The structure of DNA-containing complexes suggests the idea for a new adaptive sensor

We report here on our recent structural and spectroscopic studies of the complexes formed when DNA is attached to Langmuir layers, in particular to octadecylamine layer. Synchrotron radiation reflectivity points out that in the case of amino–DNA complex, even if the subphase contains DNA in its native double stranded form, the formed complex consists of denaturated, single stranded DNA, opposite to the more common case in which a complex is formed with DNA in its native, double stranded form. This result is also supported by spectroscopic FT-IR and ellipsometric studies, and is shown to occur only in the presence of the amino group.Basing on this, we suggest here that an adaptive sensing element for a new DNA sensor for the crude recognition of DNA could be build exploiting the capability of the amino group to induce DNA splitting into the single stranded form. Such sensor will be “taught” by exposure to the DNA that is to be detected, which will attach in the denaturated form. The sensor will then be capable of recognizing by hybridization to the complementary part of the particular DNA sequence for which it was prepared. After usage, the sensing element could then be “erased” by exposure to high temperature or to strong basic conditions, to remove the DNA single strand attached to the amino groups, and then it would be usable again for the detection of any other particular DNA sequence of interest.