Quantitation of amyloid beta peptides in CSF by surface enhanced MALDI-TOF

Alzheimer's disease is characterized by the deposition of amyloid plaques in the brain. The major components of these plaques are β-amyloid (Aβ) peptides. The CSF concentration of these peptides can therefore provide a valuable biomarker for potentially predicting the state of disease and/or monitoring the efficacy of a drug aiming to inhibit the formation of amyloid plaques. Although the concentration of a given peptide in CSF can easily be measured by ELISA methods, few methods are able to simultaneously observe and distinguish between various peptides of similar yet slightly different amino acid composition. The Surface Enhanced Laser Desorption/Ionization-Time Of Flight mass spectrometry (SELDI-TOF) technology, a platform combining the use of an antibody and MALDI-TOF, can be used to simultaneously detect and quantitate various Aβ peptides with sensitivities in the picomolar range.