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 plat form of chemistry that is suitable for the development of biosensor and mic roarray technologies. Experiments were performed using a fiber optic nuclei c acid biosensor based on total internal reflection fluorescence to examine the effects of the presence of non-complementary DNA on the detection of h ybridization of complementary target DNA, The work has: focused on the rate s and extent of hybridization in the presence and absence of non-selective adsorption using fluocescein-labeled DNA. a stop-flow system of 137 muL vol ume 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 signi ficantly faster rate than hybridization of complementary oligomers (cDNA) i n all cases. The presence of ncBNA oligonucleotides did not inhibit selecti ve interactions between immobilized DNA and cDNA in solution. The presence of high concentrations of nan-complementary genomic DNA had little effect o n the extent of hybridization of complementary oligonucleotides, but actual ly reduced the response times of sensors to cDNA oligonucleotides.