Anionic magnetite nanoparticle conjugated with pyrrolidinyl peptide nucleic acid for DNA base discrimination

Magnetite nanoparticles ( MNPs) were surface modified with anionic poly( N-acryloyl glycine) ( PNAG) and streptavidin for specific interaction with biotin-conjugated pyrrolidinyl peptide nucleic acid ( PNA). Hydrodynamic size ( Dh) of PNAGgrafted MNPs varied from 334 to 496 nm depending on the loading ratio of the MNP to NAG in the reaction. UV-visible and fluorescence spectrophotometries were used to confirm the successful immobilization of streptavidin and PNA on the MNPs. About 291 pmol of the PNA/ mg MNP was immobilized on the particle surface. The PNA-functionalized MNPs were effectively used as solid supports to differentiate between fully complementary and noncomplementary/ single-base mismatch DNA using the PNA probe. These novel anionic MNPs can be efficiently applicable for use as a magnetically guidable support for DNA base discrimination.