Electrochemically determined biosensing ability of DNA probed by using poly(propylenedioxythiophene)

An electrochemical synthesis of series of functionalized poly(alkyldioxythiophene) derivatives in ionic liquids was undertaken. Poly(3,4-propylenedioxythiophene) (PProDOT), poly(3,4-dimethylpropylenedioxythiophene) (Me2-PProDOT) and poly(3,4-diethylpropylenedioxythiophene) (Et2-PProDOT) were electrodeposited in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. These conjugated polymer based thin films were then exploited as label-free oligonucleotide (ODN) sensors. It was found that electrochemical properties of the polymer are unaffected in the presence of a noncomplementary ODN, contrary to this, significant changes can be observed on addition of a complementary ODN target, in the electrolytic medium. Further lower value of current obtained in oxidized states in double strand nucleotides indicates increases in stiffness of polymer structures