PNA-modified magnetic nanoparticles and their hybridization with single-stranded DNA target: Surface enhanced Raman scatterings study

A 4-pyridyldithiol-derivatized peptide nucleic acid (PNA), which was designed to recognize a specific gene, was attached to 3-mercapropropyloxysilane coated magnetic nanoparticles (MNPs) via a thiol-disulfide exchange reaction. Subsequently, PNA-functionalized magnetic nanoparticles (PMNPs) were prepared. Sequentially the PMNPs were challenged with non-complementary and perfect-match DNA targets. The entire procedure was monitored using surface-enhanced Raman scattering (SERS). The results showed that the PMNPs were able to efficiently hybridize with the perfect-match ssDNA target and showed no affinity towards non-complementary DNA. This approach may provide a means of direct and label-free gene analysis.