Electrochemical Aptamer-Based Biosensors for the Detection of Cardiac Biomarkers

TLDR

Rapid, accurate diagnostics for early cardiovascular abnormalities are critical, and biosensors that detect elevated cardiac protein biomarkers in blood after myocardial infarction offer ideal point‑of‑care alternatives to ECGs, X‑rays, and lab immunoassays. The study presents a generic multianalyte platform using aptamer‑based electrochemical sensors for BNP‑32 and cTnI. Commercial gold screen‑printed electrodes were electrophoretically modified with polyethyleneimine/reduced graphene oxide films, covalently grafted with propargylacetic acid for click‑chemistry immobilization of azide‑terminated aptamers, and further functionalized with pyrene‑PEG anchors to reduce biofouling and enhance specificity. The BNP‑32 sensor shows a linear response from 1 pg mL⁻¹ to 1 µg mL⁻¹, while the cTnI sensor is linear from 1 pg mL⁻¹ to 10 ng mL⁻¹, demonstrating suitability for early‑stage heart‑failure diagnosis and advancing multianalyte cardiac biomarker sensing.

Abstract

Rapid and accurate diagnostic technologies for early-state identification of cardiovascular abnormalities have become of high importance to prevent and attenuate their progression. 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. 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). For this, commercial gold-based screen-printed electrodes were modified electrophoretically with polyethyleneimine/reduced graphene oxide films. 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. To ensure low biofouling and high specificity, cardiac sensors were modified with pyrene anchors carrying poly(ethylene glycol) units. 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. These electrochemical aptasensors represent a step further toward multianalyte sensing of cardiac biomarkers.