Spiegelmers as potential receptors for cTnI diagnostics

AbstractBackground:The study aim was to evaluate and compare the analytical performance of the new chemiluminescent immunoassay for cardiac troponin I (cTnI), called Access hs-TnI using DxI platform, with those of Access AccuTnI+3 method, and high-sensitivity (hs) cTnI method for ARCHITECT platform.Methods:The limits of blank (LoB), detection (LoD) and quantitation (LoQ) at 10% and 20% CV were evaluated according to international standardized protocols. For the evaluation of analytical performance and comparison of cTnI results, both heparinized plasma samples, collected from healthy subjects and patients with cardiac diseases, and quality control samples distributed in external quality assessment programs were used.Results:LoB, LoD and LoQ at 20% and 10% CV values of the Access hs-cTnI method were 0.6, 1.3, 2.1 and 5.3 ng/L, respectively. Access hs-cTnI method showed analytical performance significantly better than that of Access AccuTnI+3 method and similar results to those of hs ARCHITECT cTnI method. Moreover, the cTnI concentrations measured with Access hs-cTnI method showed close linear regressions with both Access AccuTnI+3 and ARCHITECT hs-cTnI methods, although there were systematic differences between these methods. There was no difference between cTnI values measured by Access hs-cTnI in heparinized plasma and serum samples, whereas there was a significant difference between cTnI values, respectively measured in EDTA and heparin plasma samples.Conclusions:Access hs-cTnI has analytical sensitivity parameters significantly improved compared to Access AccuTnI+3 method and is similar to those of the high-sensitivity method using ARCHITECT platform.

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Autoantibody prevalence with an improved immunoassay for detecting cardiac troponin-specific autoantibodies

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2013-0310 ◽

2014 ◽

Vol 52 (2) ◽

Cited By ~ 7

Author(s):

Tanja Savukoski ◽

Tuomo Ilva ◽

Juha Lund ◽

Pekka Porela ◽

Noora Ristiniemi ◽

...

Keyword(s):

Myocardial Infarction ◽

Emergency Department ◽

Chest Pain ◽

Cardiac Troponin ◽

Troponin I ◽

State Of The Art ◽

Cardiac Troponin I ◽

High Prevalence ◽

Sandwich Type ◽

Pain Patients

AbstractCardiac troponin-specific autoantibodies (cTnAAb) can interfere with the measurement of cardiac troponin I (cTnI) by immunoassays used for the diagnosis of myocardial infarction (MI). Here, an improved version of a previous autoantibody assay was validated and used to evaluate the cTnAAb prevalence in a cohort of consecutive chest pain patients presenting to an emergency department.Admission samples from 510 patients with suspected MI were analyzed in parallel with two sandwich-type cTnAAb assays based on different cTnI epitopes used to capture cardiac troponin-bound cTnAAbs.Sample-specific backgrounds were lower for the new assay than for the old assay (median 1225 vs. 2693 counts, p<0.001). Net signals of cTnAAb-positive samples were higher for the new assay than for the old assay (median 5076 vs. 3921 counts, p<0.001). Of all patients, 9.2% were cTnAAb-positive for the new assay and 7.3% for the old assay (p=0.013). Previous cardiac problems were not associated with cTnAAb status and cTnAAb status did not correlate with the 12-month outcome.With our new and more sensitive autoantibody assay, approximately one out of ten patients who presented to the initial cardiac triage had detectable amounts of cTnAAbs in the circulation. Because these cTnAAbs can interfere with state-of-the-art cTnI assays, their high prevalence should be acknowledged by clinical chemists, physicians, and kit manufacturers.

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Characterization of Cardiac Troponin I Raman Signature in Bovine Serum Albumin and Human Blood Serum for the Potential Diagnosis of Myocardial Infarction

Natural Products Chemistry & Research ◽

10.4172/2329-6836.1000200 ◽

2016 ◽

Vol 04 (01) ◽

Author(s):

Sara Moghaddamjoo

Keyword(s):

Myocardial Infarction ◽

Bovine Serum Albumin ◽

Serum Albumin ◽

Blood Serum ◽

Human Blood ◽

Bovine Serum ◽

Cardiac Troponin ◽

Troponin I ◽

Cardiac Troponin I

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Full-Size Cardiac Troponin I and Its Proteolytic Fragments in Blood of Patients with Acute Myocardial Infarction: Antibody Selection for Assay Development

Clinical Chemistry ◽

10.1373/clinchem.2017.286211 ◽

2018 ◽

Vol 64 (7) ◽

pp. 1104-1112 ◽

Cited By ~ 18

Author(s):

Ivan A Katrukha ◽

Alexander E Kogan ◽

Alexandra V Vylegzhanina ◽

Alexey V Kharitonov ◽

Natalia N Tamm ◽

...

Keyword(s):

Myocardial Infarction ◽

Acute Myocardial Infarction ◽

Cardiac Troponin ◽

Troponin I ◽

Cardiac Troponin I ◽

Amino Acid Residues ◽

Serum Samples ◽

Before And After ◽

Stable Part ◽

Serial Samples

Abstract BACKGROUND In the blood of patients with acute myocardial infarction (AMI), cardiac troponin I (cTnI) presents as an intact molecule with a repertoire of proteolytic fragments. The degradation of cTnI might negatively influence its precise immunodetection. In this study we identified cTnI fragments and calculated their ratio in the blood of patients at different times after AMI to discriminate the most stable part(s) of cTnI. METHODS Serial serum samples were collected from AMI patients within 1 to 36 h after the onset of chest pain both before and after stenting. cTnI and its fragments were immunoextracted from serum samples and analyzed by Western blotting with monoclonal antibodies (mAbs) specific to the different epitopes of cTnI and by 2 in-house immunoassays specific to the central and terminal portions of cTnI. RESULTS Intact cTnI and its 11 major fragments were detected in blood of AMI patients. The ratio of the fragments in serial samples did not show large changes in the period 1–36 h after AMI. mAbs specific to the epitopes located approximately between amino acid residues (aar) 34 and 126 stained all extracted cTnI. mAbs specific to aar 23–36 and 126–196 recognized approximately 80% to 90% (by abundance) of cTnI. CONCLUSIONS In addition to mAbs specific to the central part of cTnI (approximately aar 34–126), antibodies specific to the adjacent epitopes (approximately aar 23–36 and 126–196) could be used in assays because they recognize ≥80% of cTnI in patients' blood samples within the first 36 h after AMI.

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Spiegelmer-Based Sandwich Assay for Cardiac Troponin I Detection

International Journal of Molecular Sciences ◽

10.3390/ijms21144963 ◽

2020 ◽

Vol 21 (14) ◽

pp. 4963 ◽

Cited By ~ 1

Author(s):

Zoltán János Tolnai ◽

Judit András ◽

Zsuzsanna Szeitner ◽

Krisztina Percze ◽

László Ferenc Simon ◽

...

Keyword(s):

Amino Acid ◽

Cardiac Troponin ◽

Troponin I ◽

Cardiac Troponin I ◽

Sandwich Assay ◽

Surface Plasmon Resonance Analysis ◽

Coronary Syndrome ◽

Resonance Analysis ◽

Sandwich Type ◽

Amino Acid Stretch

Two subunits of the ternary troponin complex, I and C, have cardiac muscle specific isoforms, and hence could be applied as highly-selective markers of acute coronary syndrome. We aimed at paving the way for the development of a robust cardiac troponin I-detecting sandwich assay by replacing antibodies with nuclease resistant aptamer analogues, so-called spiegelmers. To complement the previously generated spiegelmers that were specific for the N-terminus of cTnI, spiegelmers were selected for an amino acid stretch in the proximity of the C-terminal part of the protein by using a D-amino acid composed peptide. Following the selection, the oligonucleotides were screened by filter binding assay, and surface plasmon resonance analysis of the most auspicious candidates demonstrated that this approach could provide spiegelmers with subnanomolar dissociation constant. To demonstrate if the selected spiegelmers are functional and suitable for cTnI detection in a sandwich type arrangement, AlphaLisa technology was leveraged and the obtained results demonstrated that spiegelmers with different epitope selectivity are suitable for specific detection of cTnI protein even in human plasma containing samples. These results suggest that spiegelmers could be considered in the development of the next generation cTnI monitoring assays.

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Ultrasensitive sandwich-type immunosensor for cardiac troponin I based on enhanced electrocatalytic reduction of H2O2 using β-cyclodextrins functionalized 3D porous graphene-supported Pd@Au nanocubes

Journal of Materials Chemistry B ◽

10.1039/c8tb03362e ◽

2019 ◽

Vol 7 (9) ◽

pp. 1460-1468 ◽

Cited By ~ 11

Author(s):

Xiaobo Zhang ◽

Hui Lv ◽

Yueyun Li ◽

Chunyan Zhang ◽

Ping Wang ◽

...

Keyword(s):

Cardiac Troponin ◽

Signal Amplification ◽

Troponin I ◽

Cardiac Troponin I ◽

Electrocatalytic Reduction ◽

Porous Graphene ◽

Sandwich Type ◽

Supported Pd

A signal amplification principle based on increased electrocatalytic reduction of H2O2 by the CDs-3D-PG-Pd@Au NCs using the mediated effect of Th.

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Development of Liposome-Based Immunoassay for the Detection of Cardiac Troponin I

Molecules ◽

10.3390/molecules26226988 ◽

2021 ◽

Vol 26 (22) ◽

pp. 6988

Author(s):

Remya Radha ◽

Mohammad Hussein Al-Sayah

Keyword(s):

Myocardial Infarction ◽

Human Serum ◽

Cardiac Troponin ◽

Troponin I ◽

Cardiac Troponin I ◽

Clinical Settings ◽

The Novel ◽

Fluorescent Properties ◽

Serum Samples ◽

Causes Of Mortality

Cardiovascular diseases (CVDs) are one of the foremost causes of mortality in intensive care units worldwide. The development of a rapid method to quantify cardiac troponin I (cTnI)—the gold-standard biomarker of myocardial infarction (MI) (or “heart attack”)—becomes crucial in the early diagnosis and treatment of myocardial infarction (MI). This study investigates the development of an efficient fluorescent “sandwich” immunoassay using liposome-based fluorescent signal amplification and thereby enables the sensing and quantification of serum-cTnI at a concentration relevant to clinical settings. The calcein-loaded liposomes were utilized as fluorescent nano vehicles, and these have exhibited appropriate stability and efficient fluorescent properties. The standardized assay was sensitive and selective towards cTnI in both physiological buffer solutions and spiked human serum samples. The novel assay presented noble analytical results with sound dynamic linearity over a wide concentration range of 0 to 320 ng/mL and a detection limit of 6.5 ng/mL for cTnI in the spiked human serum.

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