Nonmediated, Label-Free Based Detection of Cardiovascular Biomarker in a Biological Sample

Direct electrochemical (EC) monitoring in a cell culture medium without electron transporter as called mediator is attractive topic in vitro organoid based on chip with frequently and long-time monitoring since it can avoid to its disadvantage as stability, toxicity. Here, direct monitoring with nonmediator is demonstrated based on impedance spectroscopy under the culture medium in order to overcome the limitation of mediator. The applicability of EC monitoring is shown by detecting alpha-1-anti trypsin (A1AT) which is known as biomarkers for cardiac damage and is widely chosen in organoid cardiac cell-based chip. The validity of presented EC monitoring is proved by observing signal processing and transduction in medium, mediator, medium–mediator complex. After the observation of electron behavior, A1AT as target analyte is immobilized on the electrode and detected using antibody–antigen interaction. As a result, the result indicates limit of detection is 10 ng mL⁻¹ and linearity for the 10–1000 ng mL⁻¹ range, with a sensitivity of 3980 nF (log [g mL])⁻¹ retaining specificity. This EC monitoring is based on label-free and reagentless detection, will pave the way to use for continuous and simple monitoring of in vitro organoid platform.