Sustainable and green trends in using plant extracts for the synthesis of biogenic metal nanoparticles toward environmental and pharmaceutical advances: A review

Green approaches in synthesising nanomaterials for environmental nanobioremediation: Technological advancements, applications, benefits and challenges.

Green synthesis approaches of nanomaterials (NMs) have received considerable attention in recent years as it addresses the sustainability issues posed by conventional synthesis methods. However, recent works of literature do not present the complete picture of biogenic NMs. This paper addresses the previous gaps by providing insights into the stability and toxicity of NMs, critically reviewing the various biological agents and solvents required for synthesis, sheds light on the factors that affect biosynthesis, and outlines the applications of NMs across various sectors. Despite the advantages of green synthesis, current methods face challenges with safe and appropriate solvent selection, process parameters that affect the synthesis process, nanomaterial cytotoxicity, bulk production and NM morphology control, tedious maintenance, and knowledge deficiencies. Consequently, the green synthesis of NMs is largely trapped in the laboratory phase. Nevertheless, the environmental friendliness, biocompatibility, and sensitivities of the resulting NMs have wider applications in biomedical science, environmental remediation, and consumer industries. To the scale-up application of biogenic NMs, future research should be focused on understanding the mechanisms of the synthesis processes, identifying more biological and chemical agents that can be used in synthesis, and developing the practicality of green synthesis at the industrial scale, and optimizing the factors affecting the synthesis process. 

Green approaches in synthesising nanomaterials for environmental nanobioremediation: Technological advancements, applications, benefits and challenges

This paper investigates a new modeling approach of central composite design (CCD) in Response Surface methodology (RSM) for the optimization of methyl orange (MO) photodegradation based to the prepared materials under UV–vis irradiation. Mesoporous zinc oxide (ZnO) have been synthesized at different cerium (Ce) contents (2, 5 and 7 wt%) through a single step sol gel method. Subsequently, cerium nanoparticles (CeNPs) have been impregnated on mesoporous ZnO. The physico-chemical characteristics of each catalyst are described through several approaches. The photocatalytic activity of the prepared catalysts shows that CeNPs enhance the photocatalytic performance of ZnO at 2 wt% Ce content. MO photodergadation processes of the optimal catalyst can be mathematically described as a function of pH-solution, catalyst dosage and MO concentration being modeled by a CCD-RSM. Based on a statistical modeling (quadratic regression) and an optimization process (ANOVA analysis), the optimum conditions were achieved for pH of solution of 5.58, MO concentration of 20.72 mg L−1and catalyst dosage of 0.63 g L−1 which allowed reaching 100% of photodegradation. Overall, the value of the adjusted coefficient of determination (R2 = 0.9901) indicates that the considered model was quite suitable and that the selected CCD-RSM was successful in optimizing the photodegradation conditions of MO.

A statistical modeling-optimization approach for efficiency photocatalytic degradation of textile azo dye using cerium-doped mesoporous ZnO: A central composite design in response surface methodology

Bi-metallic nanoparticles (NPs) have appeared to be more efficient as antimicrobials than mono-metallic NPs. The fungus Aspergillus terreus-mediated synthesis of bi-metallic Ag-Cu NPs was optimized using response surface methodology (RSM) to reach the maximum yield of NPs. The optimal conditions were validated using ANOVA. The optimal conditions were 1.5 mM total metal (Ag + Cu) concentration, 1.25 mg fungal biomass, 350 W microwave power, and 15 min reaction time. The structure and shape of the synthesized NPs (mostly 20–30 nm) were characterized using several analytical tools. The biological activities of the synthesized NPs were assessed by studying their antioxidant, antibacterial, and cytotoxic activity in different NP concentrations. A dose-dependent response was observed in each test. Bi-metallic Ag-Cu NPs inhibited three clinically relevant human pathogens: Klebsiella pneumoniae, Enterobacter cloacae, and Pseudomonas aeruginosa. Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus were inhibited less. The DPPH and hydrogen peroxide scavenging activities of the NPs were high, reaching 90% scavenging. Ag-Cu NPs could be studied as antimicrobials in different applications. The optimization procedure using statistical analyses was successful in improving the yield of nanoparticles.

/pdf/optimization-of-the-synthesis-of-fungus-mediated-bi-metallic-1wzh02mq.pdf

Optimization of the Synthesis of Fungus-Mediated Bi-Metallic Ag-Cu Nanoparticles

A review on biogenic synthesis of metal nanoparticles using marine algae and its applications.

Vermicomposting: A management tool to mitigate solid waste.

Candida albicans has remained the main etiological agent of candidiasis, challenges clinicians with high mortality and morbidity. The emergence of resistance to antifungal drugs, toxicity and lower efficacy have all contributed to an urgent need to develop alternative drugs aiming at novel targets in C. albicans. Targeting the production of virulence factors, which are essential processes for infectious agents, represents an attractive substitute for the development of newer anti-infectives. The present review highlights the recent developments made in the understanding of the pathogenicity of C. albicans. Production of hydrolytic enzymes, morphogenesis and biofilm formation, along with their molecular and metabolic regulation in Candida are discussed with regard to the development of novel antipathogenic drugs against candidiasis.

Virulence and biofilms as promising targets in developing antipathogenic drugs against candidiasis

Vermicomposting is used to treat and recycle organic waste to be utilized in agriculture. This project aimed to improve the product of vermicomposting by adding biochar and microalgal biomass to the process. Experiment to vermicompost (60 days) mixed organic waste was carried out preparing 16 different treatments. The best treatment appeared to be the earthworm Eisenia fetida, 6% biochar, and the biomass of the microalgae Navicula sp. amended to the process. The product was mature vermicompost with pH 7, cation exchange capacity 70 cmolc kg−1, and the C:N ratio 9.5. All products were used as seedbeds and tested for the plant growth promotion of the vegetables Solanum lycopersicum, Capsicum annuum, and Solanum melongena. The best vermicomposting product increased plant growth, reduced the disease incidence of the leaves, and improved the disease resistance of the seeds the plants produced. Plant vigor index was highest in the best treatment varying between 4600 and 5000 depending on the plant species. For comparison, the lowest values were under 1000. Disease resistance was low for the best treatment (5%–15%) compared to the high values over 60%. The seeds ripened in the experimental plants had acquired resistance against the experimentally inoculated phytopathogen Pythium sp., known to commonly destroy seeds. In the best treatment, more than 90% of the seeds germinated while in all other treatments less than 56% germinated. In conclusion, the vermicomposting using the earthworm Eisenia fetida, 6% biochar, and the biomass of the microalgae Navicula sp. produced seedbed substate that improved the growth of vegetables and suppressed phytopathogens. The seedbed can be used in sustainable agriculture to reduce the use of fertilizers and chemicals.

Fatimah Alshehrei

Papers

A review on biogenic synthesis of metal nanoparticles using marine algae and its applications.

Vermicomposting: A management tool to mitigate solid waste.

Virulence and biofilms as promising targets in developing antipathogenic drugs against candidiasis

Vermicomposting amended with microalgal biomass and biochar produce phytopathogen-resistant seedbeds for vegetables

Synthesis of Coumarin-Analogues: Analytical, Spectral, Conformational, MOE-Docking and Antimicrobial Studies