Although flexible silicon circuits have been around for a few years, the next stage has eluded scientists - until now. If you look at a basic circuit, with just some SMCs, such as transistors, resistors, capacitors and so on, then these can mostly be placed on a flexible base already. However, complex, multi-level ICs have not been possible, so restricting ‘wearable’ circuits to relatively elementary designs. Now that complex devices are possible, PCs, or anything requiring microprocessors are viable. See this piece for more info.