Thesis (M.Sc.)--Chulalongkorn University, 2007

This research emphasize on the synthesis of a new fluorescent labeled peptide nucleic acid (PNA) and its applications as a probe for detection of DNA sequence. The PNA used in this study was a new β-pyrrolidinyl peptide nucleic acid which can bind to DNA with high affinity and specificity. Two fluorescent labeling groups, namely tetramethylrodamine and fluorescein, have been successfully attached at N-termini of PNA oligomers using solid phase strategy. The labeled PNAs in combination with anion exchange supports have been used for analyzing DNA sequences. This method relies on a selective absorption of negatively charged PNA•DNA hybrids onto the positively charged ion exchange support. The presence of PNA•DNA hybrid on solid support can be directly detected by using fluorescent microscopy. This method is capable of detecting a single mismatched base out of 9-13 base DNA targets.