After
drying, 8 mg functionalized MNPs were weighed and then 40 L of
1000 g mL−1 solution of the amino-modified aptamer was added
and final volume was adjusted to 500 L by deionized water. Then
the mixture was sonicated for 5 min. The reaction was allowed
to proceed by shaking overnight. Finally, magnetic nanoparticles
coated with aptamer were washed three times with Tris–HCl buffer
(pH 7.3) and then the solution of aptamer-MNPs were resuspended
in 500 L of Tris–HCl buffer and stored at 4 ◦C.
2.