Enhanced Detection of Brain-Derived Neurotrophic Factor (BDNF) Using a Reduced Graphene Oxide Field-Effect Transistor Aptasensor

Neurodegenerative diseases, characterized by the progressive deterioration of neuronal function and structure, pose significant global public health and economic challenges. Brain-Derived Neurotrophic Factor (BDNF), a key regulator of neuroplasticity and neuronal survival, has emerged as a critical biomarker for various neurodegenerative and psychiatric disorders, including Alzheimer's disease. Traditional diagnostic methods, such as Enzyme-Linked Immunosorbent Assay (ELISA) and electrochemiluminescence (ECL) assays, face limitations in terms of sensitivity, stability, reproducibility, and cost-effectiveness. In this research, we developed the first electrical aptasensor for BDNF detection, constructed on a flexible polyimide (PI) membrane coated with reduced graphene oxide (r-GO) and utilized an extended-gate field-effect transistor (EGFET) as the transducer. Comprehensive characterization of the sensor, coupled with the fine-tuning of aptamer concentration and the binding time of DNA aptamers to the chemical linker, was achieved through Electrochemical Impedance Spectroscopy (EIS) to boost sensitivity. Consequently, by utilizing the unique properties of r-GO and DNA aptamers, the aptasensor exhibited exceptional detection abilities, with a detection limit as low as 0.4 nM and an extensive response range spanning from 0.025 to 1000 nM. The flexible PI-based electrode offers exceptional stability, affordability, and durability for home diagnostics, enriched by the reusability of its electronic transducer, making the device highly portable and suitable for prolonged monitoring. Our aptasensor surpasses traditional methods, showcasing superior real-time performance and reliability. The high sensitivity and specificity of our aptasensor highlight its potential to significantly improve early diagnosis and therapeutic monitoring of neurodegenerative diseases such as Alzheimer's, representing a considerable advancement in the diagnosis and management of such conditions.