Novel mycosynthesis of cobalt oxide nanoparticles using Aspergillus brasiliensis ATCC 16404-optimization, characterization and antimicrobial activity

Therapeutic strategies for drug-resistant Pseudomonas aeruginosa: Metal and metal oxide nanoparticles

Pseudomonas aeruginosa (PA) is a widely prevalent opportunistic pathogen. Multiple resistant strains of PA have emerged from excessive or inappropriate use of antibiotics, making their eradication increasingly difficult. Therefore, the search for highly efficient and secure novel antimicrobial agents is crucial. According to reports, there is an increasing exploration of nanometals for antibacterial purposes. The antibacterial mechanisms involving the nanomaterials themselves, the release of ions, and the induced oxidative stress causing leakage and damage to biomolecules are widely accepted. Additionally, the study of the cytotoxicity of metal nanoparticles is crucial for their antibacterial applications. This article summarizes the types of metal nanomaterials and metal oxide nanomaterials that can be used against PA, their respective unique antibacterial mechanisms, cytotoxicity, and efforts made to improve antibacterial performance and reduce toxicity, including combination therapy with other materials and antibiotics, as well as green synthesis approaches.

Enhanced antibacterial activity and superior biocompatibility of cobalt-deposited titanium discs for possible use in implant dentistry

The clinical success of implants depends on rapid osseointegration, and new materials are being developed considering the increasing demand. Considering cobalt (Co) antibacterial characteristics, we developed Co-deposited titanium (Ti) using direct current (DC) sputtering and investigated it as a new material for implant dentistry. The material was characterized using atomic absorption spectroscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The material's surface topography, roughness, surface wettability, and hardness were also analyzed. The Co thin film (Ti-Co15) showed excellent antibacterial effects against microbes implicated in peri-implantitis. Furthermore, Ti-Co15 was compatible and favored the attachment and spreading of MG-63 cells. The alkaline phosphatase and calcium mineralization activities of MG-63 cells cultured on Ti-Co15 remained unaltered compared to Ti. These data correlated well with the time-dependent expression of ALP, RUNX-2, and BMP-2 genes involved in osteogenesis. The results demonstrate that Co-deposited Ti could be a promising material in implant dentistry.

Prevalence of Cobalt in the Environment and Its Role in Biological Processes

Cobalt (Co) is an essential trace element for humans and other animals, but high doses can be harmful to human health. It is present in some foods such as green vegetables, various spices, meat, milk products, seafood, and eggs, and in drinking water. Co is necessary for the metabolism of human beings and animals due to its key role in the formation of vitamin B12, also known as cobalamin, the biological reservoir of Co. In high concentrations, Co may cause some health issues such as vomiting, nausea, diarrhea, bleeding, low blood pressure, heart diseases, thyroid damage, hair loss, bone defects, and the inhibition of some enzyme activities. Conversely, Co deficiency can lead to anorexia, chronic swelling, and detrimental anemia. Co nanoparticles have different and various biomedical applications thanks to their antioxidant, antimicrobial, anticancer, and antidiabetic properties. In addition, Co and cobalt oxide nanoparticles can be used in lithium-ion batteries, as a catalyst, a carrier for targeted drug delivery, a gas sensor, an electronic thin film, and in energy storage. Accumulation of Co in agriculture and humans, due to natural and anthropogenic factors, represents a global problem affecting water quality and human and animal health. Besides the common chelating agents used for Co intoxication, phytoremediation is an interesting environmental technology for cleaning up soil contaminated with Co. The occurrence of Co in the environment is discussed and its involvement in biological processes is underlined. Toxicological aspects related to Co are also examined in this review.

Diversity of Mycogenic Oxide and Chalcogenide Nanoparticles: A Review

Oxide and chalcogenide nanoparticles have great potential for use in biomedicine, engineering, agriculture, environmental protection, and other research fields. The myco-synthesis of nanoparticles with fungal cultures, their metabolites, culture liquids, and mycelial and fruit body extracts is simple, cheap and environmentally friendly. The characteristics of nanoparticles, including their size, shape, homogeneity, stability, physical properties and biological activity, can be tuned by changing the myco-synthesis conditions. This review summarizes the data on the diversity of oxide and chalcogenide nanoparticles produced by various fungal species under different experimental conditions.

Marine Algae Extract (Grateloupia Sparsa) for the Green Synthesis of Co3O4NPs: Antioxidant, Antibacterial, Anticancer, and Hemolytic Activities

The aqueous extract of red algae was used for bio-inspired manufacturing of cobalt oxide nanoparticles (Co3O4NPs) and for antioxidant, antibacterial, hemolytic potency, and anticancer activity. Typical, characterization techniques include UV-Vis, SEM, EDAX, TEM, FTIR, XRD, and TGA. Using an X-ray diffraction assay, the size of the Co3O4NPs crystal was determined to range from 23.2 to 11.8 nm. Based on TEM and SEM pictures, biosynthesized Co3O4NPs' had a homogeneous spherical morphology with a 28.8 to 7.6 nm average diameter. Furthermore, Co3O4NPs biological properties were investigated, including determining the antibacterial potency using the zone of inhibition (ZOI) method and determining the minimal inhibitory concentration (MIC). The antibacterial activity of Co3O4NPs was higher than that of the ciprofloxacin standard. Alternatively, scavenging of DPPH free radical investigation was carried out to test the antioxidant capacitance of Co3O4NPs, revealing significant antioxidant ability. The biosynthesized Co3O4NPs have a dose-dependent effect on erythrocyte viability, indicating that this technique is harmless. Furthermore, bioinspired Co3O4NPs effectively against HepG2 cancer cells (IC50: 201.3 μg/ml). Co3O4NPs would be a therapeutic aid due to their antioxidant, antibacterial, and anticancer properties.

Exploiting the exceptional biosynthetic potency of the endophytic Aspergillus terreus in enhancing production of Co3O4, CuO, Fe3O4, NiO, and ZnO nanoparticles using bioprocess optimization and gamma irradiation

Developing a suitable applicative process and scaling up the microbial synthesis of nanomaterials is an attractive and emerging prospect for a future sustainable industrial production. In this paper, optimization of fermentation conditions for enhanced production of Co₃O₄, CuO, Fe₃O₄, NiO, and ZnO nanoparticles by the endophytic A. terreus ORG-1 was studied. Different cultivation conditions were evaluated. Then, a response surface methodology program was used to optimize physical conditions controlling the biosynthesis of these NPs. Finally, the use of gamma irradiation for improvement of NPs’ production was adopted. Under the optimum conditions and after gamma irradiation, the final yields of the respective NPs reached 545.71, 651.67, 463.19, 954.88, 1356.42 mg L⁻¹. To the best of our knowledge, this is the first report on the production and enhancement of different types of nanomaterials from one microbial culture that can open up the way towards the industrialization of the microbial production of nanomaterials.

Recent Trends and Advances of Co3O4 Nanoparticles in Environmental Remediation of Bacteria in Wastewater

Antibiotic resistance is a formidable global threat. Wastewater is a contributing factor to the prevalence of antibiotic-resistant bacteria and genes in the environment. There is increased interest evident from research trends in exploring nanoparticles for the remediation of antibiotic-resistant bacteria. Cobalt oxide (Co3O4) nanoparticles have various technological, biomedical, and environmental applications. Beyond the environmental remediation applications of degradation or adsorption of dyes and organic pollutants, there is emerging research interest in the environmental remediation potential of Co3O4 nanoparticles and its nanocomposites on antibiotic-resistant and/or pathogenic bacteria. This review focuses on the recent trends and advances in remediation using Co3O4 nanoparticles and its nanocomposites on antibiotic-resistant or pathogenic bacteria from wastewater. Additionally, challenges and future directions that need to be addressed are discussed.

Current Methods for Synthesis and Potential Applications of Cobalt Nanoparticles: A Review

Cobalt nanoparticles (CoNPs) are promising nanomaterials with exceptional catalytic magnetic, electronic, and chemical properties. The nano size and developed surface open a wide range of applications of cobalt nanoparticles in biomedicine along with those properties. The present review assessed the current environmentally friendly synthesis methods used to synthesize CoNPs with various properties, such as size, zeta potential, surface area, and magnetic properties. We systematized several methods and provided some examples to illustrate the synthetic process of CoNPs, along with the properties, the chemical formula of obtained CoNPs, and their method of analysis. In addition, we also looked at the potential application of CoNPs from water purification cytostatic agents against cancer to theranostic and diagnostic agents. Moreover, CoNPs also can be used as contrast agents in magnetic resonance imaging and photoacoustic methods. This review features a comprehensive understanding of the synthesis methods and applications of CoNPs, which will help guide future studies on CoNPs.

Evaluating the antibacterial effect of cobalt nanoparticles against multi-drug resistant pathogens

This study aimed to estimate the effect of cobalt nanoparticles (Co NPs) with different concentrations against multidrug-resistant (MDR) pathogenic bacteria. Three isolates of Staphylococcus aureus (gram-positive), Proteus spp. (gram-negative), and Escherichia coli (gram-negative) bacteria were extracted from various clinical examples utilizing routine methods on bacteriological culture media. The antibacterial sensitivity of commercial antibiotics such as Ciprofloxacin, Cefotaxime, Gentamycin, and Amoxicillin was broken down on a Muller Hinton agar plate and evaluated using the disk diffusion method. The study results demonstrated the antibacterial effect of the Co NPs against the bacterial isolates with three different concentrations utilized in the study. The results indicated that the Co NPs showed the highest antibacterial activity when utilizing 100 μg/ml against Escherichia coli followed by Proteus spp and Staphylococcus aureus with zones of inhibition measured as 22.2±0.1 mm, 20.3±0.15 mm, and 15.8±0.1 mm; respectively. Co NPs at a 100 μg/mL concentration showed higher inhibition zones than several common antibiotics except for Ciprofloxacin, which demonstrated better antibacterial activity against the bacterial isolates employed in this study. Scanning Electron Microscope (SEM)and X-Ray diffraction (XRD)studies confirmed that Cobalt nanoparticles (Co NPs) were synthesized from cobalt sulphate solution with a size ranging from 40 nm to 60 nm. The nanoparticles showed a crystalline structure with a round shape and smooth surface. The antibacterial resistance of Co NPs against three common bacteria such as Staphylococcus aureus, Proteus spp, and Escherichia coli was assessed in this study. The optimum concentration of the Co NPs was identified as 100 μg/ml, which could provide a similar or higher antibacterial effect.

Inspirations of Cobalt Oxide Nanoparticle Based Anticancer Therapeutics

Cobalt is essential to the metabolism of all animals due to its key role in cobalamin, also known as vitamin B12, the primary biological reservoir of cobalt as an ultra-trace element. Current cancer treatment strategies, including chemotherapy and radiotherapy, have been seriously restricted by their side effects and low efficiency for a long time, which urges us to develop new technologies for more effective and much safer anticancer therapies. Novel nanotechnologies, based on different kinds of functional nanomaterials, have been proved to act as effective and promising strategies for anticancer treatment. Based on the important biological roles of cobalt, cobalt oxide nanoparticles (NPs) have been widely developed for their attractive biomedical applications, especially their potential for anticancer treatments due to their selective inhibition of cancer cells. Thus, more and more attention has been attracted to the preparation, characterization and anticancer investigation of cobalt oxide nanoparticles in recent years, which is expected to introduce novel anticancer treatment strategies. In this review, we summarize the synthesis methods of cobalt oxide nanoparticles to discuss the advantages and restrictions for their preparation. Moreover, we emphatically discuss the anticancer functions of cobalt oxide nanoparticles as well as their underlying mechanisms to promote the development of cobalt oxide nanoparticles for anticancer treatments, which might finally benefit the current anticancer therapeutics based on functional cobalt oxide nanoparticles.

Green fabrication of Co and Co3O4 nanoparticles and their biomedical applications: A review

Nanotechnology is the fabrication, characterization, and potential application of various materials at the nanoscale. Over the past few decades, nanomaterials have attracted researchers from different fields because of their high surface-to-volume ratio and other unique and remarkable properties. Cobalt and cobalt oxide nanoparticles (NPs) have various biomedical applications because of their distinctive antioxidant, antimicrobial, antifungal, anticancer, larvicidal, antileishmanial, anticholinergic, wound healing, and antidiabetic properties. In addition to biomedical applications, cobalt and cobalt oxide NPs have been widely used in lithium-ion batteries, pigments and dyes, electronic thin film, capacitors, gas sensors, heterogeneous catalysis, and for environmental remediation purposes. Different chemical and physical approaches have been used to synthesize cobalt and cobalt oxide NPs; however, these methods could be associated with eco-toxicity, cost-effectiveness, high energy, and time consumption. Recently, an eco-friendly, safe, easy, and simple method has been developed by researchers, which uses biotic resources such as plant extract, microorganisms, algae, and other biomolecules such as starch and gelatin. Such biogenic cobalt and cobalt oxide NPs offer more advantages over other physicochemically synthesized methods. In this review, we have summarized the recent literature for the understanding of green synthesis of cobalt and cobalt oxide NPs, their characterization, and various biomedical applications.

Novel mycosynthesis of Co3O4, CuO, Fe3O4, NiO, and ZnO nanoparticles by the endophytic Aspergillus terreus and evaluation of their antioxidant and antimicrobial activities

Several fungal endophytes were isolated and screened for their ability to biosynthesize a variety of nanoparticles (NPs), as a potentially simple and eco-friendly method with low cost. Among these fungi, a promising isolate named ORG-1 was found able to synthesize five different NPs types: Co₃O₄NPs, CuONPs, Fe₃O₄NPs, NiONPs, and ZnONPs. The ORG-1 strain was identified as Aspergillus terreus according to the morphological and molecular studies. Synthesis of these NPs was initially monitored by UV-Vis spectroscopy and further characterized by Fourier transform infrared spectroscopy. X-ray diffraction patterns revealed their crystalline structure. Dynamic light scattering analysis was applied to study the particle size distribution and stability. Transmission electron microscope studies indicated the morphology of the synthesized NPs. Additionally, the biological activities of the in vitro antioxidant and antimicrobial potentials were evaluated. Co₃O₄NPs, CuONPs, Fe₃O₄NPs, NiONPs, and ZnONPs showed promising antioxidant activity with 50% inhibitory concentrations of 85.44, 96.74, 102.41, 87.41, and 108.67 μg mL^-1, respectively. The synthesized NPs exhibited potent antimicrobial activities against several plant and human pathogens. To our knowledge, this is the first report on the use of one microbial strain for the synthesis of a variety of NPs. This study suggests endophytic fungi as new and alternate platforms with an exceptional potentiality for the synthesis of NPs with promising activities. KEY POINTS: • Discovery of a promising endophytic fungus for synthesis of five different types of NPs. • Mycosynthesis and characterization of all the synthesized NPs were investigated. • The synthesized NPs showed promising antioxidant and antimicrobial activities.