Utilizing waste corn-cob in biosynthesis of noble metallic nanoparticles for antibacterial effect and catalytic degradation of contaminants

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This work describes a simple single-step method for green synthesis of colloidal gold nanoparticles (AuNPs) using Litsea cubeba (LC) fruit extract as a reducing as well as stabilizing agent simultaneously. Major parameters affecting the formation of LC-AuNPs, including gold ion concentration, reaction time, and reaction temperature were optimized using ultraviolet-visible (UV-Vis) measurements at a characteristic maximum absorbance of 535 nm. The functional groups responsible for reducing gold ions and capping AuNPs were examined by Fourier-transform infrared (FTIR) spectroscopy. Powder X-ray diffraction (XRD) analysis revealed the crystalline nature of AuNPs. Transmission electron microscopy (TEM) measurements showed that the biosynthesized LC-AuNPs were mostly spherical with an average size of 8-18 nm. The nanoparticles also demonstrated excellent ultrarapid catalytic activity for the complete reduction of 4-nitrophenol to p-aminophenol in the presence of NaBH4 within 10 min with a reaction rate constant of 0.348 min-1.

“…Besides, inorganic elements of K (14.65%) and Cl (13.26%) were also found. The presence of K and Cl elements in many plant extracts has been reported in several previous works [23,30].…”

Section: Morphological and Compositionalsupporting

confidence: 55%

“…where k is the rate constant, t is the reaction time, and A o and A t are the concentration of 4-NP at the initial and time t, respectively, was applied to determine the reaction rate constant via slope of linear regression of ln ðA t Þ over reaction time t [30].…”

Section: Catalytic Activity Of Aunpsmentioning

confidence: 99%

Biosynthesis of Gold Nanoparticles Using Litsea cubeba Fruit Extract for Catalytic Reduction of 4-Nitrophenol

Doan

Thieu

Nguyen

et al. 2020

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“…In the context, the amount of NaBH 4 was used far beyond the concentration of pollutants, so the concentra-tion of NaBH 4 could be considered as a constant during the reaction. In this regard, the reaction could be pseudo-firstorder one which the kinetics described by the linear equation ln ðAtÞ = −kt + ln ðAoÞ [30], where k is the rate constant, t is the reaction time, At and Ao are the concentrations of pollutants at the time t and initial concentration, respectively. The rate constant k is determined from the slope of the straight line using linear regression of ln ðAtÞ over the reaction time t. All catalytic and antibacterial experiments were performed in triplicate to confirm the reproducibility of the results and data are presented as mean and standard deviation.…”

mentioning

confidence: 99%

Biosynthesis of Silver and Gold Nanoparticles Using Aqueous Extract of Codonopsis pilosula Roots for Antibacterial and Catalytic Applications

Doan

Huynh

Nguyen

et al. 2020

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In this study, biogenic silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) were synthesized by a green approach using an aqueous extract from Codonopsis pilosula (CP) roots as a reducing and stabilizing agent. The formation of CP-AgNPs and CP-AuNPs was confirmed and optimized by UV-Vis spectroscopy. The CP-AgNPs and CP-AuNPs obtained under optimum conditions of metal ion concentration, reaction temperature, and reaction time were characterized by high-resolution transition electron microscopy (HR-TEM), selected area electron diffraction (SAED) analysis, field-emission scan electron microscopy (FE-SEM), powder X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, dispersive X-ray spectroscopy (EDX), and dynamic light scattering (DLS) method. It has been found that the biosynthesized CP-AgNPs and CP-AuNPs were formed in spherical shape with an average size of 10±2.5 nm and 20±3.2 nm, respectively. The biosynthesized metallic nanoparticles exhibited selective bacterial activity against three bacterial strains including two Gram-positive bacteria of Bacillus subtilis and Staphylococcus aureus and one Gram-negative bacteria of Escherichia coli. Meanwhile, there was no antibacterial activity detected toward Gram-negative Salmonella enteritidis. CP-AgNPs and CP-AuNPs also manifested an excellent catalytic performance in the reduction of 1,4-dinitrobenzene, 2-nitrophenol, 3-nitrophenol, and 4-nitrophenol.

“…The formation of metal nanoparticles (MNP) is optimized by the UV-Vis method. Gold nanoparticles (CC-AuNPs) show high antibacterial activity against three bacterial strains including Salmonella typhimurium, Bacillus cereus, and Staphylococcus aureus [18]. Gold nanoshells also have interesting physical properties, including optical and surface plasmon resonance, which can be customized during the synthesis process, giving gold nanoshells significant potential in nanomedicine [19].…”

Section: Gold Nanoparticle Synthesis Methodsmentioning

confidence: 99%

Antibacterial Properties of Functionalized Gold Nanoparticles and Their Application in Oral Biology

Huang

et al. 2020

As bacterial resistance is becoming increasingly serious, the development of antibacterial nanomaterials is an effective method of solving this problem. Gold nanoparticles have good stability and excellent biocompatibility and are easily modified, and their antibacterial properties can be enhanced by changing their structure and size or adding ingredients. Gold nanoparticles are also excellent drug carriers that can improve the antibacterial effects of loaded antibacterial drugs. After being modified and combined with other antibacterial drugs, gold nanoparticles can also play a better antibacterial role for effective antibacterial strategies against some resistant bacteria. Gold nanoparticles have photothermal effects, and modified gold nanoparticles can be a good medium for photothermal treatments to kill bacteria. By adding functionally modified gold nanoparticles, many materials can obtain much needed antibacterial properties. Gold nanoparticles can also be combined with cations, low-temperature plasma, various surface ligands, and other potential antibacterial agents. In short, the antibacterial characteristics of functionalized gold nanoparticles demonstrate that they have considerable practical application value and provide more ideas to solve antibacterial problems. At the same time, the application of gold nanoparticles in oral biology is also increasing.