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Abstract

The green synthesis of gold nanoparticles was mediated by aqueous extract of Wedelia trilobata leaves and in-vitro cytotoxic efficacy of synthesized gold nanoparticle against HCT 15 human colon cancer cell line was studied. Synthesis of nanoparticles was completed within 30-35 minutes of reaction at room temperature and structural properties of the particles were studied through standard characterization methods. Formation of gold nanoparticles was initially confirmed by a change in colour from light yellow to deep purple and the appearance of Surface Plasmon Resonance at 533nm in UV-Visible spectroscopy. The particles were mostly spherical, crystalline with face-centered cubic structure with 10-50 nm diameters, and they exhibited a high degree of agglomeration. Further, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction assay was conducted using different concentrations of gold nanoparticles (25-500µg/ml). The gold nanoparticles showed dose-dependent toxicity and the efficiency was up to 30 percent on average.

Efficient Photodegradation of Eriochrome Black-T by a Trimetallic Magnetic Self-Synthesized Nanophotocatalyst Based on Zn/Au/Fe-Embedded Poly(vinyl alcohol)

“…The highest energy gap was attained in the order of ZnO NRs, Fe 3 O 4 NPs, and the Fe 3 O 4 @PVA–Au/ZnO magnetic photocatalytic system. The electron transition from the valence band (VB) to the conduction band (CB) of Au with a band gap value of 3.4 eV provides exciton (electron–hole pairs). , According to the literature, the calculated band gap energy of the individual ZnO and Fe 3 O 4 was about 3.2 and 2.3 eV, respectively. , In this regard, the possible proposed mechanism clarifies that the photocatalyst procedure of the Fe 3 O 4 @PVA–Au/ZnO magnetic photocatalytic system can be initiated under the green LED light irradiation. Afterward, the electron transfer from the VB to the CB leads to positive and negative charges on the photocatalyst’s energy levels. , Accordingly, many studies have focused on TiO 2 application with the main photocatalytic activity as the mechanism. , Based on the proposed mechanism and the similar energy levels of CB in Au NPs and ZnO, the LSPR-excited electrons (as previously described) of the Au NPs transfer from the CB of Au NPs to the CB of ZnO, generating the same amount of holes in VB of Au NPs.…”

“…The electron transition from the valence band (VB) to the conduction band (CB) of Au with a band gap value of 3.4 eV provides exciton (electron−hole pairs). 67,68 According to the literature, the calculated band gap energy of the individual ZnO and Fe 3 O 4 was about 3.2 and 2.3 eV, respectively. 69,70 In this regard, the possible proposed mechanism clarifies that the photocatalyst procedure of the Fe 3 O 4 @PVA−Au/ZnO magnetic photocatalytic system can be initiated under the green LED light irradiation.…”

A rapid direct-differential agglutination assay for Brucella detection using antibodies conjugated with functionalized gold nanoparticles

“…Initially, for naive nanoparticles collected before reduction, absorption at 3,300-3,400 cm −1 corresponds to medium N-H stretching vibrations of hydrogen bonds in amines along with strong and broad bonds of the pendant hydroxyl (-OH) group of alcohols. Another sharp broad peak at 2,500-3,300 cm −1 originated from strong O-H stretching of pendant carboxylic acid and weak S-H stretching of thiols (Bartczak and Kanaras, 2011;Dey et al, 2018). Also, the absorption peaks at 1,640 cm −1 and 1,403 cm −1 of AuNPs are ascribed to strong C=O stretching vibrations of amides, C=C stretching of monosubstituted alkenes, carboxylic group, and relates to the sulfonyl chloride (Shikha et al, 2017).…”

Recent Advancements in Plant- and Microbe-Mediated Synthesis of Metal and Metal Oxide Nanomaterials and Their Emerging Antimicrobial Applications

“…Medicinal plants like Pachyma hoelen , Phyllanthus niruri , Olea europaea , Syzygium cumini , Kalanchoe pinnata , etc. have high concentration of active ingredients which boost the antiviral activities. , Recently, Dey et al synthesized using Wedelia trilobata leaf extract Au NPs (varying concentration) of spherical shape in a size of 50 nm for treating human colon cancer cells (HCT 15) . Varied concentrations (25–500 μg/mL) of Au NPs were evaluated (using MTT assay), and the NPs showed 30% cell toxicity at 500 μg/mL .…”

“…have high concentration of active ingredients which boost the antiviral activities. , Recently, Dey et al synthesized using Wedelia trilobata leaf extract Au NPs (varying concentration) of spherical shape in a size of 50 nm for treating human colon cancer cells (HCT 15) . Varied concentrations (25–500 μg/mL) of Au NPs were evaluated (using MTT assay), and the NPs showed 30% cell toxicity at 500 μg/mL . Thangamani et al studied the antibacterial activity against E. coli and S. aureus of Au NPs produced using Simarouba glauca leaf extract .…”