I think getting nutrients and keeping infections away might be large problems. Anyone know of some animal experiments in this direction?
Well, they are currently growing large numbers of rat neurons on glass "chips" as the brains of small robots, these require the same level of care as any brain - correct temperature, PH, nutrients, etc. Seems they also have to be very carefull to avoid contamination from bacteria / viri, I think I read the pink nutrient 'soup' (Blood serum + growth factors, nutrients etc) that the cells live in, is dosed with an antibiotic too.
Whole brains have been kept alive in-vitro, but usually for only a few hours (though some invertebrate brain require less oxygen and can last for up to a few days). I believe most in-vitro mammalian brain tests have been on rats and guinea pigs. The bigger the brain, the more energy and oxygen is required, so small brains are somewhat easier to work with.
SS