Laboratoire de Chimie

The aspect ratio of Au nanorods can be precisely engineered using near-infrared nanosecond-pulsed laser irradiation, which enables ultrafast, confined energy deposition inaccessible under continuous-wave irradiation. In this study, we demonstrate a novel method for reshaping Au nanorods encapsulated within thin (<10 nm) silica shells. By leveraging the silica shell as a rigid nanocrucible, nanosecond laser irradiation induces rapid, end-selective shortening of the Au nanorod core, creating terminal cavities of a controllable size. Transmission electron microscopy confirms that while hexadecyltrimethylammonium bromide-coated Au nanorods convert into spherical and ϕ-shaped nanoparticles, the silica shell constrains the laser induced reshaping process, preserving the rod-like morphology while systematically reducing the aspect ratio. Consequently, the distinct longitudinal and transverse plasmon resonances are retained post-irradiation. The reshaping can be precisely controlled by adjusting laser fluence, resulting in a fine-tuned aspect ratio and a significantly narrowed longitudinal resonance, an outcome typically associated with femtosecond laser systems. 4D Scanning transmission electron microscopy reveals that the Au nanorods transform from single crystal to polycrystalline structures upon irradiation, providing direct evidence that nanosecond pulsed irradiation induces complete Au core melting and rapid recrystallization within the shell - with multiple nucleation sites. Despite the polycrystalline structure the resonance peak was narrower than that of the starting nanorod. This method for fabricating Au nanorods with integrated cavities within the offers significant potential for applications in triggered drug delivery, biosensing, and photoacoustic imaging.

ABSTRACT Type II porous ionic liquids could be prepared at room temperature by dissolving up to 5 wt.% of anti ‐cryptophane‐A derivatives functionalized with alkyl or fluorinated alkyl chains in phosphonium‐ and pyrrolidinium‐based ionic liquids. In this study, we provide the first direct experimental evidence that these molecular cages retain their internal free volume when dissolved in ionic liquids. At 303 K and 1 bar, the porous ionic liquids prepared as solutions of anti ‐cryptophane‐A grafted with a ten‐carbon alkyl chain in the ionic liquids [] (1:36), [ (1:52) and [] (1:50) absorb 3.0, 3.5 and 11 times more methane than the pure ionic liquid, respectively. The solution of anti ‐cryptophane‐A grafted with a fluorinated alkyl chain in [] (1:73) absorbs in turn 1.8 times more methane than the pure ionic liquid. We show that 97(2)% of the cryptophane dissolved in [] can encapsulate one molecule of methane, whereas only 60(1)% of the cavities in solid cryptophane are available for gas encapsulation. The presence of permanent porosity in the liquid solution is further supported by controlled atmosphere NMR spectroscopy that allows to distinguish between free and caged methane, thus providing molecular‐level evidence that the gas is encapsulated in the free cryptophane cavities.

I-motifs are non-canonical, four-stranded DNA structures in cytosine-rich genomic regions, yet their protein-mediated regulation remains underexplored. Here, we identify PCBP1 (Poly(rC)-binding protein 1) as a selective i-motif-binding protein that unfolds specific i-motifs depending on their protonation and hairpin-forming propensities. Systematic truncation reveals that individual K-homology (KH) domains of PCBP1 cannot selectively bind or unfold i-motifs, but their coordinated actions restore wild-type PCBP1 functions. Using biochemical, biophysical, and molecular dynamics studies, we demonstrate that KH1+2 domains remodel i-motifs, recruiting KH3 to facilitate unfolding and efficient DNA replication. Chromatin and cell-based investigations reveal that PCBP1-knockdown increases i-motif formation at specific genomic loci, coinciding with G1/S arrest and elevated γH2AX, indicative of genomic instability. During G1/S transition, PCBP1 occupancy peaks at these i-motif loci, ensuring i-motif resolution in early S phase. These findings establish PCBP1 as a critical regulator of i-motif dynamics, directly linking its unfolding activity to G1/S transition and genome stability.

Achieving controlled and directed motion of artificial nanoscale systems in three-dimensional fluid environments remains a key-challenge in active matter, primarily due to the prevailing thermal fluctuations that rapidly randomize the particle trajectories. While significant progress has been made with micrometer-sized particles, imparting sufficient mechanical energy, or self-propulsion, to nanometer-sized particles to overcome Brownian diffusion and enable controlled transport remains a major issue for emerging applications in nanoscience and nanomedicine. Here, we address this challenge by demonstrating the fuel-free, reversible, and tunable active behavior of gold-silica (Au-SiO2) Janus nanoparticles (radius R ∼ 33 nm) induced by optical excitation. Using single particle tracking, we provide direct experimental evidence of self-thermophoresis, clearly distinguishing active motion from thermal noise. These light-driven Janus nanoparticles constitute a minimal yet robust photothermal system for investigating active matter and its manipulation at the nanoscale.

Background/Objectives: The ABCG2 transporter actively effluxes anticancer drugs, reducing their efficacy and promoting multidrug resistance (MDR). Developing oral formulations of poorly soluble ABCG2 inhibitors remains challenging due to their low solubility and intestinal permeability. This study aimed to formulate and evaluate an ABCG2 inhibitor using micro- and nanoscale drug delivery systems. Methods: To address the poor solubility and bioavailability of the corresponding active ingredient, a self-nanoemulsifying drug delivery system (SNEDDS) was developed. The SNEDDS was encapsulated into microcapsules using sodium alginate crosslinked with calcium chloride. Five microcapsule formulations were developed, varying in the inclusion of polyvinylpyrrolidone (PVP), Transcutol® HP and SNEDDS. The effects of the excipients on encapsulation efficiency, swelling capacity, enzymatic stability, dissolution, cytocompatibility, and permeability were systematically evaluated. Results: The SNEDDS exhibited monodisperse particle sizes and efficient drug entrapment. Results revealed that formulations incorporating PVP and SNEDDS improved encapsulation efficiency and bioavailability. SNEDDS-containing formulations demonstrated superior enzymatic stability in simulated gastric and intestinal fluids and provided the highest cumulative drug release in vitro. Cytotoxicity studies conducted on Caco-2 and MCF-7 cells demonstrated that our formulations were well tolerated, indicating favorable biocompatibility. Conclusions: Our findings demonstrate that SNEDDS-loaded alginate microcapsules offer an efficient platform for oral delivery of dimeric ABCG2 inhibitors, combining enhanced solubility, stability, and controlled release. The optimized formulation can be regarded as a promising strategy to enhance the oral bioavailability of efflux pump inhibitors and other poorly soluble drugs.

The role of research in renewing practices is becoming increasingly important. In its 145th issue, Glossa explores increasingly challenging topics, such as the role of assessment in clinical practice and speech-language pathology, and the importance of clinical reasoning. Other themes include the validity and adaptation of tools, with a detailed analysis of psychometric quality, linguistic context characteristics, and tool adaptability. Additionally, the issue addresses linguistic diversity and population representativeness, emphasising both intra- and interlinguistic variability.

Sprouting angiogenesis is critical for embryogenesis, wound healing, and tumor growth. Here we show that the liquid crystal framework, which has recently been leveraged to study various morphogenetic events, provides unique insight into angiogenic sprouting. In response to vascular endothelial growth factor, a potent pro-angiogenic factor, endothelial cells cultured on the surfaces of soft collagen hydrogels form elongated cell streams that coexist with more polygonal cell regions. Angiogenic sprouting initiates preferentially at cell stream tips, where nematic order gradients are most pronounced. We demonstrate that cell streams are associated with large traction forces that lead to 3D deformations of the underlying hydrogel and that stream formation results from a delicate balance between microtubule polymerization and actomyosin contractility. Finally, we show that active control of nematic order allows modulation of sprout formation, highlighting the key role of EC orientation gradients in angiogenic sprouting and paving the way for new therapeutic avenues.

Following publication, concerns were raised regarding inaccurate values presented in Tables 1,2, 5 and 6.The Authors stated that they have made errors in this Article, including the conversion of units from eV to kcal/mol, thermodynamic calculations, calculation of the free energy correction term, and use of inaccurate units of the Boltzmann constant during the calculation of recovery time.Additionally,