Biogenic Synthesis, Characterization and Antibacterial Potential Evaluation of Copper Oxide Nanoparticles Against Escherichia coli

A novel functionalized CuTi hybrid nanocomposites: facile one-pot mycosynthesis, characterization, antimicrobial, antibiofilm, antifouling and wastewater disinfection performance

BACKGROUND

The continuous progress in nanotechnology is rapid and extensive with overwhelming futuristic aspects. Through modernizing inventive synthesis protocols, a paradigm leapfrogging in novelties and findings are channeled toward fostering human health and sustaining the surrounding environment. Owing to the overpricing and jeopardy of physicochemical synthesizing approaches, the quest for ecologically adequate schemes is incontestable. By developing environmentally friendly strategies, mycosynthesis of nanocomposites has been alluring.

RESULTS

Herein, a novel architecture of binary CuO and TiO2 in nanocomposites form was fabricated using bionanofactory Candida sp., for the first time. For accentuating the structural properties of CuTi nanocomposites (CuTiNCs), various characterization techniques were employed. UV-Vis spectroscopy detected SPR at 350 nm, and XRD ascertained the crystalline nature of a hybrid system. However, absorption peaks at 8, 4.5, and 0.5 keV confirmed the presence of Cu, Ti and oxygen, respectively, in an undefined assemblage of polygonal-spheres of 15-75 nm aggregated in the fungal matrix of biomolecules as revealed by EDX, SEM and TEM. However, FTIR, ζ-potential and TGA reflected long-term stability (- 27.7 mV) of self-functionalized CuTiNCs. Interestingly, a considerable and significant biocide performance was detected at 50 µg/mL of CuTiNCs against some human and plant pathogens, compared to monometallic counterparts. Further, CuTiNCs (200 µg/mL) ceased significantly the development of Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans biofilms by 80.3 ± 1.4, 68.7 ± 3.0 and 55.7 ± 3.0%, respectively. Whereas, 64.63 ± 3.5 and 89.82 ± 4.3% antimicrofouling potentiality was recorded for 100 and 200 µg/ml of CuTiNCs, respectively; highlighting their destructive effect against marine microfoulers cells and decaying of their extracellular polymeric skeleton as visualized by SEM. Moreover, CuTiNCs (100 and 200 µg/ml) exerted significantly outstanding disinfection potency within 2 h by reducing the microbial load (i.e., total plate count, mold & yeast, total coliforms and faecal Streptococcus) in domestic and agricultural effluents reached >50%.

CONCLUSION

The synergistic efficiency provided by CuNPs and TiNPs in mycofunctionalized CuTiNCs boosted its recruitment as antiphytopathogenic, antibiofilm, antimicrofouling and disinfectant agent in various realms.

Modulating plant-soil microcosm with green synthesized ZnONPs in arsenic contaminated soil

Biogenic nanoparticle (NP), derived from plant sources, is gaining prominence as a viable, cost-effective, sustainable, and biocompatible alternative for mitigating the extensive environmental impact of arsenic on the interplay between plant-soil system. Herein, the impact of green synthesized zinc oxide nanoparticles (ZnONPs) was assessed on Catharanthus roseus root system-associated enzymes and their possible impact on microbiome niches (rhizocompartments) and overall plant performance under arsenic (As) gradients. The application of ZnONPs at different concentrations successfully modified the arsenic uptake in various plant parts, with the root arsenic levels increasing 1.5 and 1.4-fold after 25 and 50 days, respectively, at medium concentration compared to the control. Moreover, ZnONPs gradients regulated the various soil enzyme activities. Notably, urease and catalase activities showed an increase when exposed to low concentrations of ZnONPs, whereas saccharase and acid phosphatase displayed the opposite pattern, showing increased activities under medium concentration which possibly in turn influence the plant root system associated microflora. The use of nonmetric multidimensional scaling ordination revealed a significant differentiation (with a significance level of p < 0.05) in the structure of both bacterial and fungal communities under different treatment conditions across root associated niches. Bacterial and fungal phyla level analysis showed that Proteobacteria and Basidiomycota displayed a significant increase in relative abundance under medium ZnONPs concentration, as opposed to low and high concentrations, respectively. Similarly, in depth genera level analysis revealed that Burkholderia, Halomonas, Thelephora and Sebacina exhibited a notably high relative abundance in both the rhizosphere and rhizoplane (the former refers to the soil region influenced by root exudates, while the latter is the root surface itself) under medium concentrations of ZnONPs, respectively. These adjustments to the plant root-associated microcosm likely play a role in protecting the plant from oxidative stress by regulating the plant's antioxidant system and overall biomass.

Restoration of Antibacterial Activity of Inactive Antibiotics via Combined Treatment with AgNPs

Antimicrobial resistance poses a huge threat to human health around the world and calls for novel treatments. Combined formulations of NPs and antibiotics have emerged as a viable nanoplatform for combating bacterial resistance. The present research work was performed to investigate the effect of combined formulations of AgNPs with streptomycin, cefaclor, ciprofloxacin, and trimethoprim against multidrug-resistant (MDR) isolates of Staphylococcus aureus and Klebsiella pneumoniae. AgNPs have been synthesized by using the Nigella sativa seed extract, and their characteristics were analyzed. AgNPs depicted concentration-dependent antibacterial effects, as the highest concentration of AgNPs showed the strongest antibacterial activity. Interestingly, AgNPs in conjugation with antibiotics showed an enhanced antibacterial potential against both S. aureus and K. pneumoniae, which suggested synergism between the AgNPs and antibiotics. Against S. aureus, streptomycin and trimethoprim in conjugation with AgNPs presented a synergistic effect, while cefaclor and ciprofloxacin in combination with AgNPs showed an additive effect. However, all of the tested antibiotics depicted a synergistic effect against K. pneumoniae. The lowest value of MIC (0.78 μg/mL) was shown by AgNPs-Stp against S. aureus, whereas AgNPs-Tmp showed the lowest value of MIC (1.56 μg/mL) against K. pneumoniae. The most important point of the present study is that both organisms (S. aureus and K. pneumoniae) showed resistance to antibiotics but turned out to be highly susceptible when the same antibiotic was used in combination with AgNPs. These findings highlight the potential of nanoconjugates (the AgNPs-antibiotic complex) to mitigate the present-day crisis of antibiotic resistance and to combat antimicrobial infections efficiently.

In situ synthesis of polythiophene encapsulated 2D hexagonal boron nitride nanocomposite based electrochemical transducer for detection of 5-fluorouracil with high selectivity

It is difficult for the scientific community to develop a nonenzymatic sensing platform for extremely sensitive and selective detection of specific biomolecules, antibiotics, food adulterants, heavy metals, etc. One of the most significant chemotherapy drugs, 5-fluorouracil (5-Fu), which is used to treat solid malignancies, has a fluorine atom in the fifth position of the uracil molecule. Recognizing the secure and effective dosing of drugs for chemotherapy continues to be a critical concern in cancer disease management. The maintenance of the optimal 5-Fu concentration is dependent on the presence of 5-Fu in biofluids. Herein we reported a conducting polymer encapsulated 2D material, PTh/h-BN for the efficient electrochemical detection of anticancer drug 5-Fu. Furthermore, the synthesized PTh/h-BN nanocomposite was confirmed by the High-Resolution Transmission Electron Microscope (HR-TEM), High-Resolution Scanning Electron Microscope (HR-SEM), X-ray diffraction (XRD), and Fourier-Transform Infrared Spectroscopy (FT-IR). The electrical resistance of PTh/h-BN modified GCE and its sensing performance towards 5-Fu were tested using Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV) studies respectively. The analytical performance of our proposed catalyst was tested using Differential Pulse Voltammetry (DPV), and the amperometry (i-t curve) method. From the results, our proposed PTh/h-BN nanocomposite-modified GCE shows enhanced sensing performance due to higher redox peak currents, large active surface area, and high electrical conductivity. Moreover, the nanohybrid shows enhanced sensing performances with quick response time, wide linear range, the lowest limit of detection, high sensitivity, and high selectivity in the presence of various interferents. Finally, the practical applicability of the proposed sensor was tested with real-world samples with very good recovery percentages.

Bacteria assisted green synthesis of copper oxide nanoparticles and their potential applications as antimicrobial agents and plant growth stimulants

Copper oxide nanoparticles (CuO-NPs) have piqued the interest of agricultural researchers due to their potential application as fungicides, insecticides, and fertilizers. The Serratia sp. ZTB29 strain, which has the NCBI accession number MK773873, was a novel isolate used in this investigation that produced CuO-NPs. This strain can survive concentrations of copper as high as 22.5 mM and can also remove copper by synthesizing pure CuO-NPs. UV-VIS spectroscopy, DLS, Zeta potential, FTIR, TEM, and XRD techniques were used to investigate the pure form of CuO-NPs. The synthesized CuO-NPs were crystalline in nature (average size of 22 nm) with a monoclinic phase according to the XRD pattern. CuO-NPs were found to be polydisperse, spherical, and agglomeration-free. According to TEM and DLS inspection, they ranged in size from 20 to 40 nm, with a typical particle size of 28 nm. CuO-NPs were extremely stable, as demonstrated by their zeta potential of -15.4 mV. The ester (C=O), carboxyl (C=O), amine (NH), thiol (S-H), hydroxyl (OH), alkyne (C-H), and aromatic amine (C-N) groups from bacterial secretion were primarily responsible for reduction and stabilization of CuO-NPs revealed in an FTIR analysis. CuO-NPs at concentrations of 50 μg mL^-1 and 200 μg mL^-1 displayed antibacterial and antifungal activity against the plant pathogenic bacteria Xanthomonas sp. and pathogenic fungus Alternaria sp., respectively. The results of this investigation support the claims that CuO-NPs can be used as an efficient antimicrobial agent and nano-fertilizer, since, compared to the control and higher concentrations of CuO-NPs (100 mg L^-1) considerably improved the growth characteristics of maize plants.

Effect of the green synthesis of CuO plate-like nanoparticles on their photodegradation and antibacterial activities

Green synthesis of copper oxide nanoparticles and its effects on photocatalytic dye degradation and antibacterial activities are reported. The synthesis of nanoparticles by green routes provides many advantages over chemical routes, including simplicity, cost-effectiveness, and fast processing route without using any costly or harmful chemicals. Tridax procumbense (coat buttons) plant root extract was used to synthesize copper oxide nanoparticles. The synthesized Tridax procumbense-copper oxide nanoparticles (TP-CuO NPs) were characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering spectroscopy (DLS), and X-ray diffraction (XRD) techniques. The synthesized TP-CuO NPs were applied for photocatalytic dye degradation and antibacterial activity studies. The TP-CuO NPs exhibited a maximum antibacterial activity at 500 μg mL^-1 concentration against Staphylococcus aureus and E. coli showing inhibition zones of 7.5 mm and 7.2 mm, respectively. The photocatalytic ability of the TP-CuO was also tested against the textile dye Trypan blue (TB), and showed about 55% degradation after 48 h for 500 μg mL^-1 CuO NP concentration, showing a concentration-dependent degradation efficiency. This is the first work on TP-derived CuO nanoparticles and their photocatalytic and antimicrobial applications. Overall, this study supports the superiority of green-synthesized TP-CuO NPs as photocatalytic and antimicrobial agents.

An overview on mastitis-associated Escherichia coli: Pathogenicity, host immunity and the use of alternative therapies

Escherichia coli is one of the leading causes of bovine mastitis; it can cause sub-clinical, and clinical mastitis characterized by systemic changes, abnormal appearance of milk, and udder inflammation. E. coli pathogenicity in the bovine udder is due to the interaction between its virulence factors and the host factors; it was also linked to the presence of a new pathotype termed mammary pathogenic E. coli (MPEC). However, the presence of this pathotype is commonly debated. Its main virulence factor is the lipopolysaccharide (LPS) that is responsible for causing an endotoxic shock, and inducing a strong immune response by binding to the toll-like receptor 4 (TLR4), and stimulating the expression of chemokines (such as IL-8, and RANTES) and pro-inflammatory cytokines (such as IL-6, and IL-1β). This strong immune response could be used to develop alternative and safe approaches to control E. coli causing bovine mastitis by targeting pro-inflammatory cytokines that can damage the host tissue. The need for alternative treatments against E. coli is due to its ability to resist many conventional antibiotics, which is a huge challenge for curing ill animals. Therefore, the aim of this review was to highlight the pathogenicity of E. coli in the mammary gland, discuss the presence of the new putative pathotype, the mammary pathogenic E. coli (MPEC) pathotype, study the host's immune response, and the alternative treatments that are used against mastitis-associated E. coli.

New Construction of Functionalized CuO/Al2O3 Nanocomposite-Based Polymeric Sensor for Potentiometric Estimation of Naltrexone Hydrochloride in Commercial Formulations

Electrically conductive polymeric nanocomposites with nanoparticles are adaptable types of nanomaterials that are prospective for various applications. The extraordinary features of copper oxide (CuO) and aluminium oxide (Al₂O₃) nanostructures, encourages extensive studies to prospect these metal oxide nanocomposites as potential electroactive materials in sensing and biosensing applications. This study suggested a new CuO/Al₂O₃ nanocomposite-based polymeric coated wire membrane sensor for estimating naltrexone hydrochloride (NTX) in commercial formulations. Naltrexone hydrochloride and sodium tetraphenylborate (Na-TPB) were incorporated in the presence of polymeric polyvinyl chloride (PVC) and solvent mediator o-nitrophenyloctyl ether (o-NPOE) to form naltrexone tetraphenylborate (NTX-TPB) as an electroactive material. The modified sensor using NTX-TPB-CuO/Al₂O₃ nanocomposite displayed high selectivity and sensitivity for the discrimination and quantification of NTX with a linearity range 1.0 × 10^-9-1.0 × 10^-2 mol L^-1 and a regression equation E_mV = (58.25 ± 0.3) log [NTX] + 754.25. Contrarily, the unmodified coated wire sensor of NTX-TPB exhibited a Nernstian response at 1.0 × 10^-5-1.0 × 10^-2 mol L^-1 and a regression equation E_mV = (52.1 ± 0.2) log [NTX] + 406.6. The suggested modified potentiometric system was validated with respect to various criteria using the methodology recommended guidelines.