I-Corps: Electrically Polarized Hydroxyapatite Coatings

该项目将使用一种涂层方法，产生均匀的羟基磷灰石涂层，具有近乎完美的晶体域对齐。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的、永久的电极化。将调整实验条件，在复杂形状的钛合金部件（如实际外科植入应用的小销钉和螺钉）上制造厚度和孔隙度可控的均匀涂层。电极化羟基磷灰石涂层已被证明促进骨生长和愈合。新型涂层中的排列晶体域允许在极化后比任何先前测量的羟基磷灰石存储更高的电荷。通过热激退极化实验，测量了极化涂层在植入体上的总电荷。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研究其吸附和释放药物和其他物质的能力。羟基磷灰石作为一种涂层被广泛应用于改善金属植入物的生物相容性。在本研究中羟基磷灰石涂层的独特电学和表面特性可以改善矫形和牙科应用的性能，以及提出许多以前不可能使用该材料的潜在应用。涂层的强电极化可能通过促进成骨细胞粘附和增强磷酸钙沉积来加速愈合。感染会减缓恢复，需要额外的手术来更换植入物，或者在最坏的情况下导致截肢甚至致命的败血症。通过与表面离子交换，可以利用表面上的强静电电荷在手术部位控制抗生素或其他药物的输送，以减少并发症。强极化和高质子导电性也在膜过滤器、传感器和燃料电池中开辟了潜在的应用。

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.