PNA-25 Carboxyethyl Fluorene is the modified polymer of PNA containing 12 nucleobases consisting of Adenine, Aminoethoxymethyl Pyrrolopyrimidone, Aminopentyl Aminoadenine, Aminopentyl Guanine, Cytosine, Guanine and Thymine. It conforms generally to the following formula, where R represents a nucleobase.