On-line Aptamer Affinity Solid-Phase Extraction Capillary Electrophoresis-Mass Spectrometry for the Analysis of Blood α‑Synuclein

In this paper, an on-line aptamer affinity solid-phase
extraction
capillary electrophoresis-mass spectrometry method is described for
the purification, preconcentration, separation, and characterization
of α-synuclein (α-syn) in blood at the intact protein
level. A single-stranded DNA aptamer is used to bind with high affinity
and selectivity α-syn, which is a major component of Lewy bodies,
the typical aggregated protein deposits found in Parkinson’s
disease (PD). Under the conditions optimized with recombinant α-syn,
repeatability (2.1 and 5.4% percent relative standard deviation for
migration times and peak areas, respectively) and microcartridge lifetime
(around 20 analyses/microcartridge) were good, the method was linear
between 0.5 and 10 μg·mL–1, and limit
of detection was 0.2 μg·mL–1 (100 times
lower than by CE-MS, 20 μg·mL–1). The
method was subsequently applied to the analysis of endogenous α-syn
from red blood cells lysate of healthy controls and PD patients.