Displaying publications 1 - 20 of 93 in total

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  1. Diagnosis of Group A streptococcal pharyngitis by enzyme immunoassay
    Zooraidah Z, Farida J
    Family Physician, 1990;2:27-29.
    Matched MeSH terms: Immunoassay
  2. Immuno-probed multiwalled carbon nanotube surface for abdominal aortic aneurysm biomarker analysis
    Zhao X, Gopinath SCB, Zhao W
    Biotechnol Appl Biochem, 2023 Apr;70(2):502-508.
    PMID: 35661417 DOI: 10.1002/bab.2372
    Abdominal aortic aneurysm (AAA), a medical complication, occurs when the aortic area becomes swollen and very large. It is mandatory to identify AAA to avoid the breakdown of aneurysms. C-reactive protein (CRP) has been recognized as one of the biomarkers for identifying AAA due to the possibility of CRP produced in vascular tissue, which contributes to the formation of an aneurysm, and it is elevated in patients with a ruptured AAA. This research work was designed to develop an immunosensor on a multiwalled carbon nanotube (MWCNT)-modified surface to quantify the CRP level. Anti-CRP specificity was constructed on the MWCNT surface through a silane linker to interact with CRP. The detection limit of CRP was calculated as 100 pM with an R2 (determination coefficient) value of 0.9855 (y = 2.3446x - 1.9922) on a linear regression graph. The dose-dependent linear pattern was registered from 200 to 3000 pM and attained the saturation level during binding at 3000 pM. Furthermore, serum-spiked CRP showed a clear increase in the current response, proving the specific recognition of CRP in biological samples. This designed biosensor identifies CRP at a lower level and can help diagnose AAA.
    Matched MeSH terms: Immunoassay
  3. Fulltext Methods for Systematic Identification of Membrane Proteins for Specific Capture of Cancer-Derived Extracellular Vesicles
    Zaborowski MP, Lee K, Na YJ, Sammarco A, Zhang X, Iwanicki M, et al.
    Cell Rep, 2019 Apr 02;27(1):255-268.e6.
    PMID: 30943406 DOI: 10.1016/j.celrep.2019.03.003
    Analysis of cancer-derived extracellular vesicles (EVs) in biofluids potentially provides a source of disease biomarkers. At present there is no procedure to systematically identify which antigens should be targeted to differentiate cancer-derived from normal host cell-derived EVs. Here, we propose a computational framework that integrates information about membrane proteins in tumors and normal tissues from databases: UniProt, The Cancer Genome Atlas, the Genotype-Tissue Expression Project, and the Human Protein Atlas. We developed two methods to assess capture of EVs from specific cell types. (1) We used palmitoylated fluorescent protein (palmtdTomato) to label tumor-derived EVs. Beads displaying antibodies of interest were incubated with conditioned medium from palmtdTomato-expressing cells. Bound EVs were quantified using flow cytometry. (2) We also showed that membrane-bound Gaussia luciferase allows the detection of cancer-derived EVs in blood of tumor-bearing animals. Our analytical and validation platform should be applicable to identify antigens on EVs from any tumor type.
    Matched MeSH terms: Immunoassay/methods
  4. Anti-cyclic citrullinated peptide autoantibodies (anti-CCP) in Malaysian patients with rheumatoid arthritis. [Abstract]
    Yuslina MY, Shahnaz M, Too CL, Hussein H, Wahinuddin S, Eashwary M, et al.
    APLAR Journal of Rheumatology, 2006;9 Suppl 1:A187-A188.
    Background: Anti-cyclic citrullinated peptide autoantibodies (anti-CCP) is a new serological test for the diagnosis of rheumatoid arthritis (RA). It is an enzyme immunoassay (EIA) for the detection of antibodies directed toward citrullinated peptides. Studies show this test has an improved diagnostic value compared to rheumatoid factor (RF). Objective: To determine the sensitivity and specificity of anti-CCP in patients with rheumatoid arthritis and other rheumatic diseases. Method: 227 serum samples for rheumatology clinics (Putrajaya, Taiping, and Ipoh Hospital) were tested for the presence of anti-CCP and rheumatoid factor (RF). These included 171 patients diagnosed with RA and 56 from other rheumatic diseases. Patient demographic data, clinical diagnosis, radiographic information and other laboratory data were obtained from the patients' clinical notes. Results: Anti-CCP antibodies were detected in 76.6% (131/171) patients with RA and 17.9% (10/56) patients with other arthritis. The sensitivity and specificity of anti-CCP reactivity at the optimal cut off values were 66.1% and 87.5% respectively. The sensitivity of anti-CCP was higher than that for RF (41.8%). However, the presence of either anti-CCP or RF improved the sensitivity to 76.2%. Conclusion: The detection of anti-CCP alone maybe useful in the diagnosis of RA. However, when used concomitantly with RF, it can improve the diagnostic ability significantly.
    Matched MeSH terms: Immunoassay
  5. Fulltext Evaluation of the Elecsys(®) Anti-HCV II assay for routine hepatitis C virus screening of different Asian Pacific populations and detection of early infection
    Yoo SJ, Wang LL, Ning HC, Tao CM, Hirankarn N, Kuakarn S, et al.
    J Clin Virol, 2015 Mar;64:20-7.
    PMID: 25728074 DOI: 10.1016/j.jcv.2014.12.015
    Early diagnosis of hepatitis C virus (HCV) infection is essential to allow appropriate treatment and prevent transmission.
    Matched MeSH terms: Immunoassay/methods*
  6. Hev b 5 and Hev b 13 as allergen markers to estimate the allergenic potency of latex gloves
    Yeang HY, Arif SA, Raulf-Heimsoth M, Loke YH, Sander I, Sulong SH, et al.
    J Allergy Clin Immunol, 2004 Sep;114(3):593-8.
    PMID: 15356563 DOI: 10.1016/j.jaci.2004.05.039
    BACKGROUND:
    Sensitization to natural rubber latex has been linked to proteins from medical latex gloves. Various assays to estimate the amount of residual allergenic proteins extractable from latex gloves to assess their potential exposure hazard have inherent weaknesses.

    OBJECTIVE:
    This investigation was aimed at developing 2-site immunoenzymetric assays and identifying appropriate protein markers to assess the allergenic potential of latex gloves.

    METHODS:
    The presence of 6 latex allergens--Hev b 1, 2, 3, 5, 6, and 13--was measured in a cross-section of commercial latex medical gloves by using monoclonal and polyclonal antibody-based 2-site immunoenzymetric assays. The overall allergenic potential of these gloves was assessed by IgE-inhibition assay. Stepwise multiple regression analyses were performed to identify marker allergens that best explained the variation in latex glove allergenicity.

    RESULTS:
    All 6 latex allergens were detected in at least some of the glove samples. Hev b 5 and Hev b 13 were identified as the marker allergens that combined best to explain the variation in the glove allergenicity. The significant multiple correlation (R=0.855) between these 2 markers and glove allergenic potency forms the basis of an assay to gauge latex glove allergenicity.

    CONCLUSION:
    The overall allergenic potential of latex gloves can be estimated by using Hev b 5 and Hev b 13 as indicator allergens. The correlation between glove allergenicity and the level of these allergens was maintained for low-protein gloves (<200 microg/g). This estimation of glove allergenicity was superior to that obtained by using total protein readings.
    Matched MeSH terms: Immunoassay/methods
  7. Natural rubber latex allergens: new developments
    Yeang HY
    Curr Opin Allergy Clin Immunol, 2004 Apr;4(2):99-104.
    PMID: 15021061
    PURPOSE OF REVIEW:
    New allergenic latex proteins have been identified, whereas further information on known latex allergens has emerged in recent years. Although prevalence figures for sensitization to the various latex allergens have been published in several studies in the past, the data have not been collated to facilitate cross-comparison.

    RECENT FINDINGS:
    Salient characteristics of the three most recently identified latex allergens, Hev b 11, 12 and 13 are described, whereas new findings on some of the previously recognized allergens are examined. Hev b 2 is viewed from the standpoint of allergenicity and protein glycosylation, Hev b 4 in relation to its biochemical identity and molecular cloning, Hev b 5 with respect to its recombinant form, and Hev b 6 in connection with conformational IgE epitopes. Reports on sensitization or allergic reaction to purified latex allergens from recent and past work are summarized. The use of latex allergens in latex allergy diagnostics is reviewed and discussed.

    SUMMARY:
    Thirteen latex allergens have been recognized by the International Union of Immunological Societies. Based on the results of published studies, native Hev b 2, recombinant Hev b 5, native or recombinant Hev b 6, native Hev b 13, and possibly native Hev b 4 are the major allergens relevant to latex-sensitized adults. Although there is an increasing tendency to identify and characterize latex allergens largely on the basis of their recombinant forms, not all such recombinant proteins have been fully validated against their native counterparts with respect to clinical significance.
    Matched MeSH terms: Immunoassay
  8. Achieving enhanced sensitivity and accuracy in carcinoembryonic antigen (CEA) detection as an indicator of cancer monitoring using thionine/chitosan/graphene oxide nanocomposite-modified electrochemical immunosensor
    Yang H, Zhang Z, Zhou X, Binbr Abe Menen N, Rouhi O
    Environ Res, 2023 Dec 01;238(Pt 1):117163.
    PMID: 37722583 DOI: 10.1016/j.envres.2023.117163
    The current study has focused on electrochemical immunosensing of carcinoembryonic antigen (CEA) employing an immobilized antibody on a thionine, chitosan, or graphene oxide nanocomposite modified glassy carbon electrode (anti-CEA/THi-CS-GO/GCE) as an indicator of cancer monitoring. THi-CS-GO nanocomposites were made using ultrasonication, and analyses of their morphology and crystal structure using SEM, FTIR, and XRD showed that thionine and chitosan molecules were intercalated with stacking interactions with both the top and bottom of GO nanosheets. Electrochemical experiments revealed anti-CEA, THi-CS-GO/GCE to have exceptional sensitivity and selectivity towards CEA compounds. The detection limit value was established to be 0.8 pg/mL when it was discovered that variations in the decrease peak current were directly proportional to the logarithm concentration of CEA over a wide range from 10-3 to 104 ng/mL. Results of testing the immunosensor's application capability for detecting CEA in a sample of human serum show that ELISA and DPV results are very congruent. The produced immunosensor demonstrated adequate immunosensor precision in determining CEA in prepared genuine samples of human serum and clinical applications.
    Matched MeSH terms: Immunoassay/methods
  9. Fulltext SWCNT Network-FET Device for Human Serum Albumin Detection
    Yahya I, Hassan MA, Maidin NNM, Mohamed MA
    Sensors (Basel), 2022 Oct 26;22(21).
    PMID: 36365910 DOI: 10.3390/s22218212
    A thin film of single-walled carbon nanotube (SWCNT) network field-effect transistor (FET) was fabricated by a simple, fast, and reliable deposition method for electronic applications. This study aims to develop a method for fabricating a thin film of random SWCNTs to be used as a transducer to detect human serum albumin (HSA) in biosensor applications. The random SWCNT network was deposited using the airbrush technique. The morphology of the CNT network was examined by utilising atomic force microscopy (AFM) and field-emission scanning electron microscopy (FESEM), while electrical characteristics were analysed using three-terminal IV measurements. The thin film (SWCNT network) was applied as a transducer to detect human serum albumin (HSA) based on its covalent interaction with antibodies. HSA plays a significant part in the physiological functions of the human body. The surface alteration of the SWCNTs was verified using Fourier transform infrared (FTIR) spectroscopy. Electrical current-voltage measurements validated the surface binding and HSA detection. The biosensor linearly recorded a 0.47 fg/mL limit of detection (LOD) and a high sensitivity of 3.44 μA (g/mL)-1 between 1 fg/mL and 10 pg/mL. This device can also be used to identify a genuine HSA despite interference from other biomolecules (i.e., bovine serum albumin (BSA)), thus demonstrating the random SWCNT-FET immunosensor ability to quantify HSA in a complex biological environment.
    Matched MeSH terms: Immunoassay
  10. Fulltext Epidemiological screening of lymphatic filariasis among immigrants using dipstick colloidal dye immunoassay
    Wan Omar A, Sulaiman O, Yusof S, Ismail G, Fatmah MS, Rahmah N, et al.
    Malays J Med Sci, 2001 Jul;8(2):19-24.
    PMID: 22893756
    We have recently reported that a dipstick colloidal dye immunoassay (DIA) that detect parasite antigens in human serum is sensitive and specific for the diagnosis of active infection of lymphatic filariasis. Rabbit polyclonal antibodies (RbBmCAg) labelled with a commercial dye, palanil navy blue was used to detect filarial antigenemia among Indonesian and Bangladeshi immigrant workers (N= 630) at oil palm estates at Hulu Trengganu District, Peninsular Malaysia. Microfilaremia with Brugia malayi were detected in 51 (8.10 %) individuals, of which 42 (6.67 %) were among the Indonesians and 9 (1.98 %) among the Bangladeshis. Microfilaremia with Wuchereria bancrofti were detected in 33 (5.24 %) individuals of which 15 (2.38 %) were among the Indonesians and 18 (2.86 %) among the Bangladeshis workers. The DIA detected 96 (15.24 %) antigenemic cases which comprise of all the microfilaremic cases and 15 (2.38 %) amicrofilaremic cases. The amicrofilaremic cases with filarial antigenemia consisted of 9 (1. 43 %) Indonesians and 6 (0.95%) Bangladeshis. We have used 6 ul of the RbBmCAg and diluted (1:10) patients' sera per dipstick which make the DIA reagent conservative. The DIA is a rapid test and can be read in approximate 2 hours.. Additionally, coloured dots developed in the DIA can be qualitatively assessed visually for intensity. The DIA does not require sophisticated equipment or radioactivity, and therefore suitable for field application.
    Matched MeSH terms: Immunoassay
  11. Heavy/light chain assay in the monitoring of multiple myeloma
    Ting HY, Sthaneshwar P, Bee PC, Shanmugam H, Lim M
    Pathology, 2019 Aug;51(5):507-511.
    PMID: 31253381 DOI: 10.1016/j.pathol.2019.04.002
    Serum protein (SPE) and immunofixation electrophoresis (IFE) have been extensively validated for the routine use of identifying, characterising and quantifying monoclonal proteins. However, accurate quantitation of IgA monoclonal proteins can be difficult when they migrate in to the β fraction, due to co-migration with transferrin and complement components. The heavy/light chain (HLC) immunoassay is an additional tool for measuring intact immunoglobulin monoclonal proteins. Therefore, we aimed to examine the clinical utility of the HLC assay for the disease monitoring of IgG and IgA multiple myeloma (MM) patients. A total of 177 samples from 30 MM patients (21 IgG and 9 IgA) were analysed retrospectively with median number of six follow up samples per patient (range 3-13). Serum free light chains (sFLC) and HLC were quantified using Freelite and Hevylite immunoassays. Details of M-protein concentration, β-globulin levels, total immunoglobulin levels and disease treatment response were obtained from the laboratory and patient information system. Passing-Bablok regression analysis was performed to compare (i) M-protein quantification with involved HLC (iHLC) and (ii) total immunoglobulin with summated HLC pairs for each immunoglobulin type (e.g., IgGκ+IgGλ). For 127 IgG MM samples, IgG iHLC levels showed a good correlation with SPE quantification (iHLC y=0.96x+4.9; r=0.917) and summated HLC showed a good correlation with total IgG concentration (summated HLC y=0.94x+5.74; r=0.91). In total, 95/127 (75%) IgG MM follow-up samples had an abnormal HLC ratio and 122/127 (96%) had a positive SPE, probably due to the lower sensitivity of HLC assay in detecting clonality in patients with IgG MM. Consistent with this, one patient assigned a very good partial response by International Myeloma Working Group criteria would be assigned a complete response based on HLC measurements. For 50 IgA MM samples, 42/50 (84%) had an abnormal HLC ratio. Conversely, 50/50 (100%) of M-proteins showed β fraction migration and were difficult to accurately quantify by SPE. Therefore, M-protein concentration and iHLC did not correlate as well in IgA MM (y=1.9x-8.4; r=0.8) compared to IgG MM. However, there was good correlation between total IgA and summated IgA HLC (IgAκ+IgAλ y=1.35x-0.33; r=0.95). Of the 8/50 (16%) IgA samples with a normal HLC ratio, 6/8 (75%) were consistent with the disease status being in complete remission. Interestingly, in one IgA MM patient, SPE and IFE were negative, but the serum FLC ratio and involved FLC were highly abnormal, consistent with the presence of light chain escape. Our data suggest HLC measurements could add value to the current disease monitoring of MM patients. In IgG MM patients, the M-protein level correlated well with HLC values. The HLC assay complements the serum FLC assay and is especially useful for monitoring of IgA MM patients who display M-proteins migrating in the β region on SPE.
    Matched MeSH terms: Immunoassay/methods*
  12. Fulltext Sequential push-pull pumping mechanism for washing and evacuation of an immunoassay reaction chamber on a microfluidic CD platform
    Thio TH, Ibrahim F, Al-Faqheri W, Soin N, Kahar Bador M, Madou M
    PLoS One, 2015;10(4):e0121836.
    PMID: 25853411 DOI: 10.1371/journal.pone.0121836
    A centrifugal compact disc (CD) microfluidic platform with reservoirs, micro-channels, and valves can be employed for implementing a complete immunoassay. Detection or biosensor chambers are either coated for immuno-interaction or a biosensor chip is inserted in them. On microfluidic CDs featuring such multi-step chemical/biological processes, the biosensor chamber must be repeatedly filled with fluids such as enzymes solutions, buffers, and washing solutions. After each filling step, the biosensor chamber needs to be evacuated by a passive siphoning process to prepare it for the next step in the assay. However, rotational speed dependency and limited space on a CD are two big obstacles to performing such repetitive filling and siphoning steps. In this work, a unique thermo-pneumatic (TP) Push-Pull pumping method is employed to provide a superior alternative biosensor chamber filling and evacuation technique. The proposed technique is demonstrated on two CD designs. The first design features a simple two-step microfluidic process to demonstrate the evacuation technique, while the second design shows the filling and evacuation technique with an example sequence for an actual immunoassay. In addition, the performance of the filling and evacuation technique as a washing step is also evaluated quantitatively and compared to the conventional manual bench top washing method. The two designs and the performance evaluation demonstrate that the technique is simple to implement, reliable, easy to control, and allows for repeated push-pulls and thus filling and emptying of the biosensor chamber. Furthermore, by addressing the issue of rotational speed dependency and limited space concerns in implementing repetitive filling and evacuation steps, this newly introduced technique increases the flexibility of the microfluidic CD platform to perform multi-step biological and chemical processes.
    Matched MeSH terms: Immunoassay/instrumentation*
  13. Usefulness of paired samples for the Serodiagnosis of toxoplasmosis infection in a tertiary teaching Hospital in Malaysia
    Thangarajah P, Hajissa K, Wong WK, Abdullah MA, Ismail N, Mohamed Z
    BMC Infect Dis, 2019 Feb 28;19(1):202.
    PMID: 30819141 DOI: 10.1186/s12879-019-3830-9
    BACKGROUND: Accurate diagnosis of Toxoplasma gondii (T. gondii) infection remains elusive and requires a comprehensive assessment through laboratory and clinical investigation. In this study, a diagnostic algorithm based on paired serum samples and clinical data was developed and evaluated.

    METHODS: A total of 1267 suspected cases of Toxoplasma infection were enrolled in this study from January 2016 to December 2016. The cases were screened for anti-Toxoplasma IgM and IgG by electrochemiluminiscence immunoassay (ECLIA) method. Based on the serological profiles, all cases with first seropositive serum samples were considered as suggestive cases of Toxoplasma infection. Thus, second serum samples were obtained after an interval of 2 weeks. The diagnosis was made based on laboratory results and clinical data.

    RESULTS: A total of 482 T. gondii seroreactive cases were selected. The patient's records were traced and the data were analysed. Accordingly, 152 cases were diagnosed as clinically confirmed cases; 198 cases were clinically asymptomatic and 132 cases were newborn babies or infants who did not have toxoplasmosis and only acquired passive immunity from their mothers. The paired serum algorithm allowed classifying the seroreactive cases as follows: early (0.6%), acute (1.9%), reactivation (13.5%), recent (1.5%), passive immunity from mother (27.3%) and possible congenital infections (1.2%). In addition, cases of reactivated toxoplasmosis were detected among the pregnant mothers (13/82; 15.8%), children aged above 1 year (2/8; 25.0%) and immunocompetent mothers (5/135; 3.7%). Furthermore, the application of the paired serum analysis resulted in remarkably improved treatment initiation.

    CONCLUSIONS: Toxoplasmosis diagnosis and treatment can be improved through the use of paired serum diagnostic algorithm.

    Matched MeSH terms: Immunoassay
  14. Impedimetric cardiac biomarker determination in serum mediated by epoxy and hydroxyl of reduced graphene oxide on gold array microelectrodes
    Taniselass S, Arshad MKM, Gopinath SCB, Fathil MFM, Ibau C, Anbu P
    Mikrochim Acta, 2021 07 15;188(8):257.
    PMID: 34268634 DOI: 10.1007/s00604-021-04922-x
    A label-free chemical bonding strategy mediated by reduced graphene oxide (rGO) basal plane functional groups has been developed for cardiac Troponin I (cTnI) detection. Four different chemical strategies on respective electrode sensing surface were precedingly examined using electrochemical impedance spectroscopy. The impedimetric assessment was carried out by sweeping frequency at the range 0.1-500 kHz perturbated at a small amplitude of AC voltage (25 mV). The chemical strategy-4 denoted as S-4 shows a significant analytical performance on cTnI detection in spiked buffer and human serum, whereby the pre-mixture of rGO and (3-Aminopropyl)triethoxysilane (APTES) creates a large number of amine sites (-NH2), which significantly enhanced the antibody immobilization without excessive functionalization. The as-fabricated immunosensor exhibited an ultra-low limit of detection of 6.3 ag mL-1 and the lowest antigen concentration measured was at 10 ag mL-1. The immunosensor showed a linear and wide range of cTnI detection (10 ag mL-1-100 ng mL-1) in human serum with a regression coefficient of 0.9716, rapid detection (5 min of binding time), and stable and highly reproducible bioelectrode response with RSD 
    Matched MeSH terms: Immunoassay
  15. Molecular evidence and hematological alterations associated with the occurrence of coronavirus in domestic dogs in Pakistan
    Sulehria MU, Ahmad SS, Ijaz M, Mushtaq MH, Khan AY, Ghaffar A
    Trop Biomed, 2020 Dec 01;37(4):963-972.
    PMID: 33612749 DOI: 10.47665/tb.37.4.963
    Canine Enteric Coronavirus (CCoV) is one of the major enteric pathogen affecting dogs. This study aims to investigate the molecular prevalence, phylogenetic analysis, associated risk factors, and haemato-biochemical alterations in Canine Coronavirus in dogs in district Lahore, Pakistan. 450 fecal samples were collected from symptomatic dogs originating from various pet-clinics and kennels during 2018-2019. Samples were initially analyzed by sandwich lateral flow immunochromatographic assay and then further processed by RT-PCR (reverse transcriptase polymerase chain reaction) targeting the M gene followed by sequencing. RT-PCR based positive (n=20) and negative (n=20) dogs were samples for their blood for the haemato-biochemical analysis. A questionnaire was used to collect data from pet owners, in order to analyze the data for risk factors analysis by chi square test on SPSS. The prevalence of CCoV was 35.1%, and 23.8 % through Sandwich lateral flow immunochromatographic and RT-PCR respectively. Various risk factors like breed, age, sex, vomiting, diarrhea, sample source, body size, cohabitation with other animals, living environment, food, deworming history, contact with other animals or birds feces, and season were significantly associated with CCoV. The CCoV identified in Pakistan were 98% similar with the isolates from China (KT 192675, 1), South Korea (HM 130573, 1), Brazil (GU 300134, 1), Colombia (MH 717721, 1), United Kingdom (JX 082356, 1) and Tunisia (KX156806). Haematobiochemical alterations in CCoV affected dogs revealed anaemia, leucopenia, lymphopenia, neutrophilia, and decreased packed cell volume, and a significant increase in alkaline phosphate and alanine transaminase. It is concluded that infection with canine coronavirus appears widespread among dog populations in district Lahore, Pakistan. This study is the first report regarding the molecular detection and sequence analysis of CCoV in Pakistan.
    Matched MeSH terms: Immunoassay
  16. Highly sensitive and specific graphene/TiO2 impedimetric immunosensor based on plant-derived tetravalent envelope glycoprotein domain III (EDIII) probe antigen for dengue diagnosis
    Siew QY, Pang EL, Loh HS, Tan MTT
    Biosens Bioelectron, 2021 Mar 15;176:112895.
    PMID: 33358432 DOI: 10.1016/j.bios.2020.112895
    This study reports on the development of a novel impedimetric immunosensor design using plant-derived antigenic glycoprotein for the detection of dengue virus (DENV) IgG antibodies. The electrochemical immunosensor platform was constructed using screen-printed carbon electrode (SPCE) modified with graphene/titanium dioxide (G/TiO2) nanocomposite to improve the electrode in terms electrochemical performance and specific surface area. A plant-derived dengue envelope domain III (EDIII) protein was used as the antigenic probe protein in this immunosensing strategy. Under optimised sensing conditions, the immunosensor demonstrated high sensitivity towards DENV IgG in a wide linear working range (62.5-2000 ng/mL), with a limit of detection of 2.81 ng/mL. The immunosensor showed high specificity for discriminating DENV IgG against antibodies of other infectious disease, including the closely related Zika virus (ZIKV). The reliability of the immunosensor in serological diagnosis was verified by challenging the immunosensor against serum samples, compared to conventional enzyme-linked immunosorbent assay (ELISA). As shown by its remarkable performance throughout the study, the devised immunosensor is proposed as a reliable and practical diagnostic tool for the serological detection of dengue in realistic applications.
    Matched MeSH terms: Immunoassay
  17. A graphene-based dengue immunosensor using plant-derived envelope glycoprotein domain III (EDIII) as the novel probe antigen
    Siew QY, Tan SH, Pang EL, Loh HS, Tan MTT
    Analyst, 2021 Mar 21;146(6):2009-2018.
    PMID: 33523052 DOI: 10.1039/d0an02219e
    The envelope glycoprotein domain III (EDIII) of dengue virus (DENV) has been recognised as the antigenic region responsible for receptor binding. In the present work, we have proposed a novel immunosensor constructed on a graphene-coated screen-printed carbon electrode (SPCE) using plant-derived EDIII as the probe antigen to target DENV IgG antibodies. The developed immunosensor demonstrated high sensitivity towards DENV IgG within a wide linear working range (125-2000 ng mL-1) under the optimised sensing conditions. The limit of detection was determined to be 22.5 ng mL-1. The immunosensor also showed high specificity towards DENV IgG, capable of differentiating DENV IgG from the antibodies of other infectious diseases including the similarly structured Zika virus (ZIKV). The ability of the immunosensor to detect dengue antibodies in serum samples was also verified by conducting tests on mouse serum samples. The proposed immunosensor was able to provide a binary (positive/negative) response towards the serum samples comparable to the conventional enzyme-linked immunosorbent assay (ELISA), indicating promising potential for realistic applications.
    Matched MeSH terms: Immunoassay
  18. Fulltext Diagnostic techniques for COVID-19 and new developments
    Sheikhzadeh E, Eissa S, Ismail A, Zourob M
    Talanta, 2020 Dec 01;220:121392.
    PMID: 32928412 DOI: 10.1016/j.talanta.2020.121392
    COVID-19 pandemic is a serious global health issue today due to the rapid human to human transmission of SARS-CoV-2, a new type of coronavirus that causes fatal pneumonia. SARS -CoV-2 has a faster rate of transmission than other coronaviruses such as SARS and MERS and until now there are no approved specific drugs or vaccines for treatment. Thus, early diagnosis is crucial to prevent the extensive spread of the disease. The reverse transcription-polymerase chain reaction (RT-PCR) is the most routinely used method until now to detect SARS-CoV-2 infections. However, several other faster and accurate assays are being developed for the diagnosis of COVID-19 aiming to control the spread of infection through the identification of patients and immediate isolation. In this review, we will discuss the various detection methods of the SARS-CoV-2 virus including the recent developments in immunological assays, amplification techniques as well as biosensors.
    Matched MeSH terms: Immunoassay
  19. Reagentless Affimer- and antibody-based impedimetric biosensors for CEA-detection using a novel non-conducting polymer
    Shamsuddin SH, Gibson TD, Tomlinson DC, McPherson MJ, Jayne DG, Millner PA
    Biosens Bioelectron, 2021 Apr 15;178:113013.
    PMID: 33508539 DOI: 10.1016/j.bios.2021.113013
    Polyoctopamine (POct), an amine-functionalised non-conducting polymer, as the transducer layer in an electrochemical biosensor, is presented. This polymer offers versatile covalent coupling either through thiol linker conjugation, carboxyl or aldehyde functional groups without the requirement of pre- or post-surface activation. The colorectal cancer biomarker carcinoembryonic antigen (CEA) was selected as the target analyte, whilst an antibody and a synthetic binding protein, an Affimer, were used as distinct bioreceptors to demonstrate the versatility of polyoctopamine as a transducer polymer layer for oriented immobilisation of the bioreceptors. The electrodeposited polymer layer was characterised using cyclic voltammetry, electrochemical impedance spectroscopy, and on-sensor chemiluminescent blotting. The performance of optimised POct-based biosensors were tested in spiked human serum. Results showed that the electropolymerisation of octopamine on screen printed gold electrode generates a thin polymer film with low resistance. Close proximity of the immobilised bioreceptors to the transducer layer greatly enhanced the sensitivity detection. The sensitivity of the smaller monomeric bioreceptor (Affimer, 12.6 kDa) to detect CEA was comparable to the dimeric antibody (150 kDa) with limit of detection at 11.76 fM which is significantly lower than the basal clinical levels of 25 pM. However, the Affimer-based sensor had a narrower dynamic range compared to the immunosensor (1-100 fM vs. 1 fM - 100 nM, respectively). All electrochemical measurements were done in less than 5 min with small sample volumes (10 μl). Hence, polyoctopamine features a simple fabrication of impedimetric biosensors using amine-functionalisation technique, provides rapid response time with enhanced sensitivity and label-free detection.
    Matched MeSH terms: Immunoassay
  20. Fulltext Production and characterization of a polyclonal antibody of anti-rLipL21-IgG against leptospira for early detection of acute leptospirosis
    Seenichamy A, Bahaman AR, Mutalib AR, Khairani-Bejo S
    Biomed Res Int, 2014;2014:592858.
    PMID: 24860824 DOI: 10.1155/2014/592858
    Leptospirosis is one of the zoonotic diseases in animals and humans throughout the world. LipL21 is one of the important surface-exposed lipoproteins in leptospires and the most effective cross protective immunogenic antigen. It is widely considered as a diagnostic marker for leptospirosis. In this study, we evaluated the serodiagnostic potential of LipL21 protein of Leptospira interrogans serovar Pomona. We have successfully amplified, cloned, and expressed LipL21 in E. coli and evaluated its specificity by immunoblotting. Purified recombinant LipL21 (rLipL21) was inoculated into rabbits for the production of polyclonal antibody. Characterization of the purified IgG antibody against rLipL21 was performed by cross reactivity assay. Only sera from leptospirosis patients and rabbit hyperimmune sera recognized rLipL21 while the nonleptospirosis control sera showed no reaction in immunoblotting. We confirmed that anti-rLipL21-IgG antibody cross reacted with and detected only pathogenic leptospiral species and it did not react with nonpathogenic leptospires and other bacterial species. Results observed showed that anti-rLipL21-IgG antibody has high specificity and sensitivity to leptospires. The findings indicated that the antibody could be used in a diagnostic assay for detection of leptospires or their proteins in the early phase of infection.
    Matched MeSH terms: Immunoassay/methods
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