Methods and apparatus are described for the processing (for example washing, incubation, etc.) of particles in which the particles suspended in a first fluid are introduced under laminar flow conditions into at least one first microchamber or first region of the same, in which a second fluid is introduced under laminar flow conditions into at least one second region of the microchamber or of a second microchamber, in such a way as not to mix with the first fluid, and in which at least one field of force (F) acting on the particles is activated in the microchamber(s), to provoke a shift of the particles alone in a predetermined direction and to transfer the same in suspension into the second fluid; an apparatus is preferably used including at least three microchambers n microchambers arranged in sequence with each other in one direction and each connected with the microchamber immediately before it and after it with two orifices offset from each other in a direction perpendicular to the direction of sequence of the microchambers.