Synthesis and Applications of PNA and Modified PNA in Nanobiotechnology

Abstract

The structural properties that enable DNA to serve as genetic material has also been used for many nanobiotechnological applications providing DNA-based nanomaterials and nanodevices. Peptide Nucleic Acids (PNAs) are DNA mimics in which the sugar-phosphate backbone has been replaced by a polyamide chain composed of N-(2-aminoethyl)glycine repeating units, covalently linked to nucleobases through a methylene carbonyl spacer. Compared to DNA, PNA can form duplexes more stable and are more sequence-selective. In this work, we investigated the use of PNA as tool for nanobiotechnology. PNA beacons were used in connection with HPLC, as biosensors for selective label-free detection of single mismatch in DNA. A PNA beacon containing a chiral monomer has also been synthesized and has shown an improvement both in binding and in fluorescence properties if compared to the corresponding achiral probe. Furthermore, we investigated the use of PNA as model for tunable materials througth which chirality can be amplified.Then, we studied the propagation of helicity induced by a C-terminal amino acid through PNA:PNA duplexes taking into account the effect of the amino acid side chain and charge, the solvent and temperature effects. Finally, we demonstrated that PNA can be used as powerful tools for molecular computers taking advantage of their higher selectivity and the higher stability of PNA:PNA duplexes if compared to DNA:DNA duplexes.