Porphyrin Derivative Conjugated with Gold Nanoparticles for Dual-Modality Photodynamic and Photothermal Therapies In Vitro

Gold nanoparticles (Au NPs) have been confirmed to show excellent photothermal conversion property for tumor theranostic applications. To improve the antitumor efficacy, a novel nanoplatform system composed of porphyrin derivative and Au NPs was fabricated to study the dual-modality photodynamic and photothermal therapy with laser irradiation. Modified chitosan was coated on the Au NPs surface via ligand exchange between thiol groups and Au. The chitosan-coated Au NPs (QCS-SH/Au NPs) were further conjugated with meso-tetrakis(4-sulphonatophenyl)porphyrin (TPPS) via electrostatic interaction to obtain the porphyrin-conjugated Au hybrid nanoparticles (TPPS/QCS-SH/Au NPs). Size, morphology, and properties of the prepared nanoparticles were confirmed by Zeta potential, nanoparticle size analyzer, transmission electron microscopy (TEM), and UV-vis spectroscopy. Moreover, both photothermal therapy (PTT) and photodynamic therapy (PDT) were investigated. Compared with alone Au NPs or TPPS, the hybrid TPPS/QCS-SH/Au NPs with lower cytotoxicity showed durable elevated temperature to around 56 degrees C and large amount of singlet oxygen (O-1(2)) produced from TPPS. Thus, the hybrid nanoparticles showed a more significant synergistic therapy effect of hyperthermia from PTT as well as O-1(2) from PDT, which has potential applications in the tumor therapy fields.