On the surface coating of medical devices

Brief introduction to the surface coating of medical devices

brief introduction to the surface coating of medical devices

May 28, 2021

in October 2015, the U.S. Food and Drug Administration (FDA) issued a safety communication entitled "separation of lubricating coatings of vascular medical devices", followed by the final report of Medsun entitled "hydrophilic and hydrophobic coatings of medical devices for vascular system". The report contains the findings of clinicians and emphasizes the importance of procedural techniques in minimizing particulate matter production. In their communication with the industry, the U.S. Food and Drug Administration (FDA) recognized the important role of hydrophilic coatings for vascular device products. As a more invasive way and an alternative to the attendant risks, it provided doctors with greater operability and reduced the friction rupture coating of blood vessels

glass simulation use model for evaluating the coating integrity of neurovascular catheter, sheath and medical wire (left) and peripheral PTA catheter (right) (from MEDTEC medical, but through the following analysis of the brief method of medical device design and manufacture)

about coating brief

hydrophilic coating

in the past few years, new coating formulations have emerged, It eliminates the need to choose between high lubricity and the generation of small amounts of particulate matter. But until recently, these formulas can only be used in medical devices through the double coating application process, and many manufacturers are currently equipped with only a single coating process. Fortunately, the single coating formula that can be used now can significantly reduce the production of particles while maintaining the lubricity of the previous first-class hydrophilic coating

by reducing the force required to operate intravascular medical devices during vascular interventional therapy, the hydrophilic coating reduces the risk of damaging the vascular wall and prevents vasospasm. Because they allow the catheter to navigate through the tortuous vascular pathways and lesion damage sites inaccessible to uncoated devices, hydrophilic coatings also expand the range of surgical treatment sites, such as balloon catheter angioplasty, nervous system intervention, lesion crossover or local drug delivery, showing that they can reduce thrombosis. Reduced friction between treatment and support catheters also improves outcomes and reduces surgical time and costs

hydrophilic coating can reduce the friction between vascular devices by 10 to 100 times. However, the properties of hydrophilic coatings with such lubrication - the ability to absorb and exude water - also make them vulnerable to mechanical degradation, leading to the production of particles. Hydrophilic coatings introduced in the 1990s when irritant and corrosive gases were produced during decomposition - many of which are still in use today - are an obvious example. Even though the durability of the best in class coating in history can only be improved by increasing the crosslinking level, this leads to the reduction of water absorption, thereby reducing the lubricity

antibacterial coating

contact antibacterial coating is the first kind of antibacterial coating studied. Physical adsorption or chemical bonding are often used to fix organic or inorganic fungicides with strong antibacterial properties on the surface of biomedical materials. Bacteria are quickly killed by contacting the coating directly Among them, quaternary ammonium salt (QAS) is the most used organic fungicide

biomedical materials are widely used in clinical treatment, and the problem of iatrogenic infection is becoming more and more prominent, which seriously threatens people's life and health Using appropriate surface modification methods to construct antibacterial coatings on the surface of biomedical materials is an effective way to solve this kind of iatrogenic infection and the rebound of billets and downstream finished products, or it will help scrap steel. At present, according to the functions of 292 bacterial coatings applied for national invention patents, they are mainly divided into contact antibacterial coating, anti adhesion antibacterial/bactericidal coating and intelligent antibacterial coating Among them, intelligent antibacterial coating can not only solve the problem of adhesion and accumulation of contact antibacterial coating bacteria bodies; It can also realize the controllable release of bactericidal substances through physical and chemical excitation response mechanisms to avoid environmental hazards; And often through different antibacterial methods to achieve high-efficiency antibacterial effect, which is an important direction for the future development of antibacterial coatings

antibacterial coating

porous medical implant coating

the surface roughness, charge property and hydrophilicity of porous materials can affect the adhesion and colonization of bacteria. When the transverse roughness and longitudinal roughness of the porous material surface are commensurate with the size of the bacteria, it is more conducive to the adhesion of bacteria, otherwise it is not conducive to the adhesion of bacteria; When the surface of porous material is hydrophilic, it is more conducive to cell adhesion than bacteria retention; When the surface of porous materials is positively charged, it is not conducive to the growth of bacteria and the formation of biofilm

there are the following requirements for the research and development of new antibacterial materials: first, and most importantly, the biocompatibility and tissue integration ability of the material should meet the long-term needs of the human body; Secondly, if the biomaterial itself can meet the biomechanical requirements of the location of the substitute tissue and has strong plasticity, it may be the best choice to customize it into an integral antibacterial porous implant combined with 3D printing; Finally, the long-term antibacterial performance and the prevention of biological drug resistance are also issues that need to be considered. In addition, the application of new coating materials indicates that the research and development of porous antibacterial materials is multifaceted. Increasing the responsiveness of the autoimmune system to invading microorganisms and mobilizing the autoimmune system to fight against infection may be the most effective way

in short, with the continuous development of new porous materials and the discovery of new antibacterial substances, how to effectively combine the two properties to prepare more efficient antibacterial medical porous materials to meet clinical needs is still a problem that needs further discussion

source: Journal of Chinese Academy of Engineering