Servicenavigation

Project Details

Back

Projekt Print View

Development of endothelialised small diameter tissue-engineered grafts for cardiovascular surgery

Subject Area Cardiology, Angiology
General and Visceral Surgery
Biomaterials
Cardiac and Vascular Surgery
Term from 2015 to 2020
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 277253457
 
Final Report Year 2020

Final Report Abstract

Primary aim of this project was to investigate the suitability of different tissue-engineered natural materials for producing TE grade scaffolds biocompatible with human primary cells and suitable for rapid cell seeding. These TE scaffolds should represent and or mimic natural morphology and physiology of tissue, which is intended for replacement. During the project duration, I have overcome many challenges and gained insights into vascular cell-material interactions, which will be helpful in developing better solutions for vascular tissue engineering in the future. In the preparatory studies, I evaluated the behaviour of vascular cells on hybrid hydrogels consisting of alginate and various proteins including silk fibroin (SF), keratin, elastin and gelatin. My findings indicated that the cellular response to particular components of hydrogels, such as gelatin or elastin, is highly cell-specific, Whereas SF supports all cardiovascular cell types. We have also demonstrated that combining proteins with alginate is a promising strategy for hydrogel development for vessel bioprinting. In close cooperation with the team of Institute of Biomaterials, I have also tested the possibility of fabrication of 3D cylindrical structures (ADA-Gel and Alg/SF) with and without cells by bio-inkjet printing of cell suspensions in hydrogel-precursor solutions. The produced 3D vessel structure had a lumen diameter of 410 μm. The cell printing studies were first done by printing primary human fibroblasts in outer ADA-Gel layer with or without endothelial cells in gelatin inner core. In subsequent study Alg/SF for outer layer and pluronic F 127 core were used. These proofof-concept studies had shown that with bioprinting approach, we are able to construct hollow 3D vessel structures, which mimic the natural ECM environment and provide suitable microarchitecture for cells. However, more experiments about optimisation of core-shel printing are necessary. Additionally, the rheological investigations showed that Alg/SF bioink, which is viscoelastic and suitable for printing, could be used for successful creation of TE vascular scaffolds. Further, I tested the efficacy of magnetic colonization of alginate-based, Gel- and SF-containing hydrogels using the planar magnetic cell seeding technique and compared it with conventional (i.e. gravitational) cell seeding. My results demonstrated that magnetic seeding of fibroblasts and ECs dramatically improves the strength and uniformity of initial cell attachment to hydrogel surface, which can shorten culture time and may thus play a decisive role for the regenerative outcomes. However, the results obtained with less cell-compatible hydrogels indicate that the long-term efficacy of cell colonization after the cessation of magnetic field is primarily dependent on the material properties that govern the subsequent cellular responses and cell-material interaction. The colonization of 3D-printed tubular constructs with cells using radial magnetic cell seeding was subsequently attempted, but due to the encountered difficulties related to hydrogel rolling and the temperature-sensitivity of the 3D printed constructs, this objective of the project was only partly completed. In an alternative pilot study, we had employed radial magnetic cell seeding using electrospun PCL/SF 3D tubular structure, showing successful lumen colonization with co-cultured HUVECs and fibroblasts. Moreover, in parallel, I had succeeded in showing that co-culture of fibroblasts with HUVECs is important for cell-colonized TE grafts. Both cells support each other, contributing to successful ECM formation and formation of rudimentary micronetworks. Taken together, the results obtained within my project to date indicate that: (a) The reaction to scaffold material is highly cell-specific; (b) Alg/SF constitutes a promising biodegradable and highly biocompatible material suitable for 3D printing; (c) the magnetic seeding can improve colonization uniformity and efficacy of the materials which support the growth of specific vascular cell types; (d) co-cultured endothelial cells and fibroblasts strongly support mutual growth and metabolic activity, improving colonization of scaffolds; and (e) that fabrication of tubular constructs with hollow lumen using bioprinting technique is feasible. Further studies are warranted in order to fabricate Alg/SF-based vessels substitutes, colonized with HUVECs and fibroblasts, which will improve scaffold structure and functionality.

Publications

 
 

Additional Information

© 2024 DFG Disclaimer / Copyright / Privacy Policy

Textvergrößerung und Kontrastanpassung