COMPOSITE MATRICES BY 3D PRINTING AND BIOMIMETIC PROCESS

通过 3D 打印和仿生工艺制造复合基质

• 批准号: 6471721
• 负责人: BENJAMIN M WU
• 金额: $ 3.83万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6471721
• 关键词: apatites; biomaterial development /preparation; biomimetics; ceramics; dental materials; fluid flow; ion transport; polymers; printing; surface coating; tissue engineering; tissue support frame

Composite matrices containing ceramics and absorbable polymers have been proposed as scaffolding materials for bone regeneration in order to combine the osteoconductive properties of the ceramics and the mechanical resiliency of the polymers. "Biomimetic" mineralization involves the nucleation and growth of apatite crystals in a super-saturated ionic environment. Apatite coating of even inherently non-osteoconductive polymers have greatly improved osteoconductivity. Although this apatite- coating technique has been reported with a wide range or polymers, most of the published results involve simple, non-porous substrates. The creation of uniform apatite coating throughout thick (>1 cm) porous polymeric structures has not been reported. Porous scaffolds involve much higher surface-to-volume ratios than non-porous substrates, and the delivery of ions to satisfy the large surface area may be transport-limited in thick scaffolds (>1 cm) of clinically relevant dimensions. We hypothesized that by affecting the availability of essential ions for nucleation and growth, transport limitations govern the kinetics and distribution of apatite nucleation and growth within the interconnected pores of large, complex (>1 cm) tissue engineering scaffolds. This hypothesis will be tested experimentally by controlling several relevant parameters (fluid flow rate, transport length-scale, and resistance to flow) that directly affect transport behavior. Fluid flow rate controls the availability of ions per unit time, and is easily controlled by adjusting the pump speed. Transport length-scale determines the spatial uniformity of ionic delivery, and can be controlled by incorporating channels of varying dimensions throughout the thick scaffolds. Flow resistance can be controlled by varying pore size. Smaller pores result in larger flow resistance, and also produce larger surface areas. Porous multichannel devices with varying channel diameter and microporosity will be constructed by a novel computer-based manufacturing technology, which 'has been used successfully to fabricate large polymeric scaffolds possessing complex macroscopic shape (>1 cm), oriented channels (<1 cm), and interconnected porosity (0.01 - 0.1 mm). Samples will be subjected to various transport conditions, sectioned at specified strategic locations, and characterized microstructurally and chemically to determine the effects of transport parameters on coating uniformity.

含有陶瓷和可吸收聚合物的复合基质已被提出作为骨再生的支架材料，以便将陶瓷的骨传导性质和聚合物的机械弹性联合收割机结合起来。“仿生”矿化涉及磷灰石晶体在超饱和离子环境中的成核和生长。甚至固有非骨传导性聚合物的磷灰石涂层也大大改善了骨传导性。虽然这种磷灰石涂层技术已经报道了广泛的聚合物，但大多数已发表的结果涉及简单的无孔基材。尚未报道在整个厚（> 1cm）多孔聚合物结构中产生均匀的磷灰石涂层。多孔支架涉及比无孔基质高得多的表面积与体积比，并且满足大表面积的离子递送在临床相关尺寸的厚支架（> 1cm）中可能是运输受限的。我们假设，通过影响成核和生长所必需的离子的可用性，运输限制控制了磷灰石成核和生长在大型复杂（>1 cm）组织工程支架的互连孔内的动力学和分布。将通过控制直接影响输送行为的几个相关参数（流体流速、输送长度尺度和流动阻力），对这一假设进行实验检验。流体流速控制每单位时间内离子的可用性，并且可以通过调整泵速轻松控制。传输长度尺度决定了离子输送的空间均匀性，并且可以通过在整个厚支架中并入不同尺寸的通道来控制。流动阻力可以通过改变孔径来控制。较小的孔隙导致较大的流动阻力，并且还产生较大的表面积。具有不同通道直径和微孔性的多孔多通道装置将通过基于计算机的新型制造技术来构建，该技术已成功地用于制造具有复杂宏观形状（> 1cm）、定向通道（<1cm）和互连孔隙率（0.01 - 0.1mm）的大型聚合物支架。将样品置于各种运输条件下，在指定的关键位置进行切片，并进行微观结构和化学表征，以确定运输参数对涂层均匀性的影响。