Small Methods最新文献

Atomic-level surface preparation, using additive and subtractive atomic layer processes, has gradually become crucial for the more active process variations and highly selective process requirements. Precise control of surface roughness and coverage is a critical consideration in the fabrication of metal thin films. Herein, the fabrication of ultrathin, smooth Ru films with a thickness reduced to below 3 nm is reported. This process involves etching back after depositing a thick Ru film using a synergistic combination of atomic layer deposition (ALD) and atomic layer etching (ALE) techniques. The surface smoothing effect, while preserving surface coverage, is validated by initially performing the ALD process for Ru with (ethylbenzyl)(1-ethyl-1,4-cyclohexadienyl)Ru(0) precursor and O₂ gas, followed by the ALE process with 2,4-pentanedione and O₂ radicals. Under optimized conditions for atomically flat Ru surfaces, the surface quality of Ru films processed by ALD, and the combined ALD/ALE methods are compared. Consequently, it is demonstrated for the first time that the combined ALD/ALE process effectively reduces both thickness and asperities while smoothing the surface and maintaining nearly complete surface coverage down to the ≈1 nm scale. This approach enables the production of advanced electronic devices with precise control over surface properties at the Ångström level.

Organic phototransistors (OPTs) have garnered significant attention due to their potential in wearable and flexible electronics. However, achieving high carrier mobility and broadband response in organic semiconductors for OPTs remains a challenge. In this work, a new fused diketopyrrolopyrrole (FDPP) derivative is reported, 2,9-bis(4-hexylphenyl)-7H,14H-thieno[3',2':7,8]indolizino[2,1-a]thieno[3,2-g]indolizine-7,14-dione (FDPP-p-C6), synthesized through N-cyclization of DPP with an adjacent thiophene unit. This N-cyclization ensures backbone planarity, while the hexyl side chains remain distant from the fused core, minimizing steric hindrance and promoting efficient intermolecular stacking. Consequently, single crystals of FDPP-p-C6 exhibit a planar backbone and a typical herringbone packing arrangement, facilitating charge transport. The single-crystal organic field-effect transistors (OFETs) demonstrate p-type charge transport, achieving maximum mobility of 0.20 cm² V^-¹ s^-¹. Additionally, the single-crystal OPTs show promising performance, with high responsivity across a broad spectral range and a photoresponsivity of 2.2 × 10³ A W^-¹ along with a specific detectivity, derived from the noise current, of 2.8 × 10¹⁰ Jones. This study highlights the potential of FDPP as a key material for advancing single-crystal OFET and OPT technologies, propelling relevant research forward.

Biologics have low toxicity and are highly specific and biocompatible, offering advantages over small-molecule drugs. The administration of biologics in oral form provides a significant benefit in improving patient compliance. However, oral administration faces the challenge of a harsh gastrointestinal environment, including low pH, enzyme degradation, and poor intestinal epithelium permeability, which limits the bioavailability of biologics. As a result, the administration of biologics remains primarily in the parenteral form. This review introduces the physiological barriers encountered by oral biologics delivery, describes the oral biologics currently on the market or under clinical trials, as well as oral biologics-based technologies, and discusses the recent progress on novel oral delivery technologies such as nanoparticle-delivery systems, ionic liquids, and microneedles. Specifically, colon-targeted approaches for oral biologics delivery are also explored, as the colon could be a more optimal absorption site due to having less diverse proteolytic enzymes and relatively limited digestibility compared to the upper gastrointestinal tract (GIT). Lastly, the future research directions for oral biologics are highlighted and it is concluded that with an in-depth study of biological drugs and advancement in delivery methods, oral biologics can pioneer new opportunities.

Electrochemical hydrogen purification (EHP) technology with high-efficiency and easy-operation holds great potential in blended hydrogen transportation, which is currently restricted to proton exchange membrane system and Pt-based catalysts. As promising candidates used in alkaline anion exchange membrane system, Pd-based catalysts are hampered by the intense interaction between H^* and delocalized 4d electrons, resulting in unsatisfactory catalytic activity. In this study, a marked enhancement of the alkaline membrane-based EHP performance is achieved, with hydrogen purity up to 99.96% separated from a CH₄-H₂ mixture, by strategically incorporating interstitial H atoms into Pd lattices for improving the anodic hydrogen oxidation reaction. Detailed characterizations and density functional theory calculations elucidate that the presence of interstitial H localizes free electrons into Pd-H covalent bonds, thereby weakening the interaction between surface-adsorbed H^* and the catalytic surface. Moreover, operando spectroscopies and ab initio molecular dynamic simulations reveal that the enhanced interaction between the catalyst surface and interfacial water by electron delocalization, facilitates the desorption of H^* to the interfacial water layer during catalysis. This research highlights the pivotal role of electronic localization in modulating the adsorption strength of key reaction intermediates for the design of efficient Pd-based catalysts.

Atherosclerosis (AS), a chronic inflammatory disease and a leading cause of cardiovascular morbidity and mortality worldwide, is a significant contributor to disability. Neutrophil extracellular traps (NETs) have been closely associated with the progression of AS and plaque vulnerability. However, developing a treatment strategy that specifically targets neutrophils and effectively reduces NET release at the lesion site remains a major challenge. In this study, a biomimetic nanosystem with neutrophil-targeting properties is engineered. Coating Prussian blue nanoparticles with bacterial biomimetic membranes (MPB NPs) enables specific recognition and internalization by neutrophils. By hitching onto neutrophils, the MPB NPs scavenge intracellular reactive oxygen species (ROS) and suppress NET formation at the lesion site. Importantly, MPB NPs reduce the size of atherosclerotic plaques by 3.29-fold, from 22.53% to 6.85%, stabilize the plaques, and halt their progression in atherosclerotic mouse models. These findings suggest that MPB NPs offer a promising therapeutic strategy for atherosclerosis, and provide a versatile platform for the treatment of NET-associated diseases.

Liver fibrosis (LF) is characterized by excessive production of reactive oxygen species (ROS), abnormal activation of hepatic stellate cells (HSCs), and subsequent extracellular matrix (ECM) deposition. The complexity of multiple interrelated pathways involved in this process makes it challenging for monotherapy to achieve the desired therapeutic effects. To address this issue, this study designs a ROS-activated heterodimer conjugate (VTO) to collaboratively alleviate LF. Additionally, a biomimetic high-density lipoprotein is utilized for encapsulation, resulting in the formation of PL-VTO, which enables natural liver targeting. Once PL-VTO is delivered to the fibrotic liver, it can respond and release both parent drugs upon encountering the high ROS microenvironment, effectively scavenge ROS, induce quiescence of activated HSCs, and reduce collagen deposition, ultimately reversing LF. Overall, this study presents a feasible and versatile nanotherapeutic approach to enhance the prodrug-driven treatment of LF.

Heavy metals, including Sb, are major pollutants with limits on their allowed concentration in drinking water. Therefore, there is a need for sensitive, simple, and portable detection methods for which electrochemical sensors are ideally suited. In this current study, Meta-chemical surfaces are developed for electrochemical sensing by patterning gold electrode surfaces with a mixture of black phosphorus (BP) and polymethyl methacrylate (PMMA) as nanoclusters using dip-pen nanolithography. It is found that the surface-to-volume ratio (S/V), fill factor, and ink composition affect the sensitivity of the sensor for Sb detection. The S/V ratio and fill factor can be altered by the dwell time, which has a complex effect on the limit of detection (varying from 14 to 24 ppb with the changes in the dwell time). Density functional theory calculations show that the binding between Sb(III) and BP is more exergonic in the presence of PMMA. These results are significant because they allow for the development of more sensitive Sb sensors, which can affect the wider field of the detection of heavy metals in drinking water sources and achieve higher efficiency than the commonly used instruments.

Reducing platinum (Pt) usage and enhancing its catalytic performance in the hydrogen oxidation reaction (HOR) and the oxygen reduction reaction (ORR) are vital for advancing fuel cell technology. This study presents the design and investigation of monolayer and few-layer Pt structures with high platinum utilization, developed through theoretical calculations. By minimizing the metal thickness from 1 to 3 atomic layers, an atomic utilization rate ranging from 66.66% to 100% is achieved, in contrast to conventional multilayer Pt structures. This reduction resulted in a unique surface coordination environment. These thinner structures exhibited nonlinear fluctuations in key electronic characteristics-such as the d-band center, surface charge, and work function-as the atomic layer thickness decreased. These variations significantly impacted species adsorption and the Pt-H₂O interfacial structure, which in turn affected the catalytic activity. Notably, 1-layer Pt exhibited the best performance for HOR, while 3-layer Pt showed high activity for both HOR and ORR. The findings establish a clear relationship between atomic layer thickness, surface characteristics, adsorption behavior, electric double-layer structure, and catalytic performance in Pt systems. This research contributes to a deeper understanding of precision atomic-structured electrocatalyst design and paves the way for the development of highly effective, low-loading Pt-based catalytic materials.

Plasmonic nanocrystals have the potential to be widely used in green energy-related applications, due to their excellent optical properties and high reactivity over a wide range of solar wavelengths. Another benefit of using plasmonic nanocrystals for optical applications is that these nanocrystals strongly enhance Raman scattering and are therefore widely used in sensors. Recently, nanocomposites of porous materials deposited on plasmonic nanocrystals are demonstrated to enhance chemical reactivity by concentrating reactants on the surface of plasmonic nanocrystals. Here, three different plasmonic nanocrystals producing plasmonic responses within 400-900 nm are used as templates, and MOF-801 (Zr-based MOF) is produced on these nanocrystals as photocatalysts for the CO₂ reduction reaction. Using nanocomposites as CO₂ reduction reaction photocatalysts, the CO₂ conversion rate can reach >50% within 30 min. The CO₂ reduction reactivity of nanocomposites can be improved by the composition and morphology of plasmonic nanocrystals (increased by 40-50%), due to stronger synergistic effects and higher surface area to volume ratio. This report demonstrates that by controlling the plasmonic responses of nanocrystals, it is possible to realize photocatalysts that can be used for CO₂ reduction reactions over a wide range of solar wavelengths.

Perovskite oxides exhibit excellent performance in water oxidation, but still lacks a precise regulation strategy for the active sites, while the reaction mechanism is poorly understood. Herein, an ion-induced effect (IIE) is proposed of Ce, Ni dual site doped LaCoO₃(CeNi-LaCoO₃), where Ni²⁺ induces the binding of Co species into bimetallic sites, and Ce⁴⁺ induces the activation of Co species and reduces the Co-O binding energy. Benefiting from the IIE of Ni²⁺ and Ce⁴⁺, the optimized Ce_0.15La_0.85Ni_0.3Co_0.7O₃ exhibits excellent OER performance with an overpotential of only 330 mV when the current density reached 10 mA cm^-2, the Tafel slope of 70.93 mV dec^-1 as well as good stability. Theoretical calculations further reveal that the OER occurring on CeNi-LaCoO₃ follows the LOM mechanism, and IIE caused by the doping of the Ce, Ni dual site induces the conversion of Co²⁺ to Co³⁺, optimizes the electron arrangement, modulates the electron transfer capacity of the Co site, promotes the conversion of lattice oxygen to OH^-, lowers the energy barrier for the participation of bulk oxygen in the OER, and thus promotes the OER performance. This work is expected to provide reliable support for the application of high-efficiency perovskite-based OER catalysts.