ACS Materials Letters最新文献

Anisotropic fluorescent materials, such as surface-functionalized carbon nanotubes and organic crystals, show promise in sensing and signal detection but suffer from lack of tunability and ease of synthesis. In contrast, metal–organic nanotubes (MONTs) offer structural flexibility akin to MOFs since they are synthesized in the same manner. While a few fluorescent MONTs have been reported, their emission arises from ligand-to-metal charge transfer or second harmonic generation, neither of which takes advantage of their ability to employ designer ligands. Herein, a new fluoranthene-core di-1,2,4-triazole ligand with sky blue emission has been synthesized for fluorescent MONTs. Fluorescent MONTs were successfully synthesized by doping small amounts (1–10%) of the fluoranthene ligand into an isostructural silver MONT reaction. These fluorescent MONTs were characterized by single-crystal X-ray diffraction, PXRD, and NMR spectroscopy following acid digestion, which quantified the amount of fluoranthene dopant. Notably, the fluorophore can even be added postsynthetically after the MONTs are already synthesized, demonstrating ligand exchange.

Atherosclerosis is critically driven by inflammation, inadequately addressed by current lipid-lowering therapies. Curcumin has anti-inflammatory and antioxidant properties but poor bioavailability. We develop a biohybrid nanoparticle, termed CP@Leuko, featuring a curcumin-loaded poly(lactic-co-glycolic) acid core within a leukocyte membrane protein-modified zwitterionic lipid shell. The coating enables active targeting of inflamed plaques, resulting in approximately 3-fold greater accumulation in the aortas of ApoE–/– mice versus controls. CP@Leuko modulates inflammation by reducing TNF-α and elevating IL-10 levels in serum and aortic tissues. The treatment attenuates plaque progression, reducing en face aortic plaque area from 25.15% to 11.76% and the aortic root lesion area from 36.69% to 17.10%. It decreases the necrotic core size by about 16.24% while increasing collagen content approximately 1.8-fold, thereby enhancing plaque stability. The formulation significantly improves serum lipid profiles and demonstrates excellent biocompatibility. In summary, CP@Leuko represents a targeted nanotherapeutic strategy leveraging anti-inflammatory efficacy for atherosclerosis treatment.

Photoswitchable adsorbents have garnered widespread interest because of their tunable behavior when exposed to light. Modulation strategies are primarily achieved through weak interactions, based on steric hindrance, such as alterations in pore size or the creation of gated pores, while relatively few focus on the direct regulation of stronger adsorptive interactions. Here, we report the incorporation of heteroaryl azobenzene to construct photoresponsive adsorbents, enabling the modulation of strong adsorptive interactions. As a proof of concept, phenylazoindole (PAI) was introduced as a photoresponsive motif into MOF followed by the addition of Cu^I as the π-complexing active sites, yielding Cu^I-incorporated U67-PAI. The isomerization of PAI alters the surface electrostatic potential surrounding Cu^I from −0.24 to +0.21 eV, thereby modulating the adsorptive interactions. Upon irradiation, Cu^I/U67-PAI exhibited an up to 40% change in CO uptake. This work expands the design toolbox for light-responsive adsorbents with controllable adsorptive interactions.

Driven by environmental concerns regarding conventional polymer-based materials, biomolecule-derived bulk solids, such as glasses and plastics, are attracting increasing attention. Here, we report molecular glasses consisting of a hydrophobic cholesterol scaffold. By designing intermolecular hydrogen bonding, crystallization was suppressed; however, the glassy state was kinetically unstable. We explored a simple strategy of mixing two cholesterol derivatives in the expectation that this would produce a greater diversity in intermolecular interactions and thereby enhance the glass-forming ability. Gratifyingly, we obtained stable, humidity-resistant, transparent glasses with tunable mechanical properties in a scalable manner. The optimized glass exhibited a hardness of H = 88 MPa and a reduced modulus of E_r = 3.1 GPa (nanoindentation analysis), values comparable to those of known molecular glasses and approaching those of conventional polycarbonate glass. This study highlights a promising strategy for developing sustainable hydrophobic organic glassy materials.

Developing plastics that integrate biomass-derived components while achieving high mechanical strength and recyclability remains a formidable challenge. Here, we report chemically recyclable COPI plastics fabricated by reversibly cross-linking low-molecular-weight boronic acid-terminated polyimide (BPI) with vinyl-diol-functionalized castor oil (VCO) through dynamic boronic ester bonds. The resulting soft-rigid hybrid networks, reinforced by reversible boronic ester linkages, hydrogen bonding, and π-π stacking, exhibit exceptional performance, including a tensile strength of ∼170.6 MPa, a Young’s modulus of ∼2.5 GPa, and a glass transition temperature of ∼217.6 °C. Benefiting from reversible boronic esters, COPI plastics can be selectively depolymerized in DMAc/ethanol to recover high-purity BPI and biodegradable VCO. Integrating COPI with carbon fibers yields CF/COPI composites whose mechanical properties rival CF/epoxy thermosets while maintaining chemical recyclability. This work demonstrates an effective strategy for creating ultrastrong, processable, and recyclable plastics and composites by reversibly cross-linking rigid and flexible segments through well-designed dynamic chemistries.

Circularly polarized luminescence and nonlinear optical techniques have garnered considerable attention due to their minimal energy loss and superior optical penetration. However, there is still a lack of mature strategies for designing materials that combine these two exceptional optical properties. Herein, two chiral cofacial naphthalenediimide-based crystals and their enantiomers (R-2NDI-1/S-2NDI-1 and R-2NDI-2/S-2NDI-2) feature yellowish-green circular polarized luminescence emissions centered at ca. 525 and 550 nm, with the g_lum values as high as ±4.1 × 10^–2 and ±6.1 × 10^–2, as well as two-photon excited emissions centered at 525 and 530 nm, with two-photon absorption cross-section values at 770 nm up to 2.662 × 10³ and 2.693 × 10³ GM, respectively. Experimental results, theoretical calculations, and crystal structure analysis demonstrate that the observed circularly polarized luminescence and two-photon absorption arise from a synergistic intramolecular and intermolecular electronic coupling effect. This approach offers a promising strategy for the future development of multifunctional crystalline optical materials.

Bidirectional photoresponsivity devices play an important role in visual information processing and visual computing. However, the heterojunction structure of conventional bidirectional photoresponsivity devices limits the diversity of material choices. This work presents a novel preparation method based on conjugated ultrathin polymer films, which introduces traps through the spin-coating of a low-concentration semiconductor solution onto a strongly hydrophobic substrate to form an ultrathin film to obtain devices exhibiting bidirectional photoresponsivity. The tunable bidirectional photoresponsivity enables the devices to successfully mimic biological synaptic behaviors such as excitatory postsynaptic currents (EPSC), inhibitory postsynaptic currents (IPSC), paired-pulse facilitation (PPF), and learning and forgetting behaviors. This work provides a new strategy for the preparation of all-optical artificial synapses that are suitable for practical applications that require large-scale processing. Finally, neural networks are used for image recognition, achieving a recognition rate of over 95%.

Redox-targeted flow batteries (RTFBs) are promising for large-scale energy storage but suffer from poor solid booster utilization. This study examines how binder selection affects the reaction rate between a LiFePO₄/FePO₄ solid booster composite and a dissolved [Fe(CN)₆]^4–/3– redox mediator. The porosity and hydrophilicity of LiFePO₄ composites correlate with booster utilization, determined by galvanostatic cell cycling and by in situ UV–Vis spectroscopy. Compared with state-of-the-art polyvinylidene difluoride composites, booster pellets containing non-fluorinated, biodegradable polycaprolactone or cellulose acetate binders exhibit up to 175% higher LiFePO₄ conversion rates and improved capacity utilization at cycling rates up to 10 mA cm^–2. Solid-material utilization directly correlates with binder hydrophilicity, establishing it as a key design parameter for RTFBs and offering a straightforward path toward more efficient and non-fluorinated booster formulations.

Emerging and re-emerging viruses with pandemic potential pose a continuous global health threat. Broad-spectrum antivirals, if available, could serve as a critical first line of defense. Here, we present a general and simple strategy to chemically functionalize natural proteins into broad-spectrum, nontoxic antivirals. Through a one-step conjugation, proteins are modified with alkyl ligands terminated by secondary amines. These functionalized proteins exhibit potent inhibitory activity against enveloped viruses HSV-2, Influenza A H1N1, and SARS-CoV-2, with half-effective concentrations (EC₅₀) ranging from nanomolar to micromolar levels. Efficacy improves with increased ligand density, and longer alkyl chains induce a shift from reversible (virustatic) to irreversible (virucidal) antiviral activity. Importantly, antiviral performance remains robust in complex serum environments, and the antiviral is most effective when administered prophylactically. This versatile platform is compatible with diverse protein scaffolds, offering a promising approach for rapid antiviral development against current and future viral threats.

Electrochemical CO₂ reduction to formic acid (HCOOH) has great potential for reducing the carbon footprint and producing liquid fuel. Although several p-block metals have been recognized to be formate-selective, the flooding of catholytes into the catalyst layer at high current densities significantly promotes the competing hydrogen evolution reaction (HER), compromising the efficiency. Here, we report a soluble-salt-inducing fabrication method to disperse formate-selective metals into the carbon matrix of gas diffusion electrodes, in contrast to the conventional surface-supported architectures. This deep metal infiltration effectively suppresses HER under flooding conditions, enabling high formate Faradaic efficiencies of 93% across a broad current density ranging from −50 to −900 mA cm^–2, using chloride-derived indium (CD-In) as a model catalyst. An unexpected compressive strain of 2–4% is also identified as the origin of the faster kinetics over CD-In. Furthermore, we demonstrate the generality of this method with other formate-selective metals, highlighting its potential for scalable CO₂ electroreduction.