Label-Free Detection of DNA Hybridization Using a Reflective Microfiber Bragg Grating Biosensor With Self-Assembly Technique

A reflective fiber-optic biosensor based on microfiber Bragg grating (mFBG) for DNA hybridization detection using layer-by-layer self-assembly technology is demonstrated. By searching the wavelength separation of two well-defined resonances of mFBG in reflection, temperature-compensated refractive index measurement has been achieved. With the help of poly(ethylenimine) (PEI), poly(acrylic acid) (PAA), and single-stranded DNA (ssDNA) for the preparation of a polyelectrolyte multilayer film, more target DNA chains are absorbed by the (PEI/PAA) ₄ (PEI/DNA) ₁ multilayer films immobilized on the surface of mFBG. The hybridization processes of the target ssDNA with the concentration of 1 μM have been monitored in real-time together with high specificity of the noncomplementary DNA target.