The heat is on: cancer-drug loaded nanoparticles for photothermal therapy

06 May 2016

Guest Web-writer Anand Devasthanam
Anand has keen interest for storytelling. He has received formal training in the fields of immunology and oncology. As an aspiring science communicator, Anand strives to help scientists take complex scientific data and core messages and turn them into a narrative that is compelling, creative and scientifically accurate.

Photothermal therapy is an emerging area of cancer treatment. Here, a photothermal agents, often nanoparticles (NPs) with a resonance peak in the 700-1200nm range, are delivered to the tumor site and are subsequently activated by light in the Near Infrared (NIR) range. As a consequence, tumor cells are thermally ablated.

In a study led by Xiaolin Li and colleagues at the Key Laboratory for Thin Film and Microfabrication and Changzheng Hospital in China, scientists used SiO2@Au core-shell NPs chemically conjugated via PEGylation to graphene oxide (GO) in conjunction with a chemotherapeutic agent to target prostate cancer cells in vitro. Using the chemotherapeutic agent Docetaxel (Dtxl), which is among the leading front line treatments for patients diagnosed with prostate cancer, the team demonstrated that Dtxl-loaded SiO2@Au@GO NPs, when activated with light in the NIR range, significantly curbed the survival of DU145 prostate cancer cells.

While SiO2@Au core-shell NPs have been used previously by other research groups to study their ability to remove tumors, Li’s team fabricated SiO2@Au@GO NPs to take advantage of their relatively low cost, large specific surface area, and efficient loading and delivery of water-soluble aromatic drug molecules. This one-two punch strategy was realized via a double shell, multifunctional approach: the inner core SiO2@Au NPs served as a photothermal inducer to bring about cellular cytotoxicity; the outer GO NPs carried the antitumor drug, Dtxl. The study found that exposing DU145 cells to the NPs alone for 24h did not result in overt cell death, suggesting that the NPs have a good safety profile. Importantly, the study showed that when NP-treated cell cultures were irradiated with a 780nm NIR laser, there was a significant decline in viable cells over a 24h period.

The study demonstrates that Dtxl-loaded SiO2@Au@GO NPs could be manufactured and potentially used an an antitumor agent for the treatment of prostate cancer. Moreover, these findings illuminate the untapped potential of NP-based photothermal agents as adjuvant agents in oncology clinical trials in the near future.