Nanoparticle-Based Detection in Cerebral Spinal Fluid of a Soluble Pathogenic Biomarker for Alzheimer’s Disease*
Alzheimer’s disease (AD) is the most common neurodegenerative dementia with an average death prognosis of 9 years. There is no definitive diagnosis of the disease other than postmortem identification of senile plaques and neurofibrillary tangles in the brain. This chapter demonstrates that the ultrasensitive nanoparticle-based bio-barcode assay can be used to determine the approximate amyloid-ß-derived diffusible ligand concentration in cerebrospinal fluid taken from 30 subjects, 15 of whom were diagnosed with the disease through postmortem analysis of the brain and 15 of whom were found not to have the disease. The key to the bio-barcode assay is the homogeneous isolation of specific antigens by means of a sandwich process involving oligonucleotide-modified gold nanoparticles and magnetic microparticle, both functionalized with Abs specific to the antigen of interest.