I-Corps: Electrically Polarized Hydroxyapatite Coatings

该项目将使用一种涂层方法，导致均匀的羟基磷灰石涂层具有近乎完美的晶区排列。涂层的独特结构促进了高温质子传导，并使涂层在室温附近具有强大的永久电极化。将调整实验条件，以在实际外科植入应用中使用的复杂形状的钛合金部件(如小销和螺丝)上生成厚度和孔隙率可控的均匀涂层。电极化羟基磷灰石涂层已经被其他人证明可以促进骨骼的生长和愈合。新型涂层中排列的晶区在极化后允许比之前测量的任何羟基磷灰石都要高得多的存储电荷。通过热刺激去极化实验测量植入物上极化涂层的总存储电荷。具有高极化涂层的原型植入物将通过与表面的离子交换来吸附和释放药物和其他物种的能力。合成的羟基磷灰石已被广泛用作涂层，以提高承载金属植入物的生物相容性。本研究中的羟基磷灰石涂层独特的电学和表面性能可以改善整形外科和牙科应用的性能，并呈现出许多以前这种材料不可能实现的潜在应用。涂层的强电极化可以通过促进成骨细胞的黏附和促进磷酸钙的沉积来潜在地加速愈合。感染可能会减缓康复，需要额外的手术来更换植入物，在最糟糕的情况下，会导致截肢，甚至致命的败血症。通过与表面的离子交换，可以利用表面上的强静电在手术部位控制抗生素或其他药物的输送，以减少并发症。强极化和高质子传导性也为膜过滤器、传感器和燃料电池开辟了潜在的应用前景。

The project will use a coating method that results in uniform hydroxyapatite coatings with near perfect alignment of crystal domains. The unique structure of the coating promotes high temperature proton conduction, and allows the coating to have a strong, permanent electrical polarization near room temperature. Experimental conditions will be tuned to make uniform coatings of controlled thickness and porosity on titanium alloy parts of complex shape, such as small pins and screws, used in actual surgical implant applications. Electrically polarized hydroxyapatite coatings have been shown by others to promote bone growth and healing. The aligned crystal domains in the novel coatings allow much higher stored electrical charge after polarization than any previously measured for hydroxyapatite. The total stored charge of the polarized coatings on implants will be measured through thermally stimulated depolarization experiments. The prototype implants with highly polarized coatings will be investigated for their ability to adsorb and release drugs and other species through ion exchange with the surface.Synthetic hydroxyapatite has found widespread use as a coating to improve bio-compatibility of load bearing metallic implants. The unique electrical and surface properties of the hydroxyapatite coatings in the present study can improve performance in orthopedic and dental applications, as well as present a number of potential applications previously not possible with this material. Strong electrical polarization of the coatings can potentially speed healing by promoting osteoblast adhesion and enhancing calcium phosphate deposition. Infections can slow recovery, necessitate additional surgery to replace the implant, or in worst cases lead to amputation or even lethal sepsis. Strong electrostatic charge on the surface can be utilized for controlled delivery of antibiotics or other drugs at the site of surgery through ion exchange with the surface in order to reduce complications. The strong polarization and high proton conductivity also opens up potential applications in membrane filters, sensors, and fuel cells.