Interfacial Steric and Molecular Bonding Effects Contributing to the Stability of Neutrally Charged Nanoemulsions

The Surface of Colloidal Metal-Organic Framework Nanoparticles Revealed by Vibrational Sum Frequency Scattering Spectroscopy

Solvation shells strongly influence the interfacial chemistry of colloidal systems, from the activity of proteins to the colloidal stability and catalysis of nanoparticles. Despite their fundamental and practical importance, solvation shells have remained largely undetected by spectroscopy. Furthermore, their ability to assemble at complex but realistic interfaces with heterogeneous and rough surfaces remains an open question. Here, we apply vibrational sum frequency scattering spectroscopy (VSFSS), an interface-specific technique, to colloidal nanocrystals with porous metal-organic frameworks (MOFs) as a case study. Due to the porous nature of the solvent-particle boundary, MOF particles challenge conventional models of colloidal and interfacial chemistry. Their multiweek colloidal stability in the absence of conventional surface ligands suggests that stability may arise in part from solvation forces. Spectra of colloidally stable Zn(2-methylimidazolate)2 (ZIF-8) in polar solvents indicate the presence of ordered solvation shells, solvent-metal binding, and spontaneous ordering of organic bridging linkers within the MOF. These findings help explain the unexpected colloidal stability of MOF colloids, while providing a roadmap for applying VSFSS to wide-ranging colloidal nanocrystals in general.

Preparation and characterization of Sorafenib nano-emulsion: impact on pharmacokinetics and toxicity; an in vitro and in vivo study

Hepatocellular carcinoma (HCC) ranks as the third leading cause of cancer-related deaths worldwide. Current treatment strategies include surgical resection, liver transplantation, liver-directed therapy, and systemic therapy. Sorafenib (Sor) is the first systemic drug authorized by the US Food and Drug Administration (FDA) for HCC treatment. Nevertheless, the conventional oral administration of Sor presents several limitations: poor solubility, low bioavailability, drug resistance development, and off-target tissue accumulation, leading to numerous adverse effects. Nano-emulsion, a nano-delivery system, is a viable carrier for poorly water-soluble drugs. It aims to enhance drug bioavailability, target organ accumulation, and reduce off-target tissue exposure, thus improving therapeutic outcomes while minimizing side effects. This study formulated Sor nano-emulsion (Sor NanoEm) using the homogenization technique. The resultant nano-emulsion was characterized by particle size (121.75 ± 12 nm), polydispersity index (PDI; 0.310), zeta potential (-12.33 ± 1.34 mV), viscosity (34,776 ± 3276 CPs), and pH (4.38 ± 0.3). Transmission Electron Microscopy exhibited spherical nano-droplets with no aggregation signs indicating stability. Furthermore, the encapsulation of Sor within the nano-emulsion sustained its release, potentially reducing the frequency of therapeutic doses. Cytotoxicity assessments on the HepG2 cell line revealed that Sor NanoEm had a significantly (P < 0.05) more potent cytotoxic effect compared to Sor suspension. Subsequent tests highlighted superior pharmacokinetic parameters and reduced dosage requirements of Sor NanoEm in mice. It exhibited an enhanced safety profile, particularly in behavior, brain, and liver, compared to its suspended form. These findings underscore the enhanced pharmacological and toxicological attributes of Sor Nano-emulsion, suggesting its potential utility in HCC treatment.

Spiers Memorial Lecture: Water at interfaces

In this article we discuss current issues in the context of the four chosen subtopics for the meeting: dynamics and nano-rheology of interfacial water, electrified/charged aqueous interfaces, ice interfaces, and soft matter/water interfaces. We emphasize current advances in both theory and experiment, as well as important practical manifestations and areas of unresolved controversy.

Preparation of Eprinomectin Nanoemulsions and Determination of Their Pharmacokinetics and Pharmacodynamics in Dairy Cows

This study aimed to develop an anthelmintic that leaves no residues and is safe and efficient for use in cows. We constructed classical pseudoternary phase diagrams using experimental animal data to optimize and characterize the eprinomectin nanoemulsion formulas. The emulsion samples prepared with ethyl acetate, polysorbate 80, and 1-propanediol as the main components were transparent and uniform when observed under a Hitachi transmission electron microscope (TEM) system. A Mastersizer 3000 laser particle size analyzer was used to determine the particle sizes of the prepared nanoemulsions. The nanoemulsions were homogeneously dispersed, with an average particle size of 12.61 nm and a polydispersity index of (PDI) 0.297. High-performance liquid chromatography confirmed no statistically significant changes in the samples after 24 months at 4 °C, 25 °C, and 37 °C; the samples exhibited long-term stability. The PK/PD studies confirmed that the injection of eprinomectin nanoemulsions at a dose of 0.2 mg/kg body weight was effective, with a withdrawal period of 0 days for dairy cows. The total extermination rate of the nanoemulsions against adult nematodes was 98.40±1.52%. The AUC_milk/plasma ratio was 0.67±0.03. The optimal dose was found to be 0.2 mg/kg body weight.