Mouse model: Optical scanning biological systems using an ultrasound-mediated light source. (Courtesy: G Hong) Researchers at Stanford University in the US have found a way to generate light deep within living tissues, potentially leading to new forms of gene and cancer therapies. The proof-of-concept approach uses ultrasound to trigger luminescence in nanoscale particles travelling through the bloodstream, and it has already been tested in tissue-mimicking “phantoms” and live mice. However, its developers caution that human trials are still some way off. Light has numerous applications in medicine and biological research. It is widely used, for example, to stimulate cell growth and in photodynamic therapies for skin and eye conditions, as well as certain types of cancer. The problem is that many potentially useful wavelengths of light are easily scattered by tissues and become attenuated over relatively short distances.…