Effects of Ultrasound on Zinc Oxide/Vermiculite/Chlorhexidine Nanocomposite Preparation and Their Antibacterial Activity

Abstract

Microbial infection and biofilm formation are both problems associated with medical implants and devices. In recent years, hybrid organic-inorganic nanocomposites based on clay minerals have attracted significant attention due to their application potential in the field of antimicrobial materials. Organic drug/metal oxide hybrids exhibit improved antimicrobial activity, and intercalating the above materials into the interlayer of clay endows a long-term and controlled-release behavior. Since antimicrobial activity is strongly related to the structure of the material, ultrasonic treatment appears to be a suitable method for the synthesis of these materials as it can well control particle size distribution and morphology. This study aims to prepare novel, structurally stable, and highly antimicrobial nanocomposites based on zinc oxide/vermiculite/chlorhexidine. The influence of ultrasonic treatment at different time intervals and under different intercalation conditions (ultrasonic action in a breaker or in a Roset’s vessel) on the structure, morphology, and particle size of prepared hybrid nanocomposite materials was evaluated by the following methods: scanning electron microscopy, X-ray diffraction, energy dispersive X-ray fluorescence spectroscopy, carbon phase analysis, Fourier transforms infrared spectroscopy, specific surface area measurement, particle size analysis, and Zeta potential analysis. Particle size analyses confirmed that the ultrasonic method contributes to the reduction of particle size, and to their homogenization/arrangement. Further, X-ray diffraction analysis confirmed that ultrasound intercalation in a beaker helps to more efficiently intercalate chlorhexidine dihydrochloride (CH) into the vermiculite interlayer space, while a Roset’s vessel contributed to the attachment of the CH molecules to the vermiculite surface. The antibacterial activity of hybrid nanocomposite materials was investigated on Gram negative (Escherichia coli, Pseudomonas aeruginosa) and Gram positive (Staphylococcus aureus, Enterococcus faecalis) bacterial strains by finding the minimum inhibitory concentration. All hybrid nanocomposite materials prepared by ultrasound methods showed high antimicrobial activity after 30 min, with a long-lasting effect and without being affected by the concentration of the antibacterial components zinc oxide (ZnO) and CH. The benefits of the samples prepared by ultrasonic methods are the rapid onset of an antimicrobial effect and its long-term duration.

Effect of Plant Nanocellulose Electrolyte, Zinc Oxide Nanoparticles, and Nano-Chlorophyll Sensitiser on the Dye-Sensitised Solar Cell Performance

“…Figure6shows the particle-size distribution of ZnO diluted with water after 5 min of ultrasound waves treatment. It turns out that the homogeneity of the size of the particles up to less than 10 nm is in agreement with Zhang et al[94] and Barabaszová et al[95].…”

Antifungal Volatilomes Mediated Defense Mechanism against Fusarium oxysporum f. sp. lycopersici, the Incitant of Tomato Wilt

“…Earlier studies reported that vermiculite could act as a superabsorbent composite and it swelled rapidly on increasing the concentration of volatilomes [ 25 ]. Vermiculite based nanoparticles, coated with CuO and ZnO could act as antibacterial activities against Staphylococcus aureus with long-acting up to 24 h [ 26 , 27 ]. In the existing study, vermiculite was used as a volatilomes immobilizing substrates in the form of organic-based formulation against the fungal pathogens.…”

Submicron-Sized Vermiculite Assisted Oregano Oil for Controlled Release and Long-Term Bacterial Inhibition

“…A similar mechanism was proposed in the case of raw vermiculite loaded with lemon essential oil [ 83 ]. Because vermiculite has been used to load not only essential oils but also many other drug compounds, [ 54 , 85 , 86 ] it is expected that SMV may be used a platform to load a variety of active molecules.…”