A simple way for targeted delivery of an antibiotic: In vitro evaluation of a nanoclay-based composite

Cobalt-substituted ZnS QDs: a diluted magnetic semiconductor and efficient photocatalyst

Recently, understanding the origin of induced magnetic characteristics in transition metal atom-doped QDs has been a major focus owing to their potential applications in the area of spintronic devices. A detailed experimental and theoretical investigation was conducted to understand the physical properties of Co-doped ZnS QDs containing different weight percentages of Co atoms [CoxZn1-xS (x = 0.00, 0.03, 0.06, and 0.09)], prepared using chemical co-precipitation techniques. X-ray diffraction studies proved that all the prepared QDs formed an extremely pure cubic zinc blende crystallographic phase free of contaminants. The validation of the quantum dot nature of all the samples was provided by the HRTEM images, BET studies, and blue shift in the absorption spectra. Both the obtained FTIR and PL spectra at room temperature also confirmed the phase purity of the prepared QDs. The observed weak ferromagnetic behavior of the doped samples was due to the presence of p-d hybridization between the 3d levels of Co2+ ions and 3p levels of S2- ions of the host ZnS QDs. Hysteresis loops that were obtained at room temperature validated this weak ferromagnetic nature. These obtained results were also supported theoretically using DFT calculations. FDTD simulations provided a detailed explanation for the observed blue shift in the absorption spectra originating from the quantum confinement effect of doped and undoped ZnS QDs. The dielectric properties of all the samples were examined properly, and it was also found that the grain boundaries contributed effectively to providing the dielectric response. The doped ZnS sample containing more Co dopants at low frequencies showed a progressive rise in polarisation loss. In addition, Co-doped ZnS QDs are efficient photocatalysts. A pH-dependent photodegradation test of ciprofloxacin (CIP) antibiotic was conducted using 9% Co-doped ZnS QDs. It was observed that 9% Co-doped ZnS nanocatalysts has sufficient capability to degrade CIP to around 94.7% in a solution of pH 10 within one hour. Therefore, besides showing photocatalytic effects, Co-doped ZnS QDs act as ideal dilute magnetic semiconductors (DMSs) and will undoubtedly become excellent candidates for the microelectronics industry because of their special ability to exhibit spin-dependent magneto-electro-optical properties that find use in spin-polarized light-emitting diodes, solid-state lasers, and spin-transistor devices.

Antioxidant Efficacy and "In Vivo" Safety of a Bentonite/Vitamin C Hybrid

L-ascorbic acid (LAA), commonly known as vitamin C, is an excellent and recognized antioxidant molecule used in pharmaceutical and cosmetic formulations. Several strategies have been developed in order to preserve its chemical stability, connected with its antioxidant power, but there is little research regarding the employment of natural clays as LAA host. A safe bentonite (Bent)-which was verified by in vivo ophthalmic irritability and acute dermal toxicity assays-was used as carrier of LAA. The supramolecular complex between LAA and clay may constitute an excellent alternative, since the molecule integrity does not seem to be affected, at least from the point of view of its antioxidant capacity. The Bent/LAA hybrid was prepared and characterized through ultraviolet (UV) spectroscopy, X-ray diffraction (XRD), infrared (IR) spectroscopy, thermogravimetric analysis (TG/DTG) and zeta potential measurements. Photostability and antioxidant capacity tests were also performed. The LAA incorporation into Bent clay was demonstrated, as well as the drug stability due to the Bent photoprotective effect onto the LAA molecule. Moreover, the antioxidant capacity of the drug in the Bent/LAA composite was confirmed.

Degradation of Ciprofloxacin by Titanium Dioxide (TiO2) Nanoparticles: Optimization of Conditions, Toxicity, and Degradation Pathway

The popular use of ciprofloxacin is often irrational, so it causes environmental pollution such as resistance. The solution to overcome environmental pollution due to ciprofloxacin is degradation by using TiO2 nanoparticles. TiO2 nanoparticles performance is influenced by environment such as light source, pH solvent, duration of lighting and TiO2 nanoparticles mass. The residual levels determination of ciprofloxacin was carried out by using a UV-Vis spectrophotometer. Toxicity test of ciprofloxacin degradation products with TiO2 nanoparticles used Escherichia coli bacteria. Liquid Chromatography Mass Spectrometry (LCMS) was used to determine the type of ciprofloxacin degradation product with TiO2 nanoparticles. The optimum condition for the ciprofloxacin degradation with TiO2 nanoparticles is lighting for 5 hours by using a white mercury UV lamp and 50 mg TiO2 nanoparticles with pH solvent of 5.5. The toxicity of ciprofloxacin degradation product with TiO2 nanoparticles was low. The smallest degradation product identified with m/z was p-fluoraniline (m/z 111). Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Synthesis and Characterization of Nanomaterial Based on Halloysite and Hectorite Clay Minerals Covalently Bridged

Halloysite is an aluminosilicate clay with a predominantly hollow tubular structure (HNTs) able to act as a nanocontainer for the encapsulation of several chemicals. However, HNTs possess low affinity for metal ions in their pristine form and they need to be modified for improving their adsorption capabilities. Therefore, to overcome this issue herein we report a straightforward approach for the covalent modification of the external surface of halloysite nanotubes with hectorite clay. Compared to halloysite, hectorite possesses a lamellar structure with higher cation exchange capacity. The covalent linkage between the two clays was verified by several techniques (FTIR spectroscopy, ¹³C CP-MAS NMR, TGA, ζ-potential, DLS, and XRD measurements) and the morphology was imaged by TEM investigations. As proof of concept the adsorption ability of the obtained nanomaterial in comparison to pristine clays was proved using ciprofloxacin and silver ions chosen as models for their different chemical characteristics.

Clay nanolayer encapsulation, evolving from origins of life to future technologies

Clays are the siblings of graphite and graphene/graphene-oxide. There are two basic ways of using clays for encapsulation of sub-micron entities such as molecules, droplets, or nanoparticles, which is either by encapsulation in the interlayer space of clay nanolayered stacked particles ("the graphite way"), or by using exfoliated clay nanolayers to wrap entities in packages ("the graphene way"). Clays maybe the prerequisites for life on earth and can also be linked to the natural formation of other two-dimensional materials such as naturally occurring graphite and its allotropes. Here we discuss state-of-the-art in the area of clay-based encapsulation and point to some future scientific directions and technological possibilities that could emerge from research in this area.