Novel bio-sensing platform based on TFBG and multifunctional 3D nanoflower

We presented a multifunctional refractive index (RI) bio-sensing platform based on tilted fiber Bragg grating (TFBG) modified with Zinc oxide nanoflower. TFBG mode coupling coefficient or the amplitude of cladding mode will vary sharply with the imaginary part of permittivity of the Zinc oxide nanoflowers. It has been demonstrated that the resonance intensity of the cladding mode decreases obviously with the addition of multifunctional nanoflower. In the experiments two self-assembly methods including silane coupler and polyelectrolytes were introduced to coat ZnO nanoflower on TFBG. By chosing different method and repeating dipping cycle, different thickness of the nanoflower layer could be achieved. Moreover, the refractive index sensitivities of ZnO coated TFBG sensors are respectively 18.4dB/RIU and 22.96dB/RIU, which are significantly improved 5 times compared to conventional bare TFBG. Benefting from strong electron transfer and adsorption as well as stability and high surface to volume ratio of ZnO, this ZnO coated TFBG RI sensor are significant and valuable for high-sensitivity and cost-effective biosensing applications.