The cells at surfaces group aims to understand the mechanisms of how human cells and tissues interact with materials/material surfaces and, in close collaboration with clinics and industry, to use this knowledge for the development of novel materials for unmet clinical needs.

We develop and use tissue-specific advanced in vitro models that more closely mimic the in vivo situation to study cell-material interactions as well as the early events of blood-material interaction and its influence on human cell response governing integration or non-integration of materials into host tissue as well as cellular processes involved in wound healing, mainly focusing on bone, skin and soft tissue. We are also interested in how drug-releasing materials can be used to steer the tissue response. Ultimately, we evaluate the predictive power of our models via correlation with in vivo results and clinical data. For this, we use state of the art techniques including gene- and protein expression analysis, siRNA or fluorescence microscopy.

Fig.1 Scanning Electron Microscopy (SEM) image of a macrophage embedded in a fibrin-gel

When damage to the body occurs, healing processes often lead to fibrosis or tissue scarring, where normal tissue is replaced by permanent scar/fibrotic tissue with impaired functionality.

Our goal is to understand the occurrence of and mechanisms involved in impaired wound healing and tissue scarring for the development of novel, material-based treatment strategies. We explore and develop new materials and fabrication concepts to create tailor-made solutions for different wound pathologies. Furthermore, we develop new advanced in vitro 3D co-culture models and use analytical tools including Microarray-technology, ELISAs, SEM or 2-photon microscopy.

• 3D scaffold based on biodegradable P4HB for the treatment of chronic skin wounds and scar tissue formation (ScarAvoid)

• Near-Infrared Light-Sensitive Polyvinyl Alcohol Hydrogel Photoresist for Spatiotemporal Control of Cell-Instructive 3D Microenvironments

• Organic ion pump-regulated stimuli-sensitive fibres for biomolecule driven oppression of fibroblast differentiation

   

Fig.2 Confocal Laser Scanning Microscopy (CLSM) image of human bone cells (actin cytoskeleton in green, nucleus in blue) on blood-derived fibrin (red) formed on mi-cro-rough titanium after 4 days of culture.

Our aim is to understand how such material properties influence different stages of the tissue response to implants, ranging from blood-material interaction to immune cell recruitment to cell differentiation processes, and to develop novel materials and material surfaces to either achieve or to avoid tissue integration.

• Enhanced endothelialization of electrospun 3D scaffold interlayers on hyperelastic membranes in pulsatile ventricular assist devices by surface functionalization or hybrid scaffold design (Zurich Heart)
   

• A predictive in vitro osseointegration model for implant surface developmen
  
   

Fig.1 Scanning Electron Microscopy (SEM) image of a macrophage embedded in a fibrin-gel

The immune response is a key element of wound healing and when the body interacts with implanted materials. Encompassing a complex and coordinated series of events, any disturbance can lead to a variety of pathologies or the development of fibrotic tissue in response to implantation of materials.

Our aim is thus to better understand how we can control the immune cell response in wound healing but also in contact with materials via immuno-engineering.

• Anti-oxidant and immune-modulatory properties of sulfated alginate derivatives on human chondrocytes and macrophages

• Convex and concave micro-structured silicone controls the shape, but not the polarization state of human macrophages

• 2017 – 2019: The TDAskin concept - a holistic wound healing approach for chronic wounds (InnoSuisse, formerly CTI N° 18524.2 PFLS-LS)
   
• 2017 – 2019: ScarAvoid - A novel approach to treat chronic skin wounds and scar tissue formation (Gebert Rüf Foundation GRS-006/16)

• 2015 – 2018: Zurich Heart Hybrid Membrane - Research on a novel assist device concept

• 2015 – 2018: Metal-ion doped TiN layers to reduce hospital acquired infection (InnoSuisse, formerly CTI N° 16302.2 PFNM-NM)

• 2015 – 2017: 3rd generation ceramic dental implant surface (ZLActive) - finished (InnoSuisse, formerly CTI N° 16873.2 PFNM-NM)