Abstract

In this work, a fast and stable oligonucleotide-magnetic nanoparticle coupling strategy has been developed and evaluated for biodetection. Magnetic nanoparticles were synthesized by a co-precipitation method using FeCl3.6H(2)O/FeCl2.4H(2)O and aqueous solution of NH3. Nanoparticles size distribution was determined to be 10-30 nm using scanning electron microscope (SEM), which was in the desired range for purification and diagnostic applications. Synthesized nanoparticles were functionalized with aldehyde groups. Brady's test confirmed the presence of aldehyde groups on the nanoparticles. NH2 modified probes were then covalently immobilized on the surface of modified particles. Ethanolamine blocker reagent was used to reduce nonspecific adsorption of the oligonucleotide on the nanoparticles. A FAM-labeled complementary oligonucleotide probe verified immobilization step. A considerable fluorescence intensity obtained after adding the probe demonstrated the ability of modified particles to capture DNA targets. The results showed that the oligonucleotide-functionalized magnetic nanoparticles could be used as a potential diagnostic kit in the field of medical diagnostic. The used particle coating method is a one-step and fast procedure to obtain functionalized particles that have high affinity to NH2-labaled probes the complementary fluorescence labeled probes were captured by synthesized particles. The obtained oligonucleotide-magnetic nanoparticle conjugate has the potential of rapid, sensitive and specific detection of target complementary oligonucleotides.