Researchers have developed a design-driven process that uses parts from a very different kind of toolkit to build complex genetic circuits for cellular engineering.According to the researchers, one of the most exciting frontiers in medicine is the use of living cells as therapies. Using this approach to treat cancer, for example, many patients have been cured of the previously untreatable disease. These advances employ the approaches of synthetic biology, a growing field that blends tools and concepts from biology and engineering, the team said.The new technology uses computational modelling to more efficiently identify useful genetic designs before building them in the lab. Faced with myriad possibilities, modelling points researchers to designs that offer real opportunity. "To engineer a cell, we first encode a desired biological function in a piece of DNA, and that DNA programme is then delivered to a human cell to guide its execution of the desired function, such as activating a gene only in response to certain signals in the cell's environment," said researcher Joshua Leonard from the Northwestern University in the US.The study, in which dozens of genetic circuits were designed and tested is published in the journal Science Advances. Like other synthetic biology technologies, a key feature of this approach is that it is intended to be readily adopted by other bioengineering groups. To date, it remains difficult and time-consuming to develop genetic programmes when relying upon trial and error. It is also challenging to implement biological functions beyond relatively simple ones, the team said.The research team used a "toolkit" of genetic parts invented in the lab and paired these parts with computational tools for simulating many potential genetic programmes before conducting experiments. They found that a wide variety of genetic programmes, each of which carries out a desired and useful function in a human cell, can be constructed such that each programme works as predicted. Not only that, but the designs worked the first time, the researchers noted.