Methods and devices for dispersion of assemblies of biological material (such as plant embryogenic mass, plant tissue, cultured plant cells, animal tissue and/or cultured animal cells) suspended in a liquid are disclosed. The methods comprise i) subjecting the assemblies of biological material to fluid dynamics forces causing axially extensional strain and radially compressional strain and ii) subjecting the assemblies of biological material to fluid dynamics forces causing axially compressional strain and radially extensional strain fluid dynamics and iii) repeating said steps i) and ii) in sequence until assemblies of biological material is dispersed into the desired smaller size. The devices may comprise a flow channel arranged in a loop configuration for re-circulation in the flow channel, the flow channel including at least one constriction, such that the assemblies of biological material flowing through the flow channel are first subjected to axially extensional strain and radially compressional strain, and then to axially compressional strain and radially extensional strain from fluid dynamics forces.
