Culture flask and culture flask assembly

A culture flask, configured to contain a culture medium and adapted for centrifugation;

• the culture flask comprising:
• a flat flask body having
• two translucent planes forming two major flat surfaces located on two opposite sides of the flask body respectively, and the two translucent planes being parallel to each other;
• at least one of the translucent planes being transparent;
• two side surfaces located between the two major flat surfaces and connecting the two major flat surfaces, each side surface having an area smaller than an area of each of the two major flat surfaces;
• an opening end located on one end of the flask body, and a flask opening formed on the opening end, and the flask opening communicating with an inner space of the flask body;
• a recess end located opposite to the opening end on the flask body;
• an imaginary straight line passing through both the opening end and the recess end being defined as a centrifuging line;
• and
• at least one collecting recess configured to collect cells in the culture medium;
• the at least one collecting recess formed on the recess end and extending from distal ends of the two major flat surfaces and two side surfaces, along the centrifuging line in a direction away from the opening end, and an area of a cross section of the at least one collecting recess that is perpendicular to the centrifuging line being gradually decreased toward a bottom of the at least one collecting recess along said direction such that the cells are collected inside the bottom of the at least one collecting recess after centrifugation;
• and
• at least one blocker protruding from an inner surface of one of the two side surfaces of the flask body and extending between the two translucent planes with two sides of the at least one blocker connected to the two translucent planes respectively;
• wherein the at least one blocker, the inner surface of said one of the two side surfaces of the flask body, and the two translucent planes form at least one gathering recess;
• the at least one blocker has a blocking surface toward the recess end, and the blocking surface inclines toward the recess end with respect to a plane perpendicular to the two translucent planes, such that an opening of the gathering recess faces toward the recess end to trap and preserve cells moving from the recess end toward the flask opening when a user removes the culture medium by tilting.