title: Optical imaging of surface-immobilized oligonucleotide probes on DNA microarrays using liquid crystals.
abstract: In this paper, we report a new label-free method for the imaging of immobilized oligonucleotide probes on DNA microarrays. The imaging principle is based on the disruption of orientations of nematic liquid crystals (LCs), 4-cyano-4'-pentylbiphenyl (5CB), by the immobilized oligonucleotides on a surface. Because LCs are birefringent materials, disruption of their orientations by the immobilized oligonucleotides can manifest as optical signals visible to the naked eye. LC cells with two homeotropic boundary conditions, which align 5CB perpendicularly to both surfaces, were developed to deliver a distinct contrast between a dark background and a bright image caused by the immobilized oligonucleotides. This design also allows the quantification of immobilized oligonucleotide concentrations through the interference colors of LCs. The LC-based imaging method has a good signal-to-noise ratio and a clear distinction between positive and negative results and is nondestructive to the immobilized oligonucleotides. These advantages make it a promising means of assessing the quality of DNA microarrays.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576.
authors.forename: Siok Lian
authors.initials: SL
authors.lastname: Lai
authors.forename: Shisheng
authors.initials: S
authors.lastname: Huang
authors.forename: Xinyan
authors.initials: X
authors.lastname: Bi
authors.forename: Kun-Lin
authors.initials: KL
authors.lastname: Yang
mesh_terms: D001483:Base Sequence; D020411:Oligonucleotide Array Sequence Analysis; D015345:Oligonucleotide Probes; D013050:Spectrometry, Fluorescence; D013499:Surface Properties
chemical_list: D015345:Oligonucleotide Probes