Halloysite nanotubes functionalized with epoxy and thiol organosilane groups to improve fracture toughness in nanocomposites

Total Bio-Based Material for Drug Delivery and Iron Chelation to Fight Cancer through Antimicrobial Activity

Bacterial involvement in cancer's development, along with their impact on therapeutic interventions, has been increasingly recognized. This has prompted the development of novel strategies to disrupt essential biological processes in microbial cells. Among these approaches, metal-chelating agents have gained attention for their ability to hinder microbial metal metabolism and impede critical reactions. Nanotechnology has also contributed to the antibacterial field by offering various nanomaterials, including antimicrobial nanoparticles with potential therapeutic and drug-delivery applications. Halloysite nanotubes (HNTs) are naturally occurring tubular clay nanomaterials composed of aluminosilicate kaolin sheets rolled multiple times. The aluminum and siloxane groups on the surface of HNTs enable hydrogen bonding with biomaterials, making them versatile in various domains, such as environmental sciences, wastewater treatment, nanoelectronics, catalytic studies, and cosmetics. This study aimed to create an antibacterial material by combining the unique properties of halloysite nanotubes with the iron-chelating capability of kojic acid. A nucleophilic substitution reaction involving the hydroxyl groups on the nanotubes' surface was employed to functionalize the material using kojic acid. The resulting material was characterized using infrared spectroscopy (IR), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM), and its iron-chelating ability was assessed. Furthermore, the potential for drug loading-specifically, with resveratrol and curcumin-was evaluated through ultraviolet (UV) analysis. The antibacterial assay was evaluated following CLSI guidelines. The results suggested that the HNTs-kojic acid formulation had great antibacterial activity against all tested pathogens. The outcome of this work yielded a novel bio-based material with dual functionality as a drug carrier and an antimicrobial agent. This innovative approach holds promise for addressing challenges related to bacterial infections, antibiotic resistance, and the development of advanced therapeutic interventions.

Facile Synthesis of Sulfur-Containing Functionalized Disiloxanes with Nonconventional Fluorescence by Thiol-Epoxy Click Reaction

Herein, a series of novel sulfur-containing functionalized disiloxanes based on a low-cost and commercially available material, i.e., 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane, and various thiol compounds were prepared by thiol-epoxy click reaction. It was found that both lithium hydroxide (LiOH) and tetrabutylammonium fluoride (TBAF) have high catalytic activity after optimizing the reaction condition, and the reaction can be carried out with high yields, excellent regioselectivity, mild reaction condition, and good tolerance of functional groups. These compounds exhibit excellent nonconventional fluorescence due to the formation of coordination bonds between Si atoms and heteroatoms (e.g., S or N) and can emit blue fluorescence upon ultraviolet (UV) irradiation. These results demonstrate that the thiol-epoxy click reaction could promisingly act as an efficient organosilicon synthetic methodology to construct various organosilicon materials with novel structures and functionality, and thus their application scope will be significantly expanded.

Biodegradable Poly(Butylene Succinate) Nanocomposites Based on Dimeric Surfactant Organomodified Clays with Enhanced Water Vapor Barrier and Mechanical Properties

Biocomposites based on biodegradable polybutylene succinate (PBS) and organomodified clays (OMt) were prepared by melt blending process. The OMt nanofillers were obtained by ion exchange reaction between sodium montmorillonite (Mt) and gemini surfactants bearing 4-decyloxyphenylacetamide hydrophobic chains and ethylene or hexylene spacer. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and rheological measurement results showed that the investigated hybrids present a uniform dispersion with an exfoliation of clay into the PBS matrix, particularly for short spacer surfactant based composites. The effect of organoclay loading and composition on the thermal, mechanical, and barrier properties was also investigated. High clay loading and long gemini surfactant spacer lead to substantial improvement of Young modulus values by 21%, while low clay content induces a reduction of the hybrid's crystallinity due to strong OMt-PBS interactions. Compared to that of the neat PBS film, a significant reduction of the water vapor permeability (WVP) by 28% was obtained by adding only 3 wt % of PBS/OMt (2) which opens up prospects for this material in the field of food packaging. This study shows that gemini surfactant-modified organoclays can be used as effective nanofillers in a PBS matrix to access to value-added nanocomposites.