Label-Free Detection of Cardiac Biomarkers: A Review on Microfluidic Electrochemical Biosensors

Biosensors are valuable tools for the detection of biological species, including cells, pathogens, proteins, and other biological molecules. Biosensing devices integrated with microfluidics not only allow for easier sample preparation, portability, and reduced detection time and cost but also offer unique features such as label-free detection and improved sensitivity. Cardiovascular diseases (CVDs), particularly acute myocardial infarction, which is considered one of the main causes of death, are currently diagnosed by electrocardiography (ECG), which has been proven to be inadequate. To overcome the limitations of ECG, the efficient detection of cardiac biomarkers and specifically the measurement of cardiac troponins (cTnT and cTnI) are suggested. This review aims to expound on microfluidics, the most recent materials to develop these devices, and their application in medical diagnosis, particularly in CVD detection. Moreover, we will explore some of the prevalent and last readout methods to investigate in-depth electrochemical label-free detection methods for CVDs, primarily based on voltammetry and electrochemical impedance spectroscopy, with the main focus on structural details.