Brilliant Blue Dye-Decorated Multifunctional Titanium Dioxide Nanoparticles for Efficient Biosensors

Abstract Plasmonic metals-impregnated fiber-optic sensors (FOSs) became emergent for biomedical diagnostic, environmental monitoring, and security uses due to their excellent reliability sensitivity, stability, and adaptability. To develop accurate, cost-effective, and reliable humidity FOSs, Brilliant Blue dye-embedded titanium dioxide nanoparticles (BBD-TiO 2 NPs as sensing elements) were synthesized using a green and controllable pulsed laser ablation in liquid (PLAL) method. The optical properties of BBD-TiO 2 NPs were adjusted via the laser energies variation from 50 to 250 mJ. Various analytical measurements including UV-Vis, Fluorescence (FL) and FTIR-ATR spectroscopy were performed to determine the NPs attributes. The absorption spectra exhibited peaks at ~241, ~302, ~406 and ~667 nm, attributed to the σ-π*, σ-σ* transitions of BBD molecules and the π-π* transition of surface plasmon resonance (SPR). The FL emission spectra at ~463 nm showed the narrowest FWHM value (33.0) at the optimal laser energy of 150 mJ. FTIR spectra of both BBD and BBD-TiO 2 NPs confirmed the presence of hydroxyl and carbonyl functional groups. Tuning of NPs size, chemical bonding, and crystal phases of these materials demonstrate BBD-TiO 2 NPs promising candidates for stable biosensors development.