Bartonella henselae
causes cat scratch disease and several other clinical entities. Infections with
B. henselae
are frequently occurring; however, the infection is only rarely diagnosed, mainly due ...to a lack of knowledge in the medical community.
Bartonella henselae
causes cat scratch disease and several other clinical entities. Infections with
B. henselae
are frequently occurring; however, the infection is only rarely diagnosed, mainly due to a lack of knowledge in the medical community. Microscopic immunofluorescence assays (IFA) are widely used for the serodiagnosis of
B. henselae
infections but are laborious and time-consuming, and interpretation is subjective. An easy and reliable method for the serological diagnosis of
B. henselae
infections is needed to overcome the shortcomings of the current IFA. Here, we report the development of an ELISA detecting human anti-
B. henselae
antibodies from serum samples. By separating the water-insoluble fraction of
B. henselae
Houston-1 via ion-exchange chromatography, 16 subfractions were generated and tested for immunoreactivity via line blotting. One particular fraction (fraction 24) was selected and spotted on ELISA plates using an industrial production platform. By use of well-characterized human sera from the strictly quality-controlled serum library of the German National Consiliary Laboratory for
Bartonella
infections, the sensitivity of this ELISA was 100% for PCR-proven infections and 76% for clinically suspected infections at a specificity of 93%. This ELISA is therefore a reliable high-throughput method allowing the serodiagnosis of
B. henselae
infections.
•For IgG detection >14 days after symptoms onset was 100.0 % for all assays.•Specificity for IgG was greater than 98 % for CLIA and LFIA compared to ELISA.•LFIA (NG-Test®) is reliable and accurate to ...diagnose SARS-CoV-2 infection.•Best agreement was observed between CLIA and LFIA assays (97 %; k = 0.936).
The emergence of new SARS-CoV-2 has promoted the development of new serological tests that could be complementary to RT-PCR. Nevertheless, the assessment of clinical performances of available tests is urgently required as their use has just been initiated for diagnose.
The aim of this study was to assess the performance of three immunoassays for the detection of SARS-CoV-2 antibodies.
Two automated immunoassays (Abbott SARS-CoV-2 CLIA IgG and Euroimmun Anti-SARS-CoV-2 ELISA IgG/IgA assays) and one lateral flow immunoassay (LFIA NG-Test® IgG-IgM COVID-19) were tested. 293 specimens were analyzed from patients with a positive RT-PCR response, from patients with symptoms consistent with COVID-19 but exhibiting a negative response to the RT-PCR detection test, and from control group specimens. Days since symptoms onset were collected from clinical information sheet associated with respiratory tract samples.
Overall sensitivity for IgG was equivalent (around 80 %) for CLIA, ELISA and LFIA. Sensitivity for IgG detection, >14 days after onset of symptoms, was 100.0 % for all assays. Overall specificity for IgG was greater for CLIA and LFIA (more than 98 %) compared to ELISA (95.8 %). Specificity was significantly different between IgA ELISA (78.9 %) and IgM LFIA (95.8 %) (p < 0.05). The best agreement was observed between CLIA and LFIA assays (97 %; k = 0.936).
Excellent sensitivity for IgG detection was obtained >14 days after onset of symptoms for all immunoassays. Specificity was also excellent for IgG CLIA and IgG LFIA. Our study shows that NG-Test® is reliable and accurate for routine use in clinical laboratories.
Because of the advantages of simplicity, cost-effectiveness and visibility, lateral-flow immunoassays (LFAs) have been widely used in the food safety field. However, the low sensitivity of LFAs needs ...to be solved. Nanozymes have amazing potential for application in biosensors due to their excellent and abundant enzyme-like characteristics. In this study, an Au@Pt nanozyme synthesized by a one-step method showed the higher affinity with TMB/H2O2 and higher catalytic efficiency than that of horseradish peroxidase (HRP). For the detection of streptomycin (STR), a typical aminoglycoside antibiotic, a novel LFA based on Au@Pt as a visual tag and an enhanced LFA based on the enzyme-like activity of Au@Pt by addition of the chromogenic substrate 3-amino-9-ethyl-carbazole (AEC) were established and compared with conventional LFA based on AuNPs. The qualitative limit of detection (LOD) was 1 ng mL−1 for the LFA based on Au@Pt as the visual tag and 0.1 ng mL−1 for the enhanced LFA based on the activity of Au@Pt, in comparison to 8 ng mL−1 for LFA based on AuNPs. Furthermore, the level of streptomycin in milk samples from Zhenjiang City was successfully evaluated by the novel LFA based on Au@Pt nanozyme. These results suggest that LFAs based on nanozymes are a promising and effective tool for food safety.
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•Au@Pt nanozyme with higher peroxidase-like activity was synthesized by a simple one-step method.•Lateral-flow immunoassays based on Au@Pt as tag and enzyme mimic showed higher sensitivity.•Lateral-flow immunoassay based on catalytic activity of Au@Pt was used to detect STR in milk.
While the coronavirus disease 2019 (COVID-19) pandemic has peaked in many countries already, the current challenge is to assess population immunity on a large scale. Many serological tests are ...available and require urgent independent validation. Here, we report performance characteristics of Orient Gene Biotech COVID-19 IgG/IgM Rapid Test Cassette (OG) and compare it to Abbott SARS-CoV-2 IgG immunoassay (ASIA). Patients (
n
= 102) with a positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcriptase PCR (RT-PCR) were tested.
While the coronavirus disease 2019 (COVID-19) pandemic has peaked in many countries already, the current challenge is to assess population immunity on a large scale. Many serological tests are available and require urgent independent validation. Here, we report performance characteristics of Orient Gene Biotech COVID-19 IgG/IgM Rapid Test Cassette (OG) and compare it to Abbott SARS-CoV-2 IgG immunoassay (ASIA). Patients (
n
= 102) with a positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcriptase PCR (RT-PCR) were tested. The patients were asymptomatic (
n
= 2) or had mild (
n
= 37) or severe symptoms requiring hospitalization in a medical unit (
n
= 35) or intensive care unit (
n
= 28). Specificity was evaluated for 42 patients with previous viral and parasitic diseases as well as a high level of rheumatic factor. The sensitivity of OG was 95.8% (95% confidence interval CI95%, 89.6 to 98.8) for samples collected ≥10 days after the onset of symptoms, which was equivalent to the sensitivity of ASIA of 90.5% (CI95%, 82.8 to 95.6). OG uncovered six false-negative results of ASIA, of which two had only IgM with OG. Specificity was 100% (CI95%, 93.4 to 100) with both tests on samples, including patients infected with endemic coronavirus. Overall, OG performance characteristics indicate that the test is suitable for routine use in clinical laboratories, and its performance is equivalent to that of immunoassay. Testing OG on a larger asymptomatic population may be needed to confirm these results.
Food contaminated by foodborne pathogens causes diseases, affects individuals, and even kills those affected individuals. As such, rapid and sensitive detection methods should be developed to screen ...pathogens in food. One current detection method is lateral flow immunoassay, an efficient technique because of several advantages, including rapidity, simplicity, stability, portability, and sensitivity. This review presents the format and principle of lateral flow immunoassay strip and the development of conventional lateral flow immunoassay for detecting foodborne pathogens. Furthermore, novel strategies that can be applied to enhance the sensitivity of lateral flow immunoassay to detect foodborne pathogens are presented; these strategies include innovating new label application, designing new formats of lateral flow immunoassay, combining with other methods, and developing signal amplification systems. With these advancements, detection sensitivity and detection time can be greatly improved.
Quantum dots for Förster Resonance Energy Transfer (FRET) Cardoso Dos Santos, Marcelina; Algar, W. Russ; Medintz, Igor L. ...
TrAC, Trends in analytical chemistry (Regular ed.),
April 2020, 2020-04-00, 2020-04, Volume:
125
Journal Article
Peer reviewed
Open access
The analysis of biomolecular interactions using quantum dots (QDs) as both FRET donors and acceptors has become an established technique in the life sciences. This development has been driven by the ...unique properties of QDs, which include large surfaces for the attachment of biomolecules, high brightness and photostability, strong and spectrally broad absorption, and color-tunability via QD size, shape, and material. Applications include molecular rulers for structural analysis, small-molecule sensors, immunoassays, enzyme assays, nucleic acid assays, fluorescence imaging in-vitro and in-vivo, and molecular logic gates. Here, we will explain the theory of QD-based FRET, review some aspects of QD surface functionalization that are important for FRET, and highlight and discuss the advantages and disadvantages of QDs in FRET-biosensing using both spectroscopy and imaging techniques.
•Quantum dot bioconjugation strategies.•FRET theory for quantum dot donors and acceptors.•Biosensing using quantum dots and FRET.•Quantum dot molecular/spectroscopic rulers.•Quantum dot immunoassays, enzyme assays, and nucleic acid assays.•Multistep FRET and higher order multiplexing.•Imaging using quantum dots and FRET.
Since December 2019, the novel coronavirus, SARS-CoV-2, has garnered global attention due to its rapid transmission, which has infected more than two million people worldwide. Early detection of ...SARS-CoV-2 is one of the crucial interventions to control virus spread and dissemination. Molecular assays have been the gold standard to directly detect for the presence of viral genetic material in infected individuals. However, insufficient viral RNA at the point of detection may lead to false negative results. As such, it is important to also employ immune-based assays to determine one's exposure to SARS-CoV-2, as well as to assist in the surveillance of individuals with prior exposure to SARS-CoV-2. Within a span of 4 months, extensive studies have been done to develop serological systems to characterize the antibody profiles, as well as to identify and generate potentially neutralizing antibodies during SARS-CoV-2 infection. The vast diversity of novel findings has added value to coronavirus research, and a strategic consolidation is crucial to encompass the latest advances and developments. This review aims to provide a concise yet extensive collation of current immunoassays for SARS-CoV-2, while discussing the strengths, limitations and applications of antibody detection in SARS-CoV-2 research and control.
Because of the global spread of Zika virus, accurate and high-throughput diagnostic immunoassays are needed. We compared the sensitivity and specificity of 5 commercially available Zika virus ...serologic assays to the recommended protocol of Zika virus IgM-capture ELISA and plaque-reduction neutralization tests. Most commercial immunoassays showed low sensitivity, which can be increased.
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