ACS Applied Materials & Interfaces最新文献

The increase in carbon dioxide (CO₂) concentration in the atmosphere has resulted in adverse and irreversible effects in terms of climate change and global warming. To limit the temperature rise to less than 2 °C by the end of this century, it is urgent to reduce the CO₂ concentration in the atmosphere. Direct air capture (DAC) is considered a carbon-negative emission technology which could efficiently remove CO₂ from air. Membrane gas separation is a promising technology for CO₂ capture, owing to its higher energy efficiency, greater scale-up ability, and smaller carbon footprints compared with conventional sorption processes. The application of membranes in the DAC process (m-DAC) is still in its infancy, owing to the low CO₂ concentration (400 ppm) in air. However, simulations and laboratory studies have demonstrated the feasibility of m-DAC. With the development of high-performance membrane materials and the design of multistage membrane processes, the implementation of m-DAC will be a promising strategy for the efficient reduction of CO₂ concentration in air. This review presents current studies on the m-DAC process and recently developed membranes for CO₂/N₂ separation which could be potentially used in that process, as well as highlighting research gaps that currently represent obstacles to the wider use of membranes for m-DAC. In conclusion, challenges and future prospects are presented, along with a roadmap for the future development of m-DAC, to provide a deeper insight into m-DAC processes.

Multiheteroatom-doped metal-free porous carbons are promising candidates for oxygen reduction reaction (ORR) catalysis. However, achieving precise active-site modulation while simultaneously maximizing accessibility remains a significant challenge. Herein, a two-dimensional (2D) P,S,N-tridoped semiopen carbon honeycomb (PSN-SOCH) was synthesized via a facile multicomponent ice-templating coassembly (MIC) approach. Multiheteroatom doping efficiently modulates the electronic structure of active sites. Meanwhile, the unique highly porous 2D semiopen architecture exhibits a nanoconfinement effect for O₂ transport, which improves the mass-transfer efficiency. As a result, the PSN-SOCH catalyst exhibits a high half-wave potential of 0.87 V in 0.1 M KOH, surpassing those of 2D dual-doped counterparts as well as 2D tridoped carbon honeycombs with differing pore openness. Density functional theory calculations reveal that tridoping enhances charge delocalization and optimizes the adsorption energies of ORR intermediates, thereby accelerating reaction kinetics. Furthermore, finite-element simulations combined with the distribution of relaxation time analysis confirm that the unique semiopen framework facilitates more efficient O₂ transport. This work presents a robust two-in-one strategy for the simultaneous engineering of active sites and mass-transfer efficiency.

In recent years, the biomedical applications of metal-organic frameworks (MOFs) for drug delivery have attracted increasing attention, largely due to their outstanding advantages, such as high surface area and porosity for high loading of therapeutic agents, along with facile structural modification. However, MOF drug carriers often suffer from uncontrollable burst release and inadequate spatiotemporal control, hindering their clinical application. To address this challenge, we report a novel nanoplatform with photoresponsive properties, ZIF-90-Azo, by postsynthetic modification (PSM) of ZIF-90 with 4-aminoazobenzene groups. This system leverages the reversible trans-to-cis photoisomerization of the azobenzene moieties to construct a sophisticated photogating mechanism for controlled drug release. The resulting ZIF-90-Azo efficiently encapsulates antimicrobial agents within its porous structure. Under ultraviolet (UV) light irradiation, the extended trans-Azo groups isomerize to the bent cis-Azo form, modulating the accessible pore fraction and activating drug release. Conversely, visible-light irradiation reverts the system to its closed state, preventing on-demand release. Kinetic studies reveal a pronounced, reversible divergence in release profiles between the trans and cis states, confirming that azobenzene photoisomerization dictates the diffusion flux. This mechanism enables on-demand drug release with exquisite spatiotemporal precision via external light-triggered control. Furthermore, the material demonstrates a notable synergistic antibacterial effect stemming from the combined action triggered by UV irradiation drug release and the mild intrinsic antimicrobial activity arising from Zn²⁺ release from the MOF framework. Upon UV light irradiation, the material achieves a 100% antibacterial rate against Staphylococcus aureus (10⁶ CFU/mL). This ZIF-90-Azo system successfully demonstrates a highly efficient, on-demand drug delivery modality, offering a versatile strategy to achieve superior spatiotemporal control.

Thiazolo[5,4-d]thiazole (TTz) is a rigid, planar, π-conjugated heterocycle that has been widely used as a versatile sensing unit. To exploit the properties of the TTz unit within a metal-organic framework, we synthesized an electroactive Cd-MOF derived from thiazolo[5,4-d]thiazole, [Cd₂(DPTTZ)₂(BDC)₂]·DMF, where BDC = 1,4-benzenedicarboxylate, DPTTZ = 2,5-di(pyridine-4-yl)thiazolo[5,4-d]thiazole, and DMF = N,N-dimethylformamide, via a mixed-ligand solvothermal strategy. Single-crystal analysis reveals a three-dimensional framework crystallizing in the orthorhombic system with space group Iba2. We investigated the sensitivity and electrical conductivity (EC) of the synthesized metal-organic framework incorporating the DPTTZ ligand under exposure to guest molecules such as water and other volatile solvents. These guests can modify MOF conductivity through interactions with ligands and metal centers or via their redox properties. The MOF was processed as an electrode-supported sensing layer and evaluated by complex impedance spectroscopy under controlled relative humidity (RH) cycling. The material's sensing performance at a 3 kHz operating frequency exhibits a broad dynamic sensing range, high sensitivity to RH variations (11-95%), rapid response and recovery times (under 10 and 7 s for RH 33% and under 25 and 20 s for RH 95%), minimal hysteresis, and a high coefficient of determination (R² = 0.97), which confirms an excellent linear correlation and suggests the sensor delivers reliable, predictable performance over the measured humidity range. Mechanistic analysis attributes the impedance changes to stepwise water uptake into pore channels and interaction with polar functional sites, which enhance ionic/protonic conduction pathways. These results demonstrate that electroactive TTz-derived linkers can impart mixed-conducting behavior in MOFs and provide a viable platform for impedance-based humidity and chemosensitive sensors amenable to on-chip integration and field deployment.

Implantable medical devices require long-term stability in vivo and high biocompatibility; however, precise control of the interfacial interactions between bioceramic-coated device surfaces and biological tissues remains a critical challenge. Herein, we investigated the influence of silicate ion introduction during the wet chemical synthesis of hydroxyapatite nanoparticles on their surface nanolayer states and electrophoretic deposition behavior. Using tetraethoxysilane, we synthesized two distinct types of silicate ion-containing hydroxyapatite nanoparticles: (1) silicate ion-substituted type, in which silicate ions were incorporated into the hydroxyapatite crystal structure, and (2) silicate-coated type, in which condensed silicate ions were partially formed on the nanoparticle surface. The spectroscopic analyses revealed that the silicate ion-substituted type would introduce hydroxyl vacancies within the hydroxyapatite crystal structure. This phenomenon induced the local lattice distortions, which directly influenced the surface states of the nanoparticles (i.e., the ion-containing states of the surface nanolayer) and their electrophoretic deposition properties. In contrast, the silicate-coated type did not occur in silicate ion substitution, and the silica oligomer was adsorbed on the nanoparticle surfaces, exhibiting a stabilized zeta potential and electrophoretic deposition properties. These findings demonstrated that the timing of tetraethoxysilane addition during the wet chemical synthesis critically dictates the surface nanolayer states on the nanoparticles, offering molecular-level guidelines for designing the initial interactions with biological tissues.

Biofilm-associated infections remain a major challenge, as the inherent recalcitrance of the extracellular polymeric substance matrix renders conventional antibiotics ineffective, further driving antimicrobial resistance. To address this, combination therapies have emerged as a potent strategy to enhance therapeutic outcomes. In this study, a dual-functional, antibiotic-free nanoplatform was designed to eradicate biofilms through combined quorum sensing (QS) inhibition and chemodynamic therapy (CDT). This nanoplatform consists of calcium peroxide (CaO₂) nanoparticles coated with a quercetin/copper ion (Qe/Cu²⁺) complex. Upon exposure to the acidic biofilm microenvironment, the Qe/Cu²⁺ complex dissociates, releasing Qe and Cu²⁺ while exposing the CaO₂ core. The subsequent reaction of CaO₂ with water generates hydrogen peroxide, which is then catalyzed by Cu²⁺ via a Fenton-like reaction to produce highly bactericidal hydroxyl radicals. Simultaneously, Qe disrupts bacterial QS pathways, attenuating pathogenicity and sensitizing the biofilm-embedded bacteria to oxidative damage. This antibiotic-free nanoplatform demonstrated robust in vitro antibiofilm activity against Pseudomonas aeruginosa and Staphylococcus aureus, while significantly reducing bacterial colonization and accelerating wound healing in an infected mouse model, suggesting that the synergetic integration of QS inhibition and CDT represents a promising strategy for combating biofilm-associated infections.

Single-metal catalysts in electrocatalytic reactions often face a trade-off between activity and selectivity and are prone to structural reconstruction, leading to catalytic deactivation. Here, we report an In-Bi bimetallic alloy electrocatalyst featuring multifunctional interfacial sites. In the electrocatalytic CO₂ reduction to formate, this catalyst delivers a remarkable formate selectivity of 97.8% at -700 mA cm^-2 with excellent stability over 120 h. In situ spectroscopic characterizations combined with theoretical calculations demonstrate that alloying-induced electronic reconstruction shifts the p-band center of Bi toward the Fermi level, thereby accelerating the C-H bond formation to generate the ^*OCHO intermediate. Meanwhile, the In-Bi interfacial sites regulate the strength of the hydrogen-bonding network and facilitate H₂O activation. Therefore, this bimetallic alloy design integrates electronic reconstruction and interfacial functionality, accounting for the significantly enhanced electrocatalytic performance toward the CO₂ reduction.