Synthesis of porphyrin-conjugated silica-coated Au nanorods for synergistic photothermal therapy and photodynamic therapy of tumor

Synergistic therapy of tumor has attracted the attention of an increasing number of researchers because of its higher efficiency compared to single therapy. Herein, 4-carboxyphenyl porphyrin-conjugated silica-coated gold nanorods (AuNR@SiO₂-TCPP) were synthesized. The synergistic treatment of photothermal therapy and photodynamic therapy on A549 cancer was researched in vivo and in vitro. In the AuNR@SiO₂-TCPP, Au NRs and TCPP act as photothermal agent and photosensitizer, respectively. The temperature of the AuNR@SiO₂-TCPP (0.11 nmol L^-1) rises to 56.8 °C for 10 min under the illumination of 808 nm laser (2 Wcm^-2). In MTT assays, the viability of A549 cancer cell treated with AuNR@SiO₂-TCPP (100 μg ml^-1) is only 21%. In animal experiments, the relative tumor volumes in mice receiving AuNR@SiO₂-TCPP (5 mg kg^-1) with 660 and 808 nm irradiations were significantly inhibited and the average value is decreased to 0.78 while the average value of the control group is increased to 7.2. These results demonstrate that the AuNR@SiO₂-TCPP is a potential nanomedicine against tumor for clinical application in the near future.

A metal-semiconductor nanocomposite as an efficient oxygen-independent photosensitizer for photodynamic tumor therapy

Photodynamic therapy (PDT) is regarded as one of the most promising cancer treatments, and oxygen-independent photosensitizers have been intensively explored for advancing the development of PDT. Here, we reported on a superior hybrid nanocomposite (HNC) consisting of a metal (Au deposition) and a semiconductor (CdSe-seeded/CdS nanorods) as a photosensitizer. Under visible light, the photogenerated holes were three-dimensionally confined to the CdSe quantum dots and the delocalized electrons were transferred to the Au tips, which provided hydrogen and oxygen evolution sites for water splitting to generate reactive oxygen species (ROS) with no need for oxygen participation. Compared with semiconductors without deposited metal (i.e. raw CdSe-seeded/CdS nanorods (NRs)) under a normoxic or hypoxic environment, the HNCs exhibited substantially enhanced light-triggered ROS generation in vitro. After being modified with an Arg-Gly-Asp (RGD) peptide sequence, the nanocomposite was deemed as a tumor-targeting, long-lived and oxygen-independent photosensitizer with promoted PDT efficiency for in vivo anti-tumor therapy. This oxygen-independent nanocomposite successfully overcame the hypoxia-related PDT resistance by water splitting, which opened a window to develop conventional semiconductors as photosensitizers for effective PDT.