scholarly journals A Critical Factor for Quantifying Proteins in Unmodified Gold Nanoparticles-Based Aptasensing: The Effect of pH

Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 98
Author(s):  
Dai Lu ◽  
Dong Zhang ◽  
Qian Zhao ◽  
Xiangyang Lu ◽  
Xingbo Shi
Keyword(s):  
Gold Nanoparticles ◽  
Limit Of Detection ◽  
Protein Detection ◽  
Critical Factor ◽  
Cost Effective ◽  
Protein Corona ◽  
Target Protein ◽  
Universal Method ◽  
Salt Addition ◽  
Positively Charged

Unmodified gold nanoparticles (AuNPs)-based aptasensing (uGA) assay has been widely implemented in the determination of many different targets, but there are few reports on protein detection using uGA. Here, we designed a uGA assay for protein detection including the elimination of interfering proteins. Positively charged protein can be absorbed directly on the surface of AuNPs to form “protein corona”, which results in the aggregation of AuNPs even without salt addition, thereby preventing target protein detection. To overcome this problem, we systematically investigated the effect of modifying the pH of the solution during the uGA assay. A probe solution with a pH slightly higher than the isoelectric points (pI) of the target protein was optimal for protein detection in the uGA assay, allowing the aptamer to selectively detect the target protein. Three proteins (beta-lactoglobulin, lactoferrin, and lysozyme) with different pI were chosen as model proteins to validate our method. Positively charged interfering proteins (with pIs higher than the optimal pH) were removed by centrifugation of protein corona/AuNPs aggregates before the implementation of actual sample detection. Most importantly, the limit of detection (LOD) for all three model proteins was comparable to that of other methods, indicating the significance of modulating the pH. Moreover, choosing a suitable pH for a particular target protein was validated as a universal method, which is significant for developing a novel, simple, cost-effective uGA assay for protein detection.

scholarly journals All-Metal Terahertz Metamaterial Biosensor for Protein Detection

2021 ◽  
Author(s):  
Gangqi Wang ◽  
Fengjie Zhu ◽  
Tingting Lang ◽  
Jianjun Liu ◽  
Zhi Hong ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Refractive Index ◽  
Bovine Serum Albumin ◽  
Figure Of Merit ◽  
Limit Of Detection ◽  
Protein Detection ◽  
Cost Effective ◽  
Detection Sensitivity ◽  
Drilling Technology ◽  
Simulation Results

Abstract In this paper, a terahertz (THz) biosensor based on all-metal metamaterial is theoretically investigated and experimentally verified. This THz metamaterial biosensor uses stainless steel materials that are manufactured via laser-drilling technology. The simulation results show that the maximum refractive index (RI) sensitivity and the figure of merit (FOM) of this metamaterial sensor are 294.95 GHz/RIU and 4.03, respectively. Then, bovine serum albumin (BSA) was chosen as the detection substance to assess this biosensor’s effectiveness. The experiment results show that the detection sensitivity is 72.81 GHz/(ng/mm2) and the limit of detection (LOD) is 0.035 mg/mL. This THz metamaterial biosensor is simple, cost-effective, easy to fabricate, and have great potential in various biosensing applications.

scholarly journals Colorimetric detection of protein via the terminal protection of small-molecule-linked DNA and unmodified gold nanoparticles

RSC Advances ◽  
2018 ◽  
Vol 8 (68) ◽  
pp. 38758-38764
Author(s):  
Jianwei Zhao ◽  
Cuiping Li ◽  
Guimin Ma ◽  
Wenhui Hao ◽  
Hongxia Jia
Keyword(s):  
Gold Nanoparticles ◽  
Small Molecule ◽  
Colorimetric Detection ◽  
Protein Detection ◽  
Target Protein

A novel colorimetric strategy for protein detection was developed based on unmodified gold nanoparticles (AuNPs) and terminal protection from a target protein.

Vortex-Assisted Dispersive Liquid–Liquid Microextraction Coupled with Deproteinization for Determination of Nateglinide in Human Plasma Using HPLC/UV

2020 ◽  
Author(s):  
Mohamed A Hammad ◽  
Amira H Kamal ◽  
Reham E Kannouma ◽  
Fotouh R Mansour
Keyword(s):  
Human Plasma ◽  
High Performance ◽  
Limit Of Detection ◽  
Signal To Noise Ratio ◽  
Cost Effective ◽  
Salt Addition ◽  
Relative Standard ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

Abstract A validated method for preconcentration and determination of nateglinide in plasma was developed using vortex-assisted dispersive liquid–liquid microextraction. Different variables that affect extraction efficiency were studied and optimized, including type and volume of extractant, type and volume of disperser, pH of diluent, salt addition effect, centrifugation and vortex time. Nateglinide was extracted using 30 μL of 1-octanol as an extractant and 200 μL of methanol as a disperser. The enrichment factor reached 330 under the optimum conditions. High-performance liquid chromatography/ultraviolet was used for detection using phosphate buffer (pH 2.5, 10 mM): acetonitrile (45:55, v/v) as a mobile phase at a flow rate of 1 mL/min. The method was linear over the range of 50–20,000 ng/mL with a limit of detection of 15 ng/mL (signal-to-noise ratio = 3). Intra- and inter-day precision had %relative standard deviation <6% (n = 3) and the %recoveries were found to be between 102.5 and 105.9%. The proposed method is simple, sensitive, eco-friendly, cost-effective and powerful for microextraction of nateglinide from human plasma samples.

Colorimetric Sensing of Methyl Parathion Using Nanozymatic Activity of Gold Nanoparticles

2020 ◽  
Vol 12 (2) ◽  
pp. 232-241
Author(s):  
Anjana Pandey ◽  
Saumya Srivastava ◽  
Gayatri ◽  
Priya Rai ◽  
Ashutosh Pandey
Keyword(s):  
Gold Nanoparticles ◽  
Methyl Parathion ◽  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Cost Effective ◽  
Colorimetric Sensing ◽  
Electron Transfer Mechanism ◽  
Au Nps ◽  
New Approach ◽  
Cost Effective Technique

In this study, we have used new approach for detection of the methyl parathion residues i.e., by inhibiting half of the peroxidase-like activity of gold nanoparticles. We have investigated the peroxidase like activity of gold nanoparticles by colorimetric assay and optimized the pH, temperature, incubation time and different concentrations of H2O2 by using TMB as substrate as well as organophosphates effect on their enzyme mimetic activity. Kinetic study of gold nanoparticles has shown better catalytic activity than horseradish peroxidase at pH 3.5. The peroxidase substrate TMB (3,3,5,5-tetramethylbenzidine) can be oxidized by H2O2 by the enzymatic action of the gold nanoparticles resulting in a blue-coloured product, oxidized TMB. The principle involved behind the inhibition of enzymatic activity of nanozyme is due to hindrance of electron transfer mechanism TMB-H2O2-Au NPs system by the methyl parathion. The peroxidase activity is selectively reduced with increasing methyl parathion concentration. This sensing method has lowest limit of detection of 78.95 nM. This study can be used for development of sensitive and cost effective technique for sensing of harmful pesticides.

scholarly journals 3D-printed microfluidics integrated with optical nanostructured porous aptasensors for protein detection

2021 ◽  
Vol 188 (3) ◽  
Author(s):  
Sofia Arshavsky-Graham ◽  
Anton Enders ◽  
Shanny Ackerman ◽  
Janina Bahnemann ◽  
Ester Segal
Keyword(s):  
Limit Of Detection ◽  
Protein Detection ◽  
Target Protein ◽  
Superior Performance ◽  
Generic Model ◽  
Label Free ◽  
Uv Curable ◽  
Microfluidic Platform ◽  
Label Free Detection ◽  
3D Printed

AbstractMicrofluidic integration of biosensors enables improved biosensing performance and sophisticated lab-on-a-chip platform design for numerous applications. While soft lithography and polydimethylsiloxane (PDMS)-based microfluidics are still considered the gold standard, 3D-printing has emerged as a promising fabrication alternative for microfluidic systems. Herein, a 3D-printed polyacrylate-based microfluidic platform is integrated for the first time with a label-free porous silicon (PSi)–based optical aptasensor via a facile bonding method. The latter utilizes a UV-curable adhesive as an intermediate layer, while preserving the delicate nanostructure of the porous regions within the microchannels. As a proof-of-concept, a generic model aptasensor for label-free detection of his-tagged proteins is constructed, characterized, and compared to non-microfluidic and PDMS-based microfluidic setups. Detection of the target protein is carried out by real-time monitoring reflectivity changes of the PSi, induced by the target binding to the immobilized aptamers within the porous nanostructure. The microfluidic integrated aptasensor has been successfully used for detection of a model target protein, in the range 0.25 to 18 μM, with a good selectivity and an improved limit of detection, when compared to a non-microfluidic biosensing platform (0.04 μM vs. 2.7 μM, respectively). Furthermore, a superior performance of the 3D-printed microfluidic aptasensor is obtained, compared to a conventional PDMS-based microfluidic platform with similar dimensions. Graphical abstract

scholarly journals Fabrication of Carbon Disulfide Added Colloidal Gold Colorimetric Sensor for the Rapid and On-Site Detection of Biogenic Amines

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1738
Author(s):  
Namhyeok Choi ◽  
Bumjun Park ◽  
Min Ji Lee ◽  
Reddicherla Umapathi ◽  
Seo Yeong Oh ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Biogenic Amines ◽  
Carbon Disulfide ◽  
Colloidal Gold ◽  
Limit Of Detection ◽  
Morphological Changes ◽  
Cost Effective ◽  
Colorimetric Sensor ◽  
Single Time ◽  
Colloidal Gold Nanoparticles

Meat is often wasted due to the perceived concerns of its shelf life and preservation. Specifically, in meat formation, biogenic amines (BAs) are the major agents to spoil them. Herein, we have developed a carbon disulfide (CS2) added colloidal gold nanoparticles-based colorimetric sensor for the rapid and on-site detection of biogenic amines. Transmission electron microscopy is used to observe the morphological changes in colloidal gold nanoparticles and aggregation behavior of CS2 added to the colloidal gold nanoparticles’ solution. Raman spectroscopic analysis is further used to characterize the peaks of CS2, Cad and CS2-Cad molecules. Absorption spectroscopy is used to estimate the colorimetric differences and diffuse reflectance spectra of the samples. The sensing analysis is performed systematically in the presence and absence of CS2. CS2 added colloidal gold nanoparticles colorimetric sensor detected the BAs with a limit of detection (LOD) value of 50.00 µM. Furthermore, the developed sensor has shown an LOD of 50.00 µM for the detection of multiple BAs at a single time. The observed differences in the colorimetric and absorption signals indicate that the structure of BAs is converted to the dithiocarbamate (DTC)-BA molecule, due to the chemical reactions between the amine groups of BAs and CS2. Significantly, the developed colorimetric sensor offers distinct features such as facile fabrication approach, on-site sensing strategy, rapid analysis, visual detection, cost-effective, possibility of mass production, availability to detect multiple BAs at a single time and appreciable sensitivity. The developed sensor can be effectively used as a promising and alternative on-site tool for the estimation of BAs.

scholarly journals Revealing the Nanoparticle-Protein Corona with a Solid-State Nanopore

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3524 ◽  
Author(s):  
Diego Coglitore ◽  
Pierre Eugene Coulon ◽  
Jean-Marc Janot ◽  
Sébastien Balme
Keyword(s):  
Gold Nanoparticles ◽  
Solid State ◽  
Protein Adsorption ◽  
Internal Energy ◽  
Colloidal Stability ◽  
Protein Corona ◽  
Intrinsic Properties ◽  
Colloidal Properties ◽  
Salt Addition ◽  
Structural Category

Protein adsorption at the liquid–solid interface is an old but not totally solved topic. One challenge is to find an easy way to characterize the protein behavior on nanoparticles and make a correlation with its intrinsic properties. This work aims to investigate protein adsorption on gold nanoparticles and the colloidal properties. The protein panel was chosen from different structural categories (mainly-α, mainly-β or mix-αβ). The result shows that the colloidal stability with salt addition does not depend on the structural category. Conversely, using the single nanopore technique, we show that the mainly-α proteins form a smaller corona than the mainly-β proteins. We assign these observations to the lower internal energy of α-helices, making them more prone to form a homogeneous corona layer.

scholarly journals Facile Synthesis of Triangular and Hexagonal Anionic Gold Nanoparticles and Evaluation of Their Cytotoxicity

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1774 ◽  
Author(s):  
R. M. Tripathi ◽  
Sun-Young Yoon ◽  
Dohee Ahn ◽  
Sang J. Chung
Keyword(s):  
Gold Nanoparticles ◽  
Cellular Uptake ◽  
Cost Effective ◽  
Facile Synthesis ◽  
Cytotoxic Effects ◽  
X Ray ◽  
Transmission Electron ◽  
Environmentally Friendly Method ◽  
Positively Charged ◽  
Cellular Uptake Efficiency

Comprehension of the shape-dependent properties of gold nanoparticles (AuNPs) could benefit the advancements in cellular uptake efficiency. Spherical AuNPs have generally been used for drug delivery, and recent research has indicated that the cellular uptake of triangular AuNPs was higher than that of spherical ones. Previous reports have also revealed that chemically synthesized AuNPs were cytotoxic. Therefore, we have developed a facile, cost-effective, and environmentally friendly method for synthesizing triangular and hexagonal anionic AuNPs. The zeta potential of the synthesized AuNPs was negative, which indicated that their surface could be easily functionalized with positively charged molecules to upload drugs or biomolecules. Transmission electron microscopy (TEM) images illustrated that the largest particle size of the synthesized quasi-hexagonal AuNPs was 61 nm. The TEM images also illustrated that two types of equilateral-triangular AuNPs were synthesized: One featured sharp and the other rounded corners. The sides of the smallest and largest triangular AuNPs were 23 and 178 nm, respectively. Energy-dispersive X-ray spectra of the green-synthesized AuNPs indicated that they consisted entirely of elemental Au. The cytotoxicity of the green-synthesized AuNPs was evaluated using 3T3-L1 adipocytes. Using cell viability data, we determined that the green-synthesized AuNPs did not exhibit any cytotoxic effects on 3T3-L1 adipocytes.

scholarly journals All-metal terahertz metamaterial biosensor for protein detection

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Gangqi Wang ◽  
Fengjie Zhu ◽  
Tingting Lang ◽  
Jianjun Liu ◽  
Zhi Hong ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Figure Of Merit ◽  
Limit Of Detection ◽  
Protein Detection ◽  
Cost Effective ◽  
Detection Sensitivity ◽  
Refractive Index Sensitivity ◽  
Drilling Technology ◽  
Simulation Results ◽  
Index Sensitivity

AbstractIn this paper, a terahertz (THz) biosensor based on all-metal metamaterial is theoretically investigated and experimentally verified. This THz metamaterial biosensor uses stainless steel materials that are manufactured via laser-drilling technology. The simulation results show that the maximum refractive index sensitivity and the figure of merit of this metamaterial sensor are 294.95 GHz/RIU and 4.03, respectively. Then, bovine serum albumin was chosen as the detection substance to assess this biosensor’s effectiveness. The experiment results show that the detection sensitivity is 72.81 GHz/(ng/mm2) and the limit of detection is 0.035 mg/mL. This THz metamaterial biosensor is simple, cost-effective, easy to fabricate, and has great potential in various biosensing applications.

Target protein induced cleavage of a specific peptide for prostate-specific antigen detection with positively charged gold nanoparticles as signal enhancer

2015 ◽  
Vol 51 (52) ◽  
pp. 10521-10523 ◽  
Author(s):  
Ding Wang ◽  
Yingning Zheng ◽  
Yaqin Chai ◽  
Yali Yuan ◽  
Ruo Yuan
Keyword(s):  
Gold Nanoparticles ◽  
Prostate Specific Antigen ◽  
Electrochemical Biosensor ◽  
Specific Antigen ◽  
Antigen Detection ◽  
Target Protein ◽  
Positively Charged Gold Nanoparticles ◽  
Specific Peptide ◽  
Positively Charged

A “signal-on” electrochemical biosensor based on target protein induced cleavage of a specific peptide with positively charged gold nanoparticles (AuNPs) as signal enhancer was developed to determine prostate-specific antigen (PSA).

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