The major objective of this study is to investigate the usefulness of aptamers as in situ detection tool in
organic solvents, which are often used for environmental extraction. But two problems related to the use
of methanol-containing buffers have to be addressed. Firstly, the folding of nucleic acids can be impaired,
because of weaker hydrogen bonding interactions. Secondly, the affinity of aptamers selected in aqueous
buffers can be altered by the presence of methanol. Thus, in order to improve hydrophobicity of the DNA
pool, nucleotide with hydrophobic modification 5-(octa1,7-diynyl)-20
-deoxyuridine (ODT) has been
chosen instead of thymidine.
As a proof of concept, an adenine aptamer operating in presence 25% of methanol has been selected. We
have shown that the modified nucleotide is essential for target binding in organic media, in addition to
essential structural pattern as proposed through analysing truncated sequences analysis. The strategy
described in this paper offers preliminary insight on the adaptability of the implementation of aptamers
as key instrument for in situ detection. It could be broaden to identify other aptamers directed against
other chemical species after alcoholic extraction or for monitoring by-product traces in drugs production.