Fluorescent Immunoassays for Detection and Quantification of Cardiac Troponin I: A Short Review

Abstract

Cardiovascular diseases are considered one of the major causes of human death globally. Myocardial infarction (MI), characterized by a diminished flow of blood to the heart, presents the highest rate of morbidity and mortality among all other cardiovascular diseases. These fatal effects have triggered the need for early diagnosis of appropriate biomarkers so that countermeasures can be taken. Cardiac troponin, the central key element of muscle regulation and contraction, is the most specific biomarker for cardiac injury and is considered the “gold standard”. Due to its high specificity, the measurement of cardiac troponin levels has become the predominant indicator of MI. Various forms of diagnostic methods have been developed so far, including chemiluminescence, fluorescence immunoassay, enzyme-linked immunosorbent assay, surface plasmon resonance, electrical detection, and colorimetric protein assays. However, fluorescence-based immunoassays are considered fast, accurate and most sensitive of all in the determination of cardiac troponins post-MI. This review represents the strategies, methods and levels of detection involved in the reported fluorescence-based immunoassays for the detection of cardiac troponin I.

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

“…The limit of detection (LOD) of the assay was 6.5 ng/mL (determined as the minimum concentration of cTnI at which the mean (f − f 0 ) values over all replicates is larger than (f 0 ) by at least three standard deviations of the negative controls), which is very close the normal level (5 ng/mL) cut-off in a patient's blood. Although our results presented a higher value of LOD than the previously reported assays [2,24,[55][56][57], the assay was highly specific towards cTnI even in the presence of other interference proteins in the human serum and, more importantly, it has a wide linear dynamic range from right above the normal concentrations (LOD) of cTnI to 320 ng/mL.…”

“…Over the last couple of decades, the use of immunoassays for clinical and research purposes has gained remarkable attention due to their ability to accurately detect specific antigen or antibody molecules within a short span of time. There are different strategies used for the development of immunoassays; however, the "sandwich" immunoassay is one of the most reported assay designs for the detection of cTnI in the last few years [13,15,[24][25][26]. This assay design is based on capturing the targeted antigen between a "capture" antibody and a "detecting" antibody where each binds at a different and a distant epitope.…”

Electroanalytical point-of-care detection of gold standard and emerging cardiac biomarkers for stratification and monitoring in intensive care medicine - a review

“…As such there are numerous reviews tackling many topics and their application to the detection of CBs which we direct the reader towards. These include general CB biosensors [ 133 – 136 ], lab-on-a-chip devices [ 137 ], fluorescence [ 138 ], colourimetric [ 139 ] nanomaterial-based [ 140 , 141 ], acoustic-wave [ 142 ], potentiometric [ 143 ], and optical [ 144 ] to name just a few. Additionally, there have been reviews for electrochemical strategies [ 145 – 147 ], which often highlight a small number of markers or cover multiple detection methods.…”

A Case of Elevated Troponin I Level After Packed Red Blood Cell Transfusion With Normal Coronary Angiography

“…Frequently reported conditions are acute heart failure, pulmonary embolism, myocarditis, renal failure, sepsis, and severe aortic stenosis [ 1 ]. Falsely elevated results can also happen due to analytical interferences with the assay [ 2 , 3 ]. Most common causes include fibrin clots, heterophile antibodies, microparticles contained in the sample, rheumatoid factor, interference by bilirubin, hemolysis, and elevated alkaline phosphatase activity [ 3 , 4 ].…”