Mechanoelectrical transduction in the hydrogel-based biomimetic sensors

Abstract

The study addresses the phenomenon of mechanoelectrical transduction in polyelectrolyte hydrogelsand, in particular, the search of the driving force for the change of the electrical potential of a gel underthe applied mechanical stretch. Polyelectrolyte gels of calcium and magnesium salts of polymethacrylicacid were synthesized by the radical polymerization in water solution. Their electrical potential mea-sured by microcapillary electrodes was negative and fall within 100–140 mV range depending on thenature of a counterion and the networking density of a gel. The rectangular samples (∼10 mm in lengthand 2 × 2 mm in cross-section) of gel-based sensors underwent the dynamic axial deformation, and thesimultaneous monitoring of their geometrical dimensions and the electrical potential was performed.Sensor elongation resulted in the overall increase of gel volume, and it was always accompanied by thegel potential change toward the depolarization (diminishing of the negative values). Theoretical modelbased on the assumption of the total electrical charge conservation in the course of the dynamic defor-mation of a filament was proposed to describe the dependence of the electrical potential of a gel on itsvolume. Good agreement between the predictions of the model and the experimental trend was shown.The proposed mechanism of mechanoelectrical transduction based on the stretch-dependant volumechanges in polyelectrolyte hydrogels might be useful to understand the nature of mechanical sensing inmuch more complex biological gels like the cell cytoskeleton.