Researchers at Utrecht University in the Netherlands have developed a new fluorescent sensor that can monitor DNA damage and repair processes in real-time in living cells and even living organisms, providing important new tools for cancer research, drug safety testing, and aging biology. The relevant results were published in the latest issue of the journal Nature Communications. Existing tools, such as antibodies or nanobodies, often bind too tightly to DNA, thereby interfering with the cell's own repair mechanism. The sensor developed this time can real-time label damaged DNA and dynamically display the repair process without interfering with cellular function. This sensor adopts small structural domains from natural proteins, which can self bind and detach from damaged sites, and can more accurately reflect the natural behavior of cells. The principle is to attach fluorescent tags to a specific protein domain originating from the cell, achieving transient recognition of damage markers. Due to its mild and reversible nature, this combination can 'light up' the damaged area without hindering the repair process. Compared with traditional methods, the new sensor enables researchers to continuously observe the entire process of damage formation, repair protein arrival, and damage disappearance in the same cell, without the need to repeat multiple experiments. The researchers validated the effectiveness of the tool in Caenorhabditis elegans. The sensor not only exhibits stability, but also captures programmed DNA breaks that occur during the development of nematodes. This proves that the new technology is not only suitable for laboratory cultured cells, but also for conducting research in living organisms. The application potential of this tool goes far beyond monitoring damage repair. It can also freely combine with other molecular modules to map the location of DNA damage in the genome, identify which proteins will aggregate around the damaged area, and even study the impact of different environments on repair efficiency by manipulating the position of damaged DNA in the nucleus. (New Society)