Many of the promised genomic drugs will be impossible to swallow as pills. Instead, they will have to be injected in minute quantities at precise intervals for months at a time. Just the job for an implantable syringe-on-a-chip. Researchers in this field refer to their goal as intelligent drug delivery. The intelligence is derived from a piece of silicon one centimetre square. Etched in the silicon is a matrix of tiny wells, each designed to hold 150 nanolitres (billionths of a litre) of medicine.