The supplementary materials for the study "Low-impedance tissue-device interface using homogeneously conductive hydrogels chemically bonded to stretchable bioelectronics" include figures and a movie. The figures cover the synthesis of a homogeneously conductive hydrogel, hydrogel homogeneity analysis, electrical conductivity and impedance of hydrogels functionalized with different aniline concentrations, electrochemical impedance spectroscopy results, XPS and UV-vis-NIR spectroscopy results, impedance of hydrogels at various pH values, stretching test of the hydrogel, electrical and mechanical properties of the hydrogel in response to changes in its swelling level, schematic illustration of hydrogel integrated on an electrode, adhesion of hydrogels applied to porcine skin and metal, reactivity of metals in acidic conditions, adhesion test on the hydrogel, optimization of hydrogel precursor ratios for strong bonding and stability in acidic environment, adhesion test on PAAm and PEDOT:PSS-PANi-PAAm hydrogels, hydrogen bonding between a TA molecule and others within the conductive hydrogel, illustration of detailed fabrication steps for stretchable bioelectronics and elastic PU wells, preparation steps for artificial skin, measurement of impedance using multichannel patch, measurement of pH using multichannel patch, impedance mapping during stretching deformation, biocompatibility of the conductive hydrogel, and in vivo impedance and pH measurement demonstration. The movie shows the stretching of the stretchable multichannel sensor array placed on the artificial tissue model. The supplementary materials provide detailed information on the synthesis, characterization, and application of the homogeneously conductive hydrogels used in the study.The supplementary materials for the study "Low-impedance tissue-device interface using homogeneously conductive hydrogels chemically bonded to stretchable bioelectronics" include figures and a movie. The figures cover the synthesis of a homogeneously conductive hydrogel, hydrogel homogeneity analysis, electrical conductivity and impedance of hydrogels functionalized with different aniline concentrations, electrochemical impedance spectroscopy results, XPS and UV-vis-NIR spectroscopy results, impedance of hydrogels at various pH values, stretching test of the hydrogel, electrical and mechanical properties of the hydrogel in response to changes in its swelling level, schematic illustration of hydrogel integrated on an electrode, adhesion of hydrogels applied to porcine skin and metal, reactivity of metals in acidic conditions, adhesion test on the hydrogel, optimization of hydrogel precursor ratios for strong bonding and stability in acidic environment, adhesion test on PAAm and PEDOT:PSS-PANi-PAAm hydrogels, hydrogen bonding between a TA molecule and others within the conductive hydrogel, illustration of detailed fabrication steps for stretchable bioelectronics and elastic PU wells, preparation steps for artificial skin, measurement of impedance using multichannel patch, measurement of pH using multichannel patch, impedance mapping during stretching deformation, biocompatibility of the conductive hydrogel, and in vivo impedance and pH measurement demonstration. The movie shows the stretching of the stretchable multichannel sensor array placed on the artificial tissue model. The supplementary materials provide detailed information on the synthesis, characterization, and application of the homogeneously conductive hydrogels used in the study.