Nanoimprint Lithography

In article number 2105733, Jinyoung Park, Suck Won Hong, and co-workers report a rotating cylindrical stamp-based nanoimprint lithography that enables direct pattern transfer of molecularly imprinted polymers (MIPs) on a fabric substrate. Nanopatterned functional MIPs serve as self-encoded filtration media for the selective separation of formaldehyde molecules, which would be highly useful for designing next-generation separation systems with the ability to capture industrial or household toxic substances.

Photodetectors

The cover image describes the design of three-electrode photo-electrochemical photodetectors based on lanthanide-doped carbon quantum dots (CQDs). Owing to the coordination of lanthanides and internal energy transfer between lanthanides and CQDs, the as-fabricated photodetectors not only show an excellent photo-response performance, but also exhibit a narrow-band response behavior. More information can be found in article number 2105683 by Lingfeng Gao, Hans Ågren, Han Zhang, and co-workers.

COVID-19 Diagnostics

In article number 2104009, Jiang Xu, Yan Zhang, Taotao Lao, and co-workers present a handheld microfluidic filtration platform that enables rapid, low-cost and robust self-testing of the SARS-CoV-2 virus. The cover design emphasizes its important advantages: (1) Equipment-free handheld injection, represented by the hands manipulation; (2) Visible and easy readout: a Taichi diagram is used to distinguish the negative/positive results, which is in line with the meaning of Taichi (Yin/Yang) in traditional Chinese culture. The Taichi eyes are filled with illustrational structures of negative/positive nanocomplexes; (3) Reusable chips: the flow arrows at both inlet and outlet indicate that the chip can be repeatedly cleaned and injected.

Nanocomposite Double-Network Hydrogels

A multi-responsive magnetic nanocomposite double-network hydrogel is developed for controlled protein delivery in article number 2105997 by Cheng-Hsun Lu and Yi-Cheun Yeh. Proteins are rapidly released from the hydrogel network at acidic pH and high temperature. This study provides a new strategy for hydrogel design to present multi-stimuli responsiveness for biomedical applications.

A horizon scanning of the surface modification techniques for fiber materials and their application in wearable electronics is offered. Apart from the general physical and chemical treatments, a new approach of self-assembly via π–π stacking is included for the first time. The scoped techniques are expected to shed light on the rational design of future fiber based wearable electronics.

The development of cancer diagnostic imaging and treatment is a major concern worldwide. This review systematically summarizes the recent progress of multifunctional single-component nanoparticles in the applications of cancer theranostics. The structure design, categories of nanoparticles, targeted strategies, biomedical applications, potential barriers, challenges, and prospects for the future clinical practice of this rapidly growing field are discussed.

Recent developments of MOFs as catalysts for chemocatalytic hydrogen production are comprehensively summarized. The importance of this field and the merits of MOFs as heterogeneous catalysts are delineated. The characterization of MOF-based catalysts and the mechanism of chemocatalytic hydrogen production involving MOF-based catalysts are of specific concern. Finally, future prospects with remaining challenges are suggested.

Recent trends in small-molecule prodrug nanoassemblies (SMP-NAs) are outlined, and the corresponding self-assembly mechanisms are discussed in detail. Besides, the smart stimuli-responsive SMP-NAs and the combination therapy based on SMP-NAs are summarized, with special emphasis on the structure–function relationships. Finally, the outlooks and potential challenges of SMP-NAs in cancer therapy are highlighted.

Simple integration of UV-optical engine for the cylinder roll-assisted nanoimprinting process is presented to enable high-throughput pattern transfer, especially on fabric substrates. This approach involves the use of molecularly imprinted polymers to spatially construct free-standing perforated micro/nanostructures with functions that can serve as a self-encoding filtration medium for the selective separation of formaldehyde molecules.

Lanthanide-doped carbon quantum dots (CQDs) synthesized by a facile hydrothermal approach are directly used as active materials for photo-electrochemical type photodetectors. The strong coordination of lanthanides can enhance the light absorption, while the internal energy transfer between lanthanides and CQDs can improve the photo-response performance. Moreover, the specific excitation region of lanthanides endows the doped CQDs narrow-band response properties.

The microfluidic diagnostic platform combining sandwich immunoassay and hydrodynamic filtration described here enables rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The nano- and micro- beads are coated with antibodies targeting nucleocapsid proteins. Microfluidic filtration discards free nanobeads but retains antigen-bridged complexes in the observation zone, where a display of red/white color indicates the positive/negative result.

In this work, the non-steady state active motion of Janus micromotors (JM) as a function of fuel concentration, JM concentration, and time after fuel addition is studied. Characterization by dynamic light scattering and the analyses presented provide new insights into the mechanism of active motion in non-steady state systems.

In InP/ZnSe/ZnS quantum dots with near-unity luminescence, carrier trapping into shallow defects at a picosecond timescale is a key mechanism to reduce the quantum yield. The carrier trapping assisted by ZnSe phonons can slow down with increasing the energy gap between the band-edge and shallow trap states.

The formation and evolution of solid electrolyte interphase (SEI) on graphite with and without structural defects are investigated using operando electrochemical atomic force microscope, ex situ X-ray photoelectron spectroscopy and density functional theory calculations. Structural defects affect the graphite inducing formation of a uniform, denser, thinner, and more passivating SEI. The SEI on graphite with defects is enriched in LiF.

Combining atomic-resolution images from annular dark-field scanning transmission electron microscopy with reactive molecular modelling, it is revealed that the folding edge formation has statistical preferences under geometric conditions based on the orientation mismatch. It is further investigated how loading directions and strong interlayer friction, interplay with WS₂ lattice's crack preference, govern the deformation and fracture pattern around folding edges.

A novel biological strategy via NH₄Ga(OH)₂CO₃ nanotube intermediate is presented for fabrication of Ga₂O₃ nanotube. All species from urea enzymolysis are subtly used for the interfacial growth of NH₄Ga(OH)₂CO₃ nanotube in aqueous solution of gallium salts at 20–50 °C, and the balance between the rate of CO₂ bubble fusion and NH₄Ga(OH)₂CO₃ precipitation is the key point.

Tunable Pt edge-doped MoS₂ electrocatalysts are fabricated by focused ion beam etching and photoreduction techniques for enhanced hydrogen evolution reaction activity with less consumption of Pt. Impressive high performance is obtained from the synergistic effect between Pt nanoparticles (NPs) and edge active sites, as well as the increased potential near edges.

Surface structure and bulk charge are regulated by introducing high-valence Ta⁵⁺ ions for achieving stable and safe cathodes toward high-energy Li-ion batteries. The critical roles of the structure and charge regulation in improving structural stability are revealed, providing a novel and integrated insight into the functional mechanisms of high-valence ions substitution in Ni-rich cathodes.

A spiropyran-appended cucurbit[6]uril is designed, and demonstrated to be able to translocate into cytosol, followed by lateral polymerization to yield a large 2D material that exceeds the size limit allowed by endocytic uptake pathway. With this advance, 2D platforms for intracellular signaling or theranostics that displays potency beyond conventional, small, endocytosable counterparts are in sight.

Hard carbon nanosheets with vertically oriented (002) planes are synthesized and used as a model hard carbon to investigate the sodiation phase transformation by synchrotron X-ray spectromicroscopy. The results for the first time unveil the heterogeneous nature of sodiation in hard carbon and highlight the importance of increasing nucleation sites to enhance performance.

A new liquid metal elastomer composite architecture is reported with independently controllable thermal conductivity and density. Quantitative design maps that describe the relationship between composite and filler properties reveal new strategies to enhance material and functional properties. A lightweight inclusion with a low-density phase resulted in a significant decrease in density with only a modest decrease in thermal conductivity.

An injectable immunotherapeutic thermogel is developed to improve the phagocytic ability of antigen presenting cells to tumor debris and damage-associated molecular patterns released after tumor radiofrequency ablation (RFA) via inhibiting rho-associated kinases signal pathway. Such strategy remarkably prolongs the survival of mice after RFA treatment, showing great potential for clinical translation as an improvement strategy for RFA.

The new ratiometric fluorescence probe OFP-NA-NO₂ can sense amyloid β (Aβ) and inhibit the formation of Aβ aggregates by covalent binding. Also, this probe can effectively down-regulate the level of TNF-α and restore the Aβ-clearing ability of microglia, thereby alleviating the neurotoxicity of Aβ aggregates. This work offers a promising strategy for early diagnosis and treatment of neurodegenerative diseases.

A series of warm white, pure white, and cold white electroluminescent carbon dots light-emitting diodes (CDs-LEDs)is successfully demonstrated through controlling aggregation degrees of CDs. These CDs-LEDs exhibit adjustable correlated color temperatures (2863–11240 K) in sequence along the blackbody radiation curve and reach maximum brightness and external quantum efficiency upto 1414–4917 cd m⁻² and 0.08–0.87%, respectively.

A nano-carrier based on phase-change materials is constructed to achieve the safe intravenous injection and controllable release of thrombin through a simple method. The smart nano-carrier-induced tumor-vascular infarction improved the therapeutic specificity and efficacy of coagulation-based tumor therapy.

An intrinsically stretchable, self-healing, transparent, and ion-conductive hydrogel is utilized to fabricate NO₂ gas sensors. The sensing mechanism reveals that the redox reaction of NO₂ at the electrode–hydrogel interface induces current variation. The sensor exhibits high sensitivity (119.9%/ppm), ultralow limit of detection (86 ppt), good selectivity. Meanwhile, it can operate in both anaerobic and aerobic environments at room temperature.

A single-crystalline 2D covalent organic framework is studied with respect to permeation of gaseous and vaporous substances. The free-standing material is demonstrated to be open for molecular effusion due to an unprecedentedly high pore density. At the same time, the structure of the 2D membrane is found to enable surface diffusion of condensable species.

The effect of supported Pd single atoms on H₂S gas sensing behavior is investigated by combing density functional theory calculations with quasi in situ XPS analysis. The dehydrogenation of HS bonds into sulfur species on Pd atomic sites is a main cause for such H₂S sensing signal. A sensing model for H₂S on supported Pd atomic sites is proposed.

The Ni–Fe LDO-V_Ni enriched with nickel vacancies is successfully prepared by selective etching method. The existence of nickel cationic vacancies can promote the formation of abundant Ni³⁺ (t_2g⁶e_g¹) with the optimized electron filling of e_g, which makes the Ni–Fe LDO-V_Ni based electrode have a superior long term cyclic stability for Li–O₂ battery.

A facile yet powerful surface engineering strategy by in situ photoactivation is proposed to CdS photoanodes. This approach reduces surface charge recombination through the formation of thiosulfate ion and forms a uniform nanoporous morphology via dissolving Cd²⁺ with phosphate ions on the surface. The resultant photoanodes present significantly prompted performance for photoelectrochemical application.

The engineering of the graphene's valence band upon the chemical derivatization by ketones and carboxyls is shown. The appearance of a set of localized states related to molecular orbitals of the introduced functionalities is signified. An empirical approach for the analysis and prediction of the impact of a certain functional group on the graphenes’ electronic structure is stated.

LMO/SP/NF interlayer brings about a new catalytic strategy based on the original proposed lithiation/delithiation behavior triggered by overpotential driving force. This behavior allows the Li⁺ from the dissociated LiPSs species to diffuse on both the surface and bulk channels in the catalysts and thus accelerate the Li-S reaction kinetics.

A sea urchin-shaped Co₂P/Co@NCNT is synthesized, which not only acts as metal anchoring carrier, but also provides an efficient three-phase region. Subsequently, the metal cobalt is replaced by Pt NPs through in situ substitution reaction to form CoPt₃ alloy connected with Co₂P and encapsulated in NCNT ensuring good dispersion, exposing more active sites, and regulating the surface electronic structure.

A kind of engineered platelet micromotors is proposed, which can be driven by near-infrared light, target the tumor site, and be activated by tumor microenvironment to release small-size platelet-derived microparticles nanomotors, realizing deep penetration into tumor tissue.