Application of surface modification of low temperature plasma metal biomaterials

• Categories:Technical Support
• Author:plasma cleaning machine-surface treatment equipment-CRF plasma machine-Sing Fung Intelligent Manufacturing
• Origin:
• Time of issue:2021-02-19
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(Summary description)The application of low temperature plasma to the surface modification of metal biomaterials can be divided into three categories: improving biocompatibility, immobilizing bioactive macromolecules and improving the physical corrosion resistance of metals. 1. Improve biocompatibility: When metal materials are implanted into living organisms, biocompatibility requirements must be met. Biocompatibility refers to the degree to which a material is compatible with blood and tissue. Graft polymerization of hydrophilic functional groups on the surface of metal biomaterials to improve the surface properties of metal biomaterials is an important surface modification method, which is mainly used to improve the biocompatibility of materials and the growth induction of living cells, so as to make them have better biological activity. 2. Grafting Inorganic Matter on Metal Matrix: Calcium and phosphorus are the basic components of bone tissue. A layer of CA-P or HA on the surface of metal implants can effectively improve their compatibility with bone tissue and inducement to osteogenesis. It can be modified by plasma spraying (PSC). The high potential difference between electrodes is used to generate an arc discharge (>10000℃), which ionizes the gas around the electrodes into plasma, and then impacts the suspended surface modification powder at high speed to make it settle on the metal surface. Plasma spraying is a widely used deposition method at present. It can provide high adhesion between the substrate and the surface modification layer, and can obtain a complete coating (4O ~ 54M). Coatings formed by this process can rapidly nucleate and grow in body fluids. However, as a high temperature process, it has some disadvantages such as uneven density, inconsistent structure, large variation range of binding strength and so on. Moreover, the decomposition of hydroxyapatite in the spraying process may lead to the desolvation phenomenon in the environment of body fluids. In order to improve the composition and structure of HA coating, another heat treatment or steam bath is needed after spraying. Such as spraying the products in the vapor pressure of the o. 15 mpa, temperature of 125 ℃ steam environment for 6 h steam bath, can make the most of the amorphous phase into HA crystalline state, and coating produced by other breakdown products will resume as crystalline HA phase, which greatly improved the stability of the coating of the amorphous hydroxyapatite coating has good stability, but relative to the functional hydroxyapatite coating, due to the improvement of the surface density. It also detracts from its osteogenic induction. Therefore, in the actual preparation process should be selected according to the specific requirements of the use of the material, the selection of suitable technological conditions. At present, many domestic units are using plasma surface modification technology to actively carry out the research on the surface modification and surface film synthesis of biomedical materials, in order to solve the key technical problems such as anticoagulant, biocompatibility, polymer surface hydrophilicity, anti-calcification, and cell adsorption growth and inhibition. Shanghai Institute of Ceramics, Chinese Academy of Sciences uses plasma spraying technology. Significant progress has been made in the improvement of artificial bone by ZrO2 coating on material surface.