Coupling intraoperative bioprinting and surgical micropuncture for synergistic scaffold vascularization.

Intraoperative bioprinting (IOB) is an advanced approach enabling the reconstruction of tissue defects by precisely bioprinting biologics under surgical settings. However, IOB has limited translational potential in its current form secondary to difficulty in establishing a rapidly functional, anastomosed vascular network. Micropuncture (MP) is an innovative microsurgical approach that overcomes this obstacle by creating targeted perforations in the host macrovasculature to stimulate angiogenesis, thereby facilitating microvascular ingrowth into adjacent bioprinted constructs. This study presents the first attempt of MP-induced vascularization of intraoperatively bioprinted constructs (10 mm × 15 mm × 3 mm). After precise optimization of bioink and cell compositions, IOB was performed in rat hindlimbs using rat aortic endothelial cell (RAOEC)-laden bioink to synergistically promote vascularization in conjugation with MP. The combination of MP and RAOECs demonstrated the highest values across all parameters such as a 1.8-fold vessel density increase, 2-fold increase in vessel length, a 2.5-fold increase in PECAM-1 expression, and a 4.2-fold increase in F4/80 expression on Day 40 compared to the bioink-only group. Additionally, perfusion was observed in bioprinted constructs, confirming functional microvascular anastomoses to the host. Taken together, the present study proposes an advanced pre-clinical strategy that integrates IOB for customized bioprinted platforms with MP to rapidly achieve effective in-situ vascularization.