Comparison of Single- and Mixed-Sized Gold Nanoparticles on Lateral Flow Assay for Albumin Detection

The sensitivity and reproducibility of the lateral flow assay can be influenced by multiple factors, such as the size of gold nanoparticles (GNPs) employed. Here, we evaluated the analytical performance of single-sized and mixed-sized GNPs using a simple lateral flow assay (LFA) platform. This platform was used as a model assay to diagnose albumin levels and demonstrate the analytical performance of single-sized and mixed-sized GNPs in LFA tests. Two sizes of GNPs@anti-bovine serum albumin (BSA) conjugate proteins were mixed at different ratios. The unique optical properties of the GNPs induced a distinguishing color-shedding effect on the single- and mixed-sized GNPs@anti-BSA conjugates interacting with the target analyte BSA spotted on the test line. The use of mixed-sized GNPs@anti-BSA conjugates enhanced signal relative to the 20 nm GNPs, and provided superior stability compared with solely employing the large GNPs (50 nm). The proposed platform in this study could provide an efficient BSA detection mechanism that can be utilized as a model biomarker for confronting chronic kidney disease.

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Performance comparison of single and mixed-sized gold nanoparticles on straightforward lateral flow assay for albumin detection

10.3762/bxiv.2020.144.v1 ◽

2020 ◽

Author(s):

Sasima Chotithammakul ◽

Dakrong Pissuwan

Keyword(s):

Gold Nanoparticles ◽

Signal Amplification ◽

Test Line ◽

Testing Procedure ◽

Performance Comparison ◽

Lateral Flow ◽

Lateral Flow Assay ◽

Analytical Performance ◽

Detection Mechanism ◽

Multiple Factors

The sensitivity of the lateral flow assay can be influenced by multiple factors, such as the size of gold nanoparticles (GNPs) employed, which affect the sensitivity and reproducibility of the assay testing procedure. Here, we evaluated the analytical performance of single-sized and mixed-sized GNPs using a simple lateral flow assay (LFA) platform. This platform was used as a model assay to diagnose albumin levels and demonstrate the analytical performance of single-sized and mixed-sized GNPs in LFA tests. Two sizes of GNPs@anti-bovine serum albumin (BSA) conjugate proteins were mixed at different ratios. The unique optical properties of the GNPs induced a distinguishing color-shedding effect on the single and mixed-sized GNPs@anti-BSA conjugates interacting with the target analyte BSA spotted on the test line. The use of mixed-sized GNPs@anti-BSA conjugates enhanced signal amplification, and provided superior stability compared with solely employing the large GNPs (50 nm). The proposed platform in this study could provide an efficient BSA detection mechanism that can be utilized as a biomarker for confronting chronic kidney disease.

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Electrochemical studies of lateral flow assay test results for procalcitonin detection

Journal of Electrochemical Science and Engineering ◽

10.5599/jese.1127 ◽

2021 ◽

Author(s):

Yachana Gupta Gupta ◽

Kalpana ◽

Aditya Sharma Ghrera

Keyword(s):

Gold Nanoparticles ◽

Detection Limit ◽

Qualitative Analysis ◽

Test Line ◽

Lateral Flow ◽

Lateral Flow Assay ◽

Quantitative Detection ◽

Cyclic Voltammograms ◽

Paper Strip ◽

Electrochemical Studies

In this study, the lateral flow assay (LFA) has been developed for the detection of bacterial infection (BI) by specific biomarker procalcitonin (PCT), without a need for complicated instrumentations and technical expertise. For the development of the assay, gold nanoparticles (AuNP) and their conjugates with antibodies specific to the model antigen PCT are assessed. Polyclonal antibody (pAb) labelled with gold nanoparticles (AuNP) to obtain the AuNP-pAb complex and the specific monoclonal antibody (mAb) have been dropped at the test zone. This complex is placed over the conjugate line of the LFA strip. In the absence of PCT or the presence of other biomarkers, the test line remained colourless, which revealed the specificity of assay towards PCT among a pool of various analytes. Herein, observations have been made through two different platforms for quantitative and qualitative analysis for the detection of PCT biomarker. The qualitative analysis has been performed on the basis of appearance red color in the test band, while for quantitative analysis, a novel approach has been adopted. Herein, the nitrocellulose membrane (paper strip) is cut out from the LFA strip and used for electrochemical studies under similar solution conditions. Different paper strips presented different cyclic voltammograms (CV) that could be correlated to varying PCT concentrations captured at the test line of the paper strip. The qualitative detection limit for PCT using this LFA was determined to be 2 ng/ml and the quantitative detection limit was 1 ng/ml. The electrochemical response studies of the paper strip by CV technique revealed the sensitivity value of 0.695 mA ng/ml.

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Preparation of Glycopolymer-Modified Gold Nanoparticles and a New Approach for a Lateral Flow Assay

Bulletin of the Chemical Society of Japan ◽

10.1246/bcsj.20100303 ◽

2011 ◽

Vol 84 (5) ◽

pp. 466-470 ◽

Cited By ~ 15

Author(s):

Jin Ishii ◽

Masayuki Toyoshima ◽

Miyuki Chikae ◽

Yuzuru Takamura ◽

Yoshiko Miura

Keyword(s):

Gold Nanoparticles ◽

Lateral Flow ◽

Lateral Flow Assay ◽

New Approach

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Evaluation of LDBio Aspergillus ICT Lateral Flow Assay for IgG and IgM Antibody Detection in Chronic Pulmonary Aspergillosis

Journal of Clinical Microbiology ◽

10.1128/jcm.00538-19 ◽

2019 ◽

Vol 57 (9) ◽

Cited By ~ 7

Author(s):

Elizabeth Stucky Hunter ◽

Malcolm D. Richardson ◽

David W. Denning

Keyword(s):

United Kingdom ◽

Line Intensity ◽

Test Line ◽

Lateral Flow ◽

Lateral Flow Assay ◽

Antibody Detection ◽

Resource Constrained ◽

Pulmonary Aspergillosis ◽

Chronic Pulmonary Aspergillosis ◽

Specific Igg

ABSTRACT Detecting Aspergillus-specific IgG is critical to diagnosing chronic pulmonary aspergillosis (CPA). Existing assays are often cost- and resource-intensive and not compatible with resource-constrained laboratory settings. LDBio Diagnostics has recently commercialized a lateral flow assay based on immunochromatographic technology (ICT) that detects Aspergillus antibodies (IgG and IgM) in less than 30 min, requiring minimal laboratory equipment. A total of 154 CPA patient sera collected at the National Aspergillosis Centre (Manchester, United Kingdom) and control patient sera from the Peninsula Research Bank (Exeter, United Kingdom) were evaluated. Samples were applied to the LDBio Aspergillus ICT lateral flow assay, and results were read both visually and digitally. Results were compared with Aspergillus IgG titers in CPA patients, measured by ImmunoCAP-specific IgG assays. For proven CPA patients versus controls, sensitivity and specificity for the LDBio Aspergillus ICT were 91.6% and 98.0%, respectively. In contrast, the routinely used ImmunoCAP assay exhibited 80.5% sensitivity for the same cohort (cutoff value, 40 mg of antigen-specific antibodies [mgA]/liter). The assay is easy to perform but challenging to read when only a very faint band is present (5/154 samples tested). The ImmunoCAP Aspergillus IgG titer was also compared with the Aspergillus ICT test line intensity or rate of development, with weak to moderate correlations. The Aspergillus ICT lateral flow assay exhibits excellent sensitivity for serological diagnosis of CPA. Quantifying IgG from test line intensity measurements is not reliable. Given the short run time, simplicity, and limited resources needed, the LDBio Aspergillus ICT is a suitable diagnostic tool for CPA in resource-constrained settings.

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Lateral-Flow Assay for Rapid Serodiagnosis of Human Leptospirosis

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.8.1.166-169.2001 ◽

2001 ◽

Vol 8 (1) ◽

pp. 166-169 ◽

Cited By ~ 60

Author(s):

Henk L. Smits ◽

C. K. Eapen ◽

Sheela Sugathan ◽

Mariamma Kuriakose ◽

M. Hussein Gasem ◽

...

Keyword(s):

Positive Result ◽

Immunosorbent Assay ◽

Rapid Detection ◽

Test Line ◽

Lateral Flow ◽

Immunoglobulin M ◽

Lateral Flow Assay ◽

Enzyme Linked Immunosorbent Assay ◽

Specific Immunoglobulin ◽

Human Sera

ABSTRACT An assay device for the rapid detection ofLeptospira-specific immunoglobulin M (IgM) antibodies in human sera is presented. The sensitivity (85.8%) and specificity (93.6%) of the assay compared well (91.9% agreement) with those of an IgM enzyme-linked immunosorbent assay routinely used in the serodiagnosis of leptospirosis. The sensitivity of the assay varied with the stage of the disease. The assay uses stabilized components and is simply performed by the addition of serum and sample fluid to the sample well of the assay device. The assay is read after 10 min, and a positive result is obtained when staining of the test line is observed.

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An Attempt to Develop an Aptamer Lateral-Flow Assay (ALFA) for Easy, Rapid, and Sensitive Detection of Lethal Mushroom Toxin α-amanitin

10.1101/2021.09.27.461950 ◽

2021 ◽

Author(s):

Qingchuan Chen ◽

Chen Fan ◽

Haozhe Huang ◽

Binglin Xu ◽

Yeqing Zong

Keyword(s):

Test Line ◽

Test Strip ◽

Lateral Flow ◽

Lateral Flow Assay ◽

Detection Methods ◽

Mushroom Poisoning ◽

Control Line ◽

Ph Tolerance ◽

Higher Temperature ◽

Target Binding

Amatoxins contribute to the majority of mushroom poisoning, most prominently, α-amanitin. Since mushroom is a common foodstuff worldwide, an easy, rapid, sensitive test for α-amanitin is needed. Several detection methods for α-amanitin have been developed, including HPLC, LC-MS, and ELISA, and LFIA. Aptamers have several advantages compared to antibodies: easy development via SELEX, longer shelf life, and higher temperature- and pH-tolerance. Aptamer Lateral Flow Assay (ALFA) is a similar technology compared to LFIA but incorporates aptamers as target-recognizing agents. This study attempted to develop an ALFA test strip for α-amanitin using a previously-developed aptamer, however failure of generating a colorimetric readout at the test line is persisted throughout all experiments, even though the concept is fully-proved and the control line functions normally. The failure is attributed to the small size of the molecule, leading to immobilization difficulties on the nitrocellulose membrane to form the test line, and the hindering of effective "surround" mechanism of aptamer-target binding (instead of "adhere", when the target molecule is large, e.g. a protein). It is concluded that ALFAs for small-molecules whose aptamer-target interaction has not yet been studied and modeled in detail remains a challenge, despite ALFAs' large potential.

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