Recently, bio-electronic devices which can in real-time collect electrophysiological signals such as electrocardiograms (ECGs), electromyograms (EMGs), and electroencephalograms (EEGs) have been actively investigated corresponding to the change in healthcare monitoring paradigm. Flexible bio-electronics which are attachable to the human skin can collect the important bio-signals regardless of spatial and temporal constraints differently with conventional rigid bio-electronics. However, most of studies on the fabrication of flexible bio-electronics require high-cost equipment and complicated process. In this presentation, we will demonstrate highly sensitive flexible bio-electrodes using biocompatible composite materials, which can detect electrophysiological signals (such as EMG, and ECG) more accurately without the negative aspects during the wearing. We will also discuss the practical approach for the flexible bio-electronics fabricated using solution-process at low-temperature in an ambient atmosphere. We believe that this work can contribute to realize wearable nanoelectronics embedded into the healthcare monitoring systems. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (NRF-2017R1A2B2003808).