3D bioprinting of tissue-engineered bladder patches containing neurovascular networks using conductive microgel

Current tissue-engineered bladder patches are hindered by the absence of coordinated neurovascular regeneration, which limits their functional repair capacity. This study aimed to develop a neurovascularized bladder patch (NVBP) and assess its efficacy in bladder defect repair. GelMA-MXene (GM) conductive hydrogel microspheres encapsulating adipose-derived stem cells (ADSCs) were initially prepared to induce efficient differentiation of ADSCs into neural and vascular lineages within a conductive microenvironment. These pre-differentiated neural and vascular microspheres were then formulated into a microgel bioink, facilitating the construction of the NVBP using 3D bioprinting technology. Results indicated that GM microspheres enhanced ADSCs viability, proliferation, and stemness markers (Sox2/Nanog). Upon induction, GM microspheres upregulated the expression of neural-related genes (TUBB3, MAP2, Nestin, GAP43) and vascular-related genes (KDR, ANGPT1). Transcriptomic analysis and validation results demonstrated that the PI3K-Akt signaling pathway was significantly enriched, and the expression of Tnn and Pik3cd genes within it was also upregulated. This pathway might contribute to the effect on MXene’s promotion of ADSCs’ differentiation into neural and vascular lineages. The microgel bioink exhibited shear-thinning behavior, a broad printing temperature range, and excellent self-healing and fatigue resistance. The 3D bioprinted NVBP effectively maintained stable neural and vascular phenotypes. In an in vivo rat model, NVBP significantly enhanced bladder capacity (923.76 ± 119.80 µL) and compliance (27.04 ± 5.22 µL/mmHg). Histological analysis revealed improved smooth muscle organization, reduced collagen deposition, and significantly increased areas positive for βIII-Tubulin, PECAM1, and α-SMA in the NVBP group. In summary, NVBP promotes rat bladder tissue remodeling and functional recovery through synergistic neurovascular regeneration, offering a novel biomimetic strategy for bladder tissue engineering and is worthy of further in-depth research. 3D bioprinting of tissue-engineered bladder patches containing neurovascular networks using conductive microgel