Influences of non-selective interactions of nucleic acids on response rates of nucleic acid fiber optic biosensors

The immobilization of oligonucleotides to solid surfaces can provide a platform of chemistry that is suitable for the development of biosensor and microarray technologies. Experiments were performed using a fiber optic nucleic acid biosensor based on total internal reflection fluorescence to examine the effects of the presence of non-complementary DNA on the detection of hybridization of complementary target DNA, The work has: focused on the rates and extent of hybridization in the presence and absence of non-selective adsorption using fluocescein-labeled DNA. a stop-flow system of 137 muL volume permitted rapid introduction and mixing of each sample. Response times measured were on the order of seconds to minutes. Non-selective adsorption of non-complementary oligonucleotides (ncDNA) was found to occur at a significantly faster rate than hybridization of complementary oligomers (cDNA) in all cases. The presence of ncBNA oligonucleotides did not inhibit selective interactions between immobilized DNA and cDNA in solution. The presence of high concentrations of nan-complementary genomic DNA had little effect on the extent of hybridization of complementary oligonucleotides, but actually reduced the response times of sensors to cDNA oligonucleotides.