Fig. 1: Introduction of Principle.

a Schematic outline of operating principle. Gaseous emissions (blue) originating from skin are captured by a DBGS cavity (green) with two layers of pillars that facilitate gas transfer to the ambient air via passive diffusion and minimal convection. A dual sensor system facing the cavity (red) and ambient air (black) captures the difference between cavity and ambient gas. b Photographic image of the realized FDM printed cavity with electronics installed. c Rendered image illustrating gas diffusion through epidermal tissue, originating from the blood vessels and sweat glands. H₂O Water, CO₂ carbon dioxide, C₂H₆O ethanol, VOC volatile organic compounds.