(11a) DNA Hybridization Detection Using Liquid Crystals

Sensitivity to hybridization is the basis for genetic screening techniques such as fluorescence in-situ hybridization (FISH), as well as microarray based assays.  Elimination of the fluorescent marker, scanner, and the requisite labor necessary to label the DNA target, however, could allow for the fabrication of cheap and disposable point-of use devices.  Previous work demonstrated that double stranded DNA aligns 5CB and MBBA liquid crystals (LC) at 30 degrees to the extension direction, while the LC aligns parallel to extended single stranded DNA. This difference in alignment is sufficient to detect a single DNA molecule.  Detection of double stranded DNA over the background of single stranded DNA will determine the sensitivity of this approach. By orthogonally labeling double and single stranded DNA it was demonstrated that LC alignment is sensitive enough to detect hybridized DNA among single stranded probe molecules.  In situ detection of hybridization was also explored.