Method and apparatus for stirring particles in suspension such as microcarriers for anchorage-dependent living cells in a liquid culture medium

Apparatus for stirring micro-carriers in a liquid culture medium to allow living cells to grow thereon comprising:

• (a) container means for a liquid comprising a bottom and wall means extending upward therefrom,
• (b) means for imparting to the liquid culture medium a primary, generally horizontal circulatory movement about the axis of the container means and a secondary, generally vertical circulatory movement, comprising stirrer means mounted to extend into the container means with an end adjacent to and spaced from the bottom, and moved in a closed path in said vessel, and
• (c) means for causing substantially all of the liquid culture medium in the container means to be moved by said stirrer means comprising an upstanding portion extending upwardly from the bottom of the container and spaced from said wall means, thereby forming a trough in the bottom portion of the container means.

A method of stirring a liquid culture medium comprising providing a stirring vessel with provision for blocking off the corners and centre of the base of the vessel to provide an annular trough therein shaped to prevent accumulation of particles under the action of secondary motion stirring effects within the vessel, adding to the vessel liquid culture medium, introducing an elongate stirrer into said medium with it's free end spaced from the bottom of the vessel, and stirring the medium by imparting to the stirrer an orbital path with the free end moving in the trough thereby to impel the medium to circulate in the stirring vessel without accumulation.