A microfluidic printing nozzle for 3D printing may include a mixing chamber, a first inlet for connecting with a first ink source, the first inlet located at a first end of the mixing chamber, and a second inlet for connecting with a second ink source, the second inlet located at the first end of the mixing chamber. An outlet may be located at a second end of the mixing chamber, and a generally cylindrical impeller may be rotatably disposed in the mixing chamber between the first end and the second end. The cylindrical impeller may include an outer surface, and the outer surface of the impeller includes a groove, a protrusion, or both, to facilitate mixing of fluidic inks flowing from the first end to the second end of the mixing chamber.