Bioabsorbable encapsulation materials for future transient magnesium temperature sensors

Sensors and Actuators Reports, pp. 100518

Abstract

This work focuses on the study of different natural, bioabsorbable encapsulation materials, namely polylactic acid (PLA), Ecoflex, beeswax, and carnauba wax (CW), to increase the lifetime of implantable thin-film temperature sensors for biomedical applications. The resistance temperature detector (RTD) consists of a PLA substrate and a magnesium-based resistance meander structure made of the magnesium alloy WE43MEO. Sensor performance (i.e., sensitivity, response time, drift behavior, and lifetime) was evaluated under ambient air conditions in the temperature range between 30°C and 42.9°C with temperature variations of 0.3°C. Furthermore, the behavior of the Mg-based RTDs was tested on the skin during different stress scenarios such as arm movement, walking, and using an ergometer. Sensor stability in contact with phosphate buffer (PB, pH 7.4) at room temperature was studied, too. Finally, characterization was performed in a tissue-mimicking environment, between two layers of PB-soaked hydrogel (pH 7.4), at a constant temperature of 37°C for Ecoflex- and CW-encapsulated Mg-based RTDs. Moreover, the experiment was conducted using temperature variations of 1°C between 30°C and 43°C for a CW-encapsulated Mg-based RTD.

Authors 7

1. Madita Zach Aachen Institute of Nano- and Biotechnologies (INB)

   Philipps University of Marburg · FH Aachen

   Affiliation as printed

   Institute for Pharmaceutical Chemistry, Marburg University, Wilhelm-Roser-Straße 2, 35032 Marburg, Germany

   Institute of Nano- and Biotechnologies (INB), FH Aachen, Campus Jülich, Heinrich-Mußmann-Straße 1, 52428 Jülich, Germany

2. Kevin A. Janus Aachen Institute of Nano- and Biotechnologies (INB)

   Philipps University of Marburg · FH Aachen

   Affiliation as printed

   Institute for Pharmaceutical Chemistry, Marburg University, Wilhelm-Roser-Straße 2, 35032 Marburg, Germany

   Institute of Nano- and Biotechnologies (INB), FH Aachen, Campus Jülich, Heinrich-Mußmann-Straße 1, 52428 Jülich, Germany

3. Stefan Achtsnicht Aachen Institute of Nano- and Biotechnologies (INB)

   FH Aachen

   Affiliation as printed

   Institute of Nano- and Biotechnologies (INB), FH Aachen, Campus Jülich, Heinrich-Mußmann-Straße 1, 52428 Jülich, Germany

4. Heiko Iken Aachen Institute of Nano- and Biotechnologies (INB)

   FH Aachen

   Affiliation as printed

   Institute of Nano- and Biotechnologies (INB), FH Aachen, Campus Jülich, Heinrich-Mußmann-Straße 1, 52428 Jülich, Germany

5. Alexander Kopp
   Affiliation as printed

   Meotec GmbH, Philipsstraße 8, 52068 Aachen, Germany

6. Michael Keusgen

   Philipps University of Marburg

   Affiliation as printed

   Institute for Pharmaceutical Chemistry, Marburg University, Wilhelm-Roser-Straße 2, 35032 Marburg, Germany

7. Michael Josef Schöning corresponding Aachen Institute of Nano- and Biotechnologies (INB)

   Forschungszentrum Jülich · FH Aachen

   Affiliation as printed

   Institute of Biological Information Processing (IBI-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52425 Jülich, Germany

   Institute of Nano- and Biotechnologies (INB), FH Aachen, Campus Jülich, Heinrich-Mußmann-Straße 1, 52428 Jülich, Germany