A7.2 FILTRELEC

2012-2013

More than 70% of the running costs for air filter systems are caused by their energy consumption. The filter medium itself is only a small cost factor, but it is responsible for the energy efficiency of the systems. In the new Argovia project FILTRELEC, scientists from the University of Applied Science Northwestern Switzerland (FHNW) work together with colleagues from the Paul Scherrer Institute and the two companies Jakob Härdi AG and Chematest. Together they want to increase the efficiency of filters for ambient air.

Different mechanisms are responsible for filtering particles of different sizes in particle filters. Large particles are filtered through collision with a three-dimensional network of fibres. Very small particles adhere to the fibres. For particles of medium size those two mechanisms are not working efficiently. However, by using so called Elektret additives the efficiency for medium sized particles can be increased. These nanoadditives induce a permanent electrostatic charging of the fibres and herewith a virtual increase of the fibre´s diameter. Different substances that exist in the environment discharge the fibres and therefore cause a decrease in filter efficiency. In the project FILTRELEC scientists examine if a special modification of the nanoadditives and a multilayered functional filter structure can reduce the vulnerability against discharge.

In FILTRELEC researchers from the teams of Prof. Dr. Per Magnus Kristiansen (FHNW) and Prof. Dr. Jens Gobrecht (PSI) work closely together with members of the two companies Jakob Härdi AG and Chematest.

A 9.6.Nano-LTB – Low-lemperature bonding (LTB) of multichip modules by nano-size silver sintering

2012-2014

Within the project Nano-LTB scientists from the Paul Scherrer Institute (PSI: Prof. Helena Van Swygenhoven and Dr. S. Van Petegem), the University of Applied Sciences of Northwestern Switzerland (FHNW: Prof. Arne Wahlen, Prof. Nobert Hofmann) and the Swiss company ABB (Dr. Chunlei Liu) study an innovative, new method to bond electronic chips to their substrates. They analyze the microstructure of the bonding layers, their thermo-mechanical properties, load cycling capability and fatigue.

Currently, major changes are underway in the power electronics industry. It is becoming more and more important to transport and convert large amounts of power, for example, for hybrid electric vehicles or for the conversion of power generated by wind generators or solar collectors. The core electrical processing units in many of these power systems are multichip modules consisting of power semiconductors attached on ceramic substrate. As the transported power in the systems increases, the temperature in the chips and connecting layers will be raised from 125°C to 175°C and beyond.

Nowadays, the chips are bonded to the substrate by a high-lead solder. At temperatures of 175°C that will be reached in the future, these bonding layers fatigue under cyclic loading. Consequently, it is essential to find an alternative fixation of the chips to their substrate that is reliable at higher temperatures. Several companies are currently studying a low-temperature bonding using nano-silver sintering. This lead-free die-attach seems to be more robust and better suited than the traditional solder alloy, when temperatures become higher. However, currently limited experimental measurements of these sintered silver layers exist.
Within Nano-LTB the research teams from PSI, FHNW and ABB now work closely together to analyze the thermo-mechanical deformation behavior of these porous silver layers and to compute a lifetime prediction of these die-attachments. Results from the studies will be used to develop quality control methods and to predict lifetime of the modules. Additionally, they will be used to further optimize the production process.

A7.5 NanoFACTs – nano functional active component capsules for textiles

2012-2013

The Argovia project nanoFACTS aims to contribute significantly to the development of innovative textiles with active cooling mechanisms. Such functional textiles could be worn by firefighters under insulating protective clothing. Cooling underwear would offer considerable relief in challenging circumstances and could increase their safety.

Functional clothing has become an essential part of our wardrobe. Innovative technologies, however, offer new ways of equipping clothes with special functions, not only for recreational textiles but also for protective working gear. One method of adding functionality to textiles is to encapsule an active material and apply the capsules to the textile surface. Here, the capsules need to be exactly the right size; if there are too large, they will be washed off too easily. By contrast, a minimal size is needed to capture sufficient active material. Studies have shown that the optimal capsules vary in size between 100 and 10,000 nanometers. Currently, existing encapsulation methods are not well suited to the production of capsules in this range.

Within the nanoFACTS project, scientists from the University of Applied Sciences Northwestern Switzerland (Professor Uwe Pieles, Dr. Olfa Glaid, Dr. Johann Grognoux), the University of Basel (Professor Wolfgang Meier, Dr. Nico Bruns, Dr. Cornelia Pailvan, Dr. Olivier Braissant) and HeiQ Materials (Dr. Murray Height, Dr. Christoph Bradbury) strive to establish two encapsulation methods to tailor the capsule size to between 100 and 10,000 nanometers. On one hand, they push the emulsion technologies to smaller sizes (top-down approach). On the other hand, they investigate new technologies (e.g. vesicles) in a bottom-up approach. First, they will focus on the idea of developing functional capsules for thermal regulation of clothing. When the method is established, it can be applied to various active ingredients and target.

A 7.6 NanoMorph – Nanostructured surfaces for the control of polymorphism of active pharmaceuical ingredients

2012-2014

Within the project NanoMorph scientists from the teams of Prof. Patrick Shahgaldian (FHNW), Prof. Thomas Jung (PSI and University of Basel) and the Swiss company RPD Tools work closely together to develop a device for the screening of different crystalline polymorphs of active pharmaceutical ingredients in a high-throughput fashion.

Active compounds of drugs often exist in different crystalline polymorphs. These polymorphs may be different in their physicochemical as well as their biopharmacological characteristics. Therefore, patents are granted from the respective medicine authorities (such as FDA and EMEA) for just one specific polymorph with detailed properties described. For pharmaceutical companies, it is of great importance to identify the various polymorphs of an active substance and to define its characteristics at an early stage of development.

Nanostructured surfaces based on self-assembled supramolecules offer a novel approach. Crystallization of a dissolved compound in a test solution is initiated if the surface structure matches the crystal lattice. It would seem that the highly organized two-dimensional surface structure is transferred into the third dimension. The surface functions as a template seeding the crystallization. The chemical composition of the surface layer plays an important role in the process, as well as their packing density and assembly. By the variation of these factors, crystallization of specific polymorphs can be controlled.

In the NanoMorph project, scientists first produce novel self-assembled nanosurfaces and analyze these spectroscopically and microscopically. Then they test the crystallization of different pharmacologically active compounds. In the final part of the project, a commercial system will be build up that allows the fast and effective high-throughput screening of numerous substances.

A7.7 NoViDeMo – Novel viscosity and density meters for process monitoring and biomedical sensing applications

2012-2014

The goal of the NoViDeMo project is to develop a nanomechanical real-time viscosity- and densitometer for small fluid volumes. To achieve this, scientists from the teams of Dr. Thomas Braun (University of Basel), Dr. Joachim Köser and Dr. Olfa Glaied (FHNW), Dr. Jürgen Hench (Universitässpital Basel) and Mike Touzin (Endress + Hauser Flowtech AG) share their expertise and work hand in hand.

The scientists follow an approach based on cantilever technology. Here, tiny cantilevers operate in a dynamic vibration mode. Each alteration of this vibration, for example by a change in viscosity or in density of the fluid, can be precisely measured. The method does not require any labeling and is applicable for volumes of less than 50 µl.

In a first step, an existing sensing platform will be tested and optimized. Later, researchers will examine the application of the test for different industrial settings. Among these are quality control of a large variety of liquids and real-time monitoring of chemical polymer reactions. The viscosity of a solution is highly sensitive to structural changes in the dissolved polymers or proteins. Therefore, the nanomechanical viscometer can be used to observe chemical and biological reactions. Continuous monitoring may be important, for example if the polymerization is to be terminated at a specific polymer length. Besides further approaches, the interdisciplinary team of scientists will test the application of the platform as sensor for biomedical research. Here, they study the aggregation of the tau protein that is thought to play a major role in the development of Alzheimer’s disease. Substances that inhibit or stimulate the aggregation process could be identified rapidly and effectively.

The diversity of tasks within the NoViDeMo project requires a high amount of interdisciplinary teamwork. A prototype of the nanomechanical viscometer has been developed by the group of Prof. Christoph Gerber (SNI). For NoViDeMo experts from the Center for Cellular Imaging and NanoAnalytics at the Biocenter (Dr. Thomas Braun) now work together with scientists from the Institute for Chemistry and Bioanalytics of the FHNW (Dr. Joachim Köser, Dr. Olfa Glaied) and the Pathology Unit at the University Hospital Basel (Dr. Jürgen Hench). Researchers from Endress + Hauser contribute their expertise from the industrial environment.

A7.9 WBG-NPA – Wide band gap power semiconductors improved by nanoscale probe analytics

2012-2013

In the WBG-NPA project, research teams led by Professor Ernst Meyer (University of Basel), Professor Thomas Jung (Paul Scherrer Institute and University of Basel), and Dr. Holger Bartolf (ABB Corporate Research Center, Power Semiconductors) use different scanning probe microscopy methods to investigate novel semiconductors that can be used as power electronic switches.

These new semiconductors are made of “wide-band-gap” (WBG) materials. They are solid-state bodies that can be used as power switches for large electrical currents. The conductivity of a semiconductor depends on its chemical composition and structure, but also on the temperature. By implanting impurities (dopants) into the crystal lattice, scientists can alter the semiconductor’s conductivity. Due to their fast switching capabilities for high current and voltage classes, power semiconductors are used in electronic converters and inverters. These devices are required, for example, to convert renewable energy generated by wind power or photovoltaic systems into a form suitable for the distribution grid. Semiconductors that are used as such power switches should be able to switch very high currents and lose little energy under their normal working conditions. 

The semiconductors examined in the WBG-NPA project meet these requirements. Their electrons need to be stimulated by relatively high levels of energy before the semiconductor becomes conductive. They are made of materials such as silicon carbide and gallium nitride. Various dopants are incorporated into the material to modulate the conductivity. The doping process has not been studied extensively on the nanometer scale. Therefore, the project teams plan to examine wide-band-gap semiconductors in different stages using various scanning probe microscopes. They will concentrate on the different dopant atoms, establish dopant profiles, and determine their concentrations. In a further step, they will compare these experimental data to numerical simulations. These examinations are only feasible thanks to the special atomic force microscopes available at the University of Basel and the Paul Scherrer Institute (PSI).

A7.10 NANOCURE – Remineralisation of carious lesions by self assembled peptide supramolecular networks and hydroxyapatite nanocrystals

2012-2013

Within the project NANOCURE, the team led by Professor Uwe Pieles (University of Applied Sciences and Arts Northwestern Switzerland, FHNW), Professor Bert Müller (University of Basel), and Michael Hug (Credentis AG) examine a novel approach to treating dental caries.

The human body possesses huge potential for self-healing. Many of its processes regularly form and remove tissue. Our teeth are also demineralized and remineralized every time we eat. However, if the equilibrium is disturbed, a tooth cannot be remineralized and dental caries is the result. The process depends on our individual oral hygiene, the food we eat, and our oral microflora. Bacterial acids begin by causing demineralization at the weakest point of the tooth. Initial lesions or “white spots” develop. These rarely remineralize spontaneously, and normally cannot be regenerated. If the caries continues, the surface breaks down and forms a carious cavity. For over a century, the standard treatment has involved drilling open the carious area and filling it with a biocompatible material.

Credentis AG has now launched an innovative treatment method that regenerates the affected enamel. Scientists at the University of Leeds have developed a self-assembling peptide that, when applied to the carious lesion, diffuses into the initial lesion and forms a supramolecular network inside the carious lesion. As soon as this 3D network exists, the crystallisation of nanocrystals is initated and the regeneration of the white spots is induced. Initial lesions can be treated successfully with this method, but it is not yet suitable for larger cavities.

The process as a whole, and in particular the peptide’s diffusion through the enamel, is poorly understood. Within the NANOCURE project, researchers will jointly develop in vitro models to better understand the course of the treatment and to optimize treatment concepts. They will begin by using natural teeth with artificially induced carious lesions. They will then develop a tailor-made synthetic model with a special sequential compostion that makes it very similar to natural teeth. The team will later use these models to analyze and optimize the artificial healing process. Their results will help to improve the treatment and to synthesize the next generation of self-assembling peptides that will enable regeneration even in the case of advanced carious lesions.

A7.11 BioPrint – Reinforced biomimetic 3D composite bone scaffolds by rapid prototyped nanoporous ceramic powder and electrospun collagen nanofibrils

2012-2013

Within the BIOPRINT project, researchers led by engineer Ralf Schumacher (Dipl.-Ing) from the University of Applied Sciences and Arts Northwestern Switzerland work on tailored, patient-specific bone-replacing implants that mimic the characteristics of natural bone tissue. For an ideal implant, biocompatibility, biomechanical properties, and the chemistry and structure of the surface play a crucial role. The surface structure and the chemical composition must enable optimal adherence of human cells so that rapid osteointegration is possible. In addition, the material and the implant’s surface must be chemically functionalized to prevent inflammation.

The BIOPRINT reserachers aim to tailor the macroscopic 3D shape and the inner nanostructure and microscopic structure of the 3D implant scaffolds. Using a technique called rapid prototyping, they will produce specific, individual implants from synthetic analogues of naturally occurring substances. The biofunctionality will be achieved via synthesized nanoporous ceramic powder with chemical and/or biochemical additives, via postprocessing of the manufactured scaffolds, or via layered deposition of additives with specific functions such as antimicrobial activity. Additionally, the different implants will be strengthened with tiny collagen fibrils to build up stable and reinforced biomimetic implants. By applying different mechanical, analytical, and biological test systems, the researchers will be able to evaluate their results in order to identify the best combination of methods.

Partners within the BIOPRINT project are: Ralf Schumacher (Dipl.-Ing.), Institute for Medical and Analytical Technologies, University of Applied Sciences and Arts Northwestern Switzerland (FHNW); Professor Uwe Pieles, Laboratory for Nanotechnology, FHNW; Dr. Olivier Braissant, LOB2 Laboratory of Biomechanics & Biocalorimetry, University of Basel; Philipp Gruner (Dipl.-Ing.), Medicoat AG in Mägenwil.