scholarly journals Casein-Conjugated Gold Nanoparticles for Amperometric Detection of Leishmania infantum

Biosensors ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 68
Author(s):  
Mohamed Fethi Diouani ◽  
Oussama Ouerghi ◽  
Kamel Belgacem ◽  
Maher Sayhi ◽  
Radu Ionescu ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Acidic Solution ◽  
Amperometric Detection ◽  
Drug Efficacy ◽  
Visible Spectroscopy ◽  
Formation Reaction ◽  
Concentration Interval ◽  
Efficacy Assessment ◽  
Major Surface ◽  
Leishmania Parasites

Sensitive and reliable approaches targeting the detection of Leishmania are critical for effective early diagnosis and treatment of leishmaniasis. In this frame, this paper describes a rapid quantification assay to detect Leishmania parasites based on the combination of the electrocatalytic ability of gold nanoparticles (AuNPs) to act as a catalyst for the hydrogen formation reaction along with the specificity of the interaction between casein and the major surface protease of the Leishmania parasite, GP63. First, pure and casein-modified AuNPs were prepared and characterized by scanning electron microscopy and ultraviolet–visible spectroscopy. Then, casein-conjugated AuNPs were incubated with Leishsmania parasites in solution; the formed complex was collected by centrifugation, treated by acidic solution, and the pelleted AuNPs were placed on screen-printed carbon electrodes (SPCEs) and chronoamperometric measurements were carried out. Our results suggest that it is possible to detect Leishmania parasites, with a limit less than 1 parasite/mL. A linear response over a wide concentration interval, ranging from 2 × 10−2 to 2 × 105 parasites/mL, was achieved. Additionally, a pretreatment of Leishmania parasites with Amphotericin B, diminished their interaction with casein. This findings and methodology are very useful for drug efficacy assessment.

Graphene Oxide as a Substrate for Biosensors: Synthesis and Characterization

2021 ◽  
Vol 324 ◽  
pp. 87-93
Author(s):  
Mohamed Adel ◽  
Abdel Hady A. Abdel-Wahab ◽  
Ahmed Abdel-Mawgood ◽  
Ahmed Osman Egiza
Keyword(s):  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
Acidic Solution ◽  
Cost Effective ◽  
Sem Analysis ◽  
Visible Spectroscopy ◽  
Sem Images ◽  
Hummers Method ◽  
Uv Visible ◽  
Modified Hummers Method

Graphene oxide (GO) is an oxidized nanosheets of graphite with a 2D planar structure. GO could be readily complexed with bio-entities as it possesses many oxygen-containing functionalities on its surface. The preparation process is fast, easy, and cost-effective. It was prepared using modified Hummers’ method in acidic solution as a primary solvent and potassium permanganate as an oxidizing agent. Afterwards, it was successfully characterized by FTIR, UV-visible spectroscopy, as well as XRD and Raman spectroscopy, and finally, SEM analysis. It was observed that the formed GO is mainly composed of carbon and oxygen elements rich in oxygen functional groups. Furthermore, the existence of (001) plane in XRD interprets the complete oxidation of graphite with d-spacing 9 Å. Moreover, Raman spectroscopy displayed the sp3 carbon hybridization, besides, the ID/IG ratio is found to be 0.84, which confirms the disorder between graphene oxide layers. The SEM images also pointed out that graphene oxide sheets were regularly stacked together as flake-like structures. Accordingly, the richness of oxygen-containing functionalities was confirmed. Hence, it is appropriate to be used as a base transducer for biosensing applications.

Effect of Gold Nanoparticles Size on Detection of Methylphosphonic Acid Hydrolysis Product of Nerve Agent

2021 ◽  
Vol 25 (7) ◽  
pp. 1-7
Author(s):  
Fellyzra Elvya Pojol ◽  
Buong Woei Chieng ◽  
Keat Khim Ong ◽  
Rashid Jahwarhar Izuan Abd ◽  
Mohd Junaedy Osman ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Inverse Method ◽  
Direct Method ◽  
Hydrolysis Product ◽  
Spherical Shape ◽  
Methylphosphonic Acid ◽  
Visible Spectroscopy ◽  
Transmission Electron ◽  
Citrate Reduction ◽  
Chloride Trihydrate

Citrate reduction of gold (III) chloride trihydrate (HAuCl4) is commonly used method to synthesise citrate-capped gold nanoparticles (cit-AuNPs). In this study, the sequence of reagents addition was modified (“inverse” method) to synthesise smaller size of cit-AuNPs than the standard Turkevich method (“direct” method). Ultraviolet-visible spectroscopy (UV-vis) and field emission transmission electron microscopy (FETEM) confirmed the formation of cit-AuNPs. The cit-AuNPs synthesized using “inverse” method are smaller in size (14.0 ± 3.03 nm) with uniform spherical shape compared to “direct” method (23.5 ± 7.52 nm). Smaller particles size of cit-AuNPs provide higher efficiency and sensitivity for detection of methylphosphonic acid (MPA) via colorimetric incorporated with image processing with a linear range from 2.5 to 12.5 mM and a low detection limit of 6.28 mM at shorter detection period (24 to 30 s).

scholarly journals Case Report. Internal transcribed spacer sequence based molecular confirmation and drug efficacy assessment against Toxascaris leonina (Linstow, 1909) infection in Asiatic lions (Panthera leo persica)

2017 ◽  
Vol 54 (2) ◽  
pp. 152-156
Author(s):  
A. D. Moudgil ◽  
L. D. Singla ◽  
M. P. Singh
Keyword(s):  
Body Weight ◽  
Internal Transcribed Spacer ◽  
Drug Efficacy ◽  
Extended Period ◽  
Dose Schedule ◽  
Faecal Egg Count ◽  
Efficacy Assessment ◽  
Internal Transcribed Spacer Sequences ◽  
Zoological Park ◽  
Toxascaris Leonina

Summary The eggs recovered during faecal screening of Asiatic lions (kept at MC Zoological Park, Punjab, India) were delineated as Toxascaris leonina eggs based on morphometric and molecular studies (polymerase chain reaction targeting internal transcribed spacer sequences). Therapeutic management with fenbendazole @10 mg/kg body weight, once daily orally for three consecutive days proved ineffective with maximum faecal egg count reduction (FECR) on day 3 post treatments (69.35 %). But, therapeutic intervention with extended period dose schedule (5 consecutive days) with fenbendazole (@10 mg/kg body weight) proved effective and showed a maximum FECR of 95.34 % at day 7 post treatments. But, when ivermectin (@100μg/kg body weight) was given orally on three alternate days, proved effective as FECR of 95.74 % was recorded at day 7 post treatments. Thus, present study highlights the molecular confi rmation of T. leonina and its management using fenbendazole and ivermectin in Asiatic lions.

Biosynthesis of Gold Nanoparticles with Serratia marcescens Bacteria

2015 ◽  
Vol 1132 ◽  
pp. 19-35
Author(s):  
S.O. Dozie-Nwachukwu ◽  
J.D. Obayemi ◽  
Y. Danyo ◽  
G. Etuk-Udo ◽  
N. Anuku ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Serratia Marcescens ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Color Changes ◽  
Transmission Electron ◽  
Helium Ion ◽  
Ph Conditions ◽  
Uv Visible ◽  
Ion Microscopy

This paper presents the biosynthesis of gold nanoparticles from the bacteria, Serratia marcescens.The intra-and extra-cellular synthesis of gold nanoparticles is shown to occur over a range of pH and incubation times in cell-free exracts and biomass ofserratia marcescensthat were reacted with 2.5mM Tetrachloroauric acid (HAuCl4). The formation of gold nanoparticles was identified initially via color changes from yellow auro-chloride to shades of red or purple in gold nanoparticle solutions. UV-Visible spectroscopy (UV-Vis), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray spectroscopy (EDS), Helium Ion Microscopy (HIM) and Dynamic Light Scattering (DLS) were also used to characterize gold nanoparticles produced within a range of pH conditions. The results show clearly that the production of gold nanoparticles from cell-free extracts require shorter times than the production of gold nanoparticles from the biomass.

Synthesis and Characterization of Gold Nanoparticles Synthesized in Gel and Paper by Electrolysis

2019 ◽  
Vol 824 ◽  
pp. 163-167
Author(s):  
Pema Dechen ◽  
Ekasith Somsook
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Gold Nanoparticles ◽  
Room Temperature ◽  
Synthesis And Characterization ◽  
Visible Spectroscopy ◽  
Gold Leaf ◽  
Uv Visible ◽  
Scanning Electron

In this report, synthesis and characterization of gold nanoparticles (AuNPs) from gold leaf by electrolysis in two different media (gel and paper) in presence of sodium chloride (NaCl), glucose (C6H12O6) and polyvinyl pyrrolidone (PVP) at room temperature were investigated. Graphite was used as two electrodes, NaCl was used as an electrolyte, C6H12O6 was used as reducing agent and PVP was used as stabilizer to control the aggregation of the nanoparticles. UV-Visible spectroscopy (UV-Vis) and scanning electron microscopy (SEM) were used to confirm the characteristics and morphologies of the synthesized AuNPs.

scholarly journals Fabrication of Gold Nanochains with Octreotide Acetate Template

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Jing Zhou ◽  
Zhanzhao Fu ◽  
Dawei Gao ◽  
Faming Gao ◽  
Na Li ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Mtt Assay ◽  
Acidic Solution ◽  
Aqueous Environment ◽  
Amino Acid Residues ◽  
Octreotide Acetate ◽  
Transmission Electron ◽  
Gold Nanochains ◽  
Gold Nanostructure ◽  
Application Prospects

We described a facile method for assembly gold nanochains by using octreotide acetate as template in aqueous environment. In acidic solution, octreotide acetate was conferred positive charges and its structure changed to chain-like. The monodisperse negative gold nanoparticles were bound to the surface of octreotide acetate template by electrostatic attraction and the interaction of gold nanoparticles with amino acid residues (tryptophan and lysine). The fabricated gold nanostructure presented chain-like observed by transmission electron microscopy. The cytotoxicity of gold nanochains was examined by tetrazolium dye-based microtitration (MTT) assay, which demonstrated significantly less toxicity than that of octreotide acetate alone. The MTT assay also reflected the combinative action between the gold nanoparticles with octreotide acetate. Our work lays the groundwork for developing octreotide acetate-templated nanomaterials that can be used as a building block for the creation of nanomaterials. Meanwhile, the harmfulless gold nanochains have great application prospects in the biomedical filed.

Highly sensitive amperometric detection of bilirubin using enzyme and gold nanoparticles on sol–gel film modified electrode

Talanta ◽  
2011 ◽  
Vol 86 ◽  
pp. 400-407 ◽  
Author(s):  
Palanisamy Kannan ◽  
Hailan Chen ◽  
Victor Tswen-Wen Lee ◽  
Dong-Hwan Kim
Keyword(s):  
Gold Nanoparticles ◽  
Modified Electrode ◽  
Sol Gel ◽  
Amperometric Detection ◽  
Highly Sensitive ◽  
Gel Film
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