Biosensors and biomarkers: A dynamic duo towards Alzheimer's disease detection

Alzheimer's disease is the most common and costly chronic progressive neurodegenerative disorder, with the highest global public health impact. However, diagnosing this neurodegenerative disorder is challenging and often relies on traditional clinical diagnostics techniques applied after symptoms appear, which are complex, costly, time-consuming, and potentially intrusive methods. This hinders the development of effective tools for Point-of-Care applications. To address these limitations, researchers have been developing several biosensing techniques utilizing biosensors, which have excellent selectivity and sensitivity for detecting Alzheimer's disease biomarkers at an early stage more efficiently and promptly. This comprehensive study focuses on promising biomarkers for Alzheimer's disease detection in various bio-fluids, as well as the accompanying obstacles and advantages. Furthermore, we provide a comprehensive review of current biosensing techniques, focusing on electrochemical and optical biosensors, which are well-known for their exceptional sensitivity and selectivity in detecting Alzheimer's disease biomarkers. These biosensors facilitate the early diagnosis of Alzheimer's disease in point-of-care testing, thereby enhancing point-of-care applications for Alzheimer's disease. We also explore bioelectronic tongues and bioelectronic noses as innovative, non-invasive tools for detecting biomarkers in Alzheimer's disease, which further facilitates point-of-care applications for Alzheimer's disease.