VAPOR GROWN CARBON FIBERS FOR BIOMEDICAL APPLICATIONS

用于生物医学应用的气相生长碳纤维

• 批准号: 3298518
• 负责人: THOMAS APPLE
• 金额: $ 8.12万
• 依托单位: RENSSELAER POLYTECHNIC INSTITUTE
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-07-01 至 1993-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3298518
• 关键词: biomaterial development /preparation; biomaterial evaluation; boron; carbon; catalyst; chemical structure; electrical conductance; electron microscopy; electron spin resonance spectroscopy; nitrogen; nuclear magnetic resonance spectroscopy; surface property

Vapor-grown carbon fibers combine the desirable characteristics of high thermal and electrical conductivity, high strength to weight ratio, non- catastrophic failure modes, high modulus, marked anisotropy and chemical resistance. They are a relatively new form of graphite fiber which hold great promise for application in reinforced composite materials for prosthetic devices and as microelectrodes for monitoring cell processes. The inherent anisotropy of the electronic conduction suggests their application in the neural sciences. The goal of this research is to tailor or "fine-tune" the electrical and thermal conductivity, the tensile strength and the modulus and the surface properties through various doping, coating and annealing procedures to allow for their application in prosthesis and as microelectrodes and biologically-suited electrical signal transmission and nerve models. We will attempt to perfect the annular structure of vapor-grown fibers to give a "closure", the lack of active surface edges. "Closure" is necessary for those applications in the human body that require chemical inertness. This is provided by the low reactivity of the 001 planes of graphite. This "closure" also enhances the resistance to oxidation by presenting a very low reactive-edge surface area. We propose to coat fibers via plasma deposition with diamond to lower porosity and increase the physical strength of the fibers. Alternatively, surface roughness will be incorporated into the fibers when growth into tendons and muscle fibers is desired. This process will be carried out through controlled oxidation. Through the use of solid-state ESR measurements, guided by our newly developed theoretical treatment, we will characterize vapor-grown carbon fibers for biological applications. The extremely important properties of electron mobility, conductivity anisotropy, crystallite size, degree of basal plane ordering,a nd electron diffusion constant will be inferred from analysis of ESR absorption lineshapes. Electron microscopy will reveal structural modifications due to changes in growth conditions and those accompanying thermal annealing. Measurement of total surface area with krypton and active surface area with oxygen will be performed. Oxygen surface concentration will be determined by monitoring the Ols and Cls XPS intensities. Surface order will be probed with low-energy electron diffraction. The utility of these fibers as microelectrodes will be studied in collaboration with Dr. Greg Swain at the Center for Bioanalytical Research at the University of Kansas. All of the above-mentioned properties of vapor-grown fibers depend critically upon the method of their thermal and chemical preparation. New growth methods will be employed in an effort to enhance the fibers' usefulness. We will, thus, determine the optimal preparation and processing conditions which will lead to advanced materials for prothesis, neural and biochemical use.

蒸气生长的碳纤维结合了高的特征 导电性和电导率，高强度与重量比，非 - 灾难性失败模式，高模量，各向异性和化学 反抗。 它们是一种相对较新的石墨纤维形式 适用于加强复合材料的巨大希望 假体设备和作为监测细胞过程的微电极。 电子传导的固有各向异性表明它们 在神经科学中的应用。 这项研究的目的是量身定制或“微调”电气和 导热率，拉伸强度以及模量和表面 通过各种掺杂，涂层和退火程序的属性 允许其在假体和微电脱落中的应用 生物合作的电信号传递和神经模型。 我们 将尝试完善蒸气纤维的环形结构，以提供 一个“闭合”，缺乏活性表面边缘。 “关闭”是必要的 那些在人体中需要化学惰性的应用。 这 由石墨001平面的低反应性提供。 这 “闭合”还通过表现出一个非常 反应性边缘表面积低。 我们建议通过等离子体覆盖纤维 用钻石沉积至降低孔隙率并增加物理 纤维的强度。 或者，表面粗糙度将是 当生长成肌腱和肌肉纤维时，掺入纤维中 需要。 该过程将通过受控的氧化进行。 通过使用固态ESR测量结果，在我们的新近指导下 开发了理论处理，我们将表征蒸气生长的碳 生物应用的纤维。 极其重要的特性 电子迁移率，电导率各向异性，结晶石大小，程度 将从基础平面排序，和电子扩散常数从 ESR吸收线路的分析。 电子显微镜将显示 由于生长条件的变化而引起的结构修饰 伴随的热退火。 测量总表面积和 将执行具有氧气的活性表面积和活性表面积。 氧 表面浓度将通过监测OL和CLS XPS确定 强度。 将用低能电子探测表面顺序 衍射。 这些纤维作为微电极的实用性将是 与Greg Swain博士在中心合作学习 堪萨斯大学的生物分析研究。 蒸气纤维的所有上述特性取决于 至关重要的是其热和化学制备方法。 新的 生长方法将采用增强纤维的努力 用处。 因此，我们将确定最佳准备和 处理条件将导致预防材料的先进材料， 神经和生化使用。