Label-Free Plasmonic Biosensor for Rapid, Quantitative, and Highly Sensitive COVID-19 Serology: Implementation and Clinical Validation

Serological tests are essential for the control and management of COVID-19 pandemic, not only for current and historical diagnostics but especially for surveillance, epidemiological, and acquired immunity studies. Clinical COVID-19 serology is routinely performed by enzymatic or chemiluminescence immunoassays (i.e., ELISA or CLIA), which provide good sensitivities at the expense of relatively long turnaround times and specialized laboratory settings. Rapid serological tests, based on lateral flow assays, have also been developed and widely commercialized, but they suffer from limited reliability due to relatively low sensitivity and specificity. We have developed and validated a direct serological biosensor assay employing proprietary technology based on Surface Plasmon Resonance (SPR). The biosensor offers a rapid -less than 15 min- identification and quantification of SARS-CoV-2 antibodies directly in clinical samples, without the need of any signal amplification. The portable plasmonic biosensor device employs a custom-designed multi-antigen sensor biochip, combining the two main viral antigens (RBD peptide and N protein), for simultaneous detection of human antibodies targeting both antigens. The SPR serology assay reaches detection limits in the low ng mL-1 range employing polyclonal antibodies as standard, which are well below the commonly detected antibody levels in COVID-19 patients. The assay has also been implemented employing the first WHO approved anti-SARS-CoV-2 immunoglobulin standard. We have carried out a clinical validation with COVID-19 positive and negative samples (n=120) that demonstrates the excellent diagnostic sensitivity (99%) and specificity (100%). This positions our biosensor device as an accurate, robust, and easy-to-use diagnostics tool for rapid and reliable COVID-19 serology to be employed both at laboratory and decentralized settings for the management of COVID-19 patients and for the evaluation of immunological status during vaccination, treatment or in front of emerging variants.<br>

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Label-Free Plasmonic Biosensor for Rapid, Quantitative, and Highly Sensitive COVID-19 Serology: Implementation and Clinical Validation

10.26434/chemrxiv.14595654 ◽

2021 ◽

Author(s):

Olalla Calvo-Lozano ◽

MIquel Sierra ◽

Maria Soler ◽

M.-Carmen Estevez ◽

luis Chiscano-camon ◽

...

Keyword(s):

Polyclonal Antibodies ◽

Simultaneous Detection ◽

Clinical Samples ◽

Clinical Validation ◽

Label Free ◽

Serological Tests ◽

N Protein ◽

Lateral Flow Assays ◽

Low Sensitivity ◽

Biosensor Device

Serological tests are essential for the control and management of COVID-19 pandemic, not only for current and historical diagnostics but especially for surveillance, epidemiological, and acquired immunity studies. Clinical COVID-19 serology is routinely performed by enzymatic or chemiluminescence immunoassays (i.e., ELISA or CLIA), which provide good sensitivities at the expense of relatively long turnaround times and specialized laboratory settings. Rapid serological tests, based on lateral flow assays, have also been developed and widely commercialized, but they suffer from limited reliability due to relatively low sensitivity and specificity. We have developed and validated a direct serological biosensor assay employing proprietary technology based on Surface Plasmon Resonance (SPR). The biosensor offers a rapid -less than 15 min- identification and quantification of SARS-CoV-2 antibodies directly in clinical samples, without the need of any signal amplification. The portable plasmonic biosensor device employs a custom-designed multi-antigen sensor biochip, combining the two main viral antigens (RBD peptide and N protein), for simultaneous detection of human antibodies targeting both antigens. The SPR serology assay reaches detection limits in the low ng mL-1 range employing polyclonal antibodies as standard, which are well below the commonly detected antibody levels in COVID-19 patients. The assay has also been implemented employing the first WHO approved anti-SARS-CoV-2 immunoglobulin standard. We have carried out a clinical validation with COVID-19 positive and negative samples (n=120) that demonstrates the excellent diagnostic sensitivity (99%) and specificity (100%). This positions our biosensor device as an accurate, robust, and easy-to-use diagnostics tool for rapid and reliable COVID-19 serology to be employed both at laboratory and decentralized settings for the management of COVID-19 patients and for the evaluation of immunological status during vaccination, treatment or in front of emerging variants.<br>

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Detection of Coxiella burnetii Using Silicon Microring Resonator in Patient Blood Plasma

Micromachines ◽

10.3390/mi10070427 ◽

2019 ◽

Vol 10 (7) ◽

pp. 427 ◽

Cited By ~ 2

Author(s):

Bonhan Koo ◽

Choong Eun Jin ◽

Moonsuk Bae ◽

Yoon Ok Jang ◽

Ji Yeun Kim ◽

...

Keyword(s):

Infectious Disease ◽

Blood Plasma ◽

Coxiella Burnetii ◽

Q Fever ◽

Microring Resonator ◽

Clinical Samples ◽

Plasma Samples ◽

Label Free ◽

Highly Sensitive ◽

Low Sensitivity

Blood plasma from patients is a powerful resource for diagnosing infectious disease due to it having many genetic materials as well as being relatively easy to obtain. Thus, various biosensors have been investigated for diagnosing diseases in blood plasma. However, there are no optimized and validated sensors for clinical use due to the low sensitivity, complexity, and difficulties of removing the inhibitors from plasma samples. In this study, we described a silicon microring resonator sensor used to detect Coxiella burnetii from the blood plasma of Q-fever patients in a label-free, real-time manner. Q-fever is an infectious disease caused by Coxiella burnetii via direct contact or inhalation aerosols. We validated this biosensor in the blood plasma of 35 clinical samples (including 16 Q fever samples infected with Coxiella burnetii and 19 samples infected with other febrile diseases. The biosensors are capable of rapid (10 min), highly sensitive (87.5%), and specific (89.5%) detection in plasma samples compared to the use of the conventional method.

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Clinical autoantibody detection by microarray

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2016-0533 ◽

2017 ◽

Vol 55 (4) ◽

Cited By ~ 2

Author(s):

Doreen Dillaerts ◽

Heidi De Baere ◽

Xavier Bossuyt

Keyword(s):

Blood Donors ◽

Simultaneous Detection ◽

Clinical Samples ◽

Systemic Autoimmune Disease ◽

Farr Assay ◽

Nuclear Antigens ◽

Antibody Assays ◽

Low Sensitivity ◽

Autoantibody Detection ◽

Dsdna Antibodies

Abstract Background: AMiDot is a microdot array-based immunoassay that allows simultaneous detection of multiple autoantibodies on a single patient. We evaluated the AMiDot “Systemic Autoimmune Disease” (SAD) panel, which detects antibodies to 17 different antigens. Methods: AMiDot was performed on 184 samples from blood donors and on 280 randomly selected clinical samples containing antibodies to extractable nuclear antigens or to dsDNA. The results obtained by AMiDot on the clinical samples were compared to results obtained by EliA (Thermo Fisher) for anti-Ro60, anti-La, anti-RNP, anti-Scl-70, anti-CENPB, anti-Sm, and anti-Jo-1 and by Farr assay for anti-dsDNA. Discordant results were further analyzed by immunodot (D-tek). Results: Concordance between AMiDot and EliA was ≥87% and κ agreement ≥0.44. When compared to EliA and immunodot (in case of discordance between AMiDot and EliA), concordance improved to ≥91% and κ agreement to ≥0.77. The sensitivity of AMiDot (compared to EliA and immunodot, in case of discordance between AMiDot and EliA) was ≥93%, except for anti-Ro60 (84%). The concordance and κ agreement of AMiDot with the Farr assay (for dsDNA antibodies) was, respectively, 84% and 0.33. The sensitivity of AMiDot for dsDNA (compared to Farr assay) was 25%. The specificity was ≥97% (in blood donors as well as in clinical samples). The within-run imprecision was 9%–27% and the between-run imprecision 29%–39%. Conclusions: AMiDot offers an alternative to line immunodot assay. Individual antibody assays might suffer from low sensitivity.

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Evaluation of rapid, cassette immunochromatographic tests in the serological diagnosis of COVID-19

Medycyna Doświadczalna i Mikrobiologia ◽

10.32394/mdm.73.03 ◽

2021 ◽

pp. 25-37

Author(s):

Waldemar Rastawicki ◽

Klaudia Płaza ◽

Adam Pietrusiński

Keyword(s):

Low Cost ◽

Lateral Flow ◽

Serological Diagnosis ◽

Igg Antibodies ◽

Serum Samples ◽

Serological Tests ◽

Negative Results ◽

Lateral Flow Assays ◽

Low Sensitivity ◽

Positive Results

Introduction: Lateral flow assays (LFIA) are the technology behind low-cost, simple, rapid and portable detection devices popular in biomedicine. Lately, they are very common used in serodiagnosis of SARS-CoV-2 infections. The aim of the presented study was to assess the usefulness of selected LFIA in serological diagnosis of COVID-19. Methods: The usefulness of seven lateral flow assays in the serodiagnosis of COVID-19 was evaluated (VAZYME, DIAGNOSIS, PCL, INGEZIM, BIOSENSOR, ACCU-TELL, NOVAtest). The study used 107 serum samples obtained from 74 individuals with current SARS-CoV-2 infection confirmed by RT-PCR. The ELISA-IgG (Euroimmun) was used as the reference assay for sensitivity and specificity testing. Results: The highest percentage of positive results was obtained when searching for IgG antibodies with the NOVAtest (40.6%) and DIAGNOSIS (39.2%) sets and the lowest detection for the PCL set - 25.5%. In the case of searching for IgM antibodies in all sets, significantly lower percentages of positive results compared to the IgG class were recorded. In general, all lateral flow assays showed low sensitivity in relation to the Euroimmun ELISA-IgG. The DIAGNOSIS kit (64.5%) was characterized by the highest sensitivity, and the PCL kit was the lowest (38.7%). On the other hand, the specificity of all kits was very high, almost 100% in almost all cases. Conclusions: Lateral flow assays due to their low sensitivity are not suitable for quick diagnosis of the current SARS-CoV-2 infections and cannot be an alternative to genetic or even antigen tests. They may be used only to retrospectively test the presence of IgG antibodies. However, a negative results of LFIA in suspected disease or after vaccination should be confirmed by more sensitive serological tests.

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Multiplex Recombinase Polymerase Amplification Assay for Simultaneous Detection of Treponema pallidum and Haemophilus ducreyi in Yaws-Like Lesions

Tropical Medicine and Infectious Disease ◽

10.3390/tropicalmed5040157 ◽

2020 ◽

Vol 5 (4) ◽

pp. 157

Author(s):

Michael Frimpong ◽

Shirley Victoria Simpson ◽

Hubert Senanu Ahor ◽

Abigail Agbanyo ◽

Solomon Gyabaah ◽

...

Keyword(s):

Simultaneous Detection ◽

Treponema Pallidum ◽

Recombinase Polymerase Amplification ◽

Nucleic Acid Amplification ◽

Haemophilus Ducreyi ◽

World Health ◽

Clinical Samples ◽

Successful Implementation ◽

Serological Tests

Yaws is a skin debilitating disease caused by Treponema pallidum subspecies pertenue with most cases reported in children. World Health Organization (WHO) aims at total eradication of this disease through mass treatment of suspected cases followed by an intensive follow-up program. However, effective diagnosis is pivotal in the successful implementation of this control program. Recombinase polymerase amplification (RPA), an isothermal nucleic acid amplification technique offers a wider range of differentiation of pathogens including those isolated from chronic skin ulcers with similar characteristics such as Haemophilus ducreyi (H. ducreyi). We have developed a RPA assay for the simultaneous detection of Treponema pallidum (T. pallidum) and H. ducreyi (TPHD-RPA). The assay demonstrated no cross-reaction with other pathogens and enable detection of T. pallidum and H. ducreyi within 15 min at 42 °C. The RPA assay was validated with 49 clinical samples from individuals confirmed to have yaws by serological tests. Comparing the developed assay with commercial multiplex real-time PCR, the assay demonstrated 94% and 95% sensitivity for T. pallidum and H. ducreyi, respectively and 100% specificity. This simple novel TPHD-RPA assay enables the rapid detection of both T. pallidum and H. ducreyi in yaws-like lesions. This test could support the yaws eradication efforts by ensuring reliable diagnosis, to enable monitoring of program success and planning of follow-up interventions at the community level.

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Validity of a Serological Diagnostic Kit for SARS-CoV-2 Available in Iran

Archives of Iranian Medicine ◽

10.34172/aim.2020.75 ◽

2020 ◽

Vol 23 (9) ◽

pp. 629-632

Author(s):

Hamid Reza Shamsollahi ◽

Mostafa Amini ◽

Shaban Alizadeh ◽

Saharnaz Nedjat ◽

Ali Akbari-Sari ◽

...

Keyword(s):

Diagnostic Techniques ◽

Effective Control ◽

Molecular Technique ◽

Size Estimation ◽

Medical Sciences ◽

Serological Tests ◽

Standard Case ◽

Epidemic Size ◽

Low Sensitivity ◽

Negative Controls

Background: The Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic broke out in December 2019 and is now characterized as a pandemic. Effective control of this infectious disease requires access to diagnostic techniques, for both case finding and epidemic size estimation. The molecular technique is routinely used worldwide. Although it is the "standard" case detection and management method, it has its own shortcomings. Thus, some easy-to-use rapid serological tests have been developed. Methods: One hundred and fourteen positive RT-PCR-diagnosed patients were tested by VivaDiag Kit, a brand of rapid serological kits available in hospitals affiliated to Tehran University of Medical Sciences (TUMS), Tehran, Iran. Frozen serum specimens taken from healthy people in summer and fall 2019 were also tested as negative controls. Results: Test sensitivity was 47.9% (95% confidence interval [CI]: 38.8-56.9) for IgM and 47.0% (95% CI: 38.0–56.0) for IgG. There was no difference between IgG and IgM seropositivity except in one case. Specificity was calculated as 99.0% (95% CI: 96.4–99.9) for IgM and of 100.0% (95% CI: 0.98.2–100.0) for IgG. Sensitivity was higher in men and older participants. Conclusion: This test can be used for epidemiological investigations, especially for the estimation of the level of infection in the community, after it is properly corrected for sensitivity and specificity. The low sensitivity could be attributed to the technical limitations of the kit or low levels of antibodies after infection. The different sensitivity in age and sex groups supports the hypothesis that different people show different immune responses to this virus.

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Integrating high-performing electrochemical transducers in lateral flow assay

Analytical and Bioanalytical Chemistry ◽

10.1007/s00216-021-03301-y ◽

2021 ◽

Author(s):

Antonia Perju ◽

Nongnoot Wongkaew

Keyword(s):

High Performance ◽

Point Of Care ◽

Low Cost ◽

High Sensitivity ◽

Lateral Flow ◽

Analytical Performance ◽

Label Free ◽

High Performing ◽

Lateral Flow Assays ◽

Electrochemical Transducers

AbstractLateral flow assays (LFAs) are the best-performing and best-known point-of-care tests worldwide. Over the last decade, they have experienced an increasing interest by researchers towards improving their analytical performance while maintaining their robust assay platform. Commercially, visual and optical detection strategies dominate, but it is especially the research on integrating electrochemical (EC) approaches that may have a chance to significantly improve an LFA’s performance that is needed in order to detect analytes reliably at lower concentrations than currently possible. In fact, EC-LFAs offer advantages in terms of quantitative determination, low-cost, high sensitivity, and even simple, label-free strategies. Here, the various configurations of EC-LFAs published are summarized and critically evaluated. In short, most of them rely on applying conventional transducers, e.g., screen-printed electrode, to ensure reliability of the assay, and additional advances are afforded by the beneficial features of nanomaterials. It is predicted that these will be further implemented in EC-LFAs as high-performance transducers. Considering the low cost of point-of-care devices, it becomes even more important to also identify strategies that efficiently integrate nanomaterials into EC-LFAs in a high-throughput manner while maintaining their favorable analytical performance.

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Microfluidics-Based Plasmonic Biosensing System Based on Patterned Plasmonic Nanostructure Arrays

Micromachines ◽

10.3390/mi12070826 ◽

2021 ◽

Vol 12 (7) ◽

pp. 826

Author(s):

Yanting Liu ◽

Xuming Zhang

Keyword(s):

Plasmon Resonance ◽

Point Of Care ◽

Simultaneous Detection ◽

High Sensitivity ◽

Microfluidic Chips ◽

Label Free ◽

Plasmonic Nanostructure ◽

Point Of Care Diagnostics ◽

Surface Enhanced Raman ◽

Nanostructure Arrays

This review aims to summarize the recent advances and progress of plasmonic biosensors based on patterned plasmonic nanostructure arrays that are integrated with microfluidic chips for various biomedical detection applications. The plasmonic biosensors have made rapid progress in miniaturization sensors with greatly enhanced performance through the continuous advances in plasmon resonance techniques such as surface plasmon resonance (SPR) and localized SPR (LSPR)-based refractive index sensing, SPR imaging (SPRi), and surface-enhanced Raman scattering (SERS). Meanwhile, microfluidic integration promotes multiplexing opportunities for the plasmonic biosensors in the simultaneous detection of multiple analytes. Particularly, different types of microfluidic-integrated plasmonic biosensor systems based on versatile patterned plasmonic nanostructured arrays were reviewed comprehensively, including their methods and relevant typical works. The microfluidics-based plasmonic biosensors provide a high-throughput platform for the biochemical molecular analysis with the advantages such as ultra-high sensitivity, label-free, and real time performance; thus, they continue to benefit the existing and emerging applications of biomedical studies, chemical analyses, and point-of-care diagnostics.

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Label-Free Mass Spectrometry-Based Quantification of Linker Histone H1 Variants in Clinical Samples

International Journal of Molecular Sciences ◽

10.3390/ijms21197330 ◽

2020 ◽

Vol 21 (19) ◽

pp. 7330

Author(s):

Roberta Noberini ◽

Cristina Morales Torres ◽

Evelyn Oliva Savoia ◽

Stefania Brandini ◽

Maria Giovanna Jodice ◽

...

Keyword(s):

Mass Spectrometry ◽

Histone H1 ◽

Histone Variants ◽

Linker Histone ◽

Clinical Samples ◽

Label Free ◽

Complex Samples ◽

Linker Histone H1 ◽

Ideal Tool ◽

Free Quantification

Epigenetic aberrations have been recognized as important contributors to cancer onset and development, and increasing evidence suggests that linker histone H1 variants may serve as biomarkers useful for patient stratification, as well as play an important role as drivers in cancer. Although traditionally histone H1 levels have been studied using antibody-based methods and RNA expression, these approaches suffer from limitations. Mass spectrometry (MS)-based proteomics represents the ideal tool to accurately quantify relative changes in protein abundance within complex samples. In this study, we used a label-free quantification approach to simultaneously analyze all somatic histone H1 variants in clinical samples and verified its applicability to laser micro-dissected tissue areas containing as low as 1000 cells. We then applied it to breast cancer patient samples, identifying differences in linker histone variants patters in primary triple-negative breast tumors with and without relapse after chemotherapy. This study highlights how label-free quantitation by MS is a valuable option to accurately quantitate histone H1 levels in different types of clinical samples, including very low-abundance patient tissues.

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