ZnO@MnO2 nanocomposite modified carbon paste electrode for electrochemical detection of dopamine

Facile phyto-mediated synthesis of ternary CuO/Mn3O4/ZnO nanocomposite using Nigella Sativa seeds extract: characterization,antimicrobial, and biomedical evaluations

The phyto-synthesis of ternary CuO/ Mn3O4/ZnO nanocomposite was achieved by the utilization of an eco-friendly, straightforward approach that involved the extract of Nigella sativa seeds. Our ternary nanocomposite appears to include equal amounts of CuO, Mn3O4, and ZnO based on the atomic percentages. The results indicate that a robust and thermally stable CuO/Mn3O4/ZnO nanocomposite was developed in stable nanosuspensions. The CuO/Mn3O4/ZnO nanocomposites showed antimicrobial capabilities against multidrug-resistant human pathogens. The highest biofilm reduction in viable planktonic populations of all human pathogens investigated was significantly reduced by the CuO/Mn3O4/ZnO ternary nanocomposites with a value of 18.5 µg/mL. The unique, enhanced, and triple-combined properties enabled the nanocomposite to have strong antimicrobial ability. The CuO/Mn3O4/ZnO nanocomposite exhibited strong anticancer activity against A549, MDA, HCT-116, and HepG2 cells, with selectivity index values ​​ranging from 24.72 to 41.96. The CuO/Mn3O4/ZnO nanocomposite appeared to induce selective dose-dependent nuclear condensation and cell shrinkage in the treated cancer cells, significantly inducing the apoptosis mechanism to combat cancer progression. The phytosynthetic CuO/Mn3O4/ZnO nanocomposite appears to induce selective dose-dependent nuclear condensation and cell shrinkage in treated cancer cells, significantly triggering apoptotic mechanisms to combat cancer progression. This apoptotic pathway was confirmed by the strong affinity of CuO/Mn3O4/ZnO nanocomposites for ErbBs and VEGF with potent antioxidant activity to scavenge ABTS and DPPH radicals at EC50 values ​​of 236.6 µg/mL and 134.8 µg/mL, respectively.

Recycling the powder of spent alkaline batteries as a sustainable and reusable catalyst in producing biodiesel from waste cooking oil

Alkaline batteries are widely used in contemporary society. However, their black powder, which contains metals, categorizes them as hazardous waste, posing environmental risks if not disposed of correctly. Similarly, waste cooking oil (WCO), frequently produced in homes and restaurants, is often discarded into the environment as waste. In this study, the spent black powder from alkaline batteries was effectively utilized as a catalyst for biodiesel generation from WCO. This catalyst, containing carbonaceous materials, MnO2, ZnO, and K, facilitated both esterification and transesterification processes. It featured a Brunauer-Emmett-Teller (BET) value of 31.87 m2/g. Response Surface Methodology with Central Composite Design (RSM-CCD) was used to evaluate the influence of key variables on production efficiency. The highest biodiesel yield (99.23%) was attained with a methanol-to-oil ratio of 16:1, a temperature of 70 °C, a catalyst mass of 3 wt%, and a production time of 160 min. The regeneration process revealed that n-hexane effectively removes glycerol and biodiesel residues from the catalyst. Additionally, the catalyst demonstrated strong reusability for up to five cycles, with a significant decline in catalytic activity observed after the fifth cycle. The process demonstrated an activation energy of 22.046 kJ/mol and a pre-exponential factor of 62.878 min⁻1. It was characterized as endothermic (ΔH: 19.274 kJ/mol) and non-spontaneous (ΔG: 94.666 kJ/mol). The economic assessment in this study showed that the production cost of 1 kg of biodiesel using a catalyst derived from waste batteries is $0.579, demonstrating its cost-effectiveness compared to alternative methods for large-scale applications. Fourier Transform Infrared Spectroscopy (FTIR), 13C-NMR, and 1H-NMR analyses validated the catalyst's effectiveness in converting WCO to biodiesel. Therefore, it is suggested that this catalyst be tested at an industrial scale.

Biosynthesis and activity of Zn-MnO nanocomposite in vitro with molecular docking studies against multidrug resistance bacteria and inflammatory activators

This study investigated the green synthesis of Zn-MnO nanocomposites via the fungus Penicillium rubens. Herein, the synthesized Zn-MnO nanocomposites were confirmed by UV-spectrophotometry with a top peak (370 nm). Transmission electron microscopy confirmed irregular particles with a spherical-like shape ranging from 25.13 to 36.21 nm. Numerous functional groups were detected on the surface of Zn-MnO nanocomposite via Fourier-transform infrared spectroscopy. X-Ray diffraction assay appeared that the synthesized Zn-MnO nanocomposites contained two different components, MnO (JCPDS 81-2261) and ZnO (JCPDS 36-1451), while energy dispersive X-ray spectra confirmed the occurrence of manganese, zinc, oxygen, and carbon in Zn-MnO nanocomposites. Zn-MnO nanocomposites demonstrated excellent suppress effect versus the growth of various bacteria namely Staphylococcus aureus, Methicillin-resistant S. aureus (MRSA), Salmonella typhi, and Klebsiella pneumoniae via agar well diffusion assays with inhibition areas of 36 ± 0.1, 25 ± 0.1, 27 ± 0.2, and 23 ± 0.2 mm, correspondingly. Alterations in the ultrastructure of the treated K. pneumoniae by Zn-MnO nanocomposite were recorded. Both the values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration of Zn-MnO nanocomposite extended from 15.62 to 125 µg/mL employing the examined bacteria. The antibiofilm activity of Zn-MnO nanocomposites was 82.07, 75.43, 43.65, and 41.35% at 25% MIC, and 96.54, 93.0, 94.53, and 91.11% at 75% MIC against S. aureus, MRSA, K. pneumoniae, and S. typhi, respectively. At 25 to 75% MIC, Zn-MnO nanocomposites exhibited antihemolytic activity with the maximum activity of 96.3% at 75% MIC in the presence of MRSA. Extensive molecular docking studies were performed to identify the optimal location for manganese oxide and zinc oxide nanoclusters binding to MRSA. MnO-NPs and ZnO-NPs demonstrated inhibitory activity against the crystal structure of putative minohydrolase (PDB ID: 4EWT), methicillin acyl-penicillin binding protein 2a structure (PDB ID: 1MWU) and K2U bound crystal structure of class II peptide deformylase from MRSA (PDB ID: 6JFQ). The minimum binding energy was utilized to estimate the receptor's binding site with NPs, providing additional understanding of the ways of action. Anti-inflammatory activity of Zn-MnO nanocomposites via cyclooxygenase-1 and cyclooxygenase-2 enzymes inhibition was documented with IC50 doses of 20.81 ± 0.68 µg/mL and 35.87 ± 1.35 µg/mL, respectively. Based on these outcomes, it was concluded that Zn-MnO nanocomposites could be useful agents for the management of multidrug resistant bacterial pathogens and inflammation.

Common Transition Metal Oxide Nanomaterials in Electrochemical Sensors for the Diagnosis of Monoamine Neurotransmitter‐Related Disorders

Monoamine neurotransmitters are essential for learning, mental alertness, emotions, and blood flow, among other functions. Fatal neurological disorders that signal the imbalance of these biomolecules in the human system include Parkinson's disease, myocardial infarction, Alzheimer's disease, hypoglycemia, Schizophrenia, and a host of other ailments. The diagnosis of these monoamine neurotransmitter‐related conditions revolves around the development of analytical tools with high sensitivity for the four major monoamine neurotransmitters namely dopamine, epinephrine, norepinephrine, and serotonin. The application of electrochemical sensors made from notable metal oxide nanoparticles or composites containing the metal oxide nanoparticles for the detection of these monoamine neurotransmitters was discussed herein. More importantly, the feasibility of the application of the ZnO, CuO, and TiO2 nanoparticle‐based electrochemical sensors for a comprehensive diagnosis of monoamine neurotransmitter‐related conditions was critically investigated in this review.

Large-scale production of myco-fabricated ZnO/MnO nanocomposite using endophytic Colonstachys rosea with its antimicrobial efficacy against human pathogens

In this study, a ZnO/MnO nanocomposite was myco-fabricated using the isolated endophytic Clonostachys rosea strain EG99 as the nano-factory. The extract of strain EG99, a reducing/capping agent, was successfully titrated with equal quantities of Zn(NO3)2·6H2O and Mn(NO3)2·6H2O (precursors) in a single step to fabricate the rod-shaped ZnO/MnO nanocomposite of size 6.22 nm. The ZnO/MnO nanocomposite was myco-fabricated in 20 min, and the results were validated at 350 and 400 nm using UV-Vis spectroscopy. In a 7-L bioreactor, an industrial biotechnological approach was used to scale up the biomass of this strain, EG99, and the yield of the myco-fabricated ZnO/MnO nanocomposite. A controlled fed-batch fermentation system with a specific nitrogen/carbon ratio and an identical feeding schedule was used in this production process. Higher yields were obtained by adopting a controlled fed-batch fermentation approach in a 7-L bioreactor with a regular feeding schedule using a nitrogen/carbon ratio of 1:200. Overall, the fed-batch produced 89.2 g/l of biomass at its maximum, 2.44 times more than the batch's 36.51 g/l output. Furthermore, the fed-batch's maximum ZnO/MnO nanocomposite yield was 79.81 g/l, a noteworthy 14.5-fold increase over the batch's yield of 5.52 g/l. Finally, we designed an innovative approach to manage the growth of the endophytic strain EG99 using a controlled fed-batch fermentation mode, supporting the rapid, cheap and eco-friendly myco-fabrication of ZnO/MnO nanocomposite. At a dose of 210 µg/ml, the tested myco-fabricated ZnO/MnO nanocomposite exhibited the maximum antibacterial activity against Staphylococcus aureus (98.31 ± 0.8%), Escherichia coli (96.70 ± 3.29%), and Candida albicans (95.72 ± 0.95%). At the same dose, Staphylococcus aureus biofilm was eradicated in 48 h; however, Escherichia coli and Candida albicans biofilms needed 72 and 96 h, respectively. Our myco-fabricated ZnO/MnO nanocomposite showed strong and highly selective antagonistic effects against a variety of multidrug-resistant human pathogens. Therefore, in upcoming generations of antibiotics, it might be employed as a nano-antibiotic.

Creation of a 3D Goethite-Spongin Composite Using an Extreme Biomimetics Approach

The structural biopolymer spongin in the form of a 3D scaffold resembles in shape and size numerous species of industrially useful marine keratosan demosponges. Due to the large-scale aquaculture of these sponges worldwide, it represents a unique renewable source of biological material, which has already been successfully applied in biomedicine and bioinspired materials science. In the present study, spongin from the demosponge Hippospongia communis was used as a microporous template for the development of a new 3D composite containing goethite [α-FeO(OH)]. For this purpose, an extreme biomimetic technique using iron powder, crystalline iodine, and fibrous spongin was applied under laboratory conditions for the first time. The product was characterized using SEM and digital light microscopy, infrared and Raman spectroscopy, XRD, thermogravimetry (TG/DTG), and confocal micro X-ray fluorescence spectroscopy (CMXRF). A potential application of the obtained goethite-spongin composite in the electrochemical sensing of dopamine (DA) in human urine samples was investigated, with satisfactory recoveries (96% to 116%) being obtained.

Spongin as a Unique 3D Template for the Development of Functional Iron-Based Composites Using Biomimetic Approach In Vitro

Marine sponges of the subclass Keratosa originated on our planet about 900 million years ago and represent evolutionarily ancient and hierarchically structured biological materials. One of them, proteinaceous spongin, is responsible for the formation of 3D structured fibrous skeletons and remains enigmatic with complex chemistry. The objective of this study was to investigate the interaction of spongin with iron ions in a marine environment due to biocorrosion, leading to the occurrence of lepidocrocite. For this purpose, a biomimetic approach for the development of a new lepidocrocite-containing 3D spongin scaffold under laboratory conditions at 24 °C using artificial seawater and iron is described for the first time. This method helps to obtain a new composite as "Iron-Spongin", which was characterized by infrared spectroscopy and thermogravimetry. Furthermore, sophisticated techniques such as X-ray fluorescence, microscope technique, and X-Ray diffraction were used to determine the structure. This research proposed a corresponding mechanism of lepidocrocite formation, which may be connected with the spongin amino acids functional groups. Moreover, the potential application of the biocomposite as an electrochemical dopamine sensor is proposed. The conducted research not only shows the mechanism or sensor properties of "Iron-spongin" but also opens the door to other applications of these multifunctional materials.

Hierarchical engineering of Mn2O3/carbon nanostructured electrodes for sensitive screening of acetylcholine in biological samples

Enzymeless electrochemical sensors have received considerable interest for the direct, sensitive, and selective monitoring of biomolecules in a complex biological environment.