The 5th Meeting of the RAPIDOS Chinese- European Joint Research project

The 5th Meeting of the RAPIDOS Chinese- European Joint Research project was hold at the Shanghai Jiao Tong University (SJTU) in China hosted by Prof. Ting-ting Tang.

The 5th official joint Chinese-European RAPIDOS meeting took place in Shanghai, on the 16th of October 2015.
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This meeting was organized one day after the workshop on 3D Printing and Orthopaedic Translational Research, hold in the Mingde Hall (Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences) by Prof. Ting-ting Tang and Prof. Ling Qin (Workshop on 3D Bioprinting).

First, Dr. David Eglin welcomed all the members and proposed the agenda of the working day. Then, Mr. Mike Geven, Ph.D. candidate from the University of Twente reported his advanced on the development of optimized 3D macroporous scaffolds based on PTMC and hydroxyapatite resin, manufactured using stereolithography. He is now able to fabricate patient-specific implants (from patients’ radiographic images) with specific internal architecture for orbital floor reconstruction. The addition of microspheres loaded with Chinese herb medicine extract (i.e. Icaritin) into the resin prior to the stereolithography is currently under-development in order to enhance the osteogenic property of the implant.

Then, Mr. Xi Zhang (Ph.D. candidate from the Queen Mary University of London) presented his strategy to obtain icaritin-loaded nanofibers made by electrospinning, with specific and tailored length. Controlling the exact size and length of those nanofibers will facilitate their incorporation into PTMC resin formulation, in an objective to prepare mechanically-reinforced implant films.

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Mike Geven (top) and Xi Zhang (bottom) during the presentation of their recent work.

A third presentation was given by Dr. Huipin Yan (from XPAN, The Netherlands) who reported on icaritin that enhances bone formation, which is initiated by sub-microstructured calcium phosphate ceramic. Interestingly, he showed that Icaritin interacts strongly with CaP-based scaffolds, allowing to sustain the release profile of the loaded drug. The nature of the physico-chemical interactions between those two compounds will deserve further investigation. Their in vivo investigation permitted to define the optimal and clinically-relevant dosage of Icaritin to be loaded in CaP porous scaffold, to exhibit enhanced osteogenesis.

Then, Dr. Olivier Guillaume (Postdoctoral Research Scientist in AO foundation, Davos Switzerland) demonstrated that PTMC/CaP composites were promising candidates for bone tissue engineering. Indeed, his in vitro investigations revealed that human mesenchymal stem cells were able to differentiate toward osteoblasts and to deposit calcium mineral after seeding on those composite films. Encouragingly, a first animal pilot study using rabbit calvarial defect model further demonstrated that porous scaffolds based on PTMC and CaP produced by stereolithography successfully promoted new bone in-growth (X-ray analyses obtained after 3 and 6 weeks). Further samples processing (i.e. histology and immunohistology) are being performed to confirm the osteogenic potential of PTMC/CaP implants, which will then be presented during the next RAPIDOS meeting in June 2016.

During the second part of the day, the Chinese partners gave an outlook of their investigations and the perspective of their works

Mr. Shengbing Yang (SJTU institute) reported on the development of antibacterial materials and bone substitutes to treat contaminated or infected bone defects. Two strategies were successfully developed in his laboratory, incorporating either Magnesium or modified chitosan (chitosan quaternary ammonium salt) to porous scaffolds based on PLGA and Hydroxyapatite made by 3D printing. In vitro, those implants exhibit excellent cytocompatibility, while preventing bacterial biofilm formation. Additionally, the osteogenicity of the bioactive scaffolds was also investigated using hMSCs, and further in vivo experiments will be conducted to better characterize their biocompatibility and their kinetic of degradation.

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Illustration of the new PLGA-HA scaffold manufactured by 3D Printing, presented by Mr. Shengbi Yang.

Dr. Yuxiao Lai (from SIAT) reported on the animal model of rabbit ulna bone segmental defect using PLGA/TCP/Mg composite scaffolds. They demonstrated that Mg incorporation into the PLGA/TCP implants was directly responsible to an increase of new bone formation (radiography) and of angiogenesis (MRI). Their discovery paved the way to the development and commercialization of new generation of bioactive implants for bone substitution, exhibiting both antibacterial and bone forming activities.

Following Dr Lai’s presentation, another member of the SIAT, Dr. Xinluan Wang, introduced his last advanced in the fabrication of osteochondral scaffold made of hyaluronan and PLGA/TCP. Several Chinese drugs known to facilitate bone-cartilage formation are currently being screened and loaded into this scaffold for further in vitro and in vivo characterizations.

Finally, Dr. Jiang Peng presented new techniques to further understand and characterize the natural physiological alterations that occur during osteonecrotic diseases, which are primordial criteria in the development of relevant biomaterial based tissue engineering systems. Secondly, he reported on recent research in using microcarriers for fabrication of microtissue via seeding of cells in combination with 3D printed scaffold.

Finally, the last part of the day was dedicated to the consortium management and planning of consortium scientific activities and reports, organized by Dr. Eglin David from AO foundation.

One more time, this RAPIDOS meeting gave an excellent opportunity to update all the partners on the progresses of the project, the achievements of the tasks and to discuss the next activities and to organize the forthcoming scientific events, mentioned below:

- Advanced Functional Polymers Meeting in Twente (The Netherlands) in May 2016 (https://www.utwente.nl/tnw/bst/AFPM2016/)
- International International Combined Orthopaedic Research Societies in Shenzhen province (Xian) in Sept 2016 (http://www.2016icors.org/index.html).