Simultaneous Enhancement of Intracellular Optical Imaging and Photothermal Therapeutic Response by Octaarginine-Modified Fluorescent Dye Doped Pd@Ag@SiO<SUB>2</SUB>(RITC) Multifunctional Nanoparticles

Abstract

In the work, a novel multifunctional silica-based nanoplatform (Pd@Ag@SiO2(RITC)-R8) for bioimaging and photothermal therapy (PTT) of cancer cells has been developed. The Pd@Ag nanosheets encapsulated inside silica can act as effective near-infrared (NIR) absorbers for cancer photothermal therapy. Fluorescent dye, rhodamine B isothiocyanate (RITC), was covalently doped into the silica network to provide the capacity for optical imaging. After amine modification, the Pd@Ag@SiO2(RITC)-NH2 can be further conjugated with octaarginine (R8, a cell penetrating peptide) for enhancing the uptake of nanoparticles by cells. Confocal fluorescent images and flow cytometry analysis revealed that R8-conjugated nanoparticles (Pd@Ag@SiO2(RITC)-R8) were taken up by cells more efficiently. Correspondingly, the optical imaging and photothermal therapeutic efficiency of Pd@Ag@SiO2(RITC)-R8 upon cancer cells were also raised due to their higher cellular uptake when compared with that of Pd@Ag@SiO2(RITC)-NH2. Our results indicate that these multifunctional Pd@Ag@SiO2(RITC)-R8 may have great potential for applications in imaging-guided cancer photothermal therapy.