This paper presents challenges and opportunities related to the problem of diffusion boundary determination and zone control via mobile actuator-sensor networks (MAS-net). This research theme is motivated by three example application scenarios: 1) The safe ground boundary determination of the radiation field from multiple radiation sources; 2) The nontoxic reservoir water surface boundary determination and zone control due to a toxic diffusion source; 3) The safe nontoxic 3D boundary determination and zone control of biological or chemical contamination in the air. We focus on the case of 2D diffusion process and on using a team of ground mobile robots to track the diffusion boundary. Moreover, we assume that there are a number of robots that can carry and move networked actuators to release a neutralizing chemical agent so that the shape of the polluted zone can be actively controlled. These two MAS-net applications, i.e., diffusion boundary determination and zone control, are formulated as model-based distributed control tasks. On the technological side, we focus on the node specialization and the power supply problems. On the theoretical side, some recently developed new concepts are introduced, such as the regional/zone observability, regional/zone controllability, regional/zone Luenberger observer etc. We speculate on possible further developments in the theoretical research by noting the combination of diffusion based path planning and regional analysis of the overall MAS-net distributed control system.