Gold nanoparticle-mediated signal amplification of liquid crystal biosensors for dopamine

The Analyst ◽  
2019 ◽  
Vol 144 (4) ◽  
pp. 1110-1114 ◽  
Author(s):  
Rajib Nandi ◽  
Lisha Loitongbam ◽  
Joydip De ◽  
Varsha Jain ◽  
Santanu Kumar Pal
Keyword(s):  
Gold Nanoparticles ◽  
Liquid Crystal ◽  
Gold Nanoparticle ◽  
Boronic Acid ◽  
Signal Amplification ◽  
Crystal Interface

A new design was developed for detection of dopamine using a boronic acid based amphiphile at aqueous–liquid crystal interface. The detection was highly enhanced in presence of gold nanoparticles.

scholarly journals Highly selective non-enzymatic electrochemical sensor based on a titanium dioxide nanowire–poly(3-aminophenyl boronic acid)–gold nanoparticle ternary nanocomposite

RSC Advances ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 2138-2147 ◽  
Author(s):  
N. Muthuchamy ◽  
A. Gopalan ◽  
Kwang-Pill Lee
Keyword(s):  
Gold Nanoparticles ◽  
Titanium Dioxide ◽  
Electrochemical Sensor ◽  
Gold Nanoparticle ◽  
Boronic Acid ◽  
Glucose Sensor ◽  
Ternary Nanocomposite

A highly selective and sensitive enzymeless electrochemical glucose sensor was fabricated based on a novel ternary nanocomposite composed of titanium dioxide nanowire, poly(3-aminophenyl boronic acid) and gold nanoparticles.

Contribution of gold nanoparticles to the catalytic DNA strand displacement in leakage reduction and signal amplification

2017 ◽  
Vol 53 (79) ◽  
pp. 10950-10953 ◽  
Author(s):  
Bei Wang ◽  
Xiang Zhou ◽  
Dongbao Yao ◽  
Xianbao Sun ◽  
Miao He ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Signal Amplification ◽  
Strand Displacement ◽  
New Model ◽  
Improve Efficiency ◽  
Leakage Reduction ◽  
Dna Strand Displacement ◽  
Displacement Reactions ◽  
Dna Strand

A new model using a gold nanoparticle (AuNP)–DNA system to constrain leakage and improve efficiency of catalytic toehold-mediated strand displacement reactions was outlined.

Interference of Gold Nanoparticles with In vitro Endotoxin Detection Assays

2020 ◽  
Vol 16 (2) ◽  
pp. 204-213 ◽  
Author(s):  
Melissa A. Vetten ◽  
Mary Gulumian
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Surface Reactivity ◽  
In Vitro Assays ◽  
Limulus Amebocyte Lysate ◽  
Chromogenic Assay ◽  
Nanoparticle Suspensions ◽  
Endotoxin Contamination ◽  
Factor C

Background: Endotoxin-free engineered nanoparticle suspensions are imperative for their successful applications in the field of nanomedicine as well as in the investigations in their toxicity. Gold nanoparticles are known to interfere with various in vitro assays due to their optical properties and potential for surface reactivity. In vitro endotoxin testing assays are known to be susceptible to interference caused by the sample being tested. Objective: This study aimed to identify a preferred assay for the testing of endotoxin contamination in gold nanoparticle suspensions. Methods: The interference by gold nanoparticles on three assays namely, the commonly used limulus amebocyte lysate chromogenic assay, the limulus amebocyte lysate gel-clot method, and the less common recombinant Factor C (rFC) assay, was tested. Results: Possible interference could be observed with all three assays. The interference with the absorbance- based chromogenic assay could not be overcome by dilution; whilst the qualitative nature of the gel-clot assay excluded the possibility of distinguishing between a false positive result due to enhancement of the sensitivity of the assay, and genuine endotoxin contamination. However, interference with the rFC assay was easily overcome through dilution. Conclusion: The rFC assay is recommended as an option for endotoxin contamination detection in gold nanoparticle suspensions.

scholarly journals CRISPR/Cas12a-mediated gold nanoparticle aggregation for colorimetric detection of SARS-CoV-2

2021 ◽  
Author(s):  
Yiren Cao ◽  
Jinjun Wu ◽  
Bo Pang ◽  
Hongquan Zhang ◽  
X. Chris Le
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Colorimetric Detection ◽  
Isothermal Amplification ◽  
Nanoparticle Aggregation ◽  
Cleavage Activity ◽  
Gold Nanoparticle Aggregation

The trans-cleavage activity of the target-activated CRISPR-Cas12a liberated an RNA crosslinker from a molecular transducer, which facilitated assembly of gold nanoparticles. Integration of the molecular transducer with isothermal amplification and...

scholarly journals Signal Amplification in an Optical and Dielectric Biosensor Employing Liquid Crystal-Photopolymer Composite as the Sensing Medium

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 81
Author(s):  
Hassanein Shaban ◽  
Shih-Chun Yen ◽  
Mon-Juan Lee ◽  
Wei Lee
Keyword(s):  
Dielectric Constant ◽  
Liquid Crystal ◽  
Uv Irradiation ◽  
Signal Amplification ◽  
Limit Of Detection ◽  
Optical Signal ◽  
Uv Exposure ◽  
Dielectric Anisotropy ◽  
Optical Texture ◽  
Potential Development

An optical and dielectric biosensor based on a liquid crystal (LC)–photopolymer composite was established in this study for the detection and quantitation of bovine serum albumin (BSA). When the nematic LC E7 was doped with 4-wt.% NOA65, a photo-curable prepolymer, and photopolymerized by UV irradiation at 20 mW/cm2 for 300 s, the limit of detection determined by image analysis of the LC optical texture and dielectric spectroscopic measurements was 3400 and 88 pg/mL for BSA, respectively, which were lower than those detected with E7 alone (10 μg/mL BSA). The photopolymerized NOA65, but not the prepolymer prior to UV exposure, contributed to the enhanced optical signal, and UV irradiation of pristine E7 in the absence of NOA65 had no effect on the optical texture. The effective tilt angle θ, calculated from the real-part dielectric constant ε’, decreased with increasing BSA concentration, providing strong evidence for the correlation of photopolymerized NOA65 to the intensified disruption in the vertically oriented LC molecules to enhance the optical and dielectric signals of BSA. The optical and dielectric anisotropy of LCs and the photo-curable dopant facilitate novel quantitative and signal amplification approaches to potential development of LC-based biosensors.

Fluorescence biosensor for Salmonella typhimurium detection in food based on nano-self-assembly of alendronic acid modified upconversion and gold nanoparticles

2021 ◽  
Author(s):  
Min Chen ◽  
Leiqing Pan ◽  
K. Tu
Keyword(s):  
Gold Nanoparticles ◽  
Salmonella Typhimurium ◽  
Gold Nanoparticle ◽  
Alendronic Acid ◽  
Self Assembly ◽  
Upconversion Nanoparticles ◽  
Fluorescent Biosensor ◽  
Fluorescence Biosensor

A simple and quick responsive fluorescent biosensor for Salmonella typhimurium detection based on the recognition of aptamer coupled with alendronic acid (ADA)@upconversion nanoparticles (UCNPs) and gold nanoparticle (AuNPs) has been...

scholarly journals Two helices from one chiral centre – self organization of disc shaped chiral nanoparticles

2021 ◽  
Author(s):  
Huanan Yu ◽  
Wentao Qu ◽  
Feng Liu ◽  
Georg H. Mehl
Keyword(s):  
Gold Nanoparticles ◽  
Liquid Crystal ◽  
Self Organization ◽  
Helix Formation ◽  
Chiral Nematic

Gold nanoparticles (NPs) were surface functionalized with hexanethiol groups and chiral nematic discogen ligands. A superlattice, liquid crystal behaviour and helix formation of the discs and a second helical organisation of the NPs were detected.

scholarly journals Enhanced Extracellular Synthesis of Gold Nanoparticles by Soluble Extracts from Escherichia coli Transformed with Rhizobium tropici Phytochelatin Synthase Gene

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 472
Author(s):  
Qunying Yuan ◽  
Manjula Bomma ◽  
Zhigang Xiao
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Synthesis Method ◽  
Nanoparticle Synthesis ◽  
Morphological Properties ◽  
Phytochelatin Synthase ◽  
Rhizobium Tropici ◽  
Whole Cells ◽  
E Coli ◽  
Recombinant Cells

Phytochelatins, the enzymatic products of phytochelatin synthase, play a principal role in protecting the plants from heavy metal and metalloid toxicity due to their ability to scavenge metal ions. In the present study, we investigated the capacity of soluble intracellular extracts from E. coli cells expressing R. tropici phytochelatin synthase to synthesize gold nanoparticle. We discovered that the reaction mediated by soluble extracts from the recombinant E. coli cells had a higher yield of gold nanoparticles, compared to that from the control cells. The compositional and morphological properties of the gold nanoparticles synthesized by the intracellular extracts from recombinant cells and control cells were similar. In addition, this extracellular nanoparticle synthesis method produced purer gold nanoparticles, avoiding the isolation of nanoparticles from cellular debris when whole cells are used to synthesize nanoparticles. Our results suggested that phytochelatins can improve the efficiency of gold nanoparticle synthesis mediated by bacterial soluble intracellular extracts, and the potential of extracellular nanoparticle synthesis platform for the production of nanoparticles in large quantity and pure form is worth further investigation.

A highly sensitive electrochemical microRNA-21 biosensor based on intercalating methylene blue signal amplification and a highly dispersed gold nanoparticles/graphene/polypyrrole composite

The Analyst ◽  
2021 ◽  
Vol 146 (8) ◽  
pp. 2679-2688
Author(s):  
Chammari Pothipor ◽  
Noppadol Aroonyadet ◽  
Suwussa Bamrungsap ◽  
Jaroon Jakmunee ◽  
Kontad Ounnunkad
Keyword(s):  
Methylene Blue ◽  
Gold Nanoparticles ◽  
Signal Amplification ◽  
Electrochemical Biosensor ◽  
Highly Sensitive ◽  
Highly Dispersed ◽  
Polypyrrole Composite ◽  
Amplification Strategy ◽  
Dispersed Gold ◽  
Potential Tool

An ultrasensitive electrochemical biosensor based on a gold nanoparticles/graphene/polypyrrole composite modified electrode and a signal amplification strategy employing methylene blue is developed as a potential tool for the detection of miRNA-21.

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