The invention discloses ferroferric
oxide nanoparticles as well as a preparation method and application thereof, which belong to the field of inorganic nano materials. The preparation method of the ferroferric
oxide nanoparticles comprises the following steps: (1) dissolving ferrite and
ferric salt in an
organic solvent, adding a cosolvent, carrying out ultrasonic treatment, and stirring to obtaina solution A; (2) uniformly mixing a surfactant and a cosurfactant, adding
toluene, adding the solution A, adding a NaOH solution, and stirring until the solution becomes transparent and clear to obtain a solution B; (3) adding a dispersing agent and an alkaline additive into the solution B to adjust the pH value, and stirring to obtain a
microemulsion; and (4) adding NaHCO3 into the
microemulsion, carrying out aging treatment, centrifuging, carrying out suction
filtration, washing, separating, and
drying to obtain the ferroferric
oxide nanoparticles. According to the invention,
enzyme is immobilized by adopting a covalent
coupling method, so that directional movement of an external
magnetic field can be realized,
enzyme pollution is avoided, and the
biological activity of the
enzyme is not changed.