Ultraviolet and Visible Light Used to "Target Cells"… New Cancer Treatment Method Expected

Professor Ja-Hyung Yu's Team at UNIST Develops Molecule That Repeatedly Assembles and Disassembles with Light Wavelengths, Inducing Cell Death
Potential Applications in Cancer Therapy and Fundamental Life Science Research... Published in Nano Letters

A new technology has been developed that kills cells by alternately exposing them to ultraviolet and visible light.

This technology utilizes molecules whose binding strength changes depending on the wavelength of light. It is expected to serve as a fundamental technology for treating superficial cancers such as skin cancer, as well as a molecular tool for life science research.

The research team led by Professor Ja-Hyung Yu from the Department of Chemistry at UNIST announced on October 30 that they have developed a photo-switching molecule called "Mito-AZB," which can repeatedly assemble and disassemble depending on the wavelength of light.

Research team, (from left) Professor Ja-Hyung Yu, Dr. Sangpil Kim (first author), Dr. Dohyun Kim (first author). Provided by UNIST

This molecule accumulates in the mitochondria of cells and induces apoptosis by subjecting the mitochondrial membrane to repeated mechanical pressure stress.

This is possible due to the molecule's property of assembling into a rigid fibrous structure under visible light (450 nm wavelength) and disassembling under ultraviolet light (350 nm wavelength). Depending on the presence or absence of this fibrous structure, the surface of the mitochondrial membrane undergoes repetitive physical stress, similar to being squeezed and released, causing damage. Through these damaged membranes, apoptosis-inducing substances stored in the mitochondria leak into the cytoplasm, resulting in cell death.

In actual experiments, after injecting this molecule into cells and alternately exposing them to ultraviolet and visible light, the mitochondrial membrane potential collapsed, and apoptosis-inducing substances such as reactive oxygen species and cell death signaling proteins rapidly increased within the cells. Fluorescence microscopy also confirmed that the molecule accumulated around the mitochondria in the cells.

The research team developed this molecule by combining three components: a "guide" component that targets mitochondria within the cell, an azobenzene component that changes structure and binding strength in response to light, and a fluorescent dye. The fluorescent dye was included to observe the movement and assembly process of the molecule under a fluorescence microscope.

If the guide component of the developed molecule is replaced with another substance, it can target other intracellular organelles. The research team succeeded in selectively destroying the membranes of lysosomes and endoplasmic reticulum by replacing the guide component with "morpholine" targeting lysosomes and "tosyl group" targeting the endoplasmic reticulum, respectively. Lysosomes are organelles responsible for processing cellular waste, while the endoplasmic reticulum is involved in protein synthesis and transport.

Professor Ja-Hyung Yu explained, "This study demonstrates that we can artificially alter the assembly state of molecules within cells using external stimuli such as light, and even control the resulting cellular responses. It can be used not only for treating superficial cancers such as skin cancer, where light can be directly applied, but also as a molecular tool for basic research to elucidate the functions of cellular organelles by temporarily halting or activating their functions."

Operating principle of photo-switching molecules that repeatedly assemble and disassemble according to light wavelength.

The research results were published in the international journal Nano Letters on October 8. The study was supported by the Ministry of Science and ICT and the National Research Foundation of Korea.

This content was produced with the assistance of AI translation services.