ACS Nanoscience Au最新文献

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.

Spherical and hollow molecular cages based on planar triazine (C₃N₃) hubs and aromatic phenylene connectors have been developed. The cages exhibit topologies akin to C₂₀, C₆₀, and C₇₀ fullerenes with diameters that range from 2.3 to 4.9 nm. Apertures into the cage interiors are tuned by varying the aromatic connectors situated between the C₃N₃-units. The stabilities of the C₃N₃ cages increase with size owing to reduced bending strain of planar nodes and connectors that make up the spherical aromatic networks. Doping of the cages with Li⁺ reveals the capacity of the cages for significant adsorption of gaseous H₂ and CO₂. The design of graphene-like spherical cages is also discussed.

We uncover the mechanism behind the enhancement of photoluminescence yield in monolayer WS₂ through oleic acid treatment, a promising scalable strategy for defect healing. By inducing sulfur vacancies through thermal treatment and monitoring the changes in photoluminescence yield and emission spectra, we demonstrate that in contrast to super acids, oleic acid heals the sulfur vacancy by providing substitutional oxygen, instead of hydrogen. Using density functional theory calculations, we provide insight into the underlying mechanism governing the oleic acid-mediated sulfur vacancy healing process. Our findings suggest that effective defect passivation by oxygen doping can be achieved through chemical treatment, opening a pathway for oxygen doping in transition metal dichalcogenides. However, we also highlight the limitations of chemical treatment, which may only lead to small increases in photoluminescence yield beyond a certain point.

Crystalline molecular machines provide a promising platform for integrating dynamic molecular motion into nanoscale solid-state materials, where motion can be programmed, triggered, and harnessed for functional output. This perspective highlights recent advances in the design of crystalline molecular materials that support controlled molecular motion with a focus on three key types: rotors, gears, and motors. We discuss strategies to enable internal rotational freedom, realize mechanically correlated motion, and achieve molecular motion driven by external stimuli. By bridging molecular-level design with long-range crystalline order, these systems open new avenues for the development of molecular-based dynamic crystalline materials with engineered mechanical responses.

Silver-coated gold nanostars (AuNSt@Ag) offer a powerful platform for plasmon-enhanced sensing, yet their fabrication often compromises structural sharpness and spectral tunability. Here, we report a robust and flexible method for synthesizing AuNSt@Ag with precisely controlled localized surface plasmon resonance (LSPR) across a broad spectral range, achieved by systematically optimizing multiple synthetic parameters. Strikingly, surface-enhanced Raman scattering (SERS) performance reached a maximum for bimetallic nanostars with LSPR maxima near 605-615 nm, regardless of excitation wavelength (633 or 785 nm). This reveals that local near-field enhancement at Ag-coated tips, rather than spectral overlap, governs SERS efficiency in these AuNSt@Ag systems. The optimized AuNSt@Ag structures outperform previously reported analogues, exhibiting significantly enhanced SERS capabilities, including an 80-fold increase in signal compared to optimized monometallic AuNSt resonant with the 785 nm laser line. These findings establish a new design paradigm for highly tunable and high-performance plasmonic substrates for analytical sensing applications.

The performance of nanoparticles in catalytic reactions depends critically on their surface composition. In a multielemental system, this issue becomes even more important. Here, we report that the choice of solvent in polyol reduction synthesis of high entropy alloy (HEA) nanoparticles can have a subtle but significant influence on the elemental distribution near the surface of individual nanoparticles. Our study reveals that long-chain polyethylene glycol typically produces a more uniform multielement distribution within a nanoparticle than short-chain triethylene glycol under identical experimental conditions. We performed electrochemical reduction of metal salts in both solvents to understand the reduction kinetics of metal salts, which shows that a solvent capable of improving the co-reduction of metal salts leads to the synthesis of more homogenized nanoparticles, whereas a solvent with a varying degree of reduction potency will lead to inhomogeneous elemental distribution in an HEA nanoparticle.

Graphene oxide (GO) conjugated with short polyethylenimine (PEI) chains (GO-PEI) has been designed as a candidate nanocarrier for small interfering RNA (siRNA) delivery to mammalian cells based on the efficient interaction between the positively charged GO-based platform and the negatively charged siRNA. The function and efficiency of siRNA delivery using GO-PEI were compared to those using the positive control Lipofectamine RNAiMax by analyzing the differentiation to myotubes, and myogenin gene and protein expression in C2C12 cells. RNAiMax transfection induced cellularization and reduction of both myogenin gene and protein expression, suggesting that the differentiation of C2C12 cells was triggered by gene silencing. While GO-PEI also promoted cellularization, the myogenin gene expression remained comparable to scrambled controls, whereas the protein levels were higher than those observed with RNAiMax. Mechanistically, we attributed the reduced gene silencing efficiency of GO-PEI to a poor endosomal escape, despite strong siRNA complexation. This limitation was likely due to a low buffering capacity of GO-PEI, as a significant fraction of nitrogen atoms were already protonated, reducing the availability of free amines necessary for endosomal disruption. An appropriate chemical modification to enhance siRNA release from the endosomes is therefore essential for advancing the development of GO-based platforms as versatile and efficient nanocarriers in gene therapy applications.

Tick-borne diseases have increased significantly due to several factors, including climate change. Ticks can carry diverse pathogens, and transmission is facilitated by immunosuppressive tick salivary proteins. Vaccination targeting tick salivary proteins has been proposed as a strategy to enhance broad acquired immunity against tick-borne pathogens. Given the immunosuppressive nature of these proteins, we leveraged the ability of nanoparticles to enhance antigen immunogenicity. We synthesized nanoparticles directly from tick salivary proteins, evasin-3 and tick salivary lectin pathway inhibitor (TSLPI), by desolvation with ethanol and cross-linking. Nanoparticles formulated with the CpG oligonucleotide adjuvant significantly enhanced both humoral and cellular immune responses against both evasin-3 and TSLPI in mice compared to soluble CpG adjuvanted antigens. These results demonstrate the importance of antigen delivery and presentation, particularly for poorly immunogenic antigens, and the potential for protein nanoparticles to be developed as vaccines against diverse tick-borne pathogens.