Anti-inflammatory and collagenation effects of zinc oxide-based nanocomposites biosynthesised with Mentha longifolia leaf extract.

OBJECTIVE: The integration of nanomaterials and herbal medicine has led to the design of new nanocomposites, which are therapeutically more effective. The purpose of this study was to prepare different zinc oxide (ZnO)-based nanoparticles (NPs) via Mentha longifolia extract based on gauze linen fibre and study its effects on wound healing. METHODS: The textural properties, morphology, thermal stability, purity, spectroscopic and phase structure of nanoparticles were investigated. Subsequently, male Wistar rats were subjected to wounds in six different treatment groups: Group I: control; group II: ZnO/W prepared in water (W); group III: ZnO/M synthesised with Mentha longifolia (M) extract; group IV: ZnO/copper(II) oxide (CuO)/M nanocomposite synthesised with M extract; group IV: treated with ZnO/silver (Ag)/M nanocomposite; group V: treated with ZnO/Ag/M nanocomposite; and finally, group VI: treated with ZnO/CuO/Ag/M nanocomposite. In all groups, the wounds were treated for 21 days with prepared samples. Every seven days, after measuring the decreasing rate of the wound size, tissue samples from each group were taken for histopathological analysis. The prepared tissue sections were assessed by haematoxylin and eosin staining for the formation of the epidermis, dermis and muscular tissue, and Masson's Trichrome staining for the formation of collagen fibres. RESULTS: The results showed that the ZnO/CuO/Ag/M nanocomposite was a significantly more effective wound healing material in comparison with other samples (p<0.05). CONCLUSION: In this study, the integration of ZnO/CuO/Ag nanocomposites with secondary metabolites of Mentha longifolia gave rise to a superior combination, which could support different phases of wound healing via the regulation of cytokines and growth factors in the course of healing.

Design of TiO2/Ag3BiO3 n-n heterojunction for enhanced degradation of tetracycline hydrochloride under visible-light irradiation.

Pharmaceutical residual contaminants in aquatic ecosystems have caused severe risks to human health. Affordable, eco-friendly and effective photocatalysts to deal with these pollutants has become a hot topic in the scientific community. In this research, Ag3BiO3 nanoparticles were embedded on TiO2 to form n-n heterojunction through a facile hydrothermal method. According to scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), brunauer emmett teller (BET), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), photoluminescence (PL), X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS) tests, the successful construction of TiO2/Ag3BiO3 heterojunction is proved. TiO2/Ag3BiO3 heterojunctions were employed as photocatalysts to remove tetracycline hydrochloride (TCH) under visible light irradiation in aqueous solution. Optimum TCH photodegradation efficiency was observed for TiO2/Ag3BiO3 (10%), 15.4 times superior to that of TiO2. The enhanced TCH photodegradation efficiency of TiO2/Ag3BiO3 results from improved light absorption capacity and the reduction of recombination of photogenerated charge carriers via generation of n-n heterojunctions. The mechanism of increasing the photodegradation efficiency of TCH was determined by employing reactive species quenching experiments. TiO2/Ag3BiO3 (10%) also exhibited an acceptable stability.

Tailoring Oxygen Reduction Reaction Kinetics of Fe-N-C Catalyst via Spin Manipulation for Efficient Zinc-Air Batteries.

The interaction between oxygen species and metal sites of various orbitals exhibits intimate correlation with the oxygen reduction reaction (ORR) kinetics. Herein, a new approach for boosting the inherent ORR activity of atomically dispersed Fe-N-C matrix is represented by implanting Fe atomic clusters nearby. The as-prepared catalyst delivers excellent ORR activity with half-wave potentials of 0.78 and 0.90 V in acidic and alkaline solutions, respectively. The decent ORR activity can also be validated from the high-performance rechargeable Zn-air battery. The experiments and density functional theory calculations reveal that the electron spin-state of monodispersed Fe active sites is transferred from the low spin (LS, t2g 6 eg 0) to the medium spin (MS, t2g 5 eg 1) due to the involvement of Fe atomic clusters, leading to the spin electron filling in σ∗ orbit, by which it favors OH- desorption and in turn boosts the reaction kinetics of the rate-determining step. This work paves a solid way for rational design of high-performance Fe-based single atom catalysts through spin manipulation.

Preparation of TiO2/Fe-MOF n‒n heterojunction photocatalysts for visible-light degradation of tetracycline hydrochloride.

Visible-light-assisted photocatalysis has been recognized as an effective solution to the degradation of various pollutants including antibiotics, pesticides, herbicides, microplastics, and organic dyes. Herein, an n-n heterojunction TiO2/Fe-MOF photocatalyst is reported, designed via solvothermal synthesis route. TiO2/Fe-MOF photocatalyst was characterized by XPS, BET, EIS, EDS, DRS, PL, FTIR, XRD, TEM, SEM and HRTEM techniques. Inspired by XRD, FTIR, XPS, EDS, TEM, SEM, and HRTEM analyses, the successful synthesis of n-n heterojunction TiO2/Fe-MOF photocatalysts was proved. The migration efficiency of the light-induced electron-hole pairs was confirmed by the PL and EIS tests. TiO2/Fe-MOF exhibited a significant performance for tetracycline hydrochloride (TC) removal under visible light irradiation. TC removal efficiency for TiO2/Fe-MOF (15%) nanocomposite reached 97% within 240 min, ca. 11 times higher than pure TiO2. The photocatalytic enhancement of TiO2/Fe-MOF could be attributed to the broadening the light response range, forming an n-n junction between Fe-MOF and TiO2 components, suppressing charge recombination. Based on recycling experiments, TiO2/Fe-MOF had a good potential to be used in consecutive TC degradation tests.

Antifungal activity of TiO2/AgBr nanocomposites on some phytopathogenic fungi.

TiO2/AgBr composites were synthesized by a simple ultrasonic strategy. Various instruments such as SEM, EDX, XRD, and FT-IR were exploited to investigate their characteristics. Antifungal activities of the as-obtained samples were assessed through the inactivation of Fusarium graminearum in the spore suspension method and mycelial growth inhibition of F. graminearum, Botrytis cinerea, and Sclerotinia sclerotiorum in the microdilution method. The results represented that the TiO2/AgBr samples possess higher antifungal activities on F. graminearum spores than the pure TiO2. The sample with 20 wt% silver bromide represented the highest inhibitory effect on the growth of F. graminearum so that all fungal spores were degraded in the initial times of the treatment process. The inactivation of fungal spores after 60 min was 35.2%, 97.8%, 98.9%, and 98.7%, in respect, for 5, 10, 20, and 30 weight percent of AgBr in the binary nanocomposites, while the inhibition rate was 13.4% for the pure TiO2. With increasing ultrasound irradiation time for more than 30 min, the inactivation rate constant decreased. It was also found that the antifungal activity of the nanocomposites without calcination was higher than those of the calcined materials. Considering the antifungal potential against phytopathogenic fungi and advantages such as simple synthesis and eco-friendly nature, it seems that TiO2/AgBr nanocomposites can be used instead of synthetic chemicals after additional field investigations and mass production.

Review on heterogeneous photocatalytic disinfection of waterborne, airborne, and foodborne viruses: Can we win against pathogenic viruses?

Microbial pathogenic contaminations have world widely represented a serious health hazard to humans. Viruses, as a member of microbial contaminants, seriously threaten human health due to their high environmental resistance, having small sizes, and causing an extensive range of diseases. Therefore, selecting an appropriate technology to remove viral contaminants from the air, water, and foods is of prominent significance. Traditional methods for viral disinfection have not proven to be highly practical and effective because they need high energy resources and operational expenses. In recent years, semiconductor-based photocatalysis has attracted more attention in the field of microorganism inactivation due to its outstanding performance and mild reaction conditions. Therefore, this review primarily concentrates on the recent development in viral inactivation/disinfection by heterogeneous photocatalysts. Moreover, the photocatalytic viral inactivation of waterborne, airborne, and foodborne viruses is discussed. Given the appealing merits of heterogeneous photocatalytic disinfection of viruses, there is no doubt that this technology will be an impressively active research field and a source of comfort and confidence to humans in battling against viruses.

Biologically-synthesised ZnO/CuO/Ag nanocomposite using propolis extract and coated on the gauze for wound healing applications.

Wound healing has long been recognised as a major clinical challenge for which stablishing more effective wound therapies is necessary. The generation of metallic nanocomposites using biological compounds is emerging as a new promising strategy for this purpose. In this study, four metallic nanoparticles (NPs) with propolis extract (Ext) and one without propolis including ZnO/Ext, ZnO/Ag/Ext, ZnO/CuO/Ext, ZnO/Ag/CuO/Ext and ZnO/W were prepared by microwave method and assessed for their wound healing activity on excision experimental model of wounds in rats. The developed nanocomposites have been characterised by physico-chemical methods such as X-ray diffraction, scanning electron microscopy, diffuse reflectance UV-vis spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and Brunauer-Emmett-Teller analyses. The wounded animals treated with the NPs/Ext in five groups for 18 days. Every 6 days, for measuring wound closure rate, three samples of each group were examined for histopathological analysis. The prepared tissue sections were investigated by haematoxylin and Eosin stainings for the formation of epidermis, dermis and muscular and Masson's trichrome staining for the formation of collagen fibres. These findings toughly support the probability of using this new ZnO/Ag/Ext materials dressing for a wound care performance with significant effect compared to other NPs.

Ternary TiO2/Fe3O4/CoWO4 nanocomposites: Novel magnetic visible-light-driven photocatalysts with substantially enhanced activity through p-n heterojunction.

Herein, novel magnetic TiO2/Fe3O4/CoWO4 nanocomposites were fabricated using a simple refluxing method followed by a calcination step at 450 °C. Photocatalytic activity of these nanocomposites were studied by decomposing rhodamine B, methyl orange, and fuchsine dye contaminants under visible-light illumination. Among the fabricated photocatalysts, the TiO2/Fe3O4/CoWO4 (30%) photocatalyst exhibited superior activity. The degradation rate constant for rhodamine B by this ternary nanocomposite was 8.5 and 5.6 folds greater than those of the pure TiO2 and TiO2/Fe3O4 photocatalysts, respectively. Trapping experiments showed that superoxide anion radicals played critical role during the photocatalytic process. Visible-light harvesting due to the presence of CoWO4 and effective suppression of the charge carriers from recombination due to formation of p-n heterojunction are the major parameters affecting the photocatalytic activity. Furthermore, the TiO2/Fe3O4/CoWO4 (30%) photocatalyst displayed highly stable recycling performances. The present study provides a new strategy to design and fabricate magnetically recoverable photocatalysts based on TiO2 with considerable activity under visible-light.