Pathogenic bacteria often release their DNA into the environment that they colonise. This DNA is potentially a great method of detecting specific types of bacteria, before they become pathogenic, making treatment easier and more targeted. 

There are many such methods of sensing this bacterial DNA, one such method is to use biology itself to tell us when it is present. This is possible, because DNA has a very specific structure that can bind to other molecules that mirror its structure. 

In today's episode, Dr. Yu-Yu Cheng talked about his recently published work on a DNA circuit he designed which was capable of binding to specific target DNA, like the ones emitted by pathogenic DNA. Upon binding the target DNA, the DNA circuit would light up (fluoresce) thus alerting the observer that a specific bacteria may be present in a sample.