Profile Phd Students

Anna Abbadessa

Title of the PhD project:

Biofabrication of implantable scaffolds for cartilage regeneration: from polymer synthesis to 3D printing and biofunctionalization of hydrogels.

Summary of the PhD project

The focus of my PhD project is on the development of hydrogel materials as implants for cartilage regeneration. Hydrogel systems based on thermo-sensitive synthetic polymers and chemically modified biopolymers are being characterized for their mechanical properties and their chondrogenic potential. The project involves the synthesis and characterization of polymers, which are used to develop hydrogels with desirable features. Designing smart hydrogels with the ability to tune mechanical and functional properties towards cartilage 3D bioprinting applications is the core of this project. Additionally, these hydrogels are being investigated as potential carriers for the delivery of growth factors at the implantation site to enhance further the biofunctionality of our hydrogels. Within HydroZones consortium, these hydrogels are being investigated employing in vitro, ex vivo and in vivo models by other partners.     

Relevance and Added Value for EU citizens

The presence of tissue defects in the cartilage of the knee is a common condition in Europe among young people and athletes. Cartilage defects which are not treated in early stage eventually contribute to the development of chronic diseases involving malfunctioning of the joint and pain in the knee. Current treatments involving for instance chondrocyte transplantation have shown relevant clinical results. Nevertheless, further improvements are needed to face this emerging pathological condition. More specifically, the development of novel and highly defined materials is requested in the field to achieve a full control over mechanical and biological functionality of the grafts.

Simone Stichler

Title of the PhD project:

3D printable hydrogels based on polyglycidols (PGs) and hyaluronic acid (HA) for cartilage regeneration


Summary of the PhD project

Hydrogels are widely used as synthetic ECM mimetic three dimensional (3D) matrices for cell encapsulation. Chemically they can also be designed to comply with 3D printing technologies, opening the possibility to create hierarchical tissue-like structures. However the number of cell compatible as well as printable hydrogels is still very limited. In my PhD project I therefore develop and investigate 3D printable hydrogels based on polyglycidols (PGs) and hyaluronic acid (HA), cross-linked via light mediated thiol-ene click chemistry for cartilage regeneration. For this approach thiol-functionalized PGs/HAs and allyl-functionalized PGs are synthesized and analyzed via GPC and NMR measurements. Furthermore, the influence of polymer concentration and cross-linking light intensity on mechanical properties as well as swelling behavior of the resulting hydrogels are examined. Cytocompatibility and handling characteristics of these hydrogels in vivo (in mice, minipigs and in horses), in vitro (with MSCs and Chondrocytes) and ex vivo are investigated in collaboration with other work package partners within the HydroZONES consortium.


Relevance and Added Value for EU citizens

Millions of Europeans suffer from cartilage degeneration due to age or trauma and thereby have to deal with chronic pain and lost mobility. Cartilage itself is a load bearing tissue, with a hydrogel-like structure, that functions as a low friction surface and a mechanical damper. Since it is organized into three characteristic depth zones with different compositions. One aim of HydroZONES is to develop a hierarchically structured hydrogel based scaffold, which should recapitulate the zonal distribution of the native articular cartilage. Current cartilage implants cannot provide the hierarchical tissue organization that appears to be critical for normal cartilage function. Therefore novel hydrogel systems have to be developed, to form constructs with biomimetic zonal variations.

Andrea Schwab

Title of the PhD project: 3D osteochondral tissue model

Summary of the PhD project

My PhD thesis aims to establish a 3D osteochondral model and bioreactor system in order to evaluate biomaterials for their chondral regeneration under physiological conditions in vitro. Therefore, osteochondral explants from porcine femoral condyles are isolated. Cartilage defects are created which are filled with cell free or cell loaded hydrogels, developed within HydroZONES. The osteochondral explants are cultured in an ex vivo platform (Osteo2Cult, LifeTec Group). Cartilage defect regeneration will be determined by (immune-) histological stainings, PCR and quantification of extracellular matrix composition.

Major application of the osteochondral model is the screening of the hydrogels being developed in WP1 of the HydroZONES project.  I am testing cell free as well as cell loaded hydrogels for their chondral regeneration. At least one zonally structured, bioprinted material will be evaluated in this model at the end of this project. Results will be compared with those of the in vivo study, done by consortium members in Heidelberg.

Relevance and Added Value for EU citizens

Cartilage defect treatments pose a major challenge in clinics as they often result in formation of fibrous tissue instead of native-like articular cartilage. Hence, new cartilage therapy strategies are being developed to achieve defect regeneration with functional and mechanically stable repair tissue. Therefore, pre-clinical evaluation of novel materials for cartilage regeneration in a 3D osteochondral environment are needed.

The osteochondral model represents a platform suitable for ex vivo material screening in cartilage defects of osteochondral explants in a controlled environment. Moreover, our model opens new opportunities to evaluate bio-inspired materials for material-tissue-cell-interaction, addressing biocompatibility and cartilage defect regeneration under physiological conditions.