Why do bone cells colonize glass scaffolding? One researcher says it’s like seeding a fishing environment by throwing an old Christmas tree into the water. The submerged tree provides good pockets of cover for all kinds of fish. But this isn’t really a discussion about aquatic habitats. The scientist is trying to explain why human bone cells would want to colonize medical scaffolding made out of glass fibers. “Nature abhors a void,” he says. “And the body likes certain kinds of glass.”