A research team at the Korea Institute of Science and Technology (KIST) has developed a new photodynamic chemotherapy that can increase the efficiency and reduce the pain of chemotherapy and side effects after treatment.

KIST Professor Kim Se-hoon's team has discovered new, light-based chemotherapy that can destroy cancer cells without adverse effects. (KIST)
KIST Professor Kim Se-hoon's team has discovered new, light-based chemotherapy that can destroy cancer cells without adverse effects. (KIST)

Photodynamic technology is a cancer treatment method that uses light. The treatment injects a photosensitizer that accumulates only in cancer tissues and then selectively destroys them, emitting light through a laser.

The KIST’s treatment method has far fewer side effects than radiation therapy or general chemotherapy, where damage to cancer cells' surrounding tissues is inevitable, making it possible for patients to receive multiple treatments, the university said.

However, the photosensitizer can only be used once, so for repeated treatment, hospitals have to administer the photosensitizer each time it performs the procedure.

Also, as photosensitizer remaining after treatment accumulates in the skin or eyes and causes side effects, hospitals recommended patients to stay away from sunlight and indoor lighting for a certain period after treatment.

"While there have been spurts to develop light-sensitizing agents that activate phototherapy effects only in cancer tissues, the development has failed to completely cover the unmet medical needs in the field as they are still toxic with hospitals needing to inject the substance at every procedure," the team said.

To address such concerns, the team, led by Professor Kim Se-hoon at the university, designed an internalizing RGD peptide that can selectively penetrate and target cancer tissues as a skeleton, a photosensitizer, and a quencher that controls the activity of light.

Using this peptide technology, the team developed a peptide-based photosensitizer that activates phototherapy effects only in cancer tissues.

"When the developed photosensitizer is injected into a living body, it is activated by body temperature, and aggregates into a supramolecular array designed by the team and is stored around cancer cells," it said. "Subsequent photodynamic therapy allows physicians to destroy only cancer cells and not normal cells."

As a result of applying the photodynamic therapy developed by the researchers to a tumor-implanted mouse model, the photosensitizer stored around the tumor with a single injection around the cancer tissue and continuously emitted light up to two to four weeks, the team added.

The team also stressed that they found no toxicity that destroys tissues and major organs around cancer, even with repeated exposure to light, and completely removed the cancer tissues through repeated procedures.

"We developed a cancer-targeting peptide phototherapy that forms a reservoir through supramolecular self-assembly without additional adjuvants when injected in vivo," Professor Kim said. "The developed phototherapy agent can completely remove cancer through long-term repeated phototherapy without toxicity with only one injection to the surrounding area of cancer."

Since the formulation is simple with a single component, the team expects that it will be useful in future photodynamic treatments, he added.

The results of the research were published in the journal ACS Nano.

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