The supplementary materials for the article "Low-impedance tissue-device interface using homogeneously conductive hydrogels chemically bonded to stretchable bioelectronics" by Yoonsoo Shin et al. provide comprehensive support for the research. These materials include detailed figures and movies that cover various aspects of the hydrogel synthesis, characterization, and performance in different environments. Key components of the supplementary materials are: 1. **Synthesis and Characterization of Hydrogels**: - Figures S1 to S22 illustrate the synthesis process, homogeneity analysis, electrical conductivity, impedance, and mechanical properties of the hydrogels. - Movie S1 shows the stretching of a stretchable multichannel sensor array. 2. **Homogeneity and Conductivity**: - Figures S2 and S3 provide detailed analysis of the homogeneity and conductivity of the hydrogels, including XRM images, void analysis, and impedance measurements. 3. **Electrochemical and Spectroscopic Analysis**: - Figures S4 to S6 cover electrochemical impedance spectroscopy, XPS, and UV-vis-NIR spectroscopy results. 4. **Mechanical and Swelling Properties**: - Figure S8 shows the electrical and mechanical properties of the hydrogel in response to changes in its swelling level. 5. **Integration and Adhesion**: - Figures S9 to S12 detail the integration of the hydrogel on electrodes and its adhesion to porcine skin and metal substrates. 6. **Stability and Optimization**: - Figures S13 to S15 focus on the optimization of precursor ratios for strong bonding and stability in acidic environments. 7. **Biocompatibility and In Vivo Testing**: - Figures S21 and S22 demonstrate the biocompatibility of the hydrogel and in vivo impedance and pH measurement in rat models. These supplementary materials provide a thorough understanding of the hydrogel's properties, fabrication methods, and practical applications in stretchable bioelectronics.The supplementary materials for the article "Low-impedance tissue-device interface using homogeneously conductive hydrogels chemically bonded to stretchable bioelectronics" by Yoonsoo Shin et al. provide comprehensive support for the research. These materials include detailed figures and movies that cover various aspects of the hydrogel synthesis, characterization, and performance in different environments. Key components of the supplementary materials are: 1. **Synthesis and Characterization of Hydrogels**: - Figures S1 to S22 illustrate the synthesis process, homogeneity analysis, electrical conductivity, impedance, and mechanical properties of the hydrogels. - Movie S1 shows the stretching of a stretchable multichannel sensor array. 2. **Homogeneity and Conductivity**: - Figures S2 and S3 provide detailed analysis of the homogeneity and conductivity of the hydrogels, including XRM images, void analysis, and impedance measurements. 3. **Electrochemical and Spectroscopic Analysis**: - Figures S4 to S6 cover electrochemical impedance spectroscopy, XPS, and UV-vis-NIR spectroscopy results. 4. **Mechanical and Swelling Properties**: - Figure S8 shows the electrical and mechanical properties of the hydrogel in response to changes in its swelling level. 5. **Integration and Adhesion**: - Figures S9 to S12 detail the integration of the hydrogel on electrodes and its adhesion to porcine skin and metal substrates. 6. **Stability and Optimization**: - Figures S13 to S15 focus on the optimization of precursor ratios for strong bonding and stability in acidic environments. 7. **Biocompatibility and In Vivo Testing**: - Figures S21 and S22 demonstrate the biocompatibility of the hydrogel and in vivo impedance and pH measurement in rat models. These supplementary materials provide a thorough understanding of the hydrogel's properties, fabrication methods, and practical applications in stretchable bioelectronics.