scholarly journals Ultrasensitive dynamic light scattering immunosensing platform for NT-proBNP detection using boronate affinity amplification

2022 ◽  
Vol 20 (1) ◽  
Author(s):  
Jiaqi Hu ◽  
Lu Ding ◽  
Jing Chen ◽  
Jinhua Fu ◽  
Kang Zhu ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Phenylboronic Acid ◽  
Crosslinking Agent ◽  
Fast Response ◽  
Small Sample ◽  
Complex Samples ◽  
Promising Application

AbstractHerein, we reported a new dynamic light scattering (DLS) immunosensing technology for the rapid and sensitive detection of glycoprotein N-terminal pro-brain natriuretic peptide (NT-proBNP). In this design, the boronate affinity recognition based on the interaction of boronic acid ligands and cis-diols was introduced to amplify the nanoparticle aggregation to enable highly sensitive DLS transduction, thereby lowering the limit of detection (LOD) of the methodology. After covalently coupling with antibodies, magnetic nanoparticles (MNPs) were employed as the nanoprobes to selectively capture trace amount of NT-proBNP from complex samples and facilitate DLS signal transduction. Meanwhile, silica nanoparticles modified with phenylboronic acid (SiO2@PBA) were designed as the crosslinking agent to bridge the aggregation of MNPs in the presence of target NT-proBNP. Owing to the multivalent and fast affinity recognition between NT-proBNP containing cis-diols and SiO2@PBA, the developed DLS immunosensor exhibited charming advantages over traditional immunoassays, including ultrahigh sensitivity with an LOD of 7.4 fg mL−1, fast response time (< 20 min), and small sample consumption (1 μL). The DLS immunosensor was further characterized with good selectivity, accuracy, precision, reproducibility, and practicability. Collectively, this work demonstrated the promising application of the designed boronate affinity amplified-DLS immunosensor for field or point-of-care testing of cis-diol-containing molecules. Graphical Abstract

scholarly journals Demonstration of a Label-Free and Low-Cost Optical Cavity-Based Biosensor Using Streptavidin and C-Reactive Protein

Biosensors ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Donggee Rho ◽  
Seunghyun Kim
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Optical Cavity ◽  
Sample Volume ◽  
Small Sample ◽  
Label Free ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Cavity Structure

An optical cavity-based biosensor (OCB) has been developed for point-of-care (POC) applications. This label-free biosensor employs low-cost components and simple fabrication processes to lower the overall cost while achieving high sensitivity using a differential detection method. To experimentally demonstrate its limit of detection (LOD), we conducted biosensing experiments with streptavidin and C-reactive protein (CRP). The optical cavity structure was optimized further for better sensitivity and easier fluid control. We utilized the polymer swelling property to fine-tune the optical cavity width, which significantly improved the success rate to produce measurable samples. Four different concentrations of streptavidin were tested in triplicate, and the LOD of the OCB was determined to be 1.35 nM. The OCB also successfully detected three different concentrations of human CRP using biotinylated CRP antibody. The LOD for CRP detection was 377 pM. All measurements were done using a small sample volume of 15 µL within 30 min. By reducing the sensing area, improving the functionalization and passivation processes, and increasing the sample volume, the LOD of the OCB are estimated to be reduced further to the femto-molar range. Overall, the demonstrated capability of the OCB in the present work shows great potential to be used as a promising POC biosensor.

scholarly journals Ag nanoparticles outperform Au nanoparticles for the use as label in electrochemical point-of-care sensors

2021 ◽  
Author(s):  
Franziska Beck ◽  
Carina Horn ◽  
Antje J. Baeumner
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Automatic Measurement ◽  
High Sensitivity ◽  
Differential Pulse ◽  
Small Sample ◽  
Blood Protein ◽  
User Friendliness ◽  
Response Curves ◽  
Assay Protocol

AbstractElectrochemical immunosensors enable rapid analyte quantification in small sample volumes, and have been demonstrated to provide high sensitivity and selectivity, simple miniaturization, and easy sensor production strategies. As a point-of-care (POC) format, user-friendliness is equally important and most often not combinable with high sensitivity. As such, we demonstrate here that a sequence of metal oxidation and reduction, followed by stripping via differential pulse voltammetry (DPV), provides lowest limits of detection within a 2-min automatic measurement. In exchanging gold nanoparticles (AuNPs), which dominate in the development of POC sensors, with silver nanoparticles (AgNPs), not only better sensitivity was obtained, but more importantly, the assay protocol could be simplified to match POC requirements. Specifically, we studied both nanoparticles as reporter labels in a sandwich immunoassay with the blood protein biomarker NT-proBNP. For both kinds of nanoparticles, the dose-response curves easily covered the ng∙mL−1 range. The mean standard deviation of all measurements of 17% (n ≥ 4) and a limit of detection of 26 ng∙mL−1 were achieved using AuNPs, but their detection requires addition of HCl, which is impossible in a POC format. In contrast, since AgNPs are electrochemically less stable, they enabled a simplified assay protocol and provided even lower LODs of 4.0 ng∙mL−1 in buffer and 4.7 ng∙mL−1 in human serum while maintaining the same or even better assay reliability, storage stability, and easy antibody immobilization protocols. Thus, in direct comparison, AgNPs clearly outperform AuNPs in desirable POC electrochemical assays and should gain much more attention in the future development of such biosensors.

scholarly journals Reference materials for optic nanosensor systems: reduced glutathione and chloramphenicol

2021 ◽  
Vol 17 (1) ◽  
pp. 59-69
Author(s):  
A. A. Yushina ◽  
M. K. Alenichev
Keyword(s):  
Light Scattering ◽  
Reference Material ◽  
Dynamic Light Scattering ◽  
Reference Materials ◽  
Reduced Glutathione ◽  
Point Of Care ◽  
Sampling Site ◽  
Coverage Factor ◽  
Expanded Uncertainty ◽  
Certified Value

The research provides enterprise reference material (ERM) development approach for nanosensor system on the basis of dynamic light scattering and fluorescence for qualitative and quantitative determination of nutrition pollutant - chloramphenicol antibiotic (laevomycetin), as well as marker of ischaemic stroke and a number of other diseases - reduced glutathione.ERM candidate materials were chosen chloramphenicol and reduced glutathione. The attestation procedure based on calculating-experimental approach by preparation procedure was used to determine the certified value of ERM. During the tests there were determined metrological characteristics of reference material. The certified value of ERM for reduced glutathione mass fraction is 98,5 %, the expanded uncertainty of certified value with coverage factor k=2 is ± 0,3 %. The certified value of ERM for chloramphenicol mass concentration is 10,0 g/dm3, the expanded uncertainty of certified value with coverage factor k = 2 is ± 4,0 %.The implementation of the developed ERMs showed their appropriateness for optic nanosensor systems calibration on the base of dynamic light scattering and fluorescence.We suppose that the developed enterprise reference materials further may be certified as CRM (certified reference material) and used for verification, calibration and graduation of compact detection devices of the «point of care diagnostics» type under development, which are intended for express analysis on the sampling site directly.

scholarly journals Dynamic Light Scattering Microrheology for Soft and Living Materials

Soft Matter ◽  
2021 ◽  
Author(s):  
Pamela C Cai ◽  
Brad A Krajina ◽  
Michael J Kratochvil ◽  
Lei Zou ◽  
Audrey Zhu ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Soft Materials ◽  
Single Scattering ◽  
Sample Volume ◽  
Small Sample ◽  
Viscoelastic Moduli ◽  
Small Sample Volume ◽  
Living Materials

We present a method for using dynamic light scattering in the single-scattering limit to measure the viscoelastic moduli of soft materials. This microrheology technique only requires a small sample volume...

scholarly journals Synthesis Luminescent Plasmonic Silver Nanoparticles and The Chemical Affinity towards sulphur atom in Sulphide and Thiourea molecules: Ab-Initio DFT Study

2021 ◽  
Author(s):  
Esam Bakir ◽  
Ranjith Kumar Karnati
Keyword(s):  
Silver Nanoparticles ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Limit Of Detection ◽  
Chemical Affinity ◽  
Sodium Sulphide ◽  
Sulphur Atom ◽  
Computational Calculations ◽  
Simple Reduction ◽  
Scanning Electron

Abstract Three different luminescent silver nanoparticles(AgNPs) were synthesized by simple reduction method with the different mole ratios of L-ascorbic/citrate solution and stabilized with CTAB. The prepared three AgNPs were characterized by UV, fluorescence, FTIR, dynamic light scattering measurements and Scanning Electron Microscopy. The plasmon bands of AgNPs- reddish-brown (RB), green (G) and reddish-green (RG) were centered at 565, 587 and 592 nm, respectively. The highly luminescence emission was observed for AgNPs(G). The size diameters of the prepared AgNPs-G, RG and (RB) were measured by dynamic light scattering (DLS) method at 24.3 nm, 66.28 nm and 103.46 nm, respectively. The electrochemical properties of AgNPs-RG was recorded the oxidative part of AgNPs into Ag+ at +0.23 V and the reduction part of Ag+ into Ag0 was recorded at -0.49 V vs. Ag/AgCl). Cetyl trimethylammonium bromide (CTAB) was stabilized AgNPs(RG) which recorded in infrared and scanning electron microscope measurements. The concentration of thiourea, sodium sulphide was detected by the electrochemical sensitivity of AgNPs(RG)-CTAB. A calibration curve between electrochemical sensitivity of AgNPs-CTAB vs concentration of sulphur molecule. The limit of detection (LOD) was founded 2.10 and 1.90 µmole L-1 of sodium sulphide and thiourea, respectively (R2=0.94, n=3). The computational calculations are used to illustrated the chemical affinity of sulphur atom in sodium sulphide or thiourea towards AgNPs(RG).

A Highly Sensitive Integrated a-Si:H Fluorescence Detector for Microfluidic Devices

2010 ◽  
Vol 1245 ◽  
Author(s):  
Toshihiro Kamei ◽  
Amane Shikanai
Keyword(s):  
Light Scattering ◽  
High Speed ◽  
Laser Light ◽  
Separation Efficiency ◽  
Limit Of Detection ◽  
Point Of Care ◽  
High Sensitivity ◽  
Laser Light Scattering ◽  
Fluorescent Labeling ◽  
Fluorescence Detector

AbstractMost of micromachined and/or integrated fluorescence detectors suffer from high limit of detection (LOD) compared to conventional optical system that consists of discrete optical components, which is mainly due to higher laser light scattering of integrated optics rather than detector sensitivity. In this work, we have reduced background (BG) photocurrent of an integrated hydrogenated amorphous Si (a-Si:H) fluorescence detector due to laser light scattering by nearly one order magnitude, significantly improving a LOD. The detection platform comprises a microlens and the annular fluorescence detector where a thick SiO2/Ta2O5 multilayer optical interference filter (>6 μm) is monolithically integrated on an a-Si:H pin photodiode. With a microfluidic capillary electrophoresis (CE) device mounted on the platform, the system is demonstrated to separate DNA restriction fragment digests (LOD: 58 pg/μL) as well as 2 nM of fluorescein-labeled oligomer (LOD: 240 pM) with high speed, high sensitivity and high separation efficiency. The integrated a-Si:H fluorescence detector exhibits high sensitivity for practical fluorescent labeling dyes as well as feasibility of monolithic integration with a laser diode, making it ideal for application to point-of-care microfluidic biochemical analysis.

Dynamic light scattering from gels in a poor solvent

1978 ◽  
Vol 39 (9) ◽  
pp. 955-960 ◽  
Author(s):  
E. Geissler ◽  
A.M. Hecht
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Poor Solvent
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