Multi-Active and Nanostructured Polyrotaxane-based Nano-Fibers: A new strategy for Tissue Engineering – FibRotaxanes

- Context:
Since decades, the treatment of bone diseases is a challenge due to the apparent inability of bone to self-repair. There is no effective therapy available and patients can only be helped by surgical joint replacement.
Therefore, tissue engineering for bone regeneration appears as the most promising alternative. The principle of this method mainly relies upon the promotion of cells growth on a biomaterial-based three-dimensional scaffold. In this approach the scaffold plays a key role as he must guide the cell growth, allow the synthesis of extracellular matrix and other active biological molecules and it also has to facilitate the formation of new functional tissues.
- Specifications:
There are several basic and important requirements for the design of bone regeneration scaffolds. First of all, the biomaterial has to be biocompatible (not toxic to the cells). The scaffold must also present a well-defined morphology (nano-structuration) and display a large specific surface. A high porosity with appropriate pores sizes is also a prerequisite. The scaffold must have the required mechanical strength to maintain the tissues structure. Biodegradability is also required for the biomaterial allowing a degradation rate matching the formation rate of the new tissue. The biomaterial must also display good bone induction properties and bio-mineralization. Finally, the scaffold has to interact efficiently with cells, including enhanced cell adhesion, growth, migration and differentiation function.
- Main Goal of the project:
The goal of this project is to fabricate nano/micro fibrous/porous innovative functional active biomaterials allowing cell adhesion/proliferation, drug encapsulation/release function and inducing bone repair at the site of implantation.
In order to reach this goal, pseudo-polyrotaxanes (pPR) and polyrotaxanes (PR) based on poly(e-caprolactone) (PCL) and a-cyclodextrins (CD) will be synthesized. Indeed, the peculiar properties of pPR and PR such as their topological necklace-like structure, their self-assembling character at the nano-scale, their high number of reactive hydroxyl groups (carried by the CD) and finally their biocompatibility/biodegradability will lead to the fabrication of highly structured and functional biomaterials. Furthermore, pPR and PR will be processed by an original home-made coaxial electrospinning setup under vacuum developed at LIPHT and allowing the fabrication of porous/fibrous scaffolds.
- Methodology and expected results:
The project presents a strong multidisciplinary character. Thanks to the expertise and complementarity between the partners (LIPHT, LIONS, U977), we propose the following stages to ensure the success of the project:
- Synthesis of pPR and PR and study of their structure.
- Functionalization. Peptides will be grafted onto CD before the scaffold fabrication in the case of the use of PR and after in the case of the use of pPR.
- Elaboration of nano/micro-structured porous scaffolds by electrospinning under vacuum.
- Scaffold characterization for bone regeneration.
This transverse approach allows the partners to perfectly integrate this project in their scientific strategies. Furthermore, depending on the functional molecules which are grafted on CD, this new type of materials should certainly serve for other applications in tissue engineering, membranes or sensors. Finally, we believe that the "FibRotaxanes" project will ensure the establishment of a close and fruitful collaboration between all involved partners to develop innovative biomaterials for bio-medical applications.