Gas sensors with high sensitivity are crucial for a large amount of applications. This paper shows a sensor packaging concept for highly sensitive 2D-materials such as black phosphorus (BP) or molybdenum disulfide (MoS2). The material needs on the one hand shielding against gases, which will rapidly degrade the material, such as oxygen; on the other hand, a sufficient contact of the measuring gas to function as sensor. For this purpose, flexible packaging should provide semipermeable membranes on the sensor active area. The development of a gas permeation chamber for permeation tests of polymers and sensor test within a sample gas atmosphere is presented in the paper, together with 2D-material sensor characterization.