A label-free three potential ratiometric electrochemiluminescence immunosensor for cardiac troponin I based on N-(4-aminobutyl)-N-ethylisoluminol functionalized graphene quantum dots

AbstractAccording to the World Health Organization (WHO), cardiovascular disease (CVD) is the leading cause of death in the world every year. The design and development of biosensors for the detection of CVD markers could be one of the major contributions of the scientific community to society. In this context, acetic acid functionalized graphene quantum dots (fGQDs) were used as an interface for the electrochemical detection of cardiac Troponin I (cTnI). The interaction of cTnI with fGQDs for the early diagnosis of acute myocardial infarction was investigated using cyclic voltammetry (CV) and amperometry. The carbodiimide conjugation between the N-H group of cTnI and the functionalized COOH group on GQDs enabled the detection of cTnI biomarker. The same sensing mechanism was confirmed using Fourier Transform Infrared Spectrometry (FTIR). The fGQDs modified Au electrode showed remarkable electrocatalytic oxidation of cTnI with good stability and sensitivity over a linear range of 0.17 to 3 ng mL−1 and a low detection limit of 0.02 ng mL−1. Bland-Altman plots substantiate a bias between the intra-/inter-cTnI assay and calibrated cTnI assay with 95% limits of agreement (mean difference ± 1.96 SD). The aim of this study is to describe an innovative method to detect cardiac biomarker cTnI and provide preliminary data on its diagnostic capacity. At the same time, its applicability in clinical setting will have to be validated with a significant number of samples collected from patients.

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Fluorescence Based on Surface Plasmon Coupled Emission for Ultrahigh Sensitivity Immunoassay of Cardiac Troponin I

Biomedicines ◽

10.3390/biomedicines9050448 ◽

2021 ◽

Vol 9 (5) ◽

pp. 448

Author(s):

Vien Thi Tran ◽

Heongkyu Ju

Keyword(s):

Surface Plasmon ◽

Cardiac Troponin ◽

Troponin I ◽

Limit Of Detection ◽

Delayed Diagnosis ◽

Cardiac Troponin I ◽

Quantitative Detection ◽

Fluorescence Signal ◽

Label Free ◽

Ultrahigh Sensitivity

This work demonstrates the quantitative assay of cardiac Troponin I (cTnI), one of the key biomarkers for acute cardiovascular diseases (the leading cause of death worldwide) using the fluorescence-based sandwich immune reaction. Surface plasmon coupled emission (SPCE) produced by non-radiative coupling of dye molecules with surface plasmons being excitable via the reverse Kretschmann format is exploited for fluorescence-based sandwich immunoassay for quantitative detection of cTnI. The SPCE fluorescence chip utilizes the gold (2 nm)-silver (50 nm) bimetallic thin film, with which molecules of the dye Alexa 488 (conjugated with detection antibodies) make a near field coupling with the plasmonic film for SPCE. The experimental results find that the SPCE greatly improves the sensitivity via enhancing the fluorescence signal (up to 50-fold) while suppressing the photo-bleaching, permitting markedly enhanced signal-to-noise ratio. The limit of detection of 21.2 ag mL−1 (atto-gram mL−1) is obtained, the lowest ever reported to date amid those achieved by optical technologies such as luminescence and label-free optical sensing techniques. The features discovered such as ultrahigh sensitivity may prompt the presented technologies to be applied for early diagnosis of cTnI in blood, particularly for emergency medical centers overloaded with patients with acute myocardial infarction who would suffer from time-delayed diagnosis due to insufficient assay device sensitivity.

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In Situ Construction of Oriented Pt‐PANI Needle‐Like Nanoarrays‐Based Label‐Free Aptasensor for Ultrafast and Ultrasensitive Recognition of Cardiac Troponin I

Advanced Materials Interfaces ◽

10.1002/admi.202101543 ◽

2021 ◽

pp. 2101543

Author(s):

Wei Zhang ◽

Tao Liu ◽

Yuansheng Shan ◽

Bailing Hou ◽

Zhenyu Chu ◽

...

Keyword(s):

Cardiac Troponin ◽

Troponin I ◽

Cardiac Troponin I ◽

Label Free

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Long-Range Surface Plasmon-Polariton Waveguide Biosensors for Human Cardiac Troponin I Detection

Sensors ◽

10.3390/s19030631 ◽

2019 ◽

Vol 19 (3) ◽

pp. 631 ◽

Cited By ~ 3

Author(s):

Oleksiy Krupin ◽

Pierre Berini

Keyword(s):

Long Range ◽

Surface Plasmon ◽

Cardiac Troponin ◽

Surface Plasmon Polariton ◽

Troponin I ◽

Biological Marker ◽

Cardiac Troponin I ◽

Label Free ◽

Label Free Detection ◽

Plasmon Polariton

Straight long-range surface plasmon-polariton (LRSPP) waveguides as biosensors for label-free detection are discussed. The sensors consist of 5-μm-wide 35-nm-thick gold stripes embedded in a low-index optical-grade fluoropolymer (CYTOPTM) with fluidic channels etched to the Au surface of the stripes. This work demonstrates the application of the LRSPP biosensors for the detection of human cardiac troponin I (cTnI) protein. cTnI is a biological marker for acute myocardial infarction (AMI), often referred to as a heart attack, which can be diagnosed by elevated levels of cTnI in patient blood. Direct and sandwich assays were developed and demonstrated over the concentration range from 1 to 1000 ng/mL, yielding detection limits of 430 pg/mL for the direct assay and 28 pg/mL for the sandwich assay (1 standard deviation), the latter being physiologically relevant to the early detection or onset of AMI. In addition, a novel approach for data analysis is proposed, where the analyte response is normalized to the response of the antibody layer.

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