ACS Nanoscience Au最新文献

The electrification of chemical transformations central to sustainable fuel production and waste valorization, such as overall water splitting (OWS), hydrogen evolution reaction (HER), and electrochemical reduction of CO₂ (CO₂R), presents a powerful opportunity to advance carbon-neutral energy technologies. Transition metal dichalcogenides (TMDs), particularly MoS₂, have emerged as promising electrocatalyst candidates, owing to their abundance, tunable active sites, and defect-rich structures. This review highlights recent progress in leveraging metal doping and heterostructure engineering of MoS₂ to enhance the electrocatalytic activity and selectivity. By compiling insights from experimental studies and density functional theory (DFT) predictions, we examine how defect creation, electronic structure modification, and interface design contribute to improved charge transport and catalytic efficiency. Particular emphasis is placed on rational design principles, synthetic strategies, and operando characterization methods that provide a pathway to understanding and optimizing MoS₂-based materials. We also discuss the challenges of stability, mechanistic ambiguity, and scaling while outlining opportunities to bridge theory and experiment. Collectively, this review underscores how defect and heterostructure engineering of MoS₂ can accelerate the development of efficient, sustainable electrocatalysts for both fuel generation and waste-to-value generation.

We demonstrate that the etching chemistry used during MXene synthesis from Ti₃AlC₂ MAX phase significantly influences surface functionalization and structural vacancies, which in turn affect ruthenium (Ru) ion interactions. Using hydrofluoric acid (HF) and ammonium bifluoride (NH₄HF₂) as etchants, we obtained MXene surfaces with distinct functional groups and Ti vacancies that impact Ru ion interactions and electrochemical performance. Both MXene variants (labeled MX-(H) and MX-(N), respectively) exhibited negative zeta potentials in their pristine state, but upon the addition of Ru the zeta potential for MX-(H) reached 12.9 mV while that for MX-(N) remained negative at -6.4 mV. This adsorption resulted in a 14.4-fold increase in the specific capacitance of MX-(H)/Ru compared to pristine MX-(H), whereas MX-(N)/Ru exhibited only a 4.4-fold increase over its pristine counterpart. X-ray diffraction analysis identified the formation of ammonium titanium oxide fluoride, (NH₄)₃TiOF₅, on MX-(N), which likely contributed to its reduced Ru adsorption. X-ray photoelectron spectroscopy suggested the presence of Ti vacancies in both MXene variants; however, their behavior toward Ru accommodation differed markedly, with MX-(H) showing the most obvious shift in the Ti 2p peak in the XPS survey spectrum, while MX-(N) showed the most obvious shift in the C 1s peak. Electron paramagnetic resonance spectroscopy further demonstrated a distinct alteration in the spectral signatures of MX-(H) upon Ru addition, in contrast to the negligible changes in MX-(N), indicating effective passivation of the Ti defect sites in MX-(H) via vacancy-assisted Ru doping. Cyclic voltammetry showed that Ru-incorporated MX-(H) nanocomposites exhibit more efficient redox-active sites, as reflected in their higher capacitance values. These findings highlight the pivotal role of MXene surface chemistry in controlling cation adsorption, providing valuable insights for the rational design of high-performance electrodes.

Dual plasmonic heterostructures composed of gold nanoparticles (Au NPs) and nonstoichiometric copper chalcogenides (Cu_2‑xE) have garnered attention for their unique electronic interactions between two intrinsically dissimilar constituent domains. However, the site-selective deposition of Cu_2‑xE on Au NPs remains extremely challenging due to the difficulty in controlling nucleation and regioselective overgrowth. Herein, we propose a universal Selenide (Se)-mediated approach for precise spatial control of Cu_2‑xSe on gold nano bipyramids (Au NBPs). By deliberately tuning the surfactant environment, Cu_2‑xSe can be selectively deposited on one waist, both lateral sides, and tips of Au NBPs to form UFO-like, segregated islands, and spindle-like morphologies, respectively. Furthermore, the domain size of the Cu_2‑xSe and the plasmonic properties of Au@Cu_2‑xSe can be controlled by adjusting the amount of selenium (SeO₂) precursor. This work establishes a new strategy for the rational design and fabrication of multicomponent functional nanoarchitectures with precisely controlled compositions and tailored plasmonic properties, thereby expanding their scope of applications.

Plasmonics is a rapidly growing field of research based on plasmonic nanostructures. To exploit the full potential of this fascinating class of materials, it is indispensable to tune and optimize the properties of these structures, which requires precise knowledge and optimization of their synthesis processes. Plasmonic silver nanocubes for applications in nonpolar media are obtained by an AgCl-mediated hot-injection method. In this process, catalysis by Fe species is of central importance, as the Fe species influence the reaction in multiple ways, enabling a finely balanced control of the nanocube synthesis. Using electron microscopy, optical spectroscopy, and X-ray photoelectron spectroscopy, it is shown that the Fe species not only direct the reaction of the Ag precursor to the formation of AgCl nanoparticles instead of icosahedral Ag nanoparticles but also enhance the reduction rate of AgCl, from which the Ag nanocubes are formed and grow. Based on these results, a detailed reaction mechanism is proposed. An additional comparison of the effects of different metal ions on the reaction shows that iron ions are highly likely to be specific as catalysts for this synthesis. The results also indicate that the Fe ions are likely present in the form of an organic iron complex, catalyzing the chloride transfer.

This work experimentally investigates a mechanism of rectification in molecular junctions proposed by van Dyck and Ratner, supported by theoretical modeling. The defining feature of the mechanism is the spatial separation of frontier molecular orbitals such that each tracks the two leads independently. We achieve this orbital separation in oligophenyleneethylene molecular wires with electron-rich thiols and electron-poor pyridines at their termini. Density functional theory (DFT) calculations show localization of the frontier molecular orbitals at these termini that increases with the molecular length. Measurements of rectification ratios in molecular ensemble junctions using eutectic Ga-In (EGaIn) top-contacts and Au bottom-contacts reveal a length dependence that is almost completely insensitive to the insertion of a nonconjugated methylene spacer between the thiol anchor and conjugated backbone. Simulations using nonequilibrium Green's function + DFT methods show that transport is dominated by the lowest unoccupied molecular orbitals, which track the EGaIn electrode, leading to rectification. These results validate the approach of creating molecular rectifiers by spatially separating the frontier molecular orbitals and show an approach to modeling their behavior under bias in ensemble junctions.

Dendritic cells (DCs) represent pivotal targets in immunotherapy, gene therapy, and vaccine delivery for major diseases including cancer, autoimmune diseases, and transplant rejection. Overcoming the challenge of efficient gene delivery via conventional nonviral molecules into primary DCs has been a persistent obstacle. Within this research, we introduce an innovative gene delivery system utilizing magnetic iron oxide nanocubes (MCs) encapsulated with a biocompatible polymer, poly-(lactic-co-glycolic acid) (PL), and a cationic polymer, poly-(2-(dimethylamino)-ethyl methacrylate) (PD), facilitated by a magnetic field. Positively charged MC-PL-PD and MC-PL-PD/PD (double coating of PD) composites were synthesized, and plasmid DNA (pMAX-GFP) attachment ensued. The nanocomposite with double layers coated with PD displayed increased positive charge despite the incorporation of plasmid DNA. In addition, these nanocomposites exhibited superparamagnetic properties with a saturation magnetization of 4.5 emu/g. At concentrations ranging from 25 to 100 μg/mL, the nanocomposites demonstrated minimal toxicity on bone marrow-derived dendritic cells (BMDCs) and exhibited efficient cellular uptake under the influence of a magnetic field. Composites with higher positive charges and increased amounts demonstrated enhanced plasmid transfection efficiency without activating BMDCs. These findings suggest that using MC-PL-PD and MC-PL-PD/PD nanocomposites as carriers holds promise as a viable and effective gene delivery platform to primary DCs, revealing their potential in advancing gene-based therapeutic approaches.

Near-infrared (NIR) fluorescence imaging is a powerful, noninvasive tool for cancer diagnosis, enabling real-time, high-resolution visualization of biological systems. While most probes target the first NIR window (NIR-I, 700-900 nm), recent advances focus on the second window (NIR-II, 1000-1700 nm), which offers deeper tissue penetration and reduced interference from scattering and autofluorescence. However, many current NIR-II nanoprobes show suboptimal brightness and limited validation in more human-centric models. Here, we present an orthogonal strategy combining molecular engineering, by modulating the amount and position of thiophene moieties in semiconducting polymers (SPs), with protein nanoengineering to develop ultrabright NIR-II imaging probes optimized for ex vivo bioimaging in large animal models. The molecular tuning amplifies the NIR-II fluorescence brightness while screening endogenous proteins as encapsulating matrices to improve colloidal stability and enable active targeting. Molecular docking identified bovine serum albumin as the effective candidate, and the resulting protein-complexed nanoprobes were characterized for size, colloidal stability under physiological conditions, and optical performance. Imaging performance was evaluated using tumor-mimicking phantoms in porcine lungs, simulating cancer surgery, and injected at clinically relevant concentrations into ovine brains and porcine ovaries for microvascular visualization and tissue discrimination, respectively. In all scenarios, our protein-complexed nanoprobes outperformed the FDA-approved clinical dye indocyanine green in signal-to-background ratios. Initial in vitro assays confirmed their hemocompatibility, biocompatibility, and cellular uptake in ovarian adenocarcinoma cells. This integrated approach offers a promising platform for developing next-generation ultrabright NIR-II nanoprobes with improved brightness and stability, advancing the potential for image-guided surgery and future clinical translation.

The industrial-scale production of solid lipid nanoparticles (SLNs) faces significant challenges, such as degradation during freezing and the reliance on toxic solvents for cryoprotection and active ingredient solubility, hindering their effective storage and commercialization. This study presents an innovative and sustainable approach to SLNs formulation by incorporating a natural deep eutectic solvent-based system (NaDES) as an integral part of the system. The research evaluated the cryoprotective potential of NaDES at different concentrations and freezing methods, demonstrating their ability to stabilize aluminum chloride phthalocyanine (AlClPc)-loaded SLNs during freezing and enable drying protocols to enhance particle concentration. SLNs formulations with high colloidal stability were obtained, containing 12.5% NaDES, based on low-energy methodologies and high added value. Additionally, the use of NaDES enabled a 12.5% reduction in the water content in the formulation and acted as an efficient cryoprotectant, allowing for the freezing of SLNs without compromising particle integrity. These advancements suggest a greener and potentially scalable methodology for SLNs production, positioning NaDESs as promising cryoprotectants that may enhance formulation stability, improve commercial viability, and reduce production and storage costs. This innovation may represent an initial step toward improving nanoparticle preservation and facilitating future industrial translation, with the potential to broaden nanoparticle application in nanotechnology.

The transfer of inorganic nanoparticles (NPs) into water is usually considered a challenge, as NPs are preferably synthesized in organic solvents and commonly bear hydrophobic ligands. Consequently, various methods have been reported to achieve their transfer to aqueous media. Among these, a polymer coating using amphiphilic polymers represents a particularly useful approach. These polymers can interact with the NP surface via their hydrophobic moieties, while their hydrophilic side remains exposed to the aqueous media, thus enabling dispersion in water. In this paper, we present the facile synthesis of several fluorinated, hydrosoluble amphiphilic polymers, and we study the coating of different types of metallic NPs, such as gold nanoparticles and quantum dots (QDs). Gold NPs were transferred via a phase transfer protocol, but for more sensitive QDs, we used the film hydration method. For QDs, the high hydrophobicity of fluorinated moieties on the polymer was particularly advantageous in repelling water and preserving the optical properties of QDs. Fractal arrangements in aqueous solution for polymer-coated QDs were analyzed by small-angle X-ray scattering (SAXS) but also observed by TEM. Additionally, we employed these fluorinated polymers to transfer two highly hydrophobic and fluorinated molecules (PERFECTA and PFCE), commonly used as contrast agents in ¹⁹F magnetic resonance imaging (¹⁹F MRI), into aqueous media. We evaluated their transverse and longitudinal relaxation times to assess their suitability for use as contrast agents for ¹⁹F MRI.