Antigen In Human Serum Research Articles

Development and characterisation of a 13-plex binding assay to detect Shigella antibodies in human samples

Abstract Shigella is the leading bacterial cause of diarrhea worldwide, with increasing levels of antibiotic resistance. The greatest burden is among children under five in low- and middle-income countries, and efforts are ongoing to develop vaccines against this pathogen. One of the challenges associated with the development of a vaccine against Shigella is the need for a multivalent vaccine covering the most prevalent Shigella serotypes. Epidemiological studies to better understand the prevalence of the different Shigella serotypes and inform vaccination schedules are very useful, together with clinical data showing the ability of vaccines to elicit cross-reactive antibodies. Here, we set up a Luminex-based method able to reproducibly measure antibodies specific to 13 different Shigella antigens in human sera. This method will allow to rapidly collect large amounts of data from analysis of serum samples from vaccinated subjects or people naturally exposed to Shigella, supporting the development of a vaccine against this disease.

Immunochromatography Lateral Flow Strip Enhancement Based on Passive Gold Nanoparticles Conjugation to Detect Schistosma haematobium Antigens in Human Serum

PurposeThis study aimed to develop and evaluate a lateral flow card for the detection of active Schistosoma haematobium infection.MethodsIn order to prepare the immunochromatography lateral flow strip (ICLFS), antibodies purified from schistosomiasis were conjugated passively with gold nanoparticles using a potassium carbonate buffer.ResultsThe novel ICLFS was able to correctly identify 64 out of 67 samples of schistosomiasis, 6 out of 90 samples of other parasites, and 0 out of 27 control samples. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were 95.5%, 93.3%, 90%, and 91.4% respectively. Comparatively, the sensitivity, specificity, NPV, and PPV of sandwich enzyme-linked immunosorbent assays (ELISA) conjugated with gold nanoparticles (AuNPs) were 91.1%, 88.8%, 85.9%, and 84.4% respectively. The increased sensitivity and specificity of ICLFS produced superior results to those of sandwich ELISA.ConclusionIn conclusion, ICLFS is more beneficial and precise than sandwich ELISA for detection of S. haematobium infection at early stage.

A Multiplex "Disposable Photonics" Biosensor Platform and Its Application to Antibody Profiling in Upper Respiratory Disease.

Photonic technologies promise to deliver quantitative, multiplex, and inexpensive medical diagnostic platforms by leveraging the highly scalable processes developed for the fabrication of semiconductor microchips. However, in practice, the affordability of these platforms is limited by complex and expensive sample handling and optical alignment. We previously reported the development of a disposable photonic assay that incorporates inexpensive plastic micropillar microfluidic cards for sample delivery. That system as developed was limited to singleplex assays due to its optical configuration. To enable multiplexing, we report a new approach addressing multiplex light I/O, in which the outputs of individual grating couplers on a photonic chip are mapped to fibers in a fiber bundle. As demonstrated in the context of detecting antibody responses to influenza and SARS-CoV-2 antigens in human serum and saliva, this enables multiplexing in an inexpensive, disposable, and compact format.

Different electrode system based electrochemical aptasensor for the detection of dengue virus antigen in human serum: A comparative study

The current study demonstrates the manufacturing of highly sensitive aptasensr for the robust and effective detection of dengue virus antigen. The proposed electrochemical aptasensor employs both types of electrodes, namely commercialized screen-printed electrodes (C-SPEs) and self-fabricated screen-printed electrodes (SF-SPEs), were efficiently diagnose dengue virus antigen (DENV-Ag) and shows a lower limit of detection (LOD) i.e., 0.1 μg/ml. Both the electrode types were coated with chemically synthesized ZnO-Nanomaterial, which aids in electron transport, and to make it more selective highly specific DNA-aptamer was used against the DENV antigen. SEM and Uv–Vis spectra approaches were used to characterize the synthesized nanomaterial. To confirm the DENV-antigen detection results, electrochemical analysis was performed and the sensor cross-reactivity was also checked by a close member of the dengue virus i.e., chikungunya virus (CHIKV). The developed platform based on SF-SPEs & C-SPEs performed well in human serum. This investigation found that the SF-SPEs system had advanced sensitivity and responded very well to the C-SPEs. Consequently, the SF-SPEs system has emerged as a feasible choice for low-cost and highly sensitive DENV-detection and is also applicable for other analytes diagnostics.

One-Dimensional HKUST-1-Decorated Glassy Carbon Electrode for the Sensitive Electrochemical Immunosensor of NS1 Dengue Virus Serotype-3.

In this work, simple and sensitive detection of dengue virus serotype-3 (DENV-3) antigen was accomplished by a one-dimensional (1D) HKUST-1-functionalized electrochemical sensor. 1D HKUST-1 was synthesized via a coprecipitation method using triethanolamine (TEOA) as pH modulator and structure-directing agent. The structure, morphology, and sensing performance of the HKUST-1-decorated carbon electrode were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). We found that 40 wt% TEOA transforms the octahedron HKUST-1 to the nanorods while maintaining its crystal structure and providing chemical stability. The 1D HKUST-1-decorated carbon electrode successfully detects the antigen in the range of 0.001-10 ng/mL with a detection limit of 0.932 pg/mL. The immunosensor also exhibits remarkable performance in analyzing the antigen in human serum and showed recovery as high as ∼98% with excellent selectivity and reproducibility.

A Facile Graphene Conductive Polymer Paper Based Biosensor for Dopamine, TNF-α, and IL-6 Detection.

Paper-based biosensors are a potential paradigm of sensitivity achieved via microporous spreading/microfluidics, simplicity, and affordability. In this paper, we develop decorated paper with graphene and conductive polymer (herein referred to as graphene conductive polymer paper-based sensor or GCPPS) for sensitive detection of biomolecules. Planetary mixing resulted in uniformly dispersed graphene and conductive polymer ink, which was applied to laser-cut Whatman filter paper substrates. Scanning electron microscopy and Raman spectroscopy showed strong attachment of conductive polymer-functionalized graphene to cellulose fibers. The GCPPS detected dopamine and cytokines, such as tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6) in the ranges of 12.5-400 µM, 0.005-50 ng/mL, and 2 pg/mL-2 µg/mL, respectively, using a minute sample volume of 2 µL. The electrodes showed lower detection limits (LODs) of 3.4 µM, 5.97 pg/mL, and 9.55 pg/mL for dopamine, TNF-α, and IL-6 respectively, which are promising for rapid and easy analysis for biomarkers detection. Additionally, these paper-based biosensors were highly selective (no serpin A1 detection with IL-6 antibody) and were able to detect IL-6 antigen in human serum with high sensitivity and hence, the portable, adaptable, point-of-care, quick, minute sample requirement offered by our fabricated biosensor is advantageous to healthcare applications.

B-089 Development of a Secondary Standard for Quantitation of IgG Antibodies to SARS-CoV-2 Proteins in a Multiplex Assay

Abstract Background Serological surveillance is essential for monitoring disease burden and vaccine uptake at an individual and population level. During the pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), several serological assays were developed and obtained emergency use authorization to detect antibodies after infection. At that time, the need was to differentiate the infected from the naïve population, and these qualitative assays played a critical role in disease management. In the wake of vaccinations, there is a need for the development of quantitative assays. The world health organization (WHO) developed an international standard for quantitation. We performed this study to develop and validate an in-house secondary standard for our multiplex assay based on this WHO standard. Methods We developed a novel multiplex assay for quantifying human IgG antibodies to four different SARS-CoV-2 antigens in human serum or plasma. We have used Luminex® xMAP® technology for this assay and immobilized four recombinant proteins, namely, the receptor-binding domain of S1(RBD), nucleocapsid protein (NP), S1 protein (S1), and trimeric Spike protein (trimer) on internally coded magnetic microspheres. We procured lyophilized WHO quantification standard 20/136 from the National Institute for Biological Standards and Control (NIBSC), which has the arbitrary assignment of 1000 BAU/mL after reconstitution in 0.25 mL. We tested this standard in the range of 10 to 0.01 BAU/mL for the standard curve. We tested NIBSC 20/162 control reagent using this assay for the linearity of dilution. Thirty-seven samples from the NIBSC verification panel were also tested for this evaluation. We also quantified IgG antibodies in 25 samples from vaccinated individuals, ten samples from vaccine breakthrough individuals, 25 samples from PCR-positive individuals, and 75 samples collected before 2019. Results The secondary standard was calibrated using the 20/136 standard. The NIBSC 20/136 and the secondary standard displayed a wide dynamic range of quantitation. The difference in the expected and actual concentrations was less than 20%. Multiple dilutions of the serum or plasma samples were used to get readings within the standard curve range. Excellent linearity was noted at various sample dilutions to get the correct quantification. We observed that vaccinated individuals had a higher concentration of binding antibodies to S1, Trimer, and RBD and were negative for NP antibodies. Conversely, the acute samples from infected individuals collected less than ten days post-positive PCR showed higher antibodies to NP than different spike proteins. The vaccine break-through infection samples showed lower NP antibodies than unvaccinated but infected individuals. Conclusion Our development of a secondary standard calibrated against WHO international standard is vital for quantitatively measuring different SARS-CoV-2 antibodies. A secondary standard can help manufacturers and users to normalize results from various assays and lots over a prolonged period.

Application of a Novel One-Side Cell Quartz Crystal Microbalance Immunosensor in the Determination of Alpha-Fetoprotein from Human Serum.

The rapid and accurate detection of alpha-fetoprotein (AFP) levels is of great significance for the diagnosis and later treatment evaluation of liver cancer. In this study, a novel integrated quartz crystal microbalance (QCM) immunosensor based on the design to contact liquids on one side only was developed for the label-free detection of AFP. Anti-AFP mouse monoclonal antibodies were immobilized onto the upper electrode surface of the pre-treatment crystals using the staphylococcus aureus protein A. The AFP antigens in human serum were captured by specific surface-coated antibodies, and testing was carried out by monitoring the corresponding changes in frequency. The concentration range of the antigen detected was 13-760 ng/mL. The frequency characteristics of the process of antibody immobilization were investigated in detail, and high reproducibility of AFP antibody immobilization was achieved (standard deviation (SD) = 2.2 Hz). The developed QCM measurement system demonstrated a short test time (only 30 min), good reproducibility (the biological activity can still maintain more than 90% of the first test till it is reused five times), and accuracy as good as the one achieved with the radioimmunoassay (the maximum relative deviation = 4.8%). The designed QCM test system can easily and quickly detect AFP concentrations up to 760 ng/mL, indicating that the developed QCM assay is likely to lead to an alternative approach in large-scale screening for liver cancer in the near future.

Electrochemical detection of carcinoembryonic antigen in human serum based on designed anti-fouling and anti-enzymolysis peptides conjugated with silk sericine-inspired beta-homoserine

Zwitterionic peptides with strong water binding ability have drawn much attention in the biomedical diagnosis field as antifouling materials. However, the proteolytic susceptibility of natural peptides in human serum or blood greatly limited their practical application. Herein, inspired by the strong stability and biocompatibility of sericin, an extended zwitterionic peptide containing unnatural β-homoserine (pβ-peptide) was designed to construct antifouling biosensors with enhance stability in complex biological fluids. The molecular dynamic simulation illustrated the strong water binding capability of the pβ-peptide owing to the formation of a large quantity of hydrogen bonds with water. Compared with the electrodes modified with normal peptide, ones modified with the designed peptide demonstrated much stronger antifouling capability and significantly enhanced stability when evaluated in human serum and blood. Furthermore, the constructed biosensor integrating the designed antifouling peptide with carcinoembryonic antigen (CEA) aptamer exhibited a great sensitivity for detecting CEA protein, with a broad linear range of 1.0 fg·mL−1-1.0 ng·mL−1 and a low detection limit of 0.33 fg·mL−1. The biosensor was competent to accurately assay CEA in clinical serum samples when compared with the commonly adopted ELISA method, which indicates a promising potential for practical applications.

Antifouling zwitterionic peptide hydrogel based electrochemical biosensor for reliable detection of prostate specific antigen in human serum

An electrochemical biosensor based on the antifouling zwitterionic peptide hydrogel (CFEFKFC) and the poly(3,4-ethylenedioxythiophene) (PEDOT) was fabricated to accurately detect prostate specific antigen (PSA) in complex human serum. The electrode was modified with the conducting polymer PEDOT and gold nanoparticles (AuNPs) in sequence through electrodeposition, and then the designed zwitterionic peptide hydrogel prepared through self-assembly was immobilized onto the modified electrode surface via the Au–S bond. The zwitterionic peptide hydrogel with cysteine terminal is easy for immobilization onto the gold surface, and it is also suitable for the immobilization of biomolecules such as PSA antibody in this work, through the formation of covalent amide bonds. The peptide hydrogel possessed excellent antifouling property, and it was able to effectively prevent the adsorption of nonspecific proteins, cells and other biomolecules. The developed antifouling biosensor showed a linear response range from 0.1 ng mL−1 to 100 ng mL−1, with a low limit of detection down to 5.6 pg mL−1. These results encourage the wide use of zwitterionic peptide hydrogels as antifouling materials in various sensing and bio-sensing devices.

A click chemistry amplified nanopore assay for ultrasensitive quantification of HIV-1 p24 antigen in clinical samples

Despite major advances in HIV testing, ultrasensitive detection of early infection remains challenging, especially for the viral capsid protein p24, which is an early virological biomarker of HIV-1 infection. Here, To improve p24 detection in patients missed by immunological tests that dominate the diagnostics market, we show a click chemistry amplified nanopore (CAN) assay for ultrasensitive quantitative detection. This strategy achieves a 20.8 fM (0.5 pg/ml) limit of detection for HIV-1 p24 antigen in human serum, demonstrating 20~100-fold higher analytical sensitivity than nanocluster-based immunoassays and clinically used enzyme-linked immunosorbent assay, respectively. Clinical validation of the CAN assay in a pilot cohort shows p24 quantification at ultra-low concentration range and correlation with CD4 count and viral load. We believe that this strategy can improve the utility of p24 antigen in detecting early infection and monitoring HIV progression and treatment efficacy, and also can be readily modified to detect other infectious diseases.

Serum BRD2 autoantibody in hepatocellular carcinoma and its detection using mimotope peptide‑conjugated BSA.

Tumor‑associated (TA) autoantibodies are considered to be promising biomarkers for the early detection of cancer, prior to the development of clinical symptoms. In the present study, a novel TA autoantibody was detected, which may prove to be useful as a diagnostic marker of human HCC using an HBx‑transgenic (HBx‑tg) hepatocellular carcinoma (HCC) mouse model. Its target antigen was identified as the bromodomain‑containing protein 2 (BRD2), a transcriptional regulator that plays a pivotal role in the transcriptional control of diverse genes. BRD2 was upregulated in HCC tissues of the H‑ras12V‑tg mouse and human subjects, as demonstrated using western blotting or immunohistochemical analysis, with the BRD2 autoantibody. In addition, the truncated BRD2 reactive to the BRD2 autoantibody was detected in tumor cell‑derived exosomes, which possibly activated TA immune responses and the generation of autoantibodies. For the detection of the serum BRD2 autoantibody, epitope mimicries of autoantigenic BRD2 were screened from a random cyclic peptide CX7C library with the BRD2 autoantibody. A mimotope with the sequence of CTSVFLPHC, which was cyclized by one pair of cysteine residues, exhibited high affinity to the BRD2 autoantibody and competitively inhibited the binding of the autoantibody to the cellular BRD2 antigen. The use of this cyclic peptide as a capture antigen in human serum enzyme‑linked immunosorbent assay allowed the distinction of patients with HCC from healthy subjects with 64.41% sensitivity and 82.42% specificity (area under the ROC curve, 0.7761), which is superior to serum alpha‑fetoprotein (AFP; 35.83% sensitivity; 100% specificity; area under the ROC curve, 0.5337) for the diagnosis of HCC. In addition, the detection of the BRD2 autoantibody combined with other autoantibody biomarkers or AFP has increased the accuracy of HCC diagnosis, suggesting that the combinational detection of cancer biomarkers, including the BRD2 autoantibody, is a promising assay for HCC diagnosis.

Peroxymonosulfate Activation on Synergistically Enhanced Single-Atom Co/Co@C for Boosted Chemiluminescence of Tris(bipyridine) Ruthenium(II) Derivative.

Tris(bipyridine) ruthenium(II)-based luminophores have been well developed in the area of electrochemiluminescence, while their applications in chemiluminescence (CL) are rarely studied due to the poor luminous efficiency and complicated CL reaction. Herein, a novel tris(bipyridine) ruthenium(II)-based ternary CL system is proposed by introducing cobalt single atoms integrated with graphene-encapsulated cobalt nanoparticles (Co SAs/Co@C) and peroxymonosulfate (PMS) as advanced coreaction accelerator and promising coreactant, respectively. On the basis of the experimental results and density functional theory calculations, it is concluded that Co@C can synergistically modulate the adsorption behavior of PMS on Co SAs and then efficiently activate PMS to produce massive singlet oxygen for remarkable CL emission. Under the optimum conditions, the as-prepared CL biosensor exhibits a good linear range, excellent sensitivity, and selectivity, holding great potential for the practical detection of prostate-specific antigen in human serum.

Validation and performance of a multiplex serology assay to quantify antibody responses following SARS-CoV-2 infection or vaccination.

ObjectivesRobust, quantitative serology assays are required to accurately measure antibody levels following vaccination and natural infection. We present validation of a quantitative, multiplex, SARS‐CoV‐2, electrochemiluminescent (ECL) serology assay; show correlation with two established SARS‐CoV‐2 immunoassays; and present calibration results for two SARS‐CoV‐2 reference standards.MethodsPrecision, dilutional linearity, ruggedness, analytical sensitivity and specificity were evaluated. Clinical sensitivity and specificity were assessed using serum from prepandemic and SARS‐CoV‐2 polymerase chain reaction (PCR)‐positive patient samples. Assay concordance to the established Roche Elecsys® Anti‐SARS‐CoV‐2 immunoassay and a live‐virus microneutralisation (MN) assay was evaluated.ResultsStandard curves demonstrated the assay can quantify SARS‐CoV‐2 antibody levels over a broad range. Assay precision (10.2−15.1% variability), dilutional linearity (≤ 1.16‐fold bias per 10‐fold increase in dilution), ruggedness (0.89−1.18 overall fold difference), relative accuracy (107−118%) and robust selectivity (102−104%) were demonstrated. Analytical sensitivity was 7, 13 and 7 arbitrary units mL−1 for SARS‐CoV‐2 spike (S), receptor‐binding domain (RBD) and nucleocapsid (N) antigens, respectively. For all antigens, analytical specificity was > 90% and clinical specificity was 99.0%. Clinical sensitivities for S, RBD and N antigens were 100%, 98.8% and 84.9%, respectively. Comparison with the Elecsys® immunoassay showed ≥ 87.7% agreement and linear correlation (Pearson r of 0.85, P < 0.0001) relative to the MN assay. Conversion factors for the WHO International Standard and Meso Scale Discovery® Reference Standard are presented.ConclusionsThe multiplex SARS‐CoV‐2 ECL serology assay is suitable for efficient, reproducible measurement of antibodies to SARS‐CoV‐2 antigens in human sera, supporting its use in clinical trials and sero‐epidemiology studies.

Electrochemical Detection of Carcinoembryonic Antigen in Human Serum Based on Designed Anti-Fouling and Anti-Enzymolysis Peptides Conjugated with Silk Sericine-Inspired Beta-Homoserine

Electrochemical Detection of Carcinoembryonic Antigen in Human Serum Based on Designed Anti-Fouling and Anti-Enzymolysis Peptides Conjugated with Silk Sericine-Inspired Beta-Homoserine

A triple-layer microchannel array chip with micro through-holes for smartphone based point-of-care testing of biomarker

Colorimetric detection on a microchip frequently suffers the sensitivity problem due to the limited optical path length. Herein, a point-of-care testing (POCT) device based on the colorimetric detection on a microchip with an array of micro through holes for enlarged optical length and an optical imaging system was demonstrated. Each micro through hole has a depth of 2 mm and a volume roughly 0.6 μl, connecting to a microchannel for the efficient reaction. Up to 32 micro through holes were arranged compactly along a round region with a diameter of 13 mm to make them effectively captured by a smartphone camera in a short distance (6.5 cm). For reliable smartphone imaging, a handheld, battery powered optical imaging cassette was made by three-dimensional (3D) printing. A data processing program was also written to realize the detection area selection, RGB (red, green, blue) value reading and detection signal calculation. With the integrated device, a biomarker, human immunodeficiency virus (HIV) p24 antigen in human serum was detected down to 20 pg/ml, much better than that with microchannels. The proposed microchip and the imaging system can be a promising POCT or on-site detection tool based on colorimetric detection.

Detection of dengue virus in Eastern India

Background: Dengue fever is a mosquito-borne tropical disease caused by the dengue virus. Symptoms typically begin three to fourteen days after infection. The virus has four serotypes; infection with one type usually gives lifelong immunity to that type, but only short-term immunity to the others. Subsequent infection with different dengue virus increases the risk of severe complications. A number of tests are available to confirm the diagnosis including detection via Dengue NS1Ag Microlisa and Dengue IgM/IgG Microlisa antibody by ELISA Method. Methods: There are three methods followed in particular to detect the dengue virus: (A) Dengue NS1 AG Microlisa is designed for in-vitro qualitative detection of Dengue NS1 antigen in human serum or plasma and is used as a screening test for testing of collected blood samples suspected for DENGUE. This method detects all four subtypes; DEN1, DEN2, DEN3 &amp; DEN4 of Dengue Virus. (B) Dengue IgM Microlisa designed for in-vitro qualitative detection of Dengue IgM Antibody in human serum or plasma and is used as a screening test for testing of collected’ blood samples suspected for DENGUE. This method also detects all four subtypes; DEN1, DEN2, DEN3 &amp; DEN4 of Dengue Virus. (C) Dengue IgG Microlisa designed for in vitro qualitative defection on Dengue IgG antibody in human serum / plasma. Duration – 6 months – July, August, September, October, November, December 2019 at KPC Medical College and Hospital, Kolkata West Bengal. Results: Among 1860 dengue samp1es, 420 sâmp1es were found to be NS1Ag positive 160 samples were found to be IgM positive and 24 samples were found to be IgG positive. Rest Samples negative for all three parameters. Conclusion: Dengue is a mosquito borne viral infection causing a severe flu like illness and sometimes causing a potentially lethal complication called severe dengue. The incidence of dengue has increased 30 fold over the last 50 years. Up to 50-100 million infections are now estimated to occur annually in over 100 endemic countries, putting almost half of the world’s population at risk. If sever dengue fever can damage the lungs, liver or heart or multiorgan failure. Blood pressure can drop to dangerous levels, causing shock and in some cases death.

A surface-enhanced electrochemiluminescence sensor based on Au-SiO2 core-shell nanocomposites doped with Ru(bpy)32+ for the ultrasensitive detection of prostate-specific antigen in human serum.

This study reports a surface-enhanced electrochemiluminescence (SEECL) sensor for the ultrasensitive detection of prostate-specific antigen (PSA) in human serum. First, we prepared the Au-SiO2 core-shell nanocomposites doped with Ru(bpy)32+ (Au@SiO2-Ru) as the ECL signal generation and amplification element of the SEECL sensor. Ru(bpy)32+ could emit ECL under the excitation of an electrochemical reaction, and generate the local surface plasmon resonance (LSPR) electromagnetic field from the gold nanoparticle (AuNP) core. The produced LSPR then effectively enhanced the ECL signals. This sensing strategy was utilized for the detection of PSA, which can be absorbed on the electrode surface by the reaction between PSA and monoclonal antibodies. When polyclonal antibody-modified Au@SiO2-Ru was added, the PSA-double-antibody sandwich structure was formed on the electrode surface and thus, the Au@SiO2-Ru were quantitatively immobilized on the electrode surface. The results show that this kind of SEECL sensor has good selectivity toward PSA. Notably, the minimum detection concentration reached 7 × 10-7 ng mL-1 under the optimum experimental conditions, which is much better than most of the previously reported approaches for the detection of PSA in serum.

IgY antibody and human neurocysticercosis: a novel approach on immunodiagnosis using Taenia crassiceps hydrophobic antigens.

Human neurocysticercosis (NCC) is a worldwide neglected disease caused by Taenia solium metacestode and responsible for various complications and neurological disorders. This study aimed to evaluate the use of specific immunoglobulin Y (IgY) produced by laying hens immunized with a hydrophobic fraction of Taenia crassiceps metacestodes (hFTc) in NCC diagnosis. Egg yolk IgY antibodies were fractionated, purified and characterized. Enzyme-linked immunosorbent assay (ELISA) was carried out to evaluate the production kinetics and avidity maturation of anti-hFTc IgY antibodies throughout the IgY obtention process. Antigen recognition tests were carried out by Western blotting and immunofluorescence antibody test using purified and specific anti-hFTc IgY antibodies for detection of parasitic antigens of T. crassiceps and T. solium metacestodes. Sandwich ELISA was performed to detect circulating immune complexes formed by IgG and parasitic antigens in human sera. The results showed high diagnostic values (93.2% sensitivity and 94.3% specificity) for immune complexes detection in human sera with confirmed NCC. In conclusion, specific IgY antibodies produced from immunized hens with hFTc antigens were efficient to detect T. solium immune complexes in human sera, being an innovative and potential tool for NCC immunodiagnosis.

Unravelling the Role of Electric and Magnetic Dipoles in Biosensing with Si Nanoresonators.

High refractive index dielectric nanoresonators are attracting much attention due to their ability to control both electric and magnetic components of light. Due to the combination of confined modes with reduced absorption losses, they have recently been proposed as an alternative to nanoplasmonic biosensors. In this context, we study the use of semirandom silicon nanocylinder arrays, fabricated with simple and scalable colloidal lithography for the efficient and reliable detection of biomolecules in biological samples. Interestingly, electric and magnetic dipole resonances are associated with two different transduction mechanisms: extinction decrease and resonance red shift. By contrasting both observables, we identify clear advantages in tracking changes in the extinction magnitude. Our data demonstrate that, despite its simplicity, the proposed platform is able to detect prostate-specific antigen in human serum with limits of detection meeting clinical needs.