Sustainable preparation of gold nanoparticles via green chemistry approach for biogenic applications

Novel premises of ‘Green Nanotechnology’ have tremendous impacts towards industrial scale revolution. The furtive extracted from natural precursors have driven to the generation of biogenic resources for the fabrication of cutting-edge nanomaterials in simple and cost-effective process. This inspection is an intension of the coupling hypothesis of Nanotechnology via ‘Green-Chemistry’ avenue. So, as to diminish the negative effects of technological applications in the health of human beings and the environment, society is focused towards a greener future. Nanoscience assures a promising future by its improvement in green chemistry to develop the 'Greenary Nanoscience and Nanotechnology'. The improvement and execution of chemical assisted processes in order to reduce the usage of harmful substances, the ‘Green Chemistry’ approach is one and only remarkable authentication, which attributed to long range surface area and higher pore volume of gold-nanoparticles. As of now, the efficient biogenic mechanism dramatically reduces the utilization and hazardous reagents have been employed to low-price natural and waste products to yield value-added nanomaterials with extensive relevance, suggesting an economical and green solution to environmental issues. In depth investigation of this critical review illustrates, novel biogenic screening platform was also conducted against antimicrobial strains and degradation of gold-nanoparticles products well explored-from selection precursors evolved from natural extracts, as well as eventually disintegration into bio-degradable yet potentially recyclable byproducts.     

Evaluation of the Antimicrobial Effect of Thymoquinone against Different Dental Pathogens: An In Vitro Study

This study aimed to evaluate the antimicrobial effect of Thymoquinone (TQ) on four different oral microorganisms. Minimum Bactericidal Concentration (MBC), Minimum Inhibition Concentration (MIC), Broth microdilution, and Well diffusion tests were used to determine the optimum antimicrobial concentrations of TQ against Streptococcus salivarius, Streptococcus oralis, Streptococcus mutans, and Staphylococcus aureus over 1, 3, 6, 12 and 24 h. Chlorhexidine 0.12% was selected as a positive control. The inhibitory effect of TQ on bacterial growth was most noticeable with S. salivarius, while the least affected was S. aureus. TQ’s MBC and MIC for S. oralis and S. aureus were comparable 2 mg/mL and 3 mg/mL, respectively. S. salivarius was most resistant to TQ and displayed a value of 5 mg/mL and 4 mg/mL for MIC and MBC, respectively. The viable count of different strains after exposure to TQ’s MBC values was most noticeable with S. aureus followed by S. oralis and S. mutans, while S. salivarius was least affected. This study emphasized the promising antimicrobial effect of TQ against the four main oral microorganisms. It has a potential preventive effect against dental caries as well as other oral diseases.     

Antimicrobial and Photocatalytic Degradation Activities of Chitosan-coated Magnetite Nanocomposite

Journal of Cluster Science - In this work, iron oxide nanoparticles (Fe3O4 NPs) were modified by chitosan (CS). Fe3O4 NPs were synthesized by co-precipitation method and their antimicrobial...     

Synthesis of Metallic Silver Nanoparticles by Fluconazole Drug and Gamma Rays to Inhibit the Growth of Multidrug-Resistant Microbes

Here we tailored a methodology, including green synthesis of silver nanoparticles (AgNPs) in aqueous solution using Fluconazole (Fluc.), a broad-spectrum antifungal agent under the influence of gamma rays. AgNPs were characterized by UV–Vis., FTIR, XRD, DLS, and TEM image. Antimicrobial activities of AgNPs, Fluc., and Ag⁺ were investigated against multidrug-resistant (MDR) bacteria and unicellular fungi. From our results, AgNPs production was found to be dependent on the concentration of Ag⁺, Fluc. and gamma doses. DLS with TEM image explained the size and shape of AgNPs and were found to be spherical with diameter of 11.65 nm. FTIR analysis indicates that, the hydroxyl, nitrogen and fluoride moiety in Fluc. were responsible for the reduction and binding process. AgNPs possesses antimicrobial activity against all tested microbes more than Ag⁺. It produced high efficacy against Acinetobacter baumannii (20.0 mm ZOI). AgNPs are synergistically active towards Candida albicans (17.0 mm ZOI). Investigated action mechanisms for AgNPs activity had been discussed. Thereby, owing to its unique features as cost-effective with continued-term stabilization, it can discover potential targets in biomedical applications and infectious diseases control.     

Response Surface Methodology Optimization of Melanin Production by <Emphasis Type="Italic">Streptomyces cyaneus</Emphasis> and Synthesis of Copper Oxide Nanoparticles Using Gamma Radiation

Melanin pigment is witnessed to be widely used in medicine, food, cosmetic preparations with strong hydrophobicity. Streptomyces cyaneus is utilized for the synthesis of melanin by optimizing culture conditions through screening of critical factors, by Response Surface Methodology as Plackett–Burman design (P-BD), while further statistical optimization was applied using Central Composite Design (CCD) for maximizing yield. Moreover, the impacts of gamma radiation and alternative frugal l-tyrosine, natural sources were studied as it predicted for remarkable rising in the pigment concentration. Herein unprecedented achievement was realized for melanin pigment production, (9.898 mg/ml) was obtaining by optimized culture condition. Also, 2.0% fava bean’s seed peel maximized melanin (9.953 mg/ml) and hence super-yield (11.113 mg/ml) was produced by a stimulus from gamma irradiation (2.5 kGy). The extracted melanin was confirmed chemically, UV–Vis, and FT-IR analysis. Copper oxide nanoparticles (CuONPs) were synthesized by radiolytic reactions of gamma radiation (30.0 kGy) in the presence of melanin as a capping agent. CuONPs were characterized by UV–Vis, DLS, XRD, and FT-IR. TEM analysis revealed the morphology of monodispersed CuONPs with a mean diameter 29.82 nm. CuONPs exhibited excellent antimicrobial activity against food born Gram-positive, Gram-negative bacteria, and fungi; they can find potential applications for the food packaging approach.