Dogs have an incredible sense of smell. In the laboratory, a simpler creature, Caenorhabditis elegans, can wriggle towards cancer cells by tracking odor tracks. Recently, at the spring meeting of the American Chemical Society, Korean University researchers reported a device that uses worms to detect lung cancer cells. This "worm on chip" could one day help doctors diagnose cancer early and noninvasively. At present, doctors diagnose lung cancer through imaging or biopsy, but these methods usually can not detect the tumor at an early stage. Therefore, the researchers decided to use Caenorhabditis elegans to develop non-invasive cancer diagnosis methods, because the worm is small (about 1 mm long), easy to grow in the laboratory and has an extraordinary sense of smell. Compared with normal cells, lung cancer cells will produce a different group of odor molecules, and Caenorhabditis elegans living in the soil will be attracted or repelled by some odors. Therefore, researchers put the nematodes into Petri dishes and add human urine, and it can be observed that the nematodes preferentially climb to the urine samples of cancer patients. The research team made a chip from polydimethylsiloxane elastomer. Each end of the chip has a hole, which is connected to the central chamber through a channel. The researchers placed the chip on an agar plate. At one end of the chip, they added a drop of medium from lung cancer cells, and at the other end, they added medium from normal lung fibroblasts. They placed the worms in the central chamber, and after an hour, they observed more worms crawling towards the lung cancer medium than the normal medium. In contrast, worms with odr-3 odor receptor gene mutations did not show this preferential behavior. The researchers estimated that the device was about 70% effective in detecting cancer cells in diluted cell culture medium. They hope to improve the accuracy and sensitivity of the method by using worms previously exposed to cancer cell culture medium. By optimizing the chip worms used to detect cultured lung cancer cells, the research team plans to continue testing urine, saliva and even human exhaled gas to determine whether the method can detect patients' lung cancer at an early stage. In other studies using chip worms, the researchers identified specific odor molecules that attract Caenorhabditis elegans to lung cancer cells, including a volatile organic compound called 2-ethyl-1-hexanol. The researchers speculate that the smell of 2-ethyl-1-hexanol may be similar to that of their favorite food. punctuate Caenorhabditis elegans is a non-toxic, harmless and independent nematode. It is also a model organism in the field of molecular biology and developmental biology. In the history of human biological research, this tiny and simple insect has also made great contributions - the phenomenon of cell apoptosis was first revealed in online insects. This time, researchers found that nematodes can smell the taste of lung cancer cells and move to these cells. At present, the effectiveness of chip worm in detecting cancer cells in diluted cell culture medium is about 70%, and the accuracy needs to be further improved. But early detection of cancer based on the taste of nematodes seems to be a potential way. (Xinhua News Agency)