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These drawbacks can be overcome by the use of biosensors as cheap and fast detection tools that can be integrated in multiplexed point-of-care devices. (4) Even though these immunoassays are developing rapidly, their main drawbacks are related to long analysis time and cross-reactivity issues. The current methods used to identify the presence of cardiac biomarkers are based on antigen–antibody recognition, such as the enzyme-linked immunosorbent assay (ELISA), or rely on fluorescence or radiochemical detection.
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Next to conventional methods for the diagnosis of eventual heart failure, such as electrocardiograms (1) and chest X-rays, (2) the detection of cardiovascular biomarkers (3) provides a simple method for early indication of the disease. It is well known that effective intervention at an early stage can prevent and attenuate their progression. Cardiovascular diseases, chronic conditions that get worse over time, are classified into four stages ranging from high risk to advanced heart failure probability, and treatment plans are provided accordingly. The need for fast and accurate diagnosis has become crucial to prevent and limit heart failure. The incidence and prevalence of cardiovascular diseases rise in many parts of the world.
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These electrochemical aptasensors represent a step further toward multianalyte sensing of cardiac biomarkers. In the case of BNP-32, the sensor developed has a linear response from 1 pg mL –1 to 1 μg mL –1 in serum for cTnI, linearity is observed from 1 pg mL –1 to 10 ng mL –1 as demanded for early-stage diagnosis of heart failure. To ensure low biofouling and high specificity, cardiac sensors were modified with pyrene anchors carrying poly(ethylene glycol) units. Covalent grafting of propargylacetic acid integrates propargyl groups onto the electrode to which azide-terminated aptamers can be immobilized using Cu(I)-based “click” chemistry. For this, commercial gold-based screen-printed electrodes were modified electrophoretically with polyethyleneimine/reduced graphene oxide films. We report here a generic approach toward multianalyte sensing platforms for cardiac biomarkers by developing aptamer-based electrochemical sensors for brain natriuretic peptide (BNP-32) and cardiac troponin I (cTnI). The capability of biosensors to determine an increase in the concentration of cardiovascular protein biomarkers in circulating blood immediately after a myocardial infarction makes them ideal point-of-care platforms and alternative approaches to electrocardiograms, chest X-rays, and different laboratory-based immunoassays. Rapid and accurate diagnostic technologies for early-state identification of cardiovascular abnormalities have become of high importance to prevent and attenuate their progression.