Zeolite-iron Oxide Hybrid on an Interdigitated Microelectrode to Auxiliary Monitoring Abdominal Aortic Aneurysms by Aptamerantibody Sandwich

Introduction: An abdominal aortic aneurysm (AAA) is a bulge/enlargement in an artery that expands over time and is more likely to rupture. Imaging techniques such as Magnetic resonance imaging and computed tomography scans are commonly used to investigate the condition of AAA. However, these techniques are expensive due to their complicated procedure. Methods: This research developed a highly sensitive zeolite-Fe-based interdigitated microelectrode (IDM) sensor to quantify osteopontin, a well-known biomarker for AAA. To quantify the osteopontin, an aptamer and antibody sandwich pattern was designed on the IDM. Aptamer was bonded to the IDM by zeolite-Fe modification with an amine. Osteopontin was allowed to interact with the aptamer and then sandwiched by an anti-osteopontin antibody. Results: This sandwich biosensor detected the osteopontin at as low as 100 pM, following a linear regression model (y = 4.8929x - 2.7467, R2 = 0.9909) over a concentration range of 100 to 3200 pM. Further, the detection with osteopontin-spiked serum was demonstrated by sandwich assay without any interferences, indicating the selective detection of osteopontin. In addition, control performances with complementary aptamer sequence and control proteins failed to increase the current flow, proving the specific detection of osteopontin. Conclusion: This highly sensitive zeolite-Fe modified IDM sensor detects osteopontin with an expanded surface area, which elevates the sensing performance compared to the existing sensors and helps to diagnose the severity of AAA.