Preparation and characterization of carboxyl functionalization of magnetite nanoparticles for oligonucleotide immobilization

Abstract

Fe(3)O(4) nanoparticles prepared by the co-precipitation of Fe(2+) and Fe(3+) with NH(4)OH were simply modified by the carboxylic acid group of 3-thiopheneacetic acid (3TA) and meso-2,3-dimercaptosuccinic acid (DMSA). These functionalized Fe(3)O(4) nanoparticles when coated with 3TA and DMSA have increased hydrophilic properties, thus causing them to be well dispersed in aqueous solutions. Then oligonucleotides (5'-AGC T-Amine-3') were immobilized on the carboxylic acid group-modified Fe(3)O(4) nanoparticles. They were characterized by using FT-IR, XRD and TEM. The concentration of the oligonucleotide-modified Fe(3)O(4) nanoparticles was investigated using a UV-vis spectrometer and compared to that of Fe(3)O(4) nanoparticles without any surface modification. The Fe(3)O(4) nanoparticles were spherical and the particle sizes were approximately 10 nm. The immobilizing efficiencies of the Fe(3)O(4) nanoparticles modified with 3TA and DMSA were higher than those of the non-functionalized Fe(3)O(4) nanoparticles.