Rapid Detection of Amyloid β1–42 via PAMAM G4 Supported Molecularly Imprinted Sensor

In this research, a novel sensor system was prepared for the rapid and selective determination of Amyloid β1-42 (Aβ1-42), a key biomarker in the early recognition of Alzheimer's disease. A screen-printed gold electrode (AuE) was used as the base for a self-assembled monolayer (SAM)-based molecularly imprinted polymer (MIP). The electrode was modified by sequential incubation in 100 mM cysteamine, 5% glutaraldehyde, and PAMAM G4 dendrimer. Electropolymerization was performed using pyrrole-3-carboxylic acid and Aβ1-42. Desorption was achieved using 500 mM HCl to remove the template molecule, generating specific recognition sites. The sensor's performance was determined by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), with additional surface characterization via SEM, XPS, and FT-IR. The nonimprinted polymer (NIP) showed no response to Aβ1-42, confirming the selectivity of the MIP. Selectivity tests using Tau protein showed minimal interference. The quantification limit (LOQ) and the limit of detection (LOD) were found to be 0.42 and 0.14 ng/mL, respectively. In diagnostic applications, the proposed sensor shows promise as a quick, sensitive, and selective way to detect Aβ1-42.