scholarly journals Label-Free and Highly-Sensitive Detection of Ochratoxin A Using One-Pot Synthesized Reduced Graphene Oxide/Gold Nanoparticles-Based Impedimetric Aptasensor

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 87
Author(s):  
Yasmin Alhamoud ◽  
Yingying Li ◽  
Haibo Zhou ◽  
Ragwa Al-Wazer ◽  
Yiying Gong ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Ochratoxin A ◽  
Fetal Malformation ◽  
Label Free ◽  
One Pot ◽  
Au Nps ◽  
Reduced Graphene ◽  
Relative Standard

Ochratoxin A (OTA) primarily obtained by the genera aspergillus and penicillium, is one of the toxic substances for different organs and systems of the human body such as the kidney, liver, neurons and the immune system. Moreover, it is considered to cause tumors and fetal malformation even at a very low concentration. Fast and sensitive assay for detection of OTA at ultralow levels in foods and agricultural products has been an increasing demand. In this study, a new label-free electrochemical biosensor based on three-dimensional reduced graphene oxide/gold nanoparticles/aptamer for OTA detection was constructed. The 3D-rGO/Au NPs nanocomposites were firstly synthesized using a one-pot hydrothermal process under optimized experimental conditions. The 3D-rGO/Au NPs with considerable particular surface area and outstanding electrical conductivity was then coated on a glass carbon electrode to provide tremendous binding sites for -SH modified aptamer via the distinctive Au–S linkage. The presence of OTA was specifically captured by aptamer and resulted in electrochemical impedance spectroscopy (EIS) signal response accordingly. The constructed impedimetric aptasensor obtained a broad linear response from 1 pg/mL to 10 ng/mL with an LOD of 0.34 pg/mL toward OTA detection, highlighting the excellent sensitivity. Satisfactory reproducibility was also achieved with the relative standard deviation (RSD) of 1.393%. Moreover, the proposed aptasensor obtained a good recovery of OTA detection in red wine samples within the range of 93.14 to 112.75% along with a low LOD of 0.023 ng/mL, indicating its applicability for OTA detection in real samples along with economical, specific, susceptible, fast, easy, and transportable merits.

Decoration of Plasma-Reduced Graphene Oxide with Uniform Gold Nanoparticles and their Redox Reaction Performance

2016 ◽  
Vol 701 ◽  
pp. 47-51
Author(s):  
Khairul Anuar Wahid ◽  
M.A.S.M. Haniff ◽  
M. Ismahadi ◽  
Ishak Abdul Azid
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Effective Area ◽  
Au Nps ◽  
Sensor Platform ◽  
Reduced Graphene ◽  
Reaction Performance ◽  
Average Size ◽  
Defective Sites

This paper reports a method to enhance the electro-activity on screen printing carbon electrode (SPCE) for electrochemical sensor platform application. The method to forming uniform gold nanoparticles on reduced graphene oxide and SPCE (Au-Nps/rGO/SPCE) based on plasma-enhanced CVD process has been investigated. The results demonstrated that the Au-NPs with high density and uniform sizes were successfully introduced via CVD process where the average size and thickness are 15.9+10nm and 2.18+0.4nm respectively. A high ID/IG ratio for Au-NPs/rGO is 1.01 which 44% higher compared to GO ID/IG ratio was observed in the Raman spectrum suggesting more defective sites on the surface of Au NPS/rGO. The redox performance of Au-NPs/rGO/SPCE has also been measured and compared with rGO/SPCE and the results shown that rGO decorated with Au-NPs has a highest redox current. The peak currents of Au-NPs/rGO are significantly increased compared to the bare SPCE with increment from 0.05mA to 0.14mA. This result is proportional with the effective surface area for SPCE that has been decorated with Au-NPs/rGO where the effective area is increased from 0.126cm2 to 0.166cm2. The peak potential at 0.01V which was found to shift up to 0.4V as the scan rate increases suggested that reaction is electrochemically reversible.

Gold nanoparticles and reduced graphene oxide-amplified label-free DNA biosensor for dasatinib detection

2018 ◽  
Vol 42 (19) ◽  
pp. 16378-16383 ◽  
Author(s):  
Fahimeh Tahernejad-Javazmi ◽  
Mehdi Shabani-Nooshabadi ◽  
Hassan Karimi-Maleh
Keyword(s):  
Prostate Cancer ◽  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Adverse Effects ◽  
Reduced Graphene Oxide ◽  
The Other ◽  
Myelogenous Leukemia ◽  
Label Free ◽  
Free Dna ◽  
Reduced Graphene

Dasatinib or sprycel is an anticancer drug for treatment of chronic myelogenous leukemia, prostate cancer, and some of the other cancers with several adverse effects.

scholarly journals A Bifunctional Nanosilver-Reduced Graphene Oxide Nanocomposite for Label-Free Electrochemical Immunosensing

2021 ◽  
Vol 9 ◽  
Author(s):  
Supakeit Chanarsa ◽  
Jaroon Jakmunee ◽  
Kontad Ounnunkad
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Limit Of Detection ◽  
Electrochemical Immunosensor ◽  
Label Free ◽  
One Pot ◽  
Reduced Graphene ◽  
Sensitivity And Selectivity ◽  
Analytical Response ◽  
Electrochemical Immunosensing

A bi-functional material based on silver nanoparticles (AgNPs)-reduced graphene oxide (rGO) composite for both electrode modification and signal generation is successfully synthesized for use in the construction of a label-free electrochemical immunosensor. An AgNPs/rGO nanocomposite is prepared by a one-pot wet chemical process. The AgNPs/rGO composite dispersion is simply cast on a screen-printed carbon electrode (SPCE) to fabricate the electrochemical immunosensor. It possesses a sufficient conductivity/electroreactivity and improves the electrode reactivity of SPCE. Moreover, the material can generate an analytical response due to the formation of immunocomplexes for detection of human immunoglobulin G (IgG), a model biomarker. Based on electrochemical stripping of AgNPs, the material reveals signal amplification without external redox molecules/probes. Under optimized conditions, the square wave voltammetric peak current is responded to the logarithm of IgG concentration in two wide linear ranges from 1 to 50 pg.ml−1 and 0.05 to 50 ng.ml−1, and the limit of detection (LOD) is estimated to be 0.86 pg.ml−1. The proposed immunosensor displays satisfactory sensitivity and selectivity. Importantly, detection of IgG in human serum using the immunosensor shows satisfactory accuracy, suggesting that the immunosensor possesses a huge potential for further development in clinical diagnosis.

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