From Nature to Function: Biodegradable Platforms for Pressure Sensing and Bioelectronic Interfaces

Klara Hänisch

AutorIn

Klara Hänisch

Titel

From Nature to Function: Biodegradable Platforms for Pressure Sensing and Bioelectronic Interfaces

Zitierfähige Url:

https://nbn-resolving.org/urn:nbn:de:bsz:14-qucosa2-1051041

Erstveröffentlichung

2026

Datum der Einreichung

15.01.2026

Datum der Verteidigung

03.03.2026

Abstract (EN)

The continuously increasing amount of electronic waste highlights the urgent need for sustainable alternatives to conventional electronic materials and devices. In particular, the growing complexity and miniaturization of modern electronics challenge established recycling strategies, motivating the development of biocompatible and biodegradable electronic systems that safely decompose or resorb after use. This dissertation explores sustainable materials and device concepts for pressure sensors and electronic substrates, combining biocompatibility, biodegradability, and compatibility with establishedfabrication processes. In the first part, a biocompatible, miniaturized pressure sensor for direct middle ear pressure monitoring is presented. Current clinical practice relies on indirect measurements via tympanometry, while direct sensing approaches remain unsuitable for routine use due to their invasiveness. The developed capacitive pressure sensor covers a pressure range from -7.5 kPa to +7.5 kPa and features a compact footprint of 2 x 4 mm², enabling direct implantation in the human middle ear. Pressure sensing is realized by an elastic dielectric capacitor structure. Additionally, wireless read-out via an integrated planar coil is investigated, which would allow for continuous pressure monitoring without the need for additional surgeries. The device demonstrates mechanical flexibility, electrical stability, and sensitivity suitable for post-operative medical applications in confined anatomical environments. Building on this concept, the second part of the thesis advances toward fully biodegradable pressure sensors. Here, natural leaf skeletons are employed as bio-sourced functional materials for both electrodes and dielectric layers in capacitive pressure sensors. The resulting devices operate in a pressure range of approximately 1–50 kPa and exhibit sensitivities comparable to state-of-the-art pressure sensors. Owing to their fully biodegradable nature, these sensors represent an ecologically benign alternative for transient sensing applications in medicine, agriculture, and industrial process monitoring, while demonstrating the feasibility of leaf-based materials in functional electronic devices. The third part addresses the broader challenge of sustainable electronic substrates compatible with modern thin-film device fabrication. A transparent, flexible, biocompatible, and decomposable composite substrate based on magnolia leaf scaffolds infiltrated with a crosslinked poly(ethylene glycol) diacrylate system (PLEX) is introduced. The material achieves optical transmittance of up to 88 % in the visible range, root-mean-square surface roughness below 0.8 nm, high mechanical durability exceeding 5000 bending cycles, and negligible swelling in water and common organic solvents. Importantly, the substrate exhibits thermal stability above 350 °C, significantly exceeding that of conventional bioderived substrates. These properties enable the fabrication of vacuum-deposited organic light-emitting diodes with performance comparable to glass references, as well as fully printed organic electrochemical transistors with on/off ratios of approximately 10^4. A comprehensive life-cycle assessment further highlights the environmental benefits of the proposed material system. Overall, this dissertation demonstrates that biocompatible and biodegradable materials can be engineered into high-performance electronic devices and substrates compatible with existing industrial processes. By bridging the gap between sustainability and functionality, this work contributes to the development of next-generation electronics with reduced environmental impact and opens new pathways for biomedical, transient, and sustainable electronic applications.

Freie Schlagwörter (EN)

Biodegradable, Leaftronics, Pressure Sensing, Bioelectronics

Klassifikation (DDC)

530

Klassifikation (RVK)

WD 2000

GutachterIn