Smart Hydrogel Swelling State Detection Based on a Power-Transfer Transduction Principle

作者：Benozir Ahmed, Christopher F. Reiche, Jules J. Magda, Florian Solzbacher, Julia Körner · 发表于：ACS Applied Polymer Materials · 年份：2024 · DOI：10.1021/acsapm.4c00808 · 被引用次数：13 · 研究领域：Advanced Sensor and Energy Harvesting Materials、Analytical Chemistry and Sensors、Conducting polymers and applications

Stimulus-responsive (smart) hydrogels are a promising sensing material for biomedical contexts due to their reversible swelling change in response to target analytes. The design of application-specific sensors that utilize this behavior requires the development of suitable transduction concepts. The presented study investigates a power-transfer-based readout approach that is sensitive to small volumetric changes of the smart hydrogel. The concept employs two thin film polyimide substrates with embedded conductive strip lines, which are shielded from each other except at the tip region, where the smart hydrogel is sandwiched in between. The hydrogel's volume change in response to a target analyte alters the distance and orientation of the thin films, affecting the amount of transferred power between the two transducer parts and, consequently, the measured sensor output voltage. With proper calibration, the output signal can be used to determine the swelling change of the hydrogel and, consequently, to quantify the stimulus. In proof-of-principle experiments with glucose- and pH-sensitive smart hydrogels, high sensitivity to small analyte concentration changes was found along with very good reproducibility and stability. The concept was tested with two exemplary hydrogels, but the transduction principle in general is independent of the specific hydrogel material, as long as it exhibits a stimulus-dependent volume change. The application vision of the presented research is to in...