Additive Micro-Manufacturing for Plastic Micro-Electro-Mechanical-Systems

PI: Prof. Dr. Juergen Brugger
Project start: 1^st October 2017
Project duration: 60 months

Summary

The manufacturing of silicon-based MEMS today is well advanced because the micro-electro-mechanical devices for automotive, domestic, health-care and consumer electronics can be fabricated with methods from IC industry. Polymer-based MEMS have a great potential for flexible electronics and biomedical applications, but to date, the techniques to engineer functional polymers into 3D microsystems, are still at their beginning because a coherent fabrication platform with the right tools and processes does not yet exist. The field could tremendously benefit from a coordinated effort in materials and manufacturing, in particular with a focus on biocompatible plastic materials. Additive manufacturing such as 3D printing and associated processing such as sintering has already started to transform traditional industry, but is not scalable much below a micrometer because the thermal processing is done in bulk or by lasers on surfaces. MEMS 4.0, in analogy with the industry 4.0 concept, aims to perform concerted research in additive manufacturing at the micro/nanoscale and associated key techniques. Using my expertise in MEMS and Nanotechnology, MEMS 4.0 will push the frontiers in new materials and new processing for MEMS by setting a focus on stencilling, printing, self-assembly and local thermal processing. This coherent processing framework will permit the use of delicate, soft, polymer materials to engineer the next generations of plastic MEMS. We are primarily targeting biodegradable implantable MEMS and permanently implantable glassy carbon MEMS. They are the most challenging to fabricate, but if successful, they also have an enormous impact for future wearables and implantables.

Progress

Along the main topics of this project, a brief overview of our recent research progress is listed in the following paragraphs:

1. Stenciling

Microstencils have been fabricated by electron beam lithography (EBL) and deep-UV (DUV) lithography and benchmarked for various application purposes including for usage on biocompatible substrates. Metallic micro/nanostructures were stenciled onto biocompatible stretchable materials leading to the discovery of an original method to create large-scale liquid metal structures on stretchable biocompatible substrates. These liquid metal structures are investigated as versatile strain gauges for polymeric MEMS.

2. Printing

One of the challenges in drug delivery systems is to encapsulate the active substance in order to protect it from deterioration. 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). The encapsulation media and the drug are sequentially inkjet printed into a reusable template, followed by UV curing of the encapsulation layer.

3. Self-assembly

An electron-tunneling based strain sensor has been developed. The sensor has the following three characteristics: i) it is built on a stretchable biocompatible substrate poly(dimethylsiloxane) (PDMS) which makes it useful for wearable or implantable devices, ii) the strain-sensitive electrical signal is measured through two self-assembled gold nanorods separated by a distance of less than 2 nm, iii) a slick device design transforms the macroscopic strain of the PDMS into a sub-Ångström displacement which can be detected through a change in the electron-tunneling current.

4. Thermal nanoprocessing

Thermal nanoprocessing of sub-100-nm structures through t-SPL is an emerging digital manufacturing technique. We have explored different ways to directly modify materials with a heated tip i.e. by annealing, melting or chemical modification. 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 into arbitrary shapes [Liu et al. Adv. Mater. 2020, (accepted)]. A comprehensive thermal nano-processing library was published as an open-access review article.

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 an innovative imprinting process. The 10 x 10 x 20 mm³-sized drug containers accommodate up to six isolated reservoirs to be loaded separately with a drug. The capsules were covered with biodegradable membranes equipped with wirelessly powered microheaters that can be each addressed individually to release mL volumes of liquid drugs in each compartment separately. Wirelessly triggered release of the drug by breaking the membrane through heating was demonstrated, posing a significant step towards power receivers and microheaters for a variety of biodegradable implantable medical devices [M. Rüegg PhD Thesis EPFL 2020].

Publications

Microfabrication of lipids for drug delivery applications

J. Park / J. Brugger; A. Bertsch (Dir.)

Lausanne, EPFL, 2025.

Additive Micro-Manufacturing for Plastic Micro-Electro-Mechanical-Systems

Summary

Progress

1. Stenciling

2. Printing

3. Self-assembly

4. Thermal nanoprocessing

5. Implantable biodegradable MEMS

Publications

Microfabrication of lipids for drug delivery applications

Laser-Induced Forward Transfer of SU-8 Microdisks as Carriers of Metallic Microdevices

Performance Comparison of Shape Memory Polymer Structures Printed by Fused Deposition Modeling and Melt Electrowriting

Development of core-shell lipid microneedles for sublingual delivery

Near-Room-Temperature Detection of Aromatic Compounds with Inkjet-Printed Plasticized Polymer Composites

Optical Ring Resonators in Sputtered Aluminum Nitride on Insulator for Integrated Photonic MEMS

Liquid-in-a-MEMS: Encapsulation of Liquid in a Microcapsule by Inkjet Printing

LIQUID-IN-A-MEMS: ENCAPSULATION OF LIQUID IN A MICROCAPSULE BY INKJET PRINTING

Laser-Induced Forward Transfer of Functional Microdevices

Comparison of electrical and optical transduction modes of DNA-wrapped SWCNT nanosensors for the reversible detection of neurotransmitters.

Liquid encapsulated drug delivery device for acoustically-controlled release

SU-8 cantilever with integrated pyrolyzed glass-like carbon piezoresistor

Precise Capillary‐Assisted Nanoparticle Assembly in Reusable Templates

FABRICATION OF TRANSFERRED FLEXIBLE PMMA STENCIL LITHOGRAPHY

SPONTANEOUS FORMATION AND PROGRAMMABLE ORIENTATION OF SURFACE WRINKLES ON THERMOSENSITIVE RESIST

Scalable fabrication of functional nanostructures on stretchable substrates by capillary-assisted particle assembly and adhesion lithography

Multiscale 2D/3D microshaping and property tuning of polymer-derived SiCN ceramics

Stretchable Conductors Fabricated by Stencil Lithography and Centrifugal Force-Assisted Patterning of Liquid Metal

High resolution meandering metal patterns enabled by nano-bridge stencil

Edge-contact MoS2 transistors made by thermal scanning probe lithography

Precise Capillary-Assisted Nanoparticle assembly in Reusable Templates

Printed Polymer Composite Sensors for Low-Power, Near Room-Temperature Detection and Classification of VOCS

Precision Surface Microtopography Regulates Cell Fate via Changes to Actomyosin Contractility and Nuclear Architecture

A Glass-Like Carbon Mems Strain Sensor

Thermomechanical nanocutting and nanostraining of 2D materials

Inkjet-printed polymer composites for the detection of volatile organic compounds

Hierarchical Micromold Structuring via 2PP Micro-Stereolithography

Electrochemical performance of polymer-derived SiOC and SiTiOC ceramic electrodes for artificial cardiac pacemaker applications

Thermomechanical Nanostraining of Two-Dimensional Materials

On the effect of linear feedback and parametric pumping on a resonator’s frequency stability

Cracks, porosity and microstructure of Ti modified polymer-derived SiOC revealed by absorption-, XRD- and XRF-contrast 2D and 3D imaging

Thermal and pH Sensitive Composite Membrane for On-Demand Drug Delivery by Applying an Alternating Magnetic Field

Thermomechanical Nanocutting of 2D Materials

In Vitro Cytocompatibility Assessment of Ti-Modified, Silicon-oxycarbide-Based, Polymer-Derived, Ceramic-Implantable Electrodes under Pacing Conditions

Thermal scanning probe lithography-a review

Biodegradable Wireless Microheaters for Transient Biomedical Implants

Phase masks for electron microscopy fabricated by thermal scanning probe lithography

A 3D Microscaffold Cochlear Electrode Array for Steroid Elution

Harnessing Poisson Effect to Realize Tunable Tunneling Nanogap Electrodes on PDMS Substrates for Strain Sensing

Liquid Assembly of Floating Nanomaterial Sheets for Transparent Electronics

Biodegradable Frequency‐Selective Magnesium Radio‐Frequency Microresonators for Transient Biomedical Implants

Wearable Triboelectric Generator based on a Hybrid Mix of Carbon Nanotube and Polymer Layers

Novel Wearable Triboelectric Generator based on a Hybrid Mix of Carbon Nanotube and Natural Polymer

Combination of thermal scanning probe lithography and ion etching to fabricate 3D silicon nanopatterns with extremely smooth surface

3D printed microchannels for sub-nL NMR spectroscopy

Bioresorbable Frequency-Selective Magnesium Microresonators Fabricated by Ion Beam Etching

PZE-transduced Suspended Microchannel Resonators for sensing applications

Preceramic Polymers as Precursor for implantable MEMS Applications

Self-assembly of micro/nanosystems across scales and interfaces

Silk Fibroin as a Resist for Thermal Scanning Probe Lithography

Flexible fabric-based wearable solid-state supercapacitor

Penciling a triboelectric nanogenerator on paper for autonomous power MEMS applications

Planar Optical Nanoantennas Resolve Cholesterol-Dependent Nanoscale Heterogeneities in the Plasma Membrane of Living Cells

Highly efficient and gentle trapping of single cells in large microfluidic arrays for time-lapse experiments

Rapid carbon nanotubes suspension in organic solvents using organosilicon polymers

Penciling A Triboelectric Power Source On Paper

High sensitivity field asymmetric ion mobility spectrometer

3D nanostructures fabricated by advanced stencil lithography

A silk-fibroin-based transparent triboelectric generator suitable for autonomous sensor network

Impedance sensing of DNA immobilization and hybridization by microfabricated alumina nanopore membranes

Composite hydrogel-loaded alumina membranes for nanofluidic molecular filtration

Organic-inorganic-hybrid-polymer microlens arrays with tailored optical characteristics and multi-focal properties

CNT and PDCs: A fruitful association? Study of a polycarbosilane–MWCNT composite

Resistless nanofabrication by stencil lithography: A review

On the micrometre precise mould filling of liquid polymer derived ceramic precursor for 300-µm-thick high aspect ratio ceramic MEMS

Development of Implantable Electrodes Based on Polymer Derived Ceramics

Liquid-Filled Sealed Mems Capsules Fabricated By Fluidic Self-Assembly

Single-Cell 3D Bio-Mems Environment With Engineered Geometry And Physiologically Relevant Stiffnesses

Actuated MEMS and NEMS for cell force spectroscopy and gas sensing applications

Three-dimensional polymeric microtiles for optically-tracked fluidic self-assembly

Influence of carbon enrichment on electrical conductivity and processing of polycarbosilane derived ceramic for MEMS applications