Biophotonic Platform for Detection of Hallmarks of Alzheimer's Disease via Combined Microfluidics and Nanofunctionalized Fiber Sensors

The emergence of Covid-19 pandemic has drawn large attention to vulnerable people affected by major diseases. According to the World Health Organization (WHO), more than 55 million people worldwide suffer from dementia. Alzheimer's disease (AD) is the predominant type of dementia, accounting for 60-70% of cases [1]. A long-standing challenge is to attain early diagnosis of AD hallmarks (tau protein,
$\tau \mathrm{P}$
; amyloid beta,
$\mathrm{A}\beta)$
by detecting them in biological fluids, thus avoiding the labor of specialized hospital personnel and the high cost of imaging examinations. Different biological fluids are being used to detect AD biomarkers, such as cerebrospinal fluid (CSF), serum, blood-plasma [2]. Biomarker level in CSF has been shown to increase in the very early stages of the disease where its elevated value makes higher the risk of a quicker development of AD dementia. Traditional methods for biomarker detection are mostly based on ELISA or mass spectrometry, which possess well-known disadvantages in comparison with electrochemical or optical approaches [3], [4].