Numerical Modelling of the Optical Properties of Plasmonic and Latex Nanoparticles to Improve the Detection Limit of Immuno-Turbidimetric Assays

Turbidimetric assays with latex nanoparticles are widely applied for the detection of biological analytes, because of their rapidity, low cost, reproducibility, and automatization. However, the detection limit can be lowered only at the price of a reduced dynamic range, due to the rapid saturation of the light scattering signal at high analyte concentration. Here, we use numerical calculations to investigate the possibility of increasing the performance of immuno-turbidimetric assays without compromising the measurement dynamic range, by combining plasmonic (gold, silver) and latex nanoparticles. Our modelling results show that plasmonic nanoparticles are compatible with a large signal change even when small aggregates are formed, i.e., at low analyte concentration. The working principle relies on the remarkable modification of the surface plasmon band when noble metal nanoparticles form oligomers, and also when latex particles are included in the aggregate. At high analyte concentration, when larger aggregates form, the latex particles can provide the required linear response of standard immuno-turbidimetric assays. Thus, the combination of the two components can be a successful strategy to improve the detection limit and the dynamic range, while maintaining all the advantages of the homogeneous immuno-turbidimetric assays.

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A simple method to construct a low-cost immunosensor based on a dithiol-functionalized polydopamine platform

New Journal of Chemistry ◽

10.1039/d0nj06241c ◽

2021 ◽

Author(s):

Bo Liu ◽

Luanying Yang ◽

Gang Wang ◽

Sha He ◽

Xiaobo Wang ◽

...

Keyword(s):

Detection Limit ◽

Linear Response ◽

Low Cost ◽

Covalent Immobilization ◽

The Self ◽

Simple Method ◽

Low Detection Limit

A simple and low-cost electrochemical CEA immunosensor was investigated via the self-polymerization of dopamine and a dithiol compound spacer for the covalent immobilization of antibodies. The designed CEA immunosensor exhibited a linear response and a low detection limit.

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A tandem giant magnetoresistance assay for one-shot quantification of clinically relevant concentrations of N-terminal pro-B-type natriuretic peptide in human blood

Analytical and Bioanalytical Chemistry ◽

10.1007/s00216-021-03227-5 ◽

2021 ◽

Author(s):

Fanda Meng ◽

Weisong Huo ◽

Jie Lian ◽

Lei Zhang ◽

Xizeng Shi ◽

...

Keyword(s):

Detection Limit ◽

Giant Magnetoresistance ◽

Dynamic Range ◽

Point Of Care ◽

Sample Volume ◽

Small Sample ◽

Broad Dynamic Range ◽

Gmr Sensors ◽

Gmr Sensor ◽

Sample Volume Requirement

AbstractWe report a microfluidic sandwich immunoassay constructed around a dual-giant magnetoresistance (GMR) sensor array to quantify the heart failure biomarker NT-proBNP in human plasma at the clinically relevant concentration levels between 15 pg/mL and 40 ng/mL. The broad dynamic range was achieved by differential coating of two identical GMR sensors operated in tandem, and combining two standard curves. The detection limit was determined as 5 pg/mL. The assay, involving 53 plasma samples from patients with different cardiovascular diseases, was validated against the Roche Cobas e411 analyzer. The salient features of this system are its wide concentration range, low detection limit, small sample volume requirement (50 μL), and the need for a short measurement time of 15 min, making it a prospective candidate for practical use in point of care analysis.

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Gold, Silver, and Electrum Electroless Plating on Additively Manufactured Laser Powder-Bed Fusion AlSi10Mg Parts: A Review

Coatings ◽

10.3390/coatings11040422 ◽

2021 ◽

Vol 11 (4) ◽

pp. 422

Author(s):

Dana Ashkenazi ◽

Alexandra Inberg ◽

Yosi Shacham-Diamand ◽

Adin Stern

Keyword(s):

Additive Manufacturing ◽

Low Cost ◽

Ion Beam ◽

Surface Finishing ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

Finishing Process ◽

Gold Silver ◽

3D Printed

Additive manufacturing (AM) revolutionary technologies open new opportunities and challenges. They allow low-cost manufacturing of parts with complex geometries and short time-to-market of products that can be exclusively customized. Additive manufactured parts often need post-printing surface modification. This study aims to review novel environmental-friendly surface finishing process of 3D-printed AlSi10Mg parts by electroless deposition of gold, silver, and gold–silver alloy (e.g., electrum) and to propose a full process methodology suitable for effective metallization. This deposition technique is simple and low cost method, allowing the metallization of both conductive and insulating materials. The AlSi10Mg parts were produced by the additive manufacturing laser powder bed fusion (AM-LPBF) process. Gold, silver, and their alloys were chosen as coatings due to their esthetic appearance, good corrosion resistance, and excellent electrical and thermal conductivity. The metals were deposited on 3D-printed disk-shaped specimens at 80 and 90 °C using a dedicated surface activation method where special functionalization of the printed AlSi10Mg was performed to assure a uniform catalytic surface yielding a good adhesion of the deposited metal to the substrate. Various methods were used to examine the coating quality, including light microscopy, optical profilometry, XRD, X-ray fluorescence, SEM–energy-dispersive spectroscopy (EDS), focused ion beam (FIB)-SEM, and XPS analyses. The results indicate that the developed coatings yield satisfactory quality, and the suggested surface finishing process can be used for many AM products and applications.

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New Compact Wearable Metamaterials Circular Patch Antennas for IoT, Medical and 5G Applications

Applied System Innovation ◽

10.3390/asi3040042 ◽

2020 ◽

Vol 3 (4) ◽

pp. 42

Author(s):

Albert Sabban

Keyword(s):

Communication Systems ◽

Dynamic Range ◽

Low Cost ◽

Patch Antennas ◽

Antenna Feed ◽

Circular Patch ◽

Wearable Antenna ◽

Wearable Antennas ◽

Feed Network ◽

Line Design

The development of compact passive and active wearable circular patch metamaterials antennas for communication, Internet of Things (IoT) and biomedical systems is presented in this paper. Development of compact efficient low-cost wearable antennas are one of the most significant challenges in development of wearable communication, IoT and medical systems. Moreover, the advantage of an integrated compact low-cost feed network is attained by integrating the antenna feed network with the antennas on the same printed board. The efficiency of communication systems may be increased by using efficient passive and active antennas. The system dynamic range may be improved by connecting amplifiers to the printed antenna feed line. Design, design considerations, computed and measured results of wearable circular patch meta-materials antennas with high efficiency for 5G, IoT and biomedical applications are presented in this paper. The circular patch antennas electrical parameters on the human body were analyzed by using commercial full-wave software. The circular patch metamaterial wearable antennas are compact and flexible. The directivity and gain of the antennas with Circular Split-Ring Resonators (CSRR) is higher by 2.5dB to 3dB than the antennas without CSRR. The resonant frequency of the antennas without CSRR is higher by 6% to 9% than the antennas with CSRR. The computed and measured bandwidth of the stacked circular patch wearable antenna with CSRR for IoT and medical applications is around 12%, for S11 lover than −6dB. The gain of the circular patch wearable antenna with CSRR is around 8dBi.

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An inexpensive, customizable microscopy system for the automated quantification and characterization of multiple adherent cell types

PeerJ ◽

10.7717/peerj.4937 ◽

2018 ◽

Vol 6 ◽

pp. e4937 ◽

Cited By ~ 3

Author(s):

Vishwaratn Asthana ◽

Yuqi Tang ◽

Adam Ferguson ◽

Pallavi Bugga ◽

Anantratn Asthana ◽

...

Keyword(s):

Tumor Cells ◽

Dynamic Range ◽

Low Cost ◽

Cell Types ◽

Cell Counting ◽

Adherent Cell ◽

Essential Components ◽

Automated Quantification ◽

Automated Microscopy ◽

Multiple Cell

Cell quantification assays are essential components of most biological and clinical labs. However, many currently available quantification assays, including flow cytometry and commercial cell counting systems, suffer from unique drawbacks that limit their overall efficacy. In order to address the shortcomings of traditional quantification assays, we have designed a robust, low-cost, automated microscopy-based cytometer that quantifies individual cells in a multiwell plate using tools readily available in most labs. Plating and subsequent quantification of various dilution series using the automated microscopy-based cytometer demonstrates the single-cell sensitivity, near-perfect R2 accuracy, and greater than 5-log dynamic range of our system. Further, the microscopy-based cytometer is capable of obtaining absolute counts of multiple cell types in one well as part of a co-culture setup. To demonstrate this ability, we recreated an experiment that assesses the tumoricidal properties of primed macrophages on co-cultured tumor cells as a proof-of-principle test. The results of the experiment reveal that primed macrophages display enhanced cytotoxicity toward tumor cells while simultaneously losing the ability to proliferate, an example of a dynamic interplay between two cell populations that our microscopy-based cytometer is successfully able to elucidate.

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Preparation and Immunological Traits of Monoclonal Antibody against Sarafloxacin

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.459.54 ◽

2012 ◽

Vol 459 ◽

pp. 54-57

Author(s):

Guo Ying Fan ◽

Jin Qing Jiang

Keyword(s):

Monoclonal Antibody ◽

Detection Limit ◽

Cell Fusion ◽

Light Chain ◽

Dynamic Range ◽

Fusion Technology ◽

Alternative Method ◽

Ic50 Values ◽

The Stability ◽

Igg1 Isotype

Through cell fusion technology, five hybridoma lines of sarafloxacin (SAR), named S1-B2, S2-C6, S2-E7, S3-C5, and S3-E5, were identified and their corresponding mAbs were of the IgG1 isotype with a k light chain. The Kaffs of all mAbs were between 2.8 and 4.6×109 L/mol. The titers and IC50 values of purified ascite fluids were in the range of 0.512–2.56×106 and 0.32–0.48 ng/mL, respectively. The performances of S1-B2 and S2-C6 were more consistent in the stability experiments. Based on the S1-B2 hybridoma, an icELISA method was developed. The dynamic range was from 0.004 to 18 ng/mL, with a detection limit for the assay and IC50 values of 0.002 and 0.32 ng/mL, respectively. Therefore, the establishment of these hybridomas may provide an alternative method for the detection of SAR residues in food-original animals.

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A Self-Powered Biosensor for the Detection of Glutathione

Biosensors ◽

10.3390/bios10090114 ◽

2020 ◽

Vol 10 (9) ◽

pp. 114 ◽

Cited By ~ 2

Author(s):

Brandon G. Roy ◽

Julia L. Rutherford ◽

Anna E. Weaver ◽

Kevin Beaver ◽

Michelle Rasmussen

Keyword(s):

Detection Limit ◽

Glucose Oxidase ◽

Power Output ◽

Low Cost ◽

Linear Range ◽

Biofuel Cell ◽

Bilirubin Oxidase ◽

Biological Molecule ◽

Enzymatic Biofuel Cell ◽

Self Powered

Glutathione is an important biological molecule which can be an indicator of numerous diseases. A method for self-powered detection of glutathione levels in solution has been developed using an enzymatic biofuel cell. The device consists of a glucose oxidase anode and a bilirubin oxidase cathode. For the detection of glutathione, the inhibition of bilirubin oxidase leads to a measurable decrease in current and power output. The reported method has a detection limit of 0.043 mM and a linear range up to 1.7 mM. Being able to detect a range of concentrations can be useful in evaluating a patient’s health. This method has the potential to be implemented as a quick, low-cost alternative to previously reported methods.

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Marine Bacterial Exopolymers-Mediated Green Synthesis of Noble Metal Nanoparticles with Antimicrobial Properties

Polymers ◽

10.3390/polym11071157 ◽

2019 ◽

Vol 11 (7) ◽

pp. 1157 ◽

Cited By ~ 7

Author(s):

Angela Scala ◽

Anna Piperno ◽

Alexandru Hada ◽

Simion Astilean ◽

Adriana Vulpoi ◽

...

Keyword(s):

Hydrothermal Vents ◽

Thermophilic Bacteria ◽

Silver Chloride ◽

Antimicrobial Properties ◽

Biological Evaluation ◽

Noble Metal Nanoparticles ◽

Ag Nps ◽

Au Nps ◽

Minimum Fungicidal Concentration ◽

Gold Silver

A straightforward and green method for the synthesis of gold, silver, and silver chloride nanoparticles (Au NPs and Ag/AgCl NPs) was developed using three different microbial exopolymers (EP) as reducing and stabilizing agents. The exopolysaccharides EPS B3-15 and EPS T14 and the poly-γ-glutamic acid γ-PGA-APA were produced by thermophilic bacteria isolated from shallow hydrothermal vents off the Eolian Islands (Italy) in the Mediterranean Sea. The production of metal NPs was monitored by UV−Vis measurements by the typical plasmon resonance absorption peak and their antimicrobial activity towards Gram-positive and Gram- negative bacteria (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa), as well as fungi (Candida albicans) was investigated. The biological evaluation showed no activity for EP-Au NPs, except against E. coli, whereas EP-Ag NPs exhibited a broad-spectrum of activity. The chemical composition, morphology, and size of EP-Ag NPs were investigated by UV–Vis, zeta potential (ζ), dynamic light scattering (DLS) measurements and transmission electron microscopy (TEM). The best antimicrobial results were obtained for EPS B3-15-Ag NPs and EPS T14-Ag NPs (Minimum Inhibitory Concentration, MIC: 9.37–45 µg/mL; Minimum Bactericidal Concentration/Minimum Fungicidal Concentration, MBC/MFC: 11.25–75 µg/mL).

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New noncompetitive immunoassays of small analytes

Clinical Chemistry ◽

10.1093/clinchem/41.7.986 ◽

1995 ◽

Vol 41 (7) ◽

pp. 986-990 ◽

Cited By ~ 4

Author(s):

U Piran ◽

W J Riordan ◽

L A Livshin

Keyword(s):

Detection Limit ◽

Liquid Phase ◽

Binding Sites ◽

Dynamic Range ◽

Lower Detection Limit ◽

Controlled Pore Glass ◽

Lower Detection ◽

Pore Glass ◽

Clinically Significant ◽

Acridinium Ester

Abstract We developed a novel noncompetitive immunoassay format for monoepitopic analytes and describe here a model assay for triiodothyronine (T3), performed on Ciba Corning's ACS:180 analyzer. Acridinium ester (AE)-labeled bivalent anti-T3 was incubated with the sample, producing AE-anti-T3/T3 complexes and unreacted AE-anti-T3. Controlled-pore glass particles (CPG) with immobilized diiodothyronine (T2) were then added in excess, to bind AE-anti-T3 possessing two unoccupied binding sites but not AE-anti-T3 bound to one or two T3 molecules. Paramagnetic particles (PMP) with immobilized anti-AE were then added to the same cuvette to capture AE-anti-T3/T3 complexes; AE-anti-T3 bound to the surface of CPG, however, was not captured, because of steric hindrance. After the incubation, the PMP was magnetically separated to remove the liquid phase and the suspended CPG from the cuvette. The chemiluminescence associate with the PMP remaining in the cuvette was then measured. This noncompetitive T3 assay exhibited a 10-fold lower detection limit than the equivalent competitive T3 assay, i.e., 0.3 vs pg/test. Imprecision (CV) in the clinically significant range was 6% or less. The assay also displayed two- to sevenfold lower cross-reactivities and a wider dynamic range.

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Sensitive Electrochemical Detection of 2,4-Dichlorophenol Using Novel Carbon Fiber Microelectrode

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.391-392.1387 ◽

2011 ◽

Vol 391-392 ◽

pp. 1387-1391

Author(s):

Zhan Jun Yang ◽

Xiao Chun Huang ◽

Juan Li ◽

Yan Yan Ren ◽

Xiao Ya Hu

Keyword(s):

Electron Microscopy ◽

Cyclic Voltammetry ◽

Detection Limit ◽

Carbon Fiber ◽

Low Cost ◽

Promising Alternative ◽

Carbon Fiber Microelectrode ◽

Electrochemical Signal ◽

Analytical System ◽

Optimized Conditions

A novel electrochemical strategy was proposed for detection of 2,4-Dichlorophenol (2,4-DCP) at fabricated carbon fiber microelectrode (CFME). The resultant CFME was characterized using scan electron microscopy (SEM) and cyclic voltammetry (CV). Upon addition of surfactant TritonX-100 in analytical system, the electrochemical signal of 2,4-DCP was obviously increased. Under the optimized conditions, the resulted CFME showed wide linear range for 2,4-DCP from 3.0×10-8to 1.8×10-6M with the detection limit of 1.0×10-8M (S/N = 3). The proposed method is simple, low-cost and convenient and will be a promising alternative for CFME fabrication.

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