A research team led by Prof. RUAN Changshun from the Shenzhen Institute of Advanced Technology (SIAT) of the Chinese Academy of Sciences has proposed a mechanical-assisted post-bioprinting strategy for challenging bone defects repair. 

The study was published in Nature Communications on Apr. 26.

Reconstruction of challenging bone defects that fail to heal spontaneously, such as large-sized segmental and osteoporotic bone defects, continues to be a perplexing issue in the clinical setting. The main difficulty lies in the restricted migration or feeble regenerative potential of the resident cells.

Bioprinting, capable of synchronous deposition of cells and biomaterials, bring a promising avenue for repair of challenging bone defects. However, it remains challenge to maintain cell viability during the bioprinting process and ameliorate mechanical stability of bioprinted cell-laden constructs.

To address this issue, the researchers developed a type ofheart-inspired hollow hydrogel-based scaffold (HHS) that can reversibly respond to external mechanical stimulations are used for active cell loading in a rapid, uniform, precise and friendly manner, similar to that the cardiac impulse attributes to systole and diastole.

 “On basis of a customized combination of gelatin methacryloyl, Laponite nanoclay, and N-acryloyl glycinamide, HHSs were first fabricated by one-step coaxial printing without any supporting materials,” said Prof. RUAN, “Our work successfully obtained HHSs with a height of 6 cm, almost reaching the critical size for human segmental bone defect”.

Owing to the tunable hollow structure of hybrid hydrogels, HHSs with attractive resilience, rapid shape recovery, and exceptional fatigue resistance are thoroughly demonstrated, which are the keys to success of this mechanical-assisted post-bioprinting strategy for loading cells.

In addition, the researchers verified the cell-laden HHSs for repair of critical-sized segmental and osteoporotic bone defects in rats, and the results showed that the cell-laden HHSs exhibited a satisfying ability to heal the challenging bone defects.

The proposed strategy effectively addresses the current challenge in extrusion bioprinting of balancing cell viability and scaffold mechanical properties, providing a universal, efficient, and promising approach to perform cell-based regenerative therapies.

Schematic illustration of the mechanical-assisted post-bioprinting strategy and fabrication of large-sized and sophisticated HHSs (Image by SIAT) 

Media Contact: LU Qun

Email: qun.lu@siat.ac.cn

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     A mechanical-assisted post-bioprinting strategy for challenging bone defects repair