MacBarb Regina F, Lindsey Derek P, Bahney Chelsea S, Woods Shane A, Wolfe Mark L, Yerby Scott A
SI-BONE, Inc., San Jose, CA, USA.
Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.
Int J Spine Surg. 2017 Jun 1;11(3):15. doi: 10.14444/4015. eCollection 2017.
An aging society and concomitant rise in the incidence of impaired bone health have led to the need for advanced osteoconductive spinal implant surfaces that promote greater biological fixation ( for interbody fusion cages, sacroiliac joint fusion implants, and artificial disc replacements). Additive manufacturing, 3D-printing, may improve bone integration by generating biomimetic spinal implant surfaces that mimic bone morphology. Such surfaces may foster an enhanced cellular response compared to traditional implant surfacing processes.
This study investigated the response of human osteoblasts to additive manufactured (AM) trabecular-like titanium implant surfaces compared to traditionally machined base material with titanium plasma spray (TPS) coated surfaces, with and without a nanocrystalline hydroxyapatite (HA) coating. For TPS-coated discs, wrought Ti6Al4V ELI was machined and TPS-coating was applied. For AM discs, Ti6Al4V ELI powder was 3D-printed to form a solid base and trabecular-like porous surface. The HA-coating was applied via a precipitation dip-spin method. Surface porosity, pore size, thickness, and hydrophilicity were characterized. Initial cell attachment, proliferation, alkaline phosphatase (ALP) activity, and calcium production of hFOB cells (=5 per group) were measured.
Cells on AM discs exhibited expedited proliferative activity. While there were no differences in mean ALP expression and calcium production between TPS and AM discs, calcium production on the AM discs trended 48% higher than on TPS discs (=0.07). Overall, HA-coating did not further enhance results compared to uncoated TPS and AM discs.
Results demonstrate that additive manufacturing allows for controlled trabecular-like surfaces that promote earlier cell proliferation and trends toward higher calcium production than TPS coating. Results further showed that nanocrystalline HA may not provide an advantage on porous titanium surfaces.
Additive manufactured porous titanium surfaces may induce a more osteogenic environment compared to traditional TPS, and thus present as an attractive alternative to TPS-coating for orthopedic spinal implants.
社会老龄化以及随之而来的骨骼健康受损发生率上升，使得人们需要先进的具有骨传导性的脊柱植入物表面，以促进更强的生物固定（用于椎间融合器、骶髂关节融合植入物和人工椎间盘置换）。增材制造，即3D打印，通过生成模仿骨形态的仿生脊柱植入物表面，可能会改善骨整合。与传统的植入物表面处理工艺相比，这种表面可能会促进更强的细胞反应。
本研究调查了人成骨细胞对增材制造（AM）的小梁状钛植入物表面的反应，并与传统加工的具有钛等离子喷涂（TPS）涂层表面的基材进行比较，有无纳米晶羟基磷灰石（HA）涂层。对于TPS涂层圆盘，对锻造的Ti6Al4V ELI进行加工并施加TPS涂层。对于AM圆盘，将Ti6Al4V ELI粉末进行3D打印以形成实心基底和小梁状多孔表面。通过沉淀浸涂旋转法施加HA涂层。对表面孔隙率、孔径、厚度和亲水性进行了表征。测量了hFOB细胞（每组 = 5）的初始细胞附着、增殖、碱性磷酸酶（ALP）活性和钙生成。
AM圆盘上的细胞表现出更快的增殖活性。虽然TPS和AM圆盘之间的平均ALP表达和钙生成没有差异，但AM圆盘上的钙生成比TPS圆盘高48%（= 0.07）。总体而言，与未涂层的TPS和AM圆盘相比，HA涂层并未进一步改善结果。
结果表明，增材制造能够制造出可控的小梁状表面，与TPS涂层相比，可促进更早的细胞增殖和更高的钙生成趋势。结果还表明，纳米晶HA在多孔钛表面可能不具有优势。
与传统的TPS相比，增材制造的多孔钛表面可能会诱导更具成骨作用的环境，因此作为矫形脊柱植入物TPS涂层的一种有吸引力的替代方案。
