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 .