An unplugged electric instrument may function, but it sounds much better when it is connected to an amplifier. Similarly, toxins and other small molecules at low concentrations in the environment or human body may emit quiet signals that are undetectable without specialized lab technology.

Now, thanks to a “cool trick” in biochemistry used to adapt a sensing platform already being deployed by Northwestern scientists to measure toxins in drinking water, researchers can detect and even measure chemicals at low enough concentrations to have use outside the lab. By attaching circuitry akin to a volume knob to “turn up” weak signals, the team has opened the door for the system to be applied to disease detection and monitoring in the human body for nucleic acids like DNA and RNA, as well as bacteria such as E. coli.

The results, which describe a system that is 10 times more sensitive than previous cell-free sensors built by the team, are published in the journal Nature Chemical Biology.

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Imagine a world where cancer treatment doesn’t rely on harsh chemicals or debilitating side effects, but instead harnesses a natural defense mechanism embedded in every cell of our bodies. Recent breakthroughs by scientists at Northwestern University suggest this may soon be a reality. They’ve uncovered a “kill switch” that could change everything we know about cancer treatment, offering a new path that sidesteps the harmful impacts of chemotherapy. But how does this hidden code work, and could it truly offer a more effective way to fight cancer?

Northwestern University scientists have uncovered a powerful “kill switch” embedded in every cell of the body, which may provide a natural defense mechanism against cancer. This kill switch operates using small RNA molecules, known as microRNAs, and large protein-coding RNAs that trigger cell self-destruction when they detect signs of cancer. The key discovery is that these molecules can effectively induce cancer cell death without allowing the cancer to develop resistance, a significant advantage over traditional chemotherapy.

The microRNAs use a mechanism called DISE (Death Induced by Survival gene Elimination) to initiate cancer cell death. DISE works by eliminating multiple genes essential for cancer cell survival, making it impossible for the cells to adapt or become resistant. Researchers found that the most effective microRNAs contain a specific sequence of six nucleotides, referred to as “6mers,” which are particularly toxic to cancer cells. This finding emerged from an exhaustive study where scientists tested all 4,096 possible combinations of these nucleotide sequences, eventually identifying the most lethal ones, which are rich in guanine (G) nucleotides.