A gas permeable, liquid impermeable membrane for use with gas sensors consists of a film forming polymer which incorporates nanoparticles selected to improve one or more of the following: permeability to gases, to selectively regulate permeability of selected gases through the membrane, to inhibit microbial growth on the membrane. A capsule shaped container consists of wall material biocompatible with a mammal GI tract and adapted to protect the electronic and sensor devices in the capsule, which contains gas composition sensors, pressure and temperature sensors, a microcontroller, a power source and a wireless transmission device. The microprocessor receives data signals from the sensors and converts the signals into gas composition and concentration data and temperature and pressure data for transmission to an external computing device. The capsule wall incorporates gas permeable nano-composite membranes with embedded catalytic and nano void producing nanoparticles, enhancing the operation, selectivity and sensitivity of the gas sensors.
