Micro Gel Beads (IMAGE) ETH Zurich Caption Micro gel beads with green fluorescent sensor bacteria. In one of the beads (centre), the sensor bacteria were killed by a substance (microscopic view). Credit ETH Zurich / Steven Schmitt and Helena Shomar Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.