Preparation of conductive and transparent dipeptide hydrogels for wearable biosensor

Conductive and transparent dipeptide hydrogels are desirable building blocks to prepare soft electronic devices and wearable biosensors due to their excellent biocompatibility, multi-functionality, and physiochemical properties similar to those of body tissues. However, the preparation of such hydrogels featuring high conductivity and transparency is a huge challenge because of the hydrophobic feature of conductive additives making the doping process difficult. To overcome this issue, hydrophilic conductive polydopamine (PDA)-doped polypyrrole (PPy) nanoparticles are introduced into the dipeptide hydrogel networks to form conductive nanofibrils in situ to achieve a good level of hydrophilic templating of the hydrogel networks. This technique creates a complete conductive network and allows visible light to pass through. The strategy proposed herein not only endows the dipeptide hydrogel with good conductivity and high transparency, but also provides a great potential application of conductive dipeptide hydrogels for body-adhered signal detection, as evidenced by the experimental data.