An abdominal aortic aneurysm (AAA) is caused by a vascular disease and results in the presence of a bulged portion (>5.5 cm) of the aorta in the abdominal area, which can rupture due to high blood pressure. Imaging techniques are broadly used to diagnose AAA and provide supporting evidence for treating the patient. Insulin-like growth factor 1 (IGF1) is a well-known biomarker for AAAs and helps to identify the severity of the disease. In this research, IGF1 was detected by dual antibodies (mono- and polyclonal) on gap-fingered (~50 µm) interdigitated dielectrode (IDE) metal oxide surfaces (5 × 6 mm). The hydroxylated IDE surface was coated with silane-PEG-COOH to reduce biofouling and improve detection. IGF1 at 1 pM (y = 1.641x-1.605; R²=0.9826) was determined to have a low detection limit by a monoclonal antibody (200 nM); the detection limit was further improved to 100 fM (y = 10.12x-3.6966; R²=0.9631) in a 10-fold increment by employing dual antibodies with low-femtomolar sensitivity. Moreover, the current responses were found to increase greatly due to this sandwich pattern at dose-dependent concentrations from 100 fM to 1 nM. Control experiments with IGF2 and IGFBP3 (1 nM) showed minor variations in current changes, indicating the specific detection of IGF1. This method employing dual antibodies on the dielectrode surface helps identify AAAs and their progression.
