At the University of Virginia, a materials engineer is turning water-rich polymers into something that behaves like living human tissue — and the National Institutes of Health has invested $2.1 million in the effort. Steven Caliari's work on hydrogels sits at a quiet but consequential frontier: the possibility that the animals long used to test drugs and study disease might one day be replaced by engineered tissue that more faithfully reflects the human body. It is a shift not merely of method but of philosophy — toward a science that asks whether we can understand life by building it, rather