Colorimetric Paper-Based Immunosensor for Simultaneous Determination of Fetuin B and Clusterin Towards Early Alzheimer’s Diagnosis

Alzheimer's disease is a devastating condition characterized by a progressive and slow brain decay in elders. Here, we developed a paper-based lateral flow immunoassay for simultaneous and fast determination of Alzheimer’s blood biomarkers, Fetuin B and Clusterin. Selective antibodies to targeted biomarkers were immobilized on gold nanoparticles (AuNP) and deposited on paper pads. After adding the sample on the paper-based device, the biofluid laterally flows towards the selective antibody, permitting AuNP-Ab accumulation on the test zone, which causes a color change from white to pink. Image analysis was performed using a customized algorithm for the automatic recognition of the area of analysis and color clustering. Colorimetric detection was compared to electrochemical methods for the precise quantification of biomarkers. The best performance was found for the color parameter “L*”. Good linearity (R2 = 0.988 and 0.998) and reproducibility (%RSD= 2.79 and 1.82%, N = 3) was demonstrated for the quantific...