Monitoring The DNA Molecule Mismatch Based On Nano-porous Material Reflectometric Interference Sensoring Technology

The reflectometric interference spectroscopy (RIFS) technology has some advantages such as high sensitivity, non-contact, nondestructive and harmless, which has attracted much attention in the research of biomolecules such as pathogens, antibodies and antigens, DNA molecules.In this study, nano-porous anode alumina membrane was made with oxalic acid electrolyte by electrochemistry anodic oxidation and was analyze the structure of the surface morphology with SEM. Nano-porous ordered structure of the anode alumina membrane is mainly decided by the voltage, current and pore widening time and so on.One kind of composite structure combing the nano-porous anode alumina membrane and an Au layer cover was used as the sample substrate. A 48bp single-stranded DNA (ssDNA) of conserved gene was employed as the probe DNA(p-DNA) molecule, which can be immobilized inside pore by the covalent bond. Using home-made reflection interference spectrum detection device system to reflect light interference signal, the Origin is used to deal with the data. Fast Fourier transform (FFT) of the Matlab editing algorithm were used to obtain the effective optical thickness which theoretically indicate the difference construction of bio-samples.The phenomena of bases mismatched when target ssDNA molecules pairing with the p-DNA to form dsDNA molecules were systematically researched with the home-made RIFS systerm. The experimental results revealed that when the four kinds of target DNA(t-DNA) molecules were the same concentration, the RIFS technique can not only distinguish between the all-A bases and all-C bases ssDNA molecule, but also discriminate between the ssDNA molecule of three bases mismatched and ssDNA molecule even with different single base mismatched in the same site position. The reasult indicated that the RIFS technology is more application.