monolayer area gradually modulated from MoS 2 to MoSe 2 and having high-quality crystallization at both the monolayer and the bilayer areas. Photoluminescence and Raman mapping studies exhibit the tunable optical properties only at the monolayer region of the as-grown heterostructures, which further demonstrates the realization of high-quality composition/bandgap modulated lateral heterostructures. This work offers an interesting and easy route for the development of high-quality layered semiconductor heterostructures for potential broad applications in integrated nanoelectronic and optoelectronic devices.

The electrical conductivity measured in Shewanella and Geobacter spp. is an intriguing physical property that is the fundamental basis for possible extracellular electron transport (EET) pathways. There is considerable debate regarding the origins of the electrical conductivity reported in these microbial cellular structures, which is essential for deciphering the EET mechanism. Here, we report systematic on-chip nanoelectronic investigations of both Shewanella and Geobacter spp. under physiological conditions to elucidate the complex basis of electrical conductivity of both individual microbial cells and biofilms. Concurrent electrical and electrochemical measurements of living Shewanella at both few-cell and the biofilm levels indicate that the apparent electrical conductivity can be traced to electrochemical-based electron transfer at the cell/electrode interface. We further show that similar results and conclusions apply to the Geobacter spp. Taken together, our study offers important insights into previously proposed physical models regarding microbial conductivities as well as EET pathways for Shewanella and Geobacter spp.

Integration of graphene with polymers to construct three-dimensional porous graphene/polymer composites (3DGPCs) has attracted considerable attention in the past few years for both fundamental studies and diverse technological applications. With the broad diversity in molecular structures of graphene and polymers via rich chemical routes, a number of 3DGPCs have been developed with unique structural, electrical, and mechanical properties, chemical tenability, and attractive functions, which greatly expands the research horizon of graphene-based composites. In particular, the properties and functions of the 3DGPCs can be readily tuned by precisely controlling the hierarchical porosity in the 3D graphene architecture as well as the intricate synergistic interactions between graphene and polymers. In this paper, we review the recent progress in 3DGPCs, including their synthetic strategies and potential applications in environmental protection, energy storage, sensors, and conducting composites. Lastly, we will conclude with a brief perspective on the challenges and future opportunities.

Ion migration has been postulated as the underlying mechanism responsible for the hysteresis in organolead halide perovskite devices. However, the electronic and ionic transport dynamics and how they impact each other in organolead halide perovskites remain elusive to date. Here we report a systematic investigation of the electronic and ionic transport dynamics in organolead halide perovskite microplate crystals and thin films using temperature-dependent transient response measurements. Our study reveals that thermally activated ionic and electronic conduction coexist in perovskite devices. The extracted activation energies suggest that the electronic transport is easier, but ions migrate harder in microplates than in thin films, demonstrating that the crystalline quality and grain boundaries can fundamentally modify electronic and ionic transport in perovskites. These findings offer valuable insight on the electronic and ionic transport dynamics in organolead halide perovskites, which is critical for optimizing perovskite devices with reduced hysteresis and improved stability and efficiency.

After a decade of intensive research on two-dimensional (2D) materials inspired by the discovery of graphene, the field of 2D electronics has reached a stage with booming materials and device architectures. However, the efficient integration of 2D functional layers with three-dimensional (3D) systems remains a significant challenge, limiting device performance and circuit design. In this review, we investigate the experimental efforts in interfacing 2D layers with 3D materials and analyze the properties of the heterojunctions formed between them. The contact resistivity of metal on graphene and related 2D materials deserves special attention, while the Schottky junctions formed between metal/2D semiconductor or graphene/3D semiconductor call for careful reconsideration of the physical models describing the junction behavior. The combination of 2D and 3D semiconductors presents a form of p-n junctions that have just marked their debut. For each type of the heterojunctions, the potential applications are reviewed briefly.

We demonstrate the type-II staggered band alignment in MoTe2/MoS2 van der Waals (vdW) heterostructures and an interlayer optical transition at ∼1.55 μm. The photoinduced charge separation between the MoTe2/MoS2 vdW heterostructure is verified by Kelvin probe force microscopy (KPFM) under illumination, density function theory (DFT) simulations and photoluminescence (PL) spectroscopy. Photoelectrical measurements of MoTe2/MoS2 vdW heterostructures show a distinct photocurrent response in the infrared regime (1550 nm). The creation of type-II vdW heterostructures with strong interlayer coupling could improve our fundamental understanding of the essential physics behind vdW heterostructures and help the design of next-generation infrared optoelectronics.

We demonstrate the use of "holey" graphene as a mask against molecular adsorption. Prepared porous graphene is transferred onto a Au{111} substrate, annealed, and then exposed to dilute solutions of 1-adamantanethiol. In the pores of the graphene lattice, we find islands of organized, self-assembled molecules. The bare Au in the pores can be regenerated by postdeposition annealing, and new molecules can be self-assembled in the exposed Au region. Graphene can serve as a robust, patternable mask against the deposition of self-assembled monolayers.

Here we present a general strategy for the fabrication of high-performance organic vertical thin film transistors (OVTFTs) based on the heterostructure of graphene and different organic semiconductor thin films. Utilizing the unique tunable work function of graphene, we show that the vertical carrier transport across the graphene-organic semiconductor junction can be effectively modulated to achieve an ON/OFF ratio greater than 10(3). Importantly, with the OVTFT design, the channel length is determined by the organic thin film thickness rather than by lithographic resolution. It can thus readily enable transistors with ultrashort channel lengths (<200 nm) to afford a delivering current greatly exceeding that of conventional planar TFTs, thus enabling a respectable operation frequency (up to 0.4 MHz) while using low-mobility organic semiconductors and low-resolution lithography. With this vertical device architecture, the entire organic channel is sandwiched and naturally protected between the source and drain electrodes, which function as the self-passivation layer to ensure stable operation of both p- and n-type OVTFTs in ambient conditions and enable complementary circuits with voltage gain. The creation of high-performance and highly robust OVTFTs can open up exciting opportunities in large-area organic macroelectronics.

We combined reflection difference microscopy, electron transport measurements, and atomic force microscopy to characterize the mechanical and electrical anisotropy of few-layer black phosphorus. We were able to identify the lattice orientations of the two-dimensional material and construct suspended structures aligned with specific crystal axes. The approach allowed us to probe the anisotropic mechanical and electrical properties along each lattice axis in separate measurements. We measured the Young's modulus of few-layer black phosphorus to be 58.6 ± 11.7 and 27.2 ± 4.1 GPa in zigzag and armchair directions. The breaking stress scaled almost linearly with the Young's modulus and was measured to be 4.79 ± 1.43 and 2.31 ± 0.71 GPa in the two directions. We have also observed highly anisotropic transport behavior in black phosphorus and derived the conductance anisotropy to be 63.7%. The test results agreed well with theoretical predictions. Our work provided very valuable experimental data and suggested an effective characterization means for future studies on black phosphorus and anisotropic two-dimensional nanomaterials in general.

Vertically oriented structures of single crystalline conductors and semiconductors are of great technological importance due to their directional charge carrier transport, high device density, and interesting optical properties. However, creating such architectures for organic electronic materials remains challenging. Here, we report a facile, controllable route for producing oriented vertical arrays of single crystalline conjugated molecules using graphene as the guiding substrate. The arrays exhibit uniform morphological and crystallographic orientations. Using an oligoaniline as an example, we demonstrate this method to be highly versatile in controlling the nucleation densities, crystal sizes, and orientations. Charge carriers are shown to travel most efficiently along the vertical interfacial stacking direction with a conductivity of 12.3 S/cm in individual crystals, the highest reported to date for an aniline oligomer. These crystal arrays can be readily patterned and their current harnessed collectively over large areas, illustrating the promise for both micro- and macroscopic device applications.

Low-temperature solution-processable electronic materials are of considerable interest for large-area, low-cost electronics, thermoelectrics, and photovoltaics. Using a soluble precursor and suitable solvent to formulate a semiconductor ink is essential for large-area fabrication of semiconductor thin films. To date, it has been shown that hydrazine can be used as a versatile solvent to process a wide range of inorganic semiconductors. However, hydrazine is highly toxic and not suitable for large-scale manufacturing. Here we report a binary mixed solvent of amine and thiol for effective dispersion and dissolution of a large number of inorganic semiconductors including Cu2S, Cu2Se, In2S3, In2Se3, CdS, SnSe, and others. The mixed solvent is significantly less toxic and safer than hydrazine, while at the same time offering the comparable capability of formulating diverse semiconductor ink with a concentration as high as >200 mg/mL. We further show that such ink material can be readily processed into high-performance semiconducting thin films (Cu2S and Cu2Se) with the highest room-temperature conductivity among solution-based materials. Furthermore, we show that complex semiconductor alloys with tunable band gaps, such as CuIn(S(x)Se(1-x))2 (0 ≤ x ≤ 1), can also be readily prepared by simply mixing Cu2S, Cu2Se, In2S3, and In2Se3 ink solutions in a proper ratio. Our study outlines a general strategy for the formulation of inorganic semiconductor ink for low-temperature processing of large-area electronic thin films on diverse substrates and can greatly impact diverse areas including flexible electronics, thermoelectrics, and photovoltaics.

With well-defined porous structures and dimensions, metal-organic frameworks (MOFs) can function as versatile templates for the growth of metallic nanostructures with precisely controlled shapes and sizes. Using MOFs as templates, metallic nanostructures can be grown without the need of bulky surfactants and thus preserve their intrinsic surface. Additionally, the high surface area of MOFs can also ensure that the surface of the template metallic nanostructures is readily accessible, which is critical for the proper function of catalysts or sensors. The hybrid metal@MOF structures have been demonstrated to exhibit useful properties not found in either component separately. Here we report the growth of ultrafine metallic nanowires inside one-dimensional MOF pores with well-controlled shape and size. Our study shows that solvent selection plays an important role in controlling precursor loading and the reduction rate inside the MOF pores for the formation of the nanowires. The growth of the well-aligned, ultrathin nanowires was monitored and characterized by transmission electron microscopy, X-ray diffraction, UV-vis spectroscopy, fluorescence studies, and Brunauer-Emmet-Teller surface area analysis.

Understanding the interfacial electrical properties between metallic electrodes and low-dimensional semiconductors is essential for both fundamental science and practical applications. Here we report the observation of thickness reduction induced crossover of electrical contact at Au/MoS2 interfaces. For MoS2 thicker than 5 layers, the contact resistivity slightly decreases with reducing MoS2 thickness. By contrast, the contact resistivity sharply increases with reducing MoS2 thickness below 5 layers, mainly governed by the quantum confinement effect. We find that the interfacial potential barrier can be finely tailored from 0.3 to 0.6 eV by merely varying MoS2 thickness. A full evolution diagram of energy level alignment is also drawn to elucidate the thickness scaling effect. The finding of tailoring interfacial properties with channel thickness represents a useful approach controlling the metal/semiconductor interfaces which may result in conceptually innovative functionalities.

Controlling the morphology of nanocrystals (NCs) is of paramount importance for both fundamental studies and practical applications. The morphology of NCs is determined by the seed structure and the following facet growth. While means for directing facet formation in NC growth have been extensively studied, rational strategies for the production of NCs bearing structure defects in seeds have been much less explored. Here, we report mechanistic investigations of high density twin formation induced by specific peptides in platinum (Pt) NC growth, on the basis of which we derive principles that can serve as guidelines for the rational design of molecular surfactants to introduce high yield twinning in noble metal NC syntheses. Two synergistic factors are identified in producing twinned Pt NCs with the peptide: (1) the altered reduction kinetics and crystal growth pathway as a result of the complex formation between the histidine residue on the peptide and Pt ions, and (2) the preferential stabilization of {111} planes upon the formation of twinned seeds. We further apply the discovered principles to the design of small organic molecules bearing similar binding motifs as ligands/surfactants to create single and multiple twinned Pd and Rh NCs. Our studies demonstrate the rich information derived from biomimetic synthesis and the broad applicability of biomimetic principles to NC synthesis for diverse property tailoring.

The combination of a chemotherapeutic drug with a multidrug resistance (MDR) modulator has emerged as a promising strategy for treating MDR cancer. To ensure two drugs could be simultaneously delivered to tumor region at the optimum ratio, and the MDR modulator could be released earlier and faster than the chemotherapeutic drug to inactivate P-glycoprotein (P-gp) and subsequently inhibit the pumping out of the chemotherapeutic drug, a smart pH-sensitive polymeric micelles system with high drug loading and precise drug ratio was designed and prepared by conjugating doxorubicin (DOX) to poly(styrene-co-maleic anhydride) (SMA) derivative with adipic dihydrazide (ADH) through a acid-cleavable hydrazone bond, and then encapsulating disulfiram (DSF), a P-gp inhibitor as well as an apoptosis inducer, into the micelles formed by the self-assembly of SMA-ADH-DOX (SAD) conjugate. The pH-sensitive polymeric micelles system enabled a temporal release of two drugs: encapsulated DSF was released fast to inhibit the activity of P-gp and restore cell apoptotic signaling pathways, while conjugated DOX was released in a sustained and pH-dependent manner and highly accumulated in drug resistant cells to exert therapeutic effect, due to the inactivation of P-gp by DSF. The smart co-delivery system was very effective in enhancing the cytotoxicity by increasing the intracellular accumulation of DOX and promoting the apoptotic response, and showed the most effective inhibitory effect on the growth of drug-resistant breast cancer xenografts as compared to other combinations of both drugs. In a word, this smart co-delivery system has significant promise for the clinical therapy of MDR cancer.

Flexible solid-state supercapacitors are of considerable interest as mobile power supply for future flexible electronics. Graphene or carbon nanotubes based thin films have been used to fabricate flexible solid-state supercapacitors with high gravimetric specific capacitances (80-200 F/g), but usually with a rather low overall or areal specific capacitance (3-50 mF/cm(2)) due to the ultrasmall electrode thickness (typically a few micrometers) and ultralow mass loading, which is not desirable for practical applications. Here we report the exploration of a three-dimensional (3D) graphene hydrogel for the fabrication of high-performance solid-state flexible supercapacitors. With a highly interconnected 3D network structure, graphene hydrogel exhibits exceptional electrical conductivity and mechanical robustness to make it an excellent material for flexible energy storage devices. Our studies demonstrate that flexible supercapacitors with a 120 μm thick graphene hydrogel thin film can exhibit excellent capacitive characteristics, including a high gravimetric specific capacitance of 186 F/g (up to 196 F/g for a 42 μm thick electrode), an unprecedented areal specific capacitance of 372 mF/cm(2) (up to 402 mF/cm(2) for a 185 μm thick electrode), low leakage current (10.6 μA), excellent cycling stability, and extraordinary mechanical flexibility. This study demonstrates the exciting potential of 3D graphene macrostructures for high-performance flexible energy storage devices.

A supramolecular interface for Si nanowire FETs has been developed with the aim of creating regenerative electronic biosensors. The key to the approach is Si-NWs functionalized with β-cyclodextrin (β-CD), to which receptor moieties can be attached with an orthogonal supramolecular linker. Here we demonstrate full recycling using the strongest biomolecular system known, streptavidin (SAv)-biotin. The bound SAv and the linkers can be selectively removed from the surface through competitive desorption with concentrated β-CD, regenerating the sensor for repeated use. An added advantage of β-CD is the possibility of stereoselective sensors, and we demonstrate here the ability to quantify the enantiomeric composition of chiral targets.

Efficient light absorption in thin-film photovoltaic (PV) devices is crucial for improving their efficiency and reducing cost. Here we have not only developed a low-cost and scalable method to fabricate a unique type of integrated-nanopillar-nanowell (i-NPW) structure by integrating nanopillar and nanowell arrays together vertically, but also demonstrated the attractive optical property of the i-NPW arrays by leveraging the advantages of "positive" and "negative" nanostructures for photon harvesting. Impressively, the 2 μm thick i-NPW arrays with only 40 nm a-Si coating obtained a day-integrated absorption of 89.27%, as opposed to only 33.45% for the planar control sample. These results suggest the feasibility and clear advantage of vertical integration of three-dimensional (3-D) nanophotonic structures, and meanwhile also pave a viable and convenient way toward a 3-D ultrathin film PV module with potency for high energy conversion efficiency.