Hybrid fixed bed cell culture substrate and bioreactor

A cell culture matrix for culturing cells in a fixed bed reactor, the cell culture matrix comprising:

• a plurality of substrate layers in a stacked arrangement of parallel layers, each layer of the plurality of substrate layers comprising a substrate material with an ordered and regular array of openings passing through the layer, the openings being separated by the substrate material having a physical structure that is substantially regular and uniform and that is configured for growing cell thereon,
• wherein the plurality of substrate layers comprises a first substrate material and a second substrate material that is different from the first substrate material in at least one physical dimension, the first substrate material and the second substrate material comprising separate layers of the plurality of substrate layers, and
• wherein the physical structure comprises a plurality of fibers.