Development of a library of highly fluorinated polymers for additive manufacturing of vascular grafts with tunable compliance and 19F-MRI visibility for in situ tissue engineering

• Applicants: Professor Dr. Ulrich Flögel; Professor Dr. Konstantin Karaghiosoff; Professorin Dr. Petra Mela
• Subject Area: Medical Physics, Biomedical Technology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 555098822

The requirements for scaffolds for tissue engineering (TE) applications are multifaceted and determine the chance of success of an implant. It is, therefore, imperative to combine material innovation with advanced manufacturing strategies to obtain functional devices suitable for clinical translation. In this project we aim at this convergence to address the unmet clinical need for small caliber vascular grafts with relevance for applications ranging from dialysis shunts to coronary bypass. Based on an in situ tissue engineering approach, we tackle two main issues in the field that jeopardize the implementation of tissue-engineered vascular grafts (TEVGs) in the clinic, namely i) the compliance mismatch between the graft and the target vessel as major contributor to graft failure, and ii) the difficulties in imaging polymeric scaffolds for longitudinal follow-up by clinically applicable monitoring techniques. Therefore, we aim at the fabrication of a TEVG with tunable compliance and porosity favoring cellular infiltration and remodeling in the body, while being visible via magnetic resonance imaging (MRI). Specifically, we target 19F-MRI as promising imaging modality for polymeric constructs since the natural background signal is negligible in contrast to standard 1H-MRI of hydrogen-rich tissues. We exploit melt electrowriting (MEW) as advanced additive manufacturing technique, that enables the deposition of micron-sized fibers according to a coded architecture in a layer-by-layer fashion. We will proceed with three main research lines according to the expertise of the applicants: • Synthesis of a library of novel highly-fluorinated polymers optimized for biocompatibility, strong 19F-MRI signal, and processability via MEW. • Development of MEW design strategies for tubular constructs with controlled mechanical behavior by exploiting the structure-property relationship of complex microporous scaffold architectures and their interaction with cells. • Establishment of artefact-free 19F-MRI protocols with high spatial resolution at fast acquisition times, and investigation of changing signal intensity caused by progressing polymer degradation. This proposal brings together multidisciplinary expertise to unleash the potential of a biomaterial library for a clinically applicable imaging modality in combination with advanced manufacturing strategies for TEVGs. The knowledge gained in this project from the biomaterial synthesis, scaffold design, and MRI will be valuable for biomedical applications beyond the engineering of vascular grafts.

• DFG Programme: Research Grants