Sensitive label-free hemoglobin detection based on polydopamine functionalized graphene oxide coated micro-tapered long-period fiber grating

The GO and PDA-GO functionalized TLPG based sensitive and label-free optical biosensor for human hemoglobin detection was demonstrated. The PDA-GO and GO were separately deposited onto fiber surface, the deposited materials provide a large number of binding sites to adsorb the hemoglobin and can further change the RI of fiber surface, and can provide more binding sites owing to the large specific surface area, and it exhibits higher sensing sensitivity of 3.14 mg/mL and the LOD can reach 0.057 mg/mL. In addition, the sensing was carried out in the presence of inference compounds and also proved its ideal reusability. The usage of PDA-GO as a bio-interface layer enables strong interference of optical waves as well as excellent biocompatibility, which is considered to be valuable for biosensing applications.