Fabrication and characterization of PNA–DNA hybrid nanostructures

Although the distinct properties and synthesis methodology of peptide nucleic acid (PNA) molecules have been established by extensive studies, the construction of an artificial nanostructure made from PNA has been examined in only a few reports. Here we study the feasibility of constructing PNA-DNA hybrid nanostructures by conventional free solution annealing and substrate assisted growth methods. For conventional free solution annealing, we introduced a 2-step annealing procedure to mitigate the self-aggregation of PNA in the formation of stable PNA-DNA hybrid structures. Atomic force microscopy images revealed the formation of PNA-DNA hybrid nanostructures smaller than normal DNA and the Raman band intensities of the hybrid gradually decreased as a few DNA strands were replaced by PNA possibly due to the fast binding properties of PNA and the structural stress between PNA and DNA.