Status symbols like silk and gold are meant to be flashed in public, but scientists from Tufts and Boston University have developed a gold-coated silk “cloak” that is designed to be heard, not seen. The new metamaterial, which could pave the way for a real-life Harry Potter-style Cloak of Invisibility, isn’t for sneaking into girls’ locker rooms, however. Because silk is biocompatible, the human body won’t reject it the way it would most other implants. This opens up a host of biomedical applications for the high-tech fabric, including implantable glucose sensors for diabetics.