Meshes can be shifted with a given distance using Shift Mesh.

Select Shift Mesh and click the upper Edit… button (to the right of Options) to open the Shift Mesh dialog. Choose the mesh to be shifted on the right box and define the values for Shift X, Shift Y, and Shift Z for the shift distance in X, Y, and Z direction, respectively. Click OK to close the dialog and go back to MeshGeo section. Click the Edit button at the bottom (the one with the red arrow) to run the command.

In the example below, there are two meshes, one for the big red particle and the other one for the small green particle. After shifting, the small green particle is moved in the negative Z-direction by 40µm.