Colloids and Interfaces

Biogenic selenium nanoparticles (SeNPs) offer promising biomedical properties, although the polymeric environment can influence their physicochemical stability and cellular interactions. In this study, SeNPs synthesized using Amphipterygium glaucum leaf extract were incorporated into a medium-molecular-weight poly(vinyl alcohol) (PVA) matrix to obtain a redispersible SeNPs@PVA89 nanocomposite. Spectroscopic, structural, morphological, thermal, and dispersion analyses showed that incorporating SeNPs preserved characteristic nanoscale and optical features while altering polymer organization. The hydrodynamic diameter increased from 153 to 320 nm, and the ζ-potential shifted from −53 to −22 mV, consistent with changes in the nanoparticle interfacial environment and a hydrated PVA layer. In human dermal fibroblasts, SeNPs@PVA89 induced concentration-dependent effects: metabolic activity was preserved at 3 and 6 µg/mL, whereas ≥12 µg/mL markedly reduced cell viability; at 3 µg/mL, morphology, F-actin organization, and wound closure were preserved. Nevertheless, confocal microscopy revealed punctate intracellular fluorescence, while transmission electron microscopy showed electron-dense material within membrane-bound vesicles, alongside mitochondrial fragmentation, cristae alterations, and rough endoplasmic reticulum remodeling. Although the elemental identity of these electron-dense structures was not directly confirmed, the findings are consistent with cellular interaction and vesicular sequestration of the nanosystem. Overall, PVA-stabilized biogenic SeNPs showed concentration-dependent cellular effects, with ultrastructural remodeling despite unchanged conventional cytocompatibility outcomes.

Efficient lepidolite flotation at neutral pH and low temperatures without depressants remains challenging. This study introduces a novel amide–diamine surfactant, N-(2-((2-aminoethyl)amino)ethyl)dodecanamide (N-123), combined with sodium oleate (NaOL), for efficiently separating lepidolite from albite and quartz. Flotation experiments on ternary mixed minerals (mass ratio 1:1:1) demonstrated that at pH 7.0, N-123/NaOL (1:4) achieved Li₂O recoveries of 84.25% at 25 °C and 73.17% at 5 °C, outperforming conventional dodecylamine (DDA)/NaOL at 54.93% at 25 °C and 32.77% at 5 °C. An amide–diamine structure provides good water solubility and a low Krafft point, enabling low-temperature flotation. Surface tension results showed that N-123 and N-123/NaOL exhibited higher surface activity than DDA and DDA/NaOL, respectively, and that both maintained relatively high surface activity at 5 °C. Wettability and froth stability tests confirmed synergistic co-assembly of N-123/NaOL at the interface, enhancing lepidolite hydrophobicity while reducing froth height and half-life to minimize gangue entrainment. ζ-potential, Fourier transform infrared (FT-IR) spectroscopy, in situ atomic force microscopy (AFM), and force measurements revealed that N-123/NaOL carried a net negative charge and co-adsorbed on lepidolite mainly via hydrophobic forces, while adsorption on albite and quartz was suppressed by electrostatic repulsion. Thus, the synergistic N-123/NaOL collector enables efficient, depressant-free lepidolite flotation.

In filtering applications, particulates build up on the filtering membrane, forming a cake layer that directly affects permeability and increases pressure across the filter. In this investigation, 10 µm microchannels were fabricated using photolithography to create filters with porosities that vary between 9% and 23%. To estimate cake layer growth, a water–glycerol solution containing a 1% volume fraction of 15 µm polystyrene particles was injected by a syringe pump into filtration media at 300, 500 and 700 µL h⁻¹ flow rates for 300 s. A differential pressure sensor was mounted across the inlet and outlet channels to measure transmembrane pressure (TMP) over time. It was found that higher flow rates accelerate particle deposition on the membrane surface, which contributes to a larger cake area and a corresponding rise in TMP. These findings will give valuable insights into clogging dynamics to optimize the filter’s efficiency and lifespan.