Abstract

Photodynamic therapy is a medical technique, which uses a combination of photosensitizing drugs and light to induce selective damage on the target tissue, by generating highly reactive singlet state of oxygen [1]. The inefficient production of singlet oxygen (¹O₂) and free radicals, to react with biological targets, can limit the use of PDT photosensitizers. Localized surface plasmon resonance (LSPR) can provide an enhancement of the reactive oxygen production [2]. In this work, we demonstrate the potential application of 100nm silica-coated gold nanoshells on PDT. Metal enhanced singlet oxygen generation (MEO) byMethylene blue (MB) water solution with silica-coated gold nanoparticles was observed and quantified. FEM calculations were used to investigate the electric field behavior around the nanoshell, and to select appropriate silica layer thickness to MEO.The MEO was experimentally evaluated using the singlet oxygen sensor green reagent (GR), a high selective sensor for singlet oxygen. The2-dimensional plasmon field enhancement distribution for the nanoshell LSPR dipole is shown in Fig. 1a. Fig. 1b presents the fluorescence emission spectra of GR in a MB aqueous solution with (black line) and without (blue line) nanoparticles.We also observed a 1.5-fold increase of the MB emission due to the nanoshell LSPR. Our results show that Silica Coated Gold nanoshell improves singlet oxygen generation (200%) on MB.

© 2017 IEEE