Before you protest, as I initially did, that some things are so simple and fundamental that they don’t really need high-tech “improvements,” realize that this device is being developed for and targeted at medical professionals, who, per this New York Times article covering the developing technology, “often have to wash their hands dozens of times a day — and may need a minute or more to do the process right, by scrubbing with soap and water.”
Room temperature plasma is reportedly very effective at sterilizing surfaces, and is already in use to clean inanimate surfaces and instruments. The plasma is produced by ionizing ordinary air, so no separate gas supply is needed. Apparently the central design challenge is making sure the box –which is basically just a high-voltage power supply–is safe to stick your hand into, and remains that way over the lifetime of the device. The plasma itself supposedly causes no discomfort and is safe for the skin, although you’d think, if they really believe that, somebody would’ve provided a photo showing a bare hand in contact with it, rather than one so conspicuously gloved.