(316e) Detection of Double and Single-Stranded DNA by 5CB

We have investigated the disruption of azimuthal alignment of the liquid crystal 5CB by double and single-stranded DNA at the solid-liquid crystal interface. A liquid crystal-based microarray has the potential to reduce expenses when compared to similar fluorescence-based systems, both with equipment capital and the elimination of the chemistry behind fluorescent labeling. Simplification of imaging equipment to a simple crossed polarized system also could increase availability of rapid genetic screening, expanding availability to diagnostic applications. Ultimately, hybridization detection could lead to a liquid-crystal based microarray. This approach uniquely differentiates between double or single-stranded DNA by detecting the inherent structure of DNA rather than detection of a molecular labeling agent. Sensitivity to the native state of DNA eliminates detection problems through nonspecific DNA binding to a sensor. We observed a minimum threshold for sensitivity has been observed to be 200 molecules per mm² with theoretical sensitivity as low as 30 molecules per mm². Combined polarized and fluorescence microscopy is used to simultaneously observe physical alignment of DNA as well as liquid crystal alignment. Anchoring energies of double and single-stranded DNA are also compared to further quantify disruption of the director field.