Artificial muscular microfibers: hydrogel with high speed tunable electroactivity

The advancement in polymer muscle-like actuator technologies is of immense importance in the development of biologically inspired designs for tissue substitutes where the mechanical robustness is combined with fast physico-chemical responsiveness, biocompatibility and electroactivity. The multiformability (films, fibres, tubules,.) and the multifunctionality (response to temperature, pH, electromagnetic excitation,.) of hydrogels make them a great candidate for electro-bio-active artificial implantable muscular fibers and as soft actuators for gentle micro-scale manipulations. With an end objective to conceive and fabricate a system with instantaneous response to external stimuli, we present the results of an experimental method used to prepare long thin self-assembled hydrogel fibers with aspect ratio greater than 105 (length/diameter). We show for the first time that these fibers are electroactive and dynamically tunable under low applied electric field (as low as 500 V m(-1)) with high potential in instantaneous sensing of pH and ionic strength variations in their surrounding medium.