Development of a novel thermogelling PEC-based ECM mimicking nanocomposite bioink for bone tissue engineering

Abstract

Non-union of large bone defects has been an existing clinical problem. 3D extrusion-based bioprinting provides an efficient approach to tackle such problems. This approach enables the use of various biomaterials, cell types and growth factors in developing a superior bone graft that is specific to the defect. In this article, we have designed and printed an ECM mimicking, self-assembled polyelectrolyte complex (PEC) based fibrous bioink using natural polymers like chitosan-polygalacturonic acid (PGA) and other biomaterials – gelatin, laponite and nanohydroxyapatite with a modified 3D printer. The developed bioink possesses a thermo-reversible sol-gel transition at physiological pH and temperature. Here, we demonstrated that post-printing, our fiber-reinforced bioink had significant cell proliferation with cell viability of >80% and negligible cell morbidity. The practicability of developing this self-assembled PEC-based bioink was assessed. Bioink with 4% gelatin (PECHLG4) had optimal printability with a minimal swelling ratio of approximately 3%. The printed scaffold had integrity for a period of 8 days under 0.5 mg/mL lysozyme concentration. We also evaluated the mechanical property of the bioink using compression analysis which gave an elastic modulus of 16 KPa. This combination of natural polymers and nanocomposite, along with a fibrous network of PECs, is itself a novel approach for 3D bioprinting and can be a preliminary proposition for the treatment of large bone defects.

Keywords:

• Bioprinting
• thermogelling
• fibrous
• bioink
• bone tissue engineering
• invivo bioprinting

Acknowledgement

The authors would like to acknowledge Mr Susant Pradhan of the confocal microscopy lab, Department of Biotechnology and Medical engineering, for his assistance in developing bioprinted samples for confocal microscopy. The authors thank Mr Anup Kumar Acharya for his extended support in conducting SEM analysis. Last but not the least, the authors would like to acknowledge Mr Haladhar Behera for technical assistance in performing the compression analysis of all the samples.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was funded by a research grant from the Science and Engineering Research Board (SERB), Department of Science and Technology, Human Resource Development, Government of India (SERB/F/10151/2018-2019).