Generally, chemotherapy is performed through administration of an anticancer drugs and irradiation.
However, these treatments also affect normal cells as well as cancer cells, damaging the immune system in body. This is why photodynamic therapy or photothermal therapy, which can be treated only locally around cancer cells, is emerging as a new alternative for cancer therapy. Photodynamic therapy(PDT) is a treatment with photodynamic agents.
The photosensitizer kills cancer cells with activated oxygen species that are activated by a laser of a specific wavelength. However, the photosensitizer remaining in the body was activated by visible light, resulting in the side effects to the normal tissues. Therefore, the patients who received the photodynamic therapy had to suffer the inconvenience of living in the dark room for a certain period of times.
Photothermal therapy is a treatment using photothermal materials. The photothermal materials burns cancer cells by using heat generated by a near-infrared laser. This has attracted attention as a new treatment technique because of reduced side effects and suffering such as hair loss and so on. However, it has been difficult to utilize clinically photothermal materials because of the limitation of accurate delivery to the tumor sites. A research team led by Prof. Jae Hyung PARK has developed smart gold nanocapsules with excellent biocompatibility and tumor-targetability by applying gold to hyaluronic acid based nanoparticles.
Particularly, hyaluronic acid on the surface of the capsules specifically binds to cancer cells, so that capsules in the body can actively find cancer cells. Furthermore, gold coated on the surface inhibits the indiscriminate activity of the photosensitizer caused by visible light in daily life when the nanocapsules releases heat and attacks cancer cells under laser irradiation. At this time, gold coated on the surface of the capsules is peeled off and the photosensitizer in the capsules selectively releases a large amount of reactive oxygen species to the tumor site to remove cancer cells. Prof. PARK said “This new gold nanocapsules will be used effectively and safely for cancer treatment and we will try to develop it as a core technology that can be used in clinical application.”
This research was published in the world’s leading authoritative journal ACS Nano as of November 11th, with the title of “GoldNanoclustered Hyaluronan Nano-Assemblies for Photothermally Maneuvered Photodynamic Tumor Ablation.”