Fluorescent Recognition for Single- and Double-Stranded Oligonucleotides Based on Rhodamine B-Modified Self-assembled Bilayers

Rhodamine B (RB) was assembled onto the surface of quartz substrate by electrostatic interaction between the fluorescence reagent RB and γ-aminopropyltriethoxysilane (APES), and the Quartz/APES/RB film was constructed. The fluorescence spectra and binding interaction of Quartz/APES/RB with single- and double- stranded oligonucleotides (ssDNA and dsDNA) in Tris-HCl buffer solution of pH 7.4 were studied. The conditions of establishment, fluorescent characterization of self-assembled bilayers, binding reaction mechanism between DNA and Quartz/APES/RB were discussed in detail. The experiment results show that the Quartz/APES/RB was allowed for an extremely highly sensitive fluorescent recognition for ssDNA and dsDNA with the detection limit of 2.4 ng l−1 and 0.85 ng l−1, respectively.