Ready to donate your flat-screen tv to medical science? Liquid crystal display (LCD) television screens and computer monitors contain a chemical compound called polyvinyl alcohol (PVA) that, oddly enough, elicits no response from the human immune system, making it suitable for use in biomedicine. Researchers at the University of York in England discovered that PVA can be extracted from old screens and used to build a variety of replacement tissues, such as blood vessels and skin grafts, as well as wound dressings impregnated with antibiotics and other medications. The researchers estimate that some 2.5 billion LCD TVs and monitors are now in use, and as consumers upgrade to the latest models, the amount of PVA that could be harvested from the waste stream is huge. All the more reason to recycle that old TV.