Alzheimer’s disease is characterized by amyloid plaques and neurofibrillary tangles, with Aβ peptides and ApoE4 being potential biomarkers; our study enhanced an SPCE device’s sensitivity using a CNT-AuNS-PEG nanocomposite for improved detection of these biomarkers in human blood. This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.