1. Stenciling:
Microstencils were first fabricated by photolithography and later by DUV lithography. Metallic micro/nanostructures were stenciled onto biocompatible stretchable materials leading to the discovery of an original method to create large-scale liquid metal structures. To overcome the issue of design topology limitations, we implemented successfully so-called bridge-stencils and exploited the blurring effect, that allow for arbitrary shapes to be stenciled [Sun et al. Advanced Materials Technologies (2023)].
2. Printing
We have developed an innovative approach for encapsulation of liquid drugs in a biocompatible micro-container to prevent evaporation of the liquid media (i.e. water). Printing was further perfected and used throughout the project to deliver improved print results of functional inks, such as drug solutions [Park et al. Advanced Functional Materials (2023)].
3. Self-assembly
A scalable transfer technique has been demonstrated to use templated capillary self-assembled nanoparticles and rods as functional devices. As demonstrator an electron-tunneling based strain sensor was developed. The sensor is built on a stretchable biocompatible substrate poly(dimethylsiloxane) (PDMS), useful for wearable or implantable devices. Yield studies to upscale the method have been performed [HSC Yu, et al. Particle & Particle Systems Characterization (2022)] and showed also, that this approach is not yet mature for being considered for reliable nano-manufacturing.
4. Thermal nanoprocessing
It was found that direct manipulation of 2D materials is an extremely compelling and versatile application of t-SPL. We have used t-SPL to locally cut 2D materials such as MoS2 or MoTe2 [Liu et al. Adv. Mater. 2020]. A comprehensive thermal nano-processing library was published as an open-access review article. [Howell et al. Microsys. Nanoeng. 2020, 6]. Finally, we have succeeded in developing a new pattern transfer method from thermal resist into dielectrics [Erbas et al. ChemRxiv, 2023].
5. Implantable biodegradable MEMS
We fabricated implantable biodegradable capsules for wireless controlled drug release made from biodegradable elastomers poly(glycerol sebacate) (PGS) and poly(octamethylene maleate (anhydride) citrate) (POMaC) by a new imprinting process. [M. Rüegg PhD Thesis EPFL 2020] The drug containers accommodate up to six isolated reservoirs to be loaded separately with a drug. The capsules were covered with thin membranes equipped with wirelessly powered magnesium microheaters. [Rüegg et al. Adv. Fun. Mater 2019, 29 (39)] The work has been reported in scientific journals and also presented as invited paper [J Park, J Brugger, 2022 International Electron Devices Meeting (IEDM), San Francisco, USA]
6. Implantable permanent MEMS
Here we focused our work on glassy carbon microsensors and demonstrated a device by using the pyrolized SU-8 integrated in a SU-8 cantilever as strain sensor. The original results are reported in a paper [J Jang, G Panusa, G Boero, J Brugger Microsystems & Nanoengineering 8 (1), 22 (2022)]. The paper shows that the glassy carbon behaves like a metallic strain gage without extraordinary piezo-resistive effect.
