Specific detection of very low concentrations of DNA oligonucleotides with DNA-coated long-period grating biosensor

摘要

Label-free biosensing using optical long-period gratings (LPGs) induced in optical fiber and coated with biological compound enables for detection and monitoring the kinetics of reactions taking places on the sensor's surface. The label -free detection effect for the LPG biosensor working near the dispersion turning point (DTP) of higher order cladding modes can be observed as resonance wavelength shift induced by binding of biomolecules to fiber surface. In this study we analyzed shift of the resonance wavelength for LPG after its functionalization with DNA layer and during DNA hybridization. It has seen found that the LPG is able to be functionalized with DNA oligonucleotide, acting as a probe and after the functionalization can selectively bind specific complementary DNA oligonucleotides in a very low concentration. DNA-coated LPG can be used as a probe capturing specific DNA sequences with wide ranges of concentrations from 0.1 to 10 pM. Hybridization of the DNA on the fiber surface has also been verified with Midorii Green florescent marker.