Development of a newly synthesized biopolymer for industrial laser-based nano-3D printing of hierarchically structured bone-cartilage implants

Abstract text (incl. figure legends and references)
Introduction

Regeneration and healing of cartilage defects is naturally a difficult task and even for the human body itself hard to achieve.

Objective

We aimed to develop biphasic polymer-based scaffold structures for the optimal treatment of bone-cartilage defects as well as to create and synthesize a suitable material, which is biocompatible, biodegradable, and can be processed via laser-based 3D printing.

Materials and Methods

A protocol for the synthesis of ACM¹ was developed, which serves as a substitute for the well-known reference system LCM², as the latter leads to acidic degradation products in tissue and corresponding inflammatory reactions. Both materials are presented in figure 1 and were succesfully 3D-printed via 2-photon polymerization. The 2PP technique, as a variable 3D printing technique from the nm- to the cm-scale, in combination with an automated manufacturing process, represents the key to the targeted microstructuring of a 3D scaffold construct with optimal adjustment of the material stiffness and the bioactivity of the selected polymers.

Fig. 1: Chemical structures of ACM and LCM.

Results

Based on the physiological conditions of bone/cartilage tissue, an osteochondral implant with suitable tissue-analogue cartilage- and bone-specific geometric, biomechanical and biochemical properties was designed and succesfully 3D-printed via 2-photon polymerization.

Fig. 2: Design of the newly created biphasic scaffold.

Conclusion

The achieved biphasic 3D-implant represents an excellent solution to simulate the chondrogenic and osteogenic extracellular matrix (ECM) and allows the adjustment of a defined degradation rate.

Acknowledgement

The results are content of the project "Poly-IMPLANT-Druck" (funding code: 13XP5089A-F) funded by BMBF. We thank BMBF very much for the financial support.

¹N. Hauptmann et al., Int. J. Mol. Sci. 2022, 23(6), 3115

²N. Hauptmann et al., Tiss. Eng. Part B: Reviews, 2019, 25(3), 167-186