Nature Inspired Anti-Biofouling Strategy for the Detection of Protein Biomarkers Directly in a Drop of Blood

Electrode biofouling in complex biological fluids is one of the major problems in analytical electrochemistry. Direct electrochemical detection in human blood remains challenging due to quick surface passivation by proteins present in blood, degrading sensor’s sensitivity. This challenge has dramatically slowed down commercialization efforts of point-of-care devices. Here we have developed a simple nature-inspired electrochemical DNA hybridization (e-hyb) assay based on steric hindrance which enable electrodes to detect nanomolar concentration of proteins (i.e. antibody) directlywithin a drop ofblood without any sample preparation. This e-hyb assay involves two DNA strands; one-captured DNA immobilized on electrode surface and another complementary reporter DNA labelled with an electroactive molecule (methylene blue) at one end and a specific recognition element at the another end. In presence of a specific large analyte binding to the small recognition element, the reporter DNA cannot reach to the electrode surface due to steric hindrance. This simple strategy enables us to quantify different protein biomarkers (HIV antibody, anti-DNP antibody, anti-DIG antibodyetc) in human blood without being limited affected by biofouling. Figure 1: e-DNA hybridization based anti-biofouling strategy for the detection of antibody in human blood Figure 1