TY - JOUR

T1 - Smart Hydrogel Swelling State Detection Based on a Power-Transfer Transduction Principle

AU - Ahmed, Benozir

AU - Reiche, Christopher F.

AU - Magda, Jules J.

AU - Solzbacher, Florian

AU - Körner, Julia

N1 - Funding Information: The reported research was supported by the Joe W. and Dorothy Dorsett Brown Foundation, the Olive Tupper Foundation, and the National Institute of General Medical Sciences of the National Institutes of Health (NIH) under Award 1R41GM130241 awarded to Sentiomed, Inc. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH or the foundations.

PY - 2024/5/10

Y1 - 2024/5/10

N2 - 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 integrate in situ blood analyte monitoring capabilities into standard (micro)catheters. The developed sensor is designed to fit into a catheter without obstructing its normal use and, therefore, offers great potential for providing a universally applicable transducer platform for smart catheter-based sensing.

AB - 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 integrate in situ blood analyte monitoring capabilities into standard (micro)catheters. The developed sensor is designed to fit into a catheter without obstructing its normal use and, therefore, offers great potential for providing a universally applicable transducer platform for smart catheter-based sensing.

KW - electromagnetic power transfer

KW - flexible sensors

KW - in situ analyte monitoring

KW - inductive coupling

KW - microcatheter

KW - Stimulus-responsive hydrogel

KW - swelling state transduction

UR - http://www.scopus.com/inward/record.url?scp=85191770418&partnerID=8YFLogxK

U2 - 10.1021/acsapm.4c00808

DO - 10.1021/acsapm.4c00808

M3 - Article

AN - SCOPUS:85191770418

VL - 6

SP - 5544

EP - 5554

JO - ACS Applied Polymer Materials

JF - ACS Applied Polymer Materials

IS - 9

ER -