Abstract: A blood storage container includes a blood storage chamber having a blood outlet port, a blood inlet chamber disposed upstream of the blood storage chamber with respect to a direction in which blood to be stored flows, a blood debubblizer for debubblizing the blood, the blood debubblizer being disposed between the blood inlet chamber and the blood storage chamber, and an air bubble stop unit for preventing air bubbles in the blood from flowing therethrough, the air bubble stop unit being disposed downstream of the blood debubblizer. The air bubble stop unit has mesh screens of different mesh sizes which are supported in a frame that is detachably disposed in the blood storage chamber.

Abstract: A silk fibroin membrane containing an entrapped biocatalyst such as an enzyme or microorganism is provided by forming a mixture of a biocatalyst solution and a silk fibroin solution, forming a membrane by casting the mixture, drying the membrane and mechanically treating the resultant membrane at a temperature and humidity to produce the membrane in .beta.-form and to structurally stabilize the membrane. Mechanically treating may be by stretching or compressing. A biocatalyst sensor is formed by coating an electrically conductive substrate with a gas-permeable layer and coating the gas-permeable layer with the silk fibroin membrane containing an entrapped biocatalyst.