Medical science often targets drugs at the proteins in cell membranes. But how do you study everything about their behavior when you can't control them? That's what UC San Diego researchers aim to fix. They've developed artificial cell membranes that grow and model themselves just like those in mammal cells, making them ideal for testing how drugs will behave. The trick is to use reversible chemical reactions that remodel phospholipids (key molecules in the cell membrane) and make the cell 'recycle' them, rather than generate them from scratch. That, in turn, saves the cell a lot of effort as its membrane grows.