From ScienceDaily: "scientists reveal how they have replaced stroke-damaged brain tissue in rats. ... by inserting tiny scaffolding with stem cells attached, it is possible to fill a hole left by stroke damage with brand new brain tissue within 7 days ... Previous experiments where stem cells have been injected into the void left by stroke damage have had some success in improving outcomes in rats. The problem is that in the damaged area there is no structural support for the stem cells and so they tend to migrate into the surrounding healthy tissues rather than filling up the hole left by the stroke. ... Using individual particles of a biodegradable polymer called PLGA that have been loaded with neural stem cells, the team of scientists have filled stroke cavities with stem cells on a ready-made support structure. ... This works really well because the stem cell-loaded PLGA particles can be injected through a very fine needle and then adopt the precise shape of the cavity. In this process the cells fill the cavity and can make connections with other cells, which helps to establish the tissue ... We would expect to see a much better improvement in the outcome after a stroke if we can fully replace the lost brain tissue, and that is what we have been able to do with our technique."