According to a press release from the University of the West of England in Bristol, a team working under Professor Ioannis Ieropoulos has developed socks with inbuilt microbial fuel cells (MFCs). These generate electric current from bacteria, using the bio-chemical energy normally used for microbial growth. MFCs have previously been used to power a mobile phone, using an electric pump (which was used only for proof of concept. The socks include a urine reservoir and a manual pump, powered by the user walking, pushes the urine over the cells. The cells power a wireless transmission board, which can send a message every two minutes.