Protocell Tunable Chemotaxis (IMAGE) Penn State Caption Tunable chemotaxis of enzyme-coated protocells could lead to precision drug deliver. Illustration of protocells, called liposomes, that have enzymes (green) attached to their external surface moving through a microfluidic device. Depending on the enzyme, protocells can be made to move toward or away from gradients of chemical signals (grey dots). Credit Ambika Somasundar, Penn State 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.