Chemistry of Materials最新文献

Despite recent advances in nanomedicine, developing multifunctional nanocarriers capable of targeted subcellular delivery and efficient gene therapy remains a significant challenge. This study reports the design, synthesis, and evaluation of a novel multifunctional polypeptide-based nanoconjugate that addresses this gap using sequential delivery, combining mitochondrial targeting and nonviral gene therapy. We engineered a poly-l-ornithine-based, polyethylene glycol-modified carrier and introduced a novel custom-designed trivalent compound (TRV3) into the structure. TRV3, conjugated to the polypeptide carrier via a redox-sensitive disulfide linker, incorporates the well-described triphenylphosphonium moiety (TPP) for mitochondrial targeting and a Cy5 fluorophore as a model drug. The resulting nanoconjugate (C-TRV3-A) demonstrated efficient endosomal escape and mitochondrial localization. Leveraging the endosomolytic properties of C-TRV3-A, we explored its potential as a nonviral vector for gene therapy. After optimizing formulation stability using a VLC-3 anionic polypeptide coating, we developed plasmid DNA polyplexes that exhibited enhanced stability and transfection efficiency in basic and advanced triple-negative breast cancer cell culture models. This multifunctional polypeptide-based nanoconjugate represents a significant advance in the field, offering a chemically versatile platform for simultaneous subcellular targeting and gene delivery that may be used in targeted cancer treatments, among other pathologies.

Zeolites are nanoporous crystalline materials critical for diverse industrial applications, yet their growth mechanisms are poorly understood. This study presents a novel integrated framework combining experimental synthesis, high-resolution imaging, coarse-grained molecular dynamics simulations, and computer vision to uncover the mechanisms of growth of SSZ-24, a 1D channel zeolite. We demonstrate how synthesis conditions, such as temperature and reactant concentration, govern crystal anisotropy and surface roughness with growth dynamics differing markedly by crystallographic orientation. Along the channels, growth involves minimal energy barriers and rapid nucleation, resulting in rough surfaces. In contrast, growth perpendicular to the channels requires cooperative molecular organization and is highly sensitive to thermodynamic and kinetic conditions, yielding smooth anisotropic surfaces under low driving forces. By simulating transmission electron microscopy (TEM) images, we bridge molecular-scale simulations with experimental observations, identifying distinct growth mechanisms along different crystal planes. This work offers molecular-level insights into zeolite crystallization, advancing the rational design of nanoporous materials. The integration of cross-disciplinary methodologies establishes a transformative framework for optimizing zeolite synthesis, with implications for broader classes of materials.

Sandwich nanostructures doped with lanthanides, where sensitizers and activators are confined to the intermediate layer between the inner and outer inert NaYF₄ layers, have been shown to be the most efficient upconversion nanoparticles (UCNPs). However, in order to achieve a high upconversion luminescence (UCL) quantum yield, a thick outer inert NaYF₄ layer and a large-size nanostructure are required, which limits their applications in biological fields such as bioimaging and biosensing. In this work, we have synthesized CaF₂@NaYbF₄:Er@CaF₂ sandwich nanostructures and found that their UC emission efficiency remarkably increases with increasing thickness of the intermediate active layer, even though the outer CaF₂ layer is thin and incomplete. In contrast to the diffuse NaYF₄@NaYbF₄:Er interfaces in NaYF₄@NaYbF₄:Er@NaYF₄ sandwich structures, the sharp CaF₂@NaYbF₄:Er interfaces not only effectively suppress energy migration to defects and surface quenchers but also guarantee a shorter Yb–Er distance on average. This leads to a reduction in energy loss and a highly efficient upconversion of energy transfer. As a result, the 20 nm-CaF₂@NaYbF₄:2%Er@CaF₂ nanoparticles emit ultrabright UCL, which is twice as intense as the UCL emitted from the larger 37 nm-α-NaYF₄@NaYbF₄:2%Er@NaYF₄ nanoparticles. These findings will enable the versatile design of bright upconversion nanoparticles with relatively small sizes, meeting the requirements for biological applications.

Scandium trifluoride is a model negative thermal expansion (NTE) material. Its simple structure can be described as an A-site vacant perovskite, and it shows isotropic NTE over a very wide temperature range (up to ∼1100 K), due to transverse vibrational motion of the fluoride. Like many framework NTE materials, it undergoes a phase transition at low pressures, adopting a rhombohedral (R3̅c) structure at >0.7 GPa and 300 K in commonly used nonpenetrating pressure media, such as silicone oil. High pressure X-ray diffraction data and gas uptake/release measurements indicate that, on compression in helium above ∼200 K, helium is inserted into ScF₃ to form the defect perovskite He_xScF₃. The incorporation of helium stiffens the structure and changes its phase behavior. At room temperature, complete filling of the structure with helium does not occur until >1.5 GPa. On compression, a cubic perovskite structure is maintained until ∼5 GPa. As the pressure was increased to ∼9.5 GPa, a further transition occurred at ∼7 GPa. The first transition at ∼5 GPa is likely to a tetragonal (P4/mbm) perovskite, but the detailed structure of the perovskite phase formed on compression above ∼7 GPa is unclear. Cooling down from 300 to 100 K in helium at ∼0.4 GPa leads to an approximate composition of He_0.1ScF₃. High pressure neutron diffraction measurements, in the temperature range 15–150 K show that the incorporation of helium increases the pressure at which the cubic (Pm3̅m) to rhombohedral (R3̅c) putative quantum structural phase transition occurs from close to 0 GPa to ∼0.2 GPa at 0 K.