Researchers have developed bacteria capable of detecting tumor DNA in live organisms, detecting colon cancer in mice. This innovation, known as "CATCH," employs CRISPR technology to identify specific DNA sequences and mutations, potentially leading to biosensors that detect infections, cancers, and diseases. The team engineered the bacteria to respond to cancer DNA and plans to apply this strategy to human cancers and infections. Although further development is needed, the biosensor could revolutionize disease detection and prevention.