Utility of peptide nucleic acids in biosensor development Laurie Connell University of Maine Orono Maine What are Peptide Nucleic Acids (PNA’s)? PNA probe signals can be more specific and stronger than DNA probes. PNA’s have neutral backbones DNA or RNA analog with a protein backbone and purine (A,G) or pyrimidine (T,C) attached through methylene carbonyl linkages. Unlike DNA and most DNA analogs they contain no sugar or phosphate groups 0.5 1 1.5 450nm tri-flur bi-flur LC01005 bi-flur From BPI Bind in a wide range of salt concentrations Can enter cells more rapidly Stronger binding between PNA/DNA than DNA/DNA PNA/DNA duplex mismatches more destabilizing than DNA/DNA duplexes Neutral backbone increases rate of hybridization Sugar backbone Peptide backbone An example of probe binding comparing a bi-labeled PNA probes(Red) to the analogous bi-labeled DNA probe (blue) and a tri-labeled DNA probes (green) in a semi- automated sandwich hybridization format. The probes in this case used the red tide alga Alexandrium as its target. Additionally PNA’s are not targets of natural enzyme destruction PNA probes are smaller than analogous DNA probes PNA’s strictly conform to Watson-Crick base paring rules