Electrochemical sensitive detection of amyloid-β oligomer harnessing cellular prion protein on AuNPs embedded poly (pyrrole-3-carboxylic acid) matrix

Amyloid-β oligomer (AβO) is believed to cause neurotoxicity which is linked to Alzheimer's disease (AD). Therefore, the detection of AβO has been proposed as an effective method for the early diagnosis of AD. In this work, several three-dimensional layers using gold nanoparticles (AuNPs) embedded in different conducting polymer matrix, including poly (thiophene-3-acetic acid), poly (pyrrole-2-carboxylic acid), and poly (pyrrole-3-carboxylic acid), were harnessed as transducers for the large surface area and high electrical conductivity. The cellular prion protein (PrP^C) was utilized as the biorecognition element for the specific detection of AβO. The prepared electrochemical sensors were fabricated and compared afterward, in terms of sensitivity and detection range for the highly sensitive detection of AβO. In comparison, the PrP^C/AuNPs embedded in Ppy-3-COOH matrix (AuNPs-E-Ppy-3-COOH matrix) was demonstrated to have higher sensitivity and wider detection range (10⁻⁹ to 10³ nM). Subsequently, through the ex vivo real sample analysis within cerebrospinal fluid and blood test, it is proved that PrP^C/AuNPs-E-Ppy-3-COOH matrix can be used for the early diagnosis of AD.