The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, 430079, People's Republic of China.
Biofabrication. 2020 Mar 27;12(2):025032. doi: 10.1088/1758-5090/ab78ed.
The fabrication technique determines the physicochemical and biological properties of scaffolds, including the porosity, mechanical strength, osteoconductivity, and bone regenerative potential. Biphasic calcium phosphate (BCP)-based scaffolds are superior in bone tissue engineering due to their suitable physicochemical and biological properties. We developed an indirect selective laser sintering (SLS) printing strategy to fabricate 3D microporous BCP scaffolds for bone tissue engineering purposes. The green part of the BCP scaffold was fabricated by SLS at a relevant low temperature in the presence of epoxy resin (EP), and the remaining EP was decomposed and eliminated by a subsequent sintering process to obtain the microporous BCP scaffolds. Physicochemical properties, cell adhesion, biocompatibility, in vitro osteogenic potential, and rabbit critical-size cranial bone defect healing potential of the scaffolds were extensively evaluated. This indirect SLS printing eliminated the drawbacks of conventional direct SLS printing at high working temperatures, i.e. wavy deformation of the scaffold, hydroxyapatite decomposition, and conversion of β-tricalcium phosphate (TCP) to α-TCP. Among the scaffolds printed with various binder ratios (by weight) of BCP and EP, the scaffold with 50/50 binder ratio (S4) showed the highest mechanical strength and porosity with the smallest pore size. Scaffold S4 showed the highest effect on osteogenic differentiation of precursor cells in vitro, and this effect was ERK1/2 signaling-dependent. Scaffold S4 robustly promoted precursor cell homing, endogenous bone regeneration, and vascularization in rabbit critical-size cranial defects. In conclusion, BCP scaffolds fabricated by indirect SLS printing maintain the physicochemical properties of BCP and possess the capacity to recruit host precursor cells to the defect site and promote endogenous bone regeneration possibly via the activation of ERK1/2 signaling.
制造技术决定了支架的物理化学和生物学特性，包括孔隙率、机械强度、骨传导性和骨再生潜力。基于双相磷酸钙（BCP）的支架在骨组织工程中具有优势，因为它们具有合适的物理化学和生物学特性。我们开发了一种间接选择性激光烧结（SLS）打印策略，用于制造用于骨组织工程的 3D 微孔 BCP 支架。BCP 支架的绿色部分是在存在环氧树脂（EP）的情况下，在相关的低温下通过 SLS 制造的，剩余的 EP 通过随后的烧结过程分解和消除，以获得微孔 BCP 支架。广泛评估了支架的物理化学性质、细胞黏附、生物相容性、体外成骨潜力和兔子临界尺寸颅骨缺损愈合潜力。这种间接 SLS 打印消除了传统直接 SLS 打印在高温下工作的缺点，即支架的波浪变形、羟基磷灰石分解以及β-磷酸三钙（TCP）向α-TCP 的转化。在打印具有不同 BCP 和 EP 结合剂比例（按重量计）的支架中，结合剂比例为 50/50 的支架（S4）表现出最高的机械强度和孔隙率，以及最小的孔径。支架 S4 在体外对前体细胞的成骨分化表现出最高的影响，这种影响依赖于 ERK1/2 信号。支架 S4 可强有力地促进前体细胞归巢、内源性骨再生和血管化，从而在兔子临界尺寸颅骨缺损中。总之，通过间接 SLS 打印制造的 BCP 支架保持了 BCP 的物理化学性质，并且具有募集宿主前体细胞到缺陷部位并促进内源性骨再生的能力，可能通过激活 ERK1/2 信号。
