Abstract: A biologically implantable containment device having a wet seal, the device being adaptable for drug formulations or cell suspensions. A porous membrane, in a tubular configuration, is formed and can be configured as part of a closed cell-tight system for loading. During loading, the containment device membrane is wet, while the loading system remains cell-tight. The containment device is wet-sealed through a combination of heat and pressure, while the system remains cell-tight. Sealing the containment device substantially or completely eliminates metabolic functioning of any organisms in the vicinity of the closure. The wet-seal is formed by melting a thermoplastic material that is in contact with the membrane. The containment device is separated from the cell-tight loading system, which remains closed after separation.