Silica hairy nanoparticles: a promising material for self-assembling processes

Engineered Mesoporous Silica-Based Nanoparticles: Characterization of Surface Properties

Mesoporous silica-based nanomaterials have emerged as multifunctional platforms with applications spanning catalysis, medicine, and nanotechnology. Since their synthesis in the early 1990s, these materials have attracted considerable interest due to their unique properties, including high surface area, tunable pore size, and customizable surface chemistry. This article explores the surface properties of a series of MSU-type mesoporous silica nanoparticles, elucidating the impact of different functionalization strategies on surface characteristics. Through an extensive characterization utilizing various techniques, such as FTIR, Z-potential, and nitrogen adsorption porosimetry, insights into the surface modifications of mesoporous silica nanoparticles are provided, contributing to a deeper understanding of their nanostructure and related interactions, and paving the way to possible unexpected actionability and potential applications.

PVDF-HFP Based, Quasi-Solid Nanocomposite Electrolytes for Lithium Metal Batteries

Composite polymer electrolytes are systems of choice for future solid-state lithium metal batteries (LMBs). Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) is among the most interesting matrices to develop new generation quasi-solid electrolytes (QSEs). Here it is reported on nanocomposites made of PVDF-HFP and pegylated SiO2 nanoparticles. Silica-based hybrid nanofillers are obtained by grafting chains of poly(ethylene glycol) methyl ether (PEG) with different molecular weight on the surface of silica nanoparticles. The functionalized nanofiller improves the mechanical, transport and electrochemical properties of the QSEs, which show good ionic conductivity values and high resistance against dendrite penetration, ensuring boosted long and safe device operation. The most promising result is obtained by dispersing 5 wt% of SiO2 functionalized with short PEG chains (PEG750, Mw = 750 g mol-1) in the PVDF-HFP matrix with an ease solvent-casting procedure. It shows ionic conductivity of 0.1 mS cm-1 at 25 °C, more than 250 h resistance to stripping/plating, and impressive results during cycling tests in LMB with LiFePO4 cathode.

Nanoparticle Exsolution from Nanoporous Perovskites for Highly Active and Stable Catalysts

Nanoporosity is clearly beneficial for the performance of heterogeneous catalysts. Although exsolution is a modern method to design innovative catalysts, thus far it is predominantly studied for sintered matrices. A quantitative description of the exsolution of Ni nanoparticles from nanoporous perovskite oxides and their effective application in the biogas dry reforming is here presented. The exsolution process is studied between 500 and 900 °C in nanoporous and sintered La_0.52 Sr_0.28 Ti_0.94 Ni_0.06 O_3±δ . Using temperature-programmed reduction (TPR) and X-ray absorption spectroscopy (XAS), it is shown that the faster and larger oxygen release in the nanoporous material is responsible for twice as high Ni reduction than in the sintered system. For the nanoporous material, the nanoparticle formation mechanism, studied by in situ TEM and small-angle X-ray scattering (SAXS), follows the classical nucleation theory, while on sintered systems also small endogenous nanoparticles form despite the low Ni concentration. Biogas dry reforming tests demonstrate that nanoporous exsolved catalysts are up to 18 times more active than sintered ones with 90% of CO₂ conversion at 800 °C. Time-on-stream tests exhibit superior long-term stability (only 3% activity loss in 8 h) and full regenerability (over three cycles) of the nanoporous exsolved materials in comparison to a commercial Ni/Al₂ O₃ catalyst.

Synthesis and Characterization of Alkoxysilane-Bearing Photoreversible Cinnamic Side Groups: A Promising Building-Block for the Design of Multifunctional Silica Nanoparticles

The present study reports on the synthesis of a new alkoxysilane-bearing light-responsive cinnamyl group and its application as a surface functionalization agent for the development of SiO₂ nanoparticles (NPs) with photoreversible tails. In detail, cinnamic acid (CINN) was activated with N-hydroxysuccinimide (NHS) to obtain the corresponding NHS-ester (CINN-NHS). Subsequently, the amine group of 3-aminopropyltriethoxysilane (APTES) was acylated with CINN-NHS leading to the generation of a novel organosilane, CINN-APTES, which was then exploited for decorating SiO₂ NPs. The covalent bond to the silica surface was confirmed by solid state NMR, whereas thermogravimetric analysis unveiled a functionalization degree much higher compared to that achieved by a conventional double-step post-grafting procedure. In light of these intriguing results, the strategy was successfully extended to naturally occurring sepiolite fibers, widely employed as fillers in technological applications. Finally, a preliminary proof of concept of the photoreversibility of the obtained SiO₂@CINN-APTES system has been carried out through UV diffuse reflectance. The overall outcomes prove the consistency and the versatility of the methodological protocol adopted, which appears promising for the design of hybrid NPs to be employed as building blocks for photoresponsive materials with the ability to change their molecular structure and subsequent properties when exposed to different light stimuli.

Controlling the anisotropic self-assembly of polybutadiene-grafted silica nanoparticles by tuning three-body interaction forces

Recently, the significant improvements in polymer composites properties have been mainly attributed to the ability of filler nanoparticles (NPs) to self-assemble into highly anisotropic self-assembled structures. In this work, we investigate the self-assembly of core-shell NPs composed of a silica core grafted with polybutadiene (PB) chains, generating the so-called "hairy" NPs (HNPs), immersed in tetrahydrofuran solvent. While uncoated silica beads aggregate forming uniform compact structures, the presence of a PB shell affects the silica NPs organization to the point that by increasing the polymer density at the corona, they tend to self-assemble into linear chain-like structures. To reproduce the experimental observations, we propose a theoretical model for the two-body that considers the van der Waals attractive energy together with the polymer-induced repulsive steric contribution and includes an additional three-body interaction term. This term arises due to the anisotropic distribution of PB, which increases their concentration near the NPs contact region. The resulting steric repulsion experienced by a third NP approaching the dimer prevents its binding close to the dimer bond and favors the growth of chain-like structures. We find good agreement between the simulated and experimental self-assembled superstructures, confirming that this three-body steric repulsion plays a key role in determining the cluster morphology of these core-shell NPs. The model also shows that further increasing the grafting density leads to low-density gel-like open structures.

Effect and mechanism of Lenvatinib@H-MnO2-FA drug delivery system in targeting intrahepatic cholangiocarcinoma

BACKGROUND

To investigate the effects of the Lenvatinib@H-MnO2-FA administration system on the proliferation and apoptosis of Intrahepatic cholangiocarcinoma (ICC) and the underlying molecular mechanism.

MATERIALS AND METHODS

In this research, hollow MnO2 (H-MnO2) was synthesized via the modified Stöber method, and H-MnO2 was modified with polyethylene glycol-bis (Amine) (NH2-PEG-NH2) and folic acid (FA) to obtain H-MnO2-PEG-FA (H-MnO2-FA). Lenvatinib was coated in the hollow cavity of H-MnO2-PEG-FA to further form a nanometre drug-carrying system (lenvatinib@H-MnO2-PEG-FA). Lenvatinib@H-MnO2-FA was characterized through transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FT-IR) was used to verify that Lenvatinib was loaded on nanoparticles. Functionally, confocal laser scanning microscopy (CLSM), 2-(4-Amidinophenyl)-6-indolecarbamidine dihydrochloride (DAPI) staining, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were performed to determine the effect of lenvatinib@H-MnO2-FA on the proliferation and apoptosis of ICC cells (9810 cells). Finally, the protein levels of Raf-1MEK1/2-ERK1/2 signalling pathway components were detected through Western blotting analysis.

RESULTS

We successfully synthesised a Lenvatinib@H-MnO2-PEG-FA administration system. The resulting nanomaterials had excellent biological stability and improved targeting effects. Functionally, lenvatinib@H-MnO2-FA inhibited the proliferation of 9810 cells. The Bcl-2 protein level was significantly downregulated, and the caspase-3 protein level was significantly upregulated, indicating that lenvatinib@H-MnO2-PEG-FA promoted the apoptosis of 9810 cells. Mechanistically, Lenvatinib@H-MnO2-FA increased the phosphorylation levels of Raf, MEK1/2 and ERK1/2.

CONCLUSIONS

H-MnO2-FA can more effectively deliver Lenvatinib to inhibit proliferation and promote apoptosis in ICC, could be the promising drug delivery nano-vehicles for delivery drugs.