A multi-well assembly (10) comprises a multi-well block (12) and a guide plate (14). The multi-well block (12) has a plurality of wells (18) each with a fluid-impermeable bottom surface (22). The guide plate (14) has a plurality of fluid passageways (34) corresponding to the wells (18) of the multi-well block (12). The guide plate (14) is configured to establish fluid communication between each well (18) and an associated fluid passageway (34) when the guide plate (14) is aligned with the multi-well block (12).