scholarly journals Lateral Flow Immunoassay for Visible Detection of Human Brucellosis Based on Blue Silica Nanoparticles

2021 ◽  
Vol 8 ◽  
Author(s):  
Lirui Ge ◽  
Dan Wang ◽  
Fengnan Lian ◽  
Jinbin Zhao ◽  
Yue Wang ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Covalent Bond ◽  
Lateral Flow ◽  
Clinical Diagnostics ◽  
Lateral Flow Immunoassay ◽  
Great Promise ◽  
Human Brucellosis ◽  
Serum Samples ◽  
Positive Serum ◽  
Health And Economic Development

Brucellosis is a highly contagious zoonosis chronic infectious disease with a strong latent capability to endanger human health and economic development via direct or indirect ways. However, the existing methods for brucellosis diagnosis are time-consuming and expensive as they require a tedious experimental procedure and a sophisticated experimental device and performance. To overcome these defects, it is truly necessary to establish a real-time, on-site, and rapid detection method for human brucellosis. Here, a lateral flow immunoassay (LFIA) with a rapid, sensitive, and alternative diagnostic procedure for human brucellosis with a high degree of accuracy was developed based on blue silica nanoparticles (SiNPs), Staphylococcal protein A (SPA), and surface Lipopolysaccharide of Brucella spp. (LPS), which can be applied for rapid and feasible detection of human brucellosis. To our knowledge, this is the first report that uses blue SiNPs as a signal probe of LFIA for the rapid diagnosis of human brucellosis. The precursor of blue SiNPs@SPA such as colorless SiNPs and blue SiNPs was synthesized at first and then coupled with SPA onto the surface of blue SiNPs by covalent bond to prepare blue SiNPs@SPA as a capture signal to catch the antibody in the brucellosis-positive serum. When SPA was combined with the antibodies in the brucellosis-positive serum, it was captured by LPS on the test line, forming an antigen–antibody sandwich structure, resulting in the T line turning blue. Finally, the results showed that it is acceptable to use blue SiNPs as visible labels of LFIA, and standard brucellosis serum (containing Brucella spp. antibody at 1,000 IU/ml) could be detected at a dilution of 10−5 and the detection limit of this method was 0.01 IU/ml. Moreover, it also demonstrated good specificity and accuracy for the detection of real human serum samples. Above all, the blue SiNPs-based LFIA that we developed provides a rapid, highly accurate, and inexpensive on-site diagnosis of human brucellosis, and shows great promise in clinical diagnostics for other diseases.

scholarly journals Lateral Flow Immunoassay with Quantum-Dot-Embedded Silica Nanoparticles for Prostate-Specific Antigen Detection

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 33
Author(s):  
Sungje Bock ◽  
Hyung-Mo Kim ◽  
Jaehi Kim ◽  
Jaehyun An ◽  
Yun-Sik Choi ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Silica Nanoparticles ◽  
Prostate Specific Antigen ◽  
False Negative ◽  
Specific Antigen ◽  
Calf Serum ◽  
High Sensitivity ◽  
Lateral Flow ◽  
Detection Sensitivity ◽  
Lateral Flow Immunoassay

Prostate cancer can be detected early by testing the presence of prostate-specific antigen (PSA) in the blood. Lateral flow immunoassay (LFIA) has been used because it is cost effective and easy to use and also has a rapid sample-to-answer process. Quantum dots (QDs) with very bright fluorescence have been previously used to improve the detection sensitivity of LFIAs. In the current study, a highly sensitive LFIA kit was devised using QD-embedded silica nanoparticles. In the present study, only a smartphone and a computer software program, ImageJ, were used, because the developed system had high sensitivity by using very bright nanoprobes. The limit of PSA detection of the developed LFIA system was 0.138 ng/mL. The area under the curve of this system was calculated as 0.852. The system did not show any false-negative result when 47 human serum samples were analyzed; it only detected PSA and did not detect alpha-fetoprotein and newborn calf serum in the samples. Additionally, fluorescence was maintained on the strip for 10 d after the test. With its high sensitivity and convenience, the devised LFIA kit can be used for the diagnosis of prostate cancer.

scholarly journals Clinical Evaluation of a COVID-19 Antibody Lateral Flow Assay using Point of Care Samples

2020 ◽  
Author(s):  
Won Lee ◽  
Steven Straube ◽  
Ryan Sincic ◽  
Jeanne A. Noble ◽  
Juan Carlos Montoy ◽  
...  
Keyword(s):  
Predictive Value ◽  
Point Of Care ◽  
Acute Infection ◽  
High Specificity ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Onset Date ◽  
Rt Pcr ◽  
Serum Samples ◽  
Antibody Positivity

ABSTRACTIntroductionThe ongoing SARS-CoV-2 pandemic has spurred the development of numerous point of care (PoC) immunoassays. Assessments of performance of available kits are necessary to determine their clinical utility. Previous studies have mostly performed these assessments in a laboratory setting, which raises concerns of translating findings for PoC use. The aim of this study was to assess the performance of a lateral flow immunoassay for the detection of SARS-CoV-2 antibodies using samples collected at PoC.MethodOne lateral flow immunoassay (Humasis® COVID-19 IgG/IgM) was tested. In total, 50 PCR RT-PCR positive and 52 RT-PCR negative samples were collected at PoC. Fifty serum specimens from Dec 2018 to Feb 2019 were used as controls for specificity. Serum samples collected between Dec 2019 to Feb 2020 were used as additional comparators. Clinical data including symptom onset date was collected from patient history and the medical record.ResultsThe overall sensitivity for the kit was 74% (95% CI: 59.7% -85.4%). The sensitivity for IgM and IgG detection >14 days after date of onset was 88% (95% CI: 68.8% -97.5%) and 84% (95% CI: 63.9% – 95.5%), with a negative predictive value (NPV) of 94% for IgM (95% CI: 83.5% - 98.8%) and 93% for IgG (95% CI: 81.8% - 97.9%). The overall specificity was 94% (95% CI: 83.5% - 98.8%). The Immunoglobulin specific specificity was 94% for IgM (95% CI: 83.5% - 98.8%) and 98% for IgG (95% CI: 89.4% - 100.0%), with a positive predictive value (PPV) of 88% for IgM (95% CI: 68.8% - 97.5%) and 95% for IgG (95% CI: 77.2% - 99.9%) respectively for samples collected from patients >14 days after date of onset. Specimen collected during early phase of COVID-19 pandemic (Dec 2019 to Feb 2020) showed 11.8% antibody positivity, and 11.3% of PCR-negative patients demonstrated antibody positivity.DiscussionHumasis® COVID-19 IgG/IgM LFA demonstrates greater than 90% PPV and NPV for samples collected 14 days after the onset of symptoms using samples collected at PoC. While not practical for the diagnosis of acute infection, the use of the lateral flow assays with high specificity may have utility for determining seroprevalence or seroconversion in longitudinal studies.

Rapid and sensitive lateral flow immunoassay for influenza antigen using fluorescently-doped silica nanoparticles

2013 ◽  
Vol 181 (1-2) ◽  
pp. 223-230 ◽  
Author(s):  
Suwussa Bamrungsap ◽  
Chayachon Apiwat ◽  
Warangkana Chantima ◽  
Tararaj Dharakul ◽  
Natpapas Wiriyachaiporn
Keyword(s):  
Silica Nanoparticles ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay

scholarly journals Development of a quantum-dot lateral flow immunoassay strip based portable fluorescence smart-phone system for ultrasensitive detection of IgM/IgG to SARS-CoV-2

2020 ◽  
Author(s):  
Bochao Liu ◽  
Jinfeng Li ◽  
Xi Tang ◽  
Ze Wu ◽  
Jinhui Lu ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Smart Phone ◽  
Protein S ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Serum Samples ◽  
Recombinant Receptor ◽  
Specific Igg ◽  
Asymptomatic Individuals ◽  
Novel Coronavirus

Background: Since December 2019, the outbreak of coronavirus disease (COVID-19) has been occurred by novel coronavirus (SARS-CoV-2). The rapid and sensitive immunoassays are urgently demanded for detecting specific antibodies as assistant diagnosis for primary screening of asymptomatic individuals, close contacts,suspected or recovered patients of COIVD-19 during the pandemic period. Methods: The recombinant receptor binding domain of SARS-CoV-2 spike protein (S-RBD) was used as the antigen to detect specific IgM and the mixture of recombinant nucleocapsid phosphoprotein (NP) and S-RBD were used to detect specific IgG by the newly designed quantum-dot lateral flow immunoassay strip (QD-LFIA), respectively. Results: A rapid and sensitive QD-LFIA based portable fluorescence smart-phone system was developed for detecting specific IgM/IgG to SARS-CoV-2 from 100 serum samples of COVID-19 patients and 450 plasma samples from healthy blood donors. Among 100 COVID-19 patients diagnosed with NAT previously, 3 were severe, 35 mild and 62 recovered cases. By using QD-LFIA, 78 (78%) and 99 (99%) samples from 100 COVID-19 patients serum were detected positive for anti-SARS-CoV-2 IgM or IgG, respectively, but only one sample (0.22%) was cross-reactive with S-RBD from 450 healthy blood donor plasmas that were collected from different areas of China. Conclusion: An ultrasensitive and specific QD-LFIA based portable fluorescence smart-phone system was developed fo r detection of specific IgM and IgG to SARS-CoV-2 infection, which could be used for investigating the prevalence or assistant diagnosis of COVID-19 in humans.

scholarly journals Lateral Flow Immunoassay Using Europium Chelate-Loaded Silica Nanoparticles as Labels

2009 ◽  
Vol 55 (1) ◽  
pp. 179-182 ◽  
Author(s):  
Xiaohu Xia ◽  
Ye Xu ◽  
Xilin Zhao ◽  
Qingge Li
Keyword(s):  
Silica Nanoparticles ◽  
Hepatitis B Surface Antigen ◽  
Lateral Flow ◽  
Ease Of Use ◽  
Clinical Samples ◽  
Complete Agreement ◽  
Analytical Sensitivity ◽  
Serum Samples ◽  
Qualitative Comparison ◽  
Europium Chelate

Abstract Background: Despite their ease of use, lateral flow immunoassays (LFIAs) often suffer from poor quantitative discrimination and low analytical sensitivity. We explored the use of a novel class of europium chelate-loaded silica nanoparticles as labels to overcome these limitations. Methods: Antibodies were covalently conjugated onto europium chelate-loaded silica nanoparticles with dextran as a linker. The resulting conjugates were used as labels in LFIA for detection of hepatitis B surface antigen (HBsAg). We performed quantification with a digital camera and Adobe Photoshop software. We also used 286 clinical samples to compare the proposed method with a quantitative ELISA. Results: A detection limit of 0.03 μg/L was achieved, which was 100 times lower than the colloidal gold-based LFIAs and lower than ELISA. A precise quantitative dose-response curve was obtained, and the linear measurement range was 0.05–3.13 μg/L, within which the CVs were 2.3%–10.4%. Regression analysis of LFIA on ELISA results gave: log (LFIA) = −0.14 log (ELISA) + 1.03 μg/L with r = 0.99 for the quantification of HBsAg in 35 positive serum samples. Complete agreement was observed for the qualitative comparison of 286 clinical samples assayed with LFIA and ELISA. Conclusions: Europium chelate-loaded silica nanoparticle labels have great potential to improve LFIAs, making them useful not only for simple screening applications but also for more sensitive and quantitative immunoassays.

Prospective Evaluation of a Rapid Nanoparticle-Based Lateral Flow Immunoassay (Stic Expert HIT®) for the Diagnosis of Heparin-Induced Thrombocytopenia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1087-1087 ◽  
Author(s):  
Claire Pouplard ◽  
Dorothee Leroux ◽  
Nathalie Hezard ◽  
Aurelien Lebreton ◽  
Anne Bauters ◽  
...  
Keyword(s):  
High Risk ◽  
Predictive Value ◽  
Conflicts Of Interest ◽  
Negative Likelihood Ratio ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Plasma Samples ◽  
Serum Samples ◽  
Heparin Induced Thrombocytopenia ◽  
Test Probability

Abstract Abstract 1087 Heparin-induced thrombocytopenia (HIT) is a severe complication of heparin treatments associated with a high risk of venous and arterial thrombosis. HIT is often difficult to diagnose in clinical practice since most patients present several potential causes of thrombocytopenia. A scoring system named 4T's and based on four criteria (i.e. Thrombocytopenia, Timing of platelet count fall, Thrombosis or other sequelae, oTher cause of thrombocytopenia) is currently used to evaluate the probability of HIT before laboratory testing. Recently, a rapid lateral flow immunoassay (LFIA) based on the use of PF4/polyanion complexes linked to biotin as antigens and of gold nanoparticles coated with antibodies specific to biotin has been developed (Stic Expert HIT®, Stago Asnières France). This test is IgG-specific since gold particles are immobilized on the nitrocellulose strip by anti-human IgG and become visible as a colored line when IgG antibodies to PF4/heparin complexes are present in the patient sample. The aim of our study was to evaluate the performances of this rapid assay in a large prospective cohort of patients with suspected HIT. In addition, we compared the results obtained with serum and plasma samples and evaluated the inter-reader reproducibility of the assay. Patients and methods: Two hundred and sixteen consecutive patients were enrolled from February to June 2012 in 10 French centers. The pretest probability of HIT was evaluated using the 4T's score blind to antibody test results. The Stic Expert HIT® was performed in each center on plasma and serum. IgG-specific ELISA (Asserachrom HPIA IgG®) and serotonin release assay were also performed in the coordinating center (Tours). HIT was confirmed only when both SRA and IgG specific H/PF4 ELISA were positive. Results: Definite HIT was diagnosed in 24 patients and the incidence of HIT therefore equaled 11.1% in our cohort. The risk of HIT was evaluated as low (LR), intermediate (IR) or high (HR) by the 4T's in 27.8%, 63.2% and 9.0% of patients enrolled, respectively. The negative predictive value of (NPV) of the 4T's was 96.6% since definite HIT was diagnosed in 2 of the 59 LR patients. Although interpretation of LFIA results is visual, the inter-reader reproducibility was excellent (Kappa test ratio higher than 0.9) whether the test was performed with plasma or serum. When performed on plasma samples, LFIA was negative in 159 patients without HIT (NPV 99.4%,) and the negative likelihood ratio (LR-) was 0.05. Results obtained with serum samples were similar with NPV and LR- values of 100% and less than 0.01, respectively. On the other hand, LFIA was positive in 54 patients, including 23 with definite HIT (positive predictive value = 42.6%), with a positive LR value of 5.87. The pre-test probability of HIT was 3.4%, 9.7%, and 36.8% in the patients classified with the 4Ts score as having low, intermediate and high risk of HIT, respectively. The post-test probability of HIT was then calculated according to the Bayes theorem and using the LR values of LFIA obtained. The probability of HIT decreased dramatically to 0.5% in IR patients when the test result was negative. Alternatively, this probability increased to 38% only when LFIA was positive. Discussion and Conclusion: One major advantage of the LFIA Stic Expert HIT® is the possibility of obtaining a result in less than 40 minutes and a strategy based on results of both this assay and the 4Ts score can therefore be proposed for the management of patients with suspected HIT in emergency conditions. The Stic Expert HIT® can be performed both on serum and plasma and a negative result is able to confidently rule out the diagnosis of HIT since NPV and LR- values are excellent (>99% and < 0.1, respectively). These performances are particularly useful in LR or IR patients, for whom heparin treatment can be continued safely if the Stic Expert HIT® is negative. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Silver-Assembled Silica Nanoparticles in Lateral Flow Immunoassay for Visual Inspection of Prostate-Specific Antigen

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4099
Author(s):  
Hyung-Mo Kim ◽  
Jaehi Kim ◽  
Sungje Bock ◽  
Jaehyun An ◽  
Yun-Sik Choi ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Silica Nanoparticles ◽  
Prostate Specific Antigen ◽  
Cancer Diagnosis ◽  
Specific Antigen ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Clinical Samples ◽  
Important Indicator ◽  
Prostate Cancer Diagnosis

Prostate-specific antigen (PSA) is the best-known biomarker for early diagnosis of prostate cancer. For prostate cancer in particular, the threshold level of PSA <4.0 ng/mL in clinical samples is an important indicator. Quick and easy visual detection of the PSA level greatly helps in early detection and treatment of prostate cancer and reducing mortality. In this study, we developed optimized silica-coated silver-assembled silica nanoparticles (SiO2@Ag@SiO2 NPs) that were applied to a visual lateral flow immunoassay (LFIA) platform for PSA detection. During synthesis, the ratio of silica NPs to silver nitrate changed, and as the synthesized NPs exhibited distinct UV spectra and colors, most optimized SiO2@Ag@SiO2 NPs showed the potential for early prostate cancer diagnosis. The PSA detection limit of our LFIA platform was 1.1 ng/mL. By applying each SiO2@Ag@SiO2 NP to the visual LFIA platform, optimized SiO2@Ag@SiO2 NPs were selected in the test strip, and clinical samples from prostate cancer patients were successfully detected as the boundaries of non-specific binding were clearly seen and the level of PSA was <4 ng/mL, thus providing an avenue for quick prostate cancer diagnosis and early treatment.

scholarly journals Laboratory diagnosis of human brucellosis in Egypt and persistence of the pathogen following treatment

2011 ◽  
Vol 5 (11) ◽  
pp. 786-791 ◽  
Author(s):  
Ayman Marei ◽  
Ghada Boghdadi ◽  
Nahla Abdel-Hamed ◽  
Rasha Hessin ◽  
Theresia Abdoel ◽  
...  
Keyword(s):  
Point Of Care ◽  
Public Health Problem ◽  
Laboratory Diagnosis ◽  
Diagnostic Value ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Human Brucellosis ◽  
Major Public Health Problem ◽  
Serum Samples ◽  
Point Of Care Test

Introduction: Brucellosis is a major public health problem in Egypt. The Brucella IgM/IgG lateral flow assay was developed as a point-of-care test for the diagnosis of human brucellosis. The aim of this study was to assess the diagnostic value of the lateral flow assay for use in Egypt. Methodology: Fifty samples of patients who presented with clinical suspicion of brucellosis over a one-year period were collected.  All samples were subjected to the Brucella IgM/IgG lateral flow assay, serum agglutination test (SAT), rose bengal RB Test (RB), 2- mercapteoethanol (2-ME), culture and PCR. SAT, 2- ME, culture and PCR were retested after the end of the treatment. Results: Culture and SAT confirmed the diagnosis of brucellosis in twenty patients.  While 90% of the samples were positive by SAT, only 30% and 85% were positive by culture and PCR respectively. The sensitivity of the lateral flow assay calculated for the Brucella IgM/IgG was 95% and specificity was 97%. Conclusion: These data show that the lateral flow assay is more suitable for diagnosis of brucellosis in Egypt than culture and SAT.  Application of the PCR on serum samples collected during follow-up revealed that the DNA of the pathogen was yet not completely cleared almost 60 days after the start of treatment with doxycycline and ciprofloxacin.

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