An immunosensor for the detection of the coronary heart disease marker apolipoprotein B-100 (ApoB-100) was developed using a glass carbon electrode, functionalized with streptavidin, and 25 μL of biotinylated anti-ApoB-100 nanobody (BiNb4) at a concentration of 100 μg/mL. Here, APOB is linked to coronary artery disorder.