REUSABLE LONG PERIOD MICROFIBER GRATING FOR DETECTION OF DNA HYBRIDIZATION

摘要

A label free, reusable and high sensitivity fiber sensor is provided by tapering a single mode fiber, fabricating a reduced diameter fiber, and periodically inducing micro-tapers by repeatedly scanning across the fiber with a pulsed CO 2 laser to fabricate a long period grating. The resulting Long Period Microfiber Grating (LPMFG) is of use as a sensing device. It allows optically detecting the change in refractive index at the grating surface with high sensitivity. This provides an optical detection method to monitor DNA hybridization. The single stranded DNA (ssDNA) probe is immobilized onto the LPMFG's surface for hybridizing with a DNA sample in order to identify the viral strain in the sample. This LPMFG-based viral sensor functions by inducing a refractive index change on the grating surface through the bio-molecule binding between the target viral ssDNA and the immobilized probe ssDNA. Regeneration of a surface-immobilized probe without a significant loss of hybridization activity retains at least 10 successive assays without any significant loss of performance (less than 10% decrease).