An on-site and portable electrochemical sensing platform based on spinel zinc ferrite nanoparticles for the quality control of paracetamol in pharmaceutical samples.

In this study, crystalline spinel zinc ferrite nanoparticles (ZnFe2O4 NPs) were successfully prepared and proposed as a high-performance electrode material for the construction of an electrochemical sensing platform for the detection of paracetamol (PCM). By modifying a screen-printed carbon electrode (SPE) with ZnFe2O4 NPs, the electrochemical characteristics of the ZnFe2O4/SPE and the electrochemical oxidation of PCM were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), chronoamperometry (CA), and differential pulse voltammetry (DPV) methods. The calculated electrochemical kinetic parameters from these techniques including electrochemically active surface area (ECSA), peak-to-peak separation (ΔEp), charge transfer resistance (Rct), standard heterogeneous electron-transfer rate constants (k0), electron transfer coefficient (α), catalytic rate constant (kcat), adsorption capacity (Γ), and diffusion coefficient (D) proved that the as-synthesized ZnFe2O4 NPs have rapid electron/mass transfer characteristics, intrinsic electrocatalytic activity, and facilitate the adsorption-diffusion of PCM molecules towards the modified electrode surface. As expected, the ZnFe2O4/SPE offered excellent analytical performance towards sensing of PCM with a detection limit of 0.29 µM, a wide linear range of 0.5-400 µM, and high electrochemical sensitivity of 1.1 µA µM-1 cm-2. Moreover, the proposed ZnFe2O4-based electrochemical nanosensor also exhibited good repeatability, high anti-interference ability, and practical feasibility toward PCM sensing in a pharmaceutical tablet. Based on these observations, the designed electrochemical platform not only provides a high-performance nanosensor for the rapid and highly efficient detection of PCM but also opens a new avenue for routine quality control analysis of pharmaceutical formulations.

Characteristics of Ag-incorporated bioactive glasses prepared by a modified sol-gel method with a shortened synthesis time and without the use of catalysts.

This work presents the preparation of bioactive glasses 70SiO2-(26 - x)CaO-4P2O5-xAg2O (with x = 0, 1, 3, 10 mol%) by a modified sol-gel method with reduced synthesis time based on hydrothermal reaction in a medium without acid or base catalysts. The synthetic materials were characterized by several physical-chemical techniques such as TG-DSC, XRD, SEM, TEM, and N2 adsorption/desorption measurement. The analysis data confirmed that the glass sample not containing Ag has a completely amorphous structure, while glass samples containing Ag exhibited a pure phase of metallic nano-silver in the glass amorphous phase. All the synthetic glasses have mesoporous structures with particle sizes of less than 30 nm. The addition of silver to the bioactive glass structure in general did not drastically reduce the specific surface areas and pore volumes of glasses as in previous studies. The bioactivity of the silver-incorporated glasses did not reduce, and even increased in the cases of bioactive glass containing 3, and 10 mol% of Ag2O. The biocompatibility of synthetic glasses with fibroblast cells (L-929) was confirmed, even with glass containing high amounts of Ag. Representatively, Ag-incorporated glass samples (sample x = 3, and x = 10) were selected to check the antibacterial ability using bacterial strain Pseudomonas aeruginosa ATCC 27853 (Pa). The obtained results indicated that these glasses exhibited good antibacterial ability to Pseudomonas aeruginosa. Thus, the synthetic method in this study proved to be a fast, environmentally friendly technique for synthesizing Ag-incorporated glass systems. The synthesized glasses show good bioactive, biocompatible, and antibacterial properties.

Enhancing the chloramphenicol sensing performance of Cu-MoS2 nanocomposite-based electrochemical nanosensors: roles of phase composition and copper loading amount.

The rational design of nanomaterials for electrochemical nanosensors from the perspective of structure-property-performance relationships is a key factor in improving the analytical performance toward residual antibiotics in food. We have investigated the effects of the crystalline phase and copper loading amount on the detection performance of Cu-MoS2 nanocomposite-based electrochemical sensors for the antibiotic chloramphenicol (CAP). The phase composition and copper loading amount on the MoS2 nanosheets can be controlled using a facile electrochemical method. Cu and Cu2O nanoparticle-based electrochemical sensors showed a higher CAP electrochemical sensing performance as compared to CuO nanoparticles due to their higher electrocatalytic activity and conductivity. Moreover, the design of Cu-MoS2 nanocomposites with appropriate copper loading amounts could significantly improve their electrochemical responses for CAP. Under optimized conditions, Cu-MoS2 nanocomposite-based electrochemical nanosensor showed a remarkable sensing performance for CAP with an electrochemical sensitivity of 1.74 µA µM-1 cm-2 and a detection limit of 0.19 µM in the detection range from 0.5-50 µM. These findings provide deeper insight into the effects of nanoelectrode designs on the analytical performance of electrochemical nanosensors.

Synthesis, Characterizations of Superparamagnetic Fe3O4-Ag Hybrid Nanoparticles and Their Application for Highly Effective Bacteria Inactivation.

In recent years, outbreaks of infectious diseases caused by pathogenic micro-organisms pose a serious threat to public health. In this work, Fe3O4-Ag hybrid nanoparticles were synthesized by simple chemistry method and these prepared nanoparticles were used to investigate their antibacterial properties and mechanism against methicilline-resistant Staphylococcus aureus (MRSA) pathogen. The formation of dimer-like nanostructure of Fe3O4-Ag hybrid NPs was confirmed by X-ray diffraction and High-resolution Transmission Electron Microscopy. Our biological analysis revealed that the Fe3O4-Ag hybrid NPs showed more noticeable bactericidal activity than that of plain Fe3O4 NPs and Ag-NPs. We suggest that the enhancement in bactericidal activity of Fe3O4-Ag hybrid NPs might be likely from main factors such as: (i) enhanced surface area property of hybrid nanoparticles; (ii) the high catalytic activity of Ag-NPs with good dispersion and aggregation stability due to the iron oxide magnetic carrier, and (iii) large direct physical contacts between the bacterial cell membrane and the hybrid nanoparticles. The superparamagnetic hybrid nanoparticles of iron oxide magnetic nanoparticles decorated with silver nanoparticles can be a potential candidate to effectively treat infectious MRSA pathogen with recyclable capability, targeted bactericidal delivery and minimum release into environment.