scholarly journals On-Site Detection of Carcinoembryonic Antigen in Human Serum

Biosensors ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 392
Author(s):  
Tohid Mahmoudi ◽  
Mohammad Pourhassan-Moghaddam ◽  
Behnaz Shirdel ◽  
Behzad Baradaran ◽  
Eden Morales-Narváez ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Human Serum ◽  
Carcinoembryonic Antigen ◽  
Limit Of Detection ◽  
Lateral Flow ◽  
Detection Sensitivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Care Providers ◽  
Lateral Flow Strips ◽  
Visual Limit

Real-time connectivity and employment of sustainable materials empowers point-of-care diagnostics with the capability to send clinically relevant data to health care providers even in low-resource settings. In this study, we developed an advantageous kit for the on-site detection of carcinoembryonic antigen (CEA) in human serum. CEA sensing was performed using cellulose-based lateral flow strips, and colorimetric signals were read, processed, and measured using a smartphone-based system. The corresponding immunoreaction was reported by polydopamine-modified gold nanoparticles in order to boost the signal intensity and improve the surface blocking and signal-to-noise relationship, thereby enhancing detection sensitivity when compared with bare gold nanoparticles (up to 20-fold in terms of visual limit of detection). Such lateral flow strips showed a linear range from 0.05 to 50 ng/mL, with a visual limit of detection of 0.05 ng/mL and an assay time of 15 min. Twenty-six clinical samples were also tested using the proposed kit and compared with the gold standard of immunoassays (enzyme linked immunosorbent assay), demonstrating an excellent correlation (R = 0.99). This approach can potentially be utilized for the monitoring of cancer treatment, particularly at locations far from centralized laboratory facilities.

scholarly journals Development of a multiplex and sensitive lateral flow immunoassay for the diagnosis of periprosthetic joint infection

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tsung-Ting Tsai ◽  
Tse-Hao Huang ◽  
Natalie Yi-Ju Ho ◽  
Yu-Pei Chen ◽  
Chung-An Chen ◽  
...  
Keyword(s):  
Synovial Fluid ◽  
Clinical Diagnosis ◽  
Periprosthetic Joint Infection ◽  
Diagnostic Tests ◽  
Joint Infection ◽  
Lateral Flow ◽  
Rapid Response ◽  
Detection Sensitivity ◽  
Lateral Flow Immunoassay ◽  
Enzyme Linked Immunosorbent Assay

Abstract The diagnosis of periprosthetic joint infection (PJI) remains a challenge. However, recent studies showed that synovial fluid biomarkers have demonstrated greater diagnostic accuracy than the currently used PJI diagnostic tests. In many diagnostic tests, combining several biomarkers into panels is critical for improving diagnostic efficiency, enhancing the diagnostic precision for specific diseases, and reducing cost. In this study, we prove that combining alpha-defensin and C-reactive protein (CRP) as biomarkers possesses the potential to provide accurate PJI diagnosis. To further verify the result, we developed a multi-target lateral flow immunoassay strip (msLFIA) with staking pad design to obtain on-site rapid response for clinical diagnosis of PJI. A total of 10 synovial fluid samples were tested using the msLFIA, and the results showed that the combined measurements of synovial fluid alpha-defensin and CRP levels were consistent with those obtained from a commercial enzyme-linked immunosorbent assay kit. In addition, we developed a multi-target lateral flow immunoassay strip (msLFIA) with staking pad design to obtain on-site rapid response for clinical diagnosis of PJI, which the multi-target design is used to increase specificity and the stacking pad design is to enhance detection sensitivity. As a result, the turnaround time of the highly sensitive test can be limited from several hours to 20 min. We expect that the developed msLFIA possesses the potential for routine monitoring of PJI as a convenient, low-cost, rapid and easy to use detection device for PJI.

scholarly journals Proposal of De Novo Antigen Test for COVID-19: Ultrasensitive Detection of Spike Proteins of SARS-CoV-2

Diagnostics ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 594 ◽  
Author(s):  
Yuta Kyosei ◽  
Mayuri Namba ◽  
Sou Yamura ◽  
Rikiya Takeuchi ◽  
Noriko Aoki ◽  
...  
Keyword(s):  
De Novo ◽  
Limit Of Detection ◽  
False Negative ◽  
Cost Effective ◽  
Detection Sensitivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antigen Test ◽  
Virus Rna ◽  
Antigen Tests ◽  
Spike Proteins

Polymerase chain reaction (PCR)-based antigen tests are technically difficult, time-consuming, and expensive, and may produce false negative results requiring follow-up confirmation with computed tomography. The global coronavirus disease 2019 (COVID-19) pandemic has increased the demand for accurate, easy-to-use, rapid, and cost-effective antigen tests for clinical application. We propose a de novo antigen test for diagnosing COVID-19 using the combination of sandwich enzyme-linked immunosorbent assay and thio-nicotinamide adenine dinucleotide (thio-NAD) cycling. Our test takes advantage of the spike proteins specific to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. The limit of detection of our test was 2.3 × 10−18 moles/assay. If the virus has ~25 spike proteins on its surface, our method should detect on the order of 10−20 moles of virus/assay, corresponding to ~104 copies of the virus RNA/assay. The detection sensitivity approaches that of PCR-based assays because the average virus RNA load used for PCR-based assays is ~105 copies per oro- or naso-pharyngeal swab specimen. To our knowledge, this is the first ultrasensitive antigen test for SARS-CoV-2 spike proteins that can be performed with an easy-to-use microplate reader. Sufficient sensitivity can be achieved within 10 min of thio-NAD cycling. Our antigen test allows for rapid, cost-effective, specific, ultrasensitive, and simultaneous multiple measurements of SARS-CoV-2, and has broad application for the diagnosis for COVID-19.

Development of Lateral Flow Immunochromatographic Strips for Micropollutants Screening Using Colorants of Aptamer Functionalized Nanogold Particles Part I Methodology and Optimization

2018 ◽  
Vol 101 (5) ◽  
pp. 1402-1407 ◽  
Author(s):  
Shuai Zhao ◽  
Shan Zhang ◽  
Sai Wang ◽  
Jiahui Liu ◽  
Yiyang Dong
Keyword(s):  
Reading Time ◽  
Limit Of Detection ◽  
Blocking Agent ◽  
Rapid Identification ◽  
Lateral Flow ◽  
Immunochromatographic Strip ◽  
Assay Performance ◽  
Nanogold Particles ◽  
Visual Limit ◽  
Optimized Conditions

Abstract A methodology of lateral flow immunochromatographic strip based on aptamer was developed for on-site detection of the small molecule micropollutants. In the present study, we try for the first time to investigate the feasibility of developing a strip assay for the analysis of micropollutants as methodological prototypes by combining the high selectivity and affinity of aptamers with the unique optical properties of nanogolds. This quantitative method was based on the competition for the aptamer between targets and DNA probes. Crucial parameters that might influence the sensitivity, such as the size of nanogolds, amount of aptamer, type and pH of streptavidin, type of nitrocellulose (NC) membrane, blocking procedure, and reading time, were systematically investigated to obtain the optimum assay performance. With the optimized conditions [nanogolds 25 nm, 50 μM aptamer, pH 8 of GSA (a type of streptavidin named “SA Gold,” which is a sulfhydrylization streptavidin), Millipore HFC 135 NC membrane, 1% bovine serum albumin as the blocking agent and added in the running buffer and sample pad soakage agents, and 20 min reading time] the aptamer-based lateral flow assay will show a low visual limit of detection and scanning reader LOD. The strip for on-site screening using colorants of aptamer functionalized nanogold particles did not require any complicated equipment and was a potential portable tool for rapid identification of micropollutants.

scholarly journals A rapid and highly sensitive biomarker detection platform based on a temperature-responsive liposome-linked immunosorbent assay

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Runkai Hu ◽  
Keitaro Sou ◽  
Shinji Takeoka
Keyword(s):  
Immunosorbent Assay ◽  
Limit Of Detection ◽  
Specific Antigen ◽  
Fluorescence Emission ◽  
Detection Sensitivity ◽  
Sensitive Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Temperature Responsive ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

Abstract The enzyme-linked immunosorbent assay (ELISA) is widely used in various fields to detect specific biomarkers. However, ELISA tests have limited detection sensitivity (≥ 1 pM), which is insufficiently sensitive for the detection of small amounts of biomarkers in the early stages of disease or infection. Herein, a method for the rapid and highly sensitive detection of specific antigens, using temperature-responsive liposomes (TLip) containing a squaraine dye that exhibits fluorescence at the phase transition temperature of the liposomes, was developed. A proof-of-concept study using biotinylated TLip and a streptavidin-immobilized microwell plate showed that the TLip bound to the plate via specific molecular recognition could be distinguished from unbound TLip within 1 min because of the difference in the heating time required for the fluorescence emission of TLip. This system could be used to detect prostate specific antigen (PSA) based on a sandwich immunosorbent assay using detection and capture antibodies, in which the limit of detection was as low as 27.6 ag/mL in a 100-μL PSA solution, 0.97 aM in terms of molar concentration. The present temperature-responsive liposome-linked immunosorbent assay provides an advanced platform for the rapid and highly sensitive detection of biomarkers for use in diagnosis and biological inspections.

scholarly journals Advantages of Highly Spherical Gold Nanoparticles as Labels for Lateral Flow Immunoassay

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3608
Author(s):  
Nadezhda A. Byzova ◽  
Anatoly V. Zherdev ◽  
Boris N. Khlebtsov ◽  
Andrey M. Burov ◽  
Nikolai G. Khlebtsov ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Au Nanoparticles ◽  
Troponin I ◽  
Limit Of Detection ◽  
Average Diameter ◽  
Covalent Immobilization ◽  
Lateral Flow ◽  
Antibody Immobilization ◽  
Site Testing ◽  
Spherical Gold Nanoparticles

The use of lateral flow immunoassays (LFIAs) for rapid on-site testing is restricted by their relatively high limit of detection (LoD). One possible way to decrease the LoD is to optimize nanoparticle properties that are used as labels. We compare two types of Au nanoparticles: usual quasispherical gold nanoparticles (C-GNPs), obtained by the Turkevich–Frens method, and superspherical gold nanoparticles (S-GNPs), obtained by a progressive overgrowth technique. Average diameters were 18.6–47.5 nm for C-GNPs and 20.2–90.4 nm for S-GNPs. Cardiomarker troponin I was considered as the target analyte. Adsorption and covalent conjugation with antibodies were tested for both GNP types. For C-GNPs, the minimal LoD was obtained with 33.7 nm nanoparticles, reaching 12.7 ng/mL for covalent immobilization and 9.9 ng/mL for adsorption. The average diameter of S-GNPs varied from 20.2 to 64.5 nm, which resulted in a decrease in LoD for an LFIA of troponin I from 3.4 to 1.2 ng/mL for covalent immobilization and from 2.9 to 2.0 ng/mL for adsorption. Thus, we obtained an 8-fold decrease in LoD (9.9 to 1.2 ng/mL) by using S-GNPs. This effect can be related to more effective antibody immobilization and improved S-GNP optical properties. The obtained results can improve LFIAs for various practically significant analytes.

Sample Preincubation Strategy for Sensitive and Quantitative Detection of Clenbuterol in Swine Urine Using a Fluorescent Microsphere–Based Immunochromatographic Assay

2014 ◽  
Vol 77 (11) ◽  
pp. 1998-2003 ◽  
Author(s):  
SHENG L. DENG ◽  
SHAN SHAN ◽  
CHAO L. XU ◽  
DAO F. LIU ◽  
YONG H. XIONG ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Rapid Screening ◽  
Immunochromatographic Assay ◽  
Quantitative Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Fluorescent Microsphere ◽  
Swine Urine ◽  
Relative Standard

We describe an ultrasensitive and quantitative immunochromatographic assay to determine the amount of clenbuterol (CLB) in swine urine. In this study, fluorescein isothiocyanate polystyrene fluorescent microspheres were used as probes. A sample preincubation strategy was introduced to this immunochromatographic assay. Results showed that the strategy evidently improved the sensitivity and accuracy of lateral flow assay. The method was completed in 20 min, and a half-maximal inhibitory concentration of 0.13 μg liter−1 was obtained. The limit of detection of the proposed method to determine CLB in swine urine was 0.01 μg liter−1, which was lower than the limit of detection of immunochromatographic assays without preincubation. Intra-and interday recoveries of spiked swine urine ranged from 85.0 to 107.5%. The relative standard deviation values of the preincubated test strip ranged from 2.7 to 12.5%. Analysis of the CLB in swine urine samples showed that the result obtained from the lateral flow assay is consistent with that obtained from a commercial enzyme-linked immunosorbent assay kit. Our results suggest that the developed fluorescent microsphere–based immunochromatographic assay may be useful as a rapid screening method to detect CLB quantitatively.

scholarly journals Photooxidation-induced fluorescence amplification system for an ultra-sensitive enzyme-linked immunosorbent assay (ELISA)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Youhee Heo ◽  
Kwanwoo Shin ◽  
Min Cheol Park ◽  
Ji Yoon Kang
Keyword(s):  
Limit Of Detection ◽  
Slight Modification ◽  
Detection Sensitivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Protein Biomarkers ◽  
Amplex Red ◽  
Rate Of Increase ◽  
Amplification Rate ◽  
Amplification System ◽  
Fluorescence Amplification

AbstractThis report suggests a method of enhancing the sensitivity of chemifluorescence-based ELISA, using photooxidation-induced fluorescence amplification (PIFA). The PIFA utilized autocatalytic photooxidation of the chemifluorescent substrate, 10-acetyl 3,7-dihydroxyphenoxazine (ADHP, Amplex Red) to amplify the fluorescent product resorufin, initially oxidized by horse radish peroxidase (HRP). As the amplification rate is proportional to the initial level of resorufin, the level of antigen labeled by HRP is quantified by analyzing the profile of fluorescence intensity. The normalized profile was interpolated into an autocatalysis model, and the rate of increase at half-maximum time was quantified by the use of an amplification index (AI). The lower limit of detection, for resorufin or HRP, was less than one-tenth that of the plate reader. It requires only slight modification of the fluorescence reader and is fully compatible with conventional or commercial ELISA. When it is applied to a commercial ELISA kit for the detection of amyloid beta, it is verified that the PIFA assay enhanced the detection sensitivity by more than a factor of 10 and was compatible with a conventional 96-well ELISA assay kit. We anticipate this PIFA assay to be used in research for the detection of low levels of proteins and for the early diagnosis of various diseases with rare protein biomarkers, at ultra-low (pg/mL) concentrations.

scholarly journals Gold Nanobeads with Enhanced Absorbance for Improved Sensitivity in Competitive Lateral Flow Immunoassays

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1488
Author(s):  
Xirui Chen ◽  
Xintao Miao ◽  
Tongtong Ma ◽  
Yuankui Leng ◽  
Liangwen Hao ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Detection Limit ◽  
Inhibitory Concentration ◽  
Fumonisin B1 ◽  
Lateral Flow ◽  
Detection Sensitivity ◽  
Lateral Flow Immunoassay ◽  
Promising Strategy ◽  
Qualitative Detection ◽  
Better Than

Background: Colloidal gold based lateral flow immunoassay (LFIA) commonly suffers from relatively low detection sensitivity due to the insufficient brightness of conventional gold nanoparticles (AuNPs) with the size of 20–40 nm. Methods: Herein, three kinds of gold nanobeads (GNBs) with the size of 94 nm, 129 nm, and 237 nm, were synthesized by encapsulating numerous hydrophobic AuNPs (10 nm) into polymer matrix. The synthesized GNBs exhibited the enhanced colorimetric signal intensity compared with 20–40 nm AuNPs. The effects of the size of GNBs on the sensitivity of LFIA with competitive format were assessed. Results: The results showed that the LFIA using 129 nm GNBs as amplified signal probes exhibits the best sensitivity for fumonisin B1 (FB1) detection with a cut-off limit (for visual qualitative detection) at 125 ng/mL, a half maximal inhibitory concentration at 11.27 ng/mL, and a detection limit at 1.76 ng/mL for detection of real corn samples, which are 8-, 3.82-, and 2.89-fold better than those of conventional AuNP40-based LFIA, respectively. The developed GNB-LFIA exhibited negligible cross-reactions with other common mycotoxins. In addition, the accuracy, precision, reliability, and practicability were demonstrated by determining real corn samples. Conclusions: All in all, the proposed study provides a promising strategy to enhance the sensitivity of competitive LFIA via using the GNBs as amplified signal probes.

scholarly journals Multiple SNPs detection for antimalarial pyrimethamine resistance via allele-specific PCR coupled with gold nanoparticles-based lateral flow biosensor

2020 ◽  
Author(s):  
Tingting Jiang ◽  
Yan Huang ◽  
Weijia Cheng ◽  
Yifei Sun ◽  
Wei Wei ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Genetic Diseases ◽  
Lateral Flow ◽  
Nucleotide Polymorphisms ◽  
Multiple Allele ◽  
Specific Pcr ◽  
Allele Specific ◽  
Allele Specific Pcr

Molecular genotyping holds tremendous potential to detect antimalarial drug resistance (ADR) related to single nucleotide polymorphisms (SNPs). However, it suffers from complicated procedures and expensive instruments. Thus, rapid point-of-care testing (POCT) molecular tools are urgently needed for field survey and clinical use. Herein, a POCT platform consisted of multiple allele-specific PCR (AS-PCR) and gold nanoparticles (AuNPs) based lateral flow biosensor was designed and developed for SNPs detection of Plasmodium falciparum dihydrofolate reductase (pfdhfr) gene related to pyrimethamine resistance. The multiple AS-PCR utilized 3' terminal artificial antepenultimate mismatch and double phosphorothioate-modified allele-specific primers. The duplex PCR amplicons with 5' terminal labeled with biotin and digoxin, respectively, could be recognized by streptavidin (SA)-AuNPs on the conjugate pad and then captured by anti-digoxin antibody through immunoreactions on the test line to produce a golden red line for detection. The system was applied to analyze SNPs in Pfdhfr N51I, C59R, and S108N of 98 clinical isolates from uncomplicated P. falciparum malaria patients. Compared with the results of nested PCR followed Sanger DNA sequencing, the sensitivity is all 97.96% (96/98) for the N51I, C59R, and S108N. For specificity, there were 100% (98/98), 95.92% (94/98), and 100% (98/98) for N51I, C59R, and S108N, respectively. The limit of detection is approximately 200 fg/μl for plasmid DNA as the template and 100 parasites/μl for blood filter paper. The established platform not only offers a powerful tool for molecular surveillance of ADR but also is easily extended to interrelated SNP profiles for infectious diseases and genetic diseases.

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