A Detection and Analysis of Fusobacterium Utilizing Changes in the Magnetic Properties of Magnetic Nanoparticles-Antibody–Antigen Aggregates

A quick and easy method to detect
Fusobacterium
species has been developed to utilize magnetic nanoparticles’ magnetic response and is applied by switching magnetic fields. The bacterium can be detected without the washing process. The magnetic nanoparticles and
Fusobacterium
species are bound by an antigen–antibody reaction and aggregated into a spherical shape using a needle-shaped magnetic yoke. The aggregation of magnetic nanoparticles improves the signal-to-noise ratio to detect the bacterium. We report that a clear tendency for the concentration of
Fusobacterium nucleatum
can be derived by analyzing the amount of reverse magnetization and the correlation coefficient of a waveform, as well as checking the principal component analysis. This analysis is useful for an accurate evaluation of the antigen. Specific detection of
Fusobacterium nucleatum
was demonstrated through the cross-reaction using
Candida albicans
. The optical density (OD) sensitivity value was around 10
⁻⁴
–10
⁻³
.