CHEMICAL ENGINEER Balaji Narasimhan is determined to help prevent common world-wide diseases such as tetanus and diphtheria. These illnesses currently require four to five injections to build up a subject’s immunity, a fact that is particularly troublesome in populations with limited access to health care. Narasimhan, an associate professor at Iowa State University, is trying to achieve the same effects with a single dose, by encapsulating vaccines in specially tailored biodegradable polymers. When injected, the polymers slowly release the vaccines in precise amounts at precise times over a one-year period, thereby maximizing immune response and making booster shots unnecessary. The precision that Narasimhan has achieved in lab tests is better than that for previous drug encapsulation systems. Narasimhan is also devising noninteractive polymers to deliver fragile proteins involved in cancer therapies. One advantage is that his polymers resist water, and thus degradation, better than other drug delivery materials. Narasimhan expects both systems to be ready for human testing within five years. Before his work with polymer-based drug delivery,Narasimhan and researchers from the Swiss chemical company Clariant invented a more efficient process for making photoresists—polymers used in the manufacture of computer chips. Clariant is now operating a pilot photoresist production facility in New Jersey that uses this process.