Cells itself cant do a thing without coordination,
Talking about cells comming together, anyone see that load of balls that stick to each other to form a shape. They have no intelligence of their own other than how to roll where commanded and stick and act a little bit like cells (except they don't divide). This kind of technology could lead to an intelligent polymorphic liquid that can make any shape and individually change color. (So the T1000 may not be so incredibly far fetched after all! :D)