Application of PTFE coating on medical equipment

Biomedical materials are high-tech new materials developed in the past 30 years, mainly used for diagnosis, treatment or replacement of human tissues and organs or to enhance their functions. Biomedical materials have a wide range of uses, such as cardiovascular disease, cerebrovascular disease, orthopedics, and so on.

Chemical structure of PTFE

Organic coatings are widely used in medical catheters and guide wires in minimally traumatic (or intravascular) interventional treatment techniques, and orthopedic wires in orthopedics. The outermost layer of the catheter is mostly made of polyethylene, which determines the shape, hardness and friction of a catheter with the vascular intima. Most of the inner layer is PTFE coating, which uses the hydrophobicity of PTFE to reduce the frictional resistance between the guide wire, balloon, stent and the lumen of the guide catheter, and prevent thrombosis. The proximal push rod segment is coated with an interventional guide wire coated with PTFE, which can enhance the passing ability of the guide wire in the human body cavity, and is suitable for calcification, twisting and occlusion of the disease. Because PTFE coating has good biocompatibility and corrosion resistance, its application on the surface of orthodontic wires can significantly stabilize the performance of orthodontic wires and increase their service time.

ptfe coating wires

In summary, PTFE coating has good biocompatibility, safety and reliability, and also has superior corrosion resistance. It can be widely used in the field of biomedical materials to provide surface lubricity and prevent biological environment from affecting materials. Corrosion, degradation, wear and nature degradation, or even destruction.

PTFE coating type

Medical PTFE is the fluoropolymer of choice for many medical device coating applications.

There are two main systems for PTFE coating: water-soluble PTFE coating and solvent-based PTFE coating.

All PTFE is made of carbon and fluorine atoms through free radical polymerization process. These PTFE polymers have a very high molecular weight. The molecular chain structure is a long straight chain of carbon and fluorine. The carbon-fluorine bond has high strength, so PTFE The polymer exhibits excellent low friction, heat resistance and chemical resistance

Application of PTFE coating

l Guide wire/mandrel

As the most basic platform of coronary intervention therapy, guide wire plays a pivotal role in the entire coronary intervention therapy process. In the process of vascular interventional therapy, the guide wire passes through the target lesion and reaches directly into the coronary artery branch, artery or vein terminal branch, and other treatment instruments can be pushed along the track into the corresponding coronary artery branch, artery or vein At the distal branch.

The guide wire includes a mandrel, a spring sheath, an outer layer of the guide wire and an end. The mandrel of the guide wire determines its main performance characteristics-the supporting force of the guide wire, the controllability of the guide wire direction and the torque transmission capacity. It is divided into: soft tip, connecting tip and support section and push rod section. The spring sheath allows the surgeon to obtain good tip tactile feedback. The spring sheath is sheathed on the soft tip of the mandrel. In order to reduce the friction on the surface of the guide wire, improve the interaction between the devices (balloon/guide wire, stent/guide wire), and improve the tracking of the guide wire in the blood vessel, coating on the surface of the guide wire Processing, namely forming the outer layer of the guide wire.

Medical device guide wires that require PTFE coating are mainly made of stainless steel. The guide wire needs the characteristics of low friction performance, good coating adhesion and high dimensional accuracy requirements for the guide wire during use. The cross-section of stainless steel wire can be round or non-circular, and it can be a single strand or multiple strands.

PTFE coating medical tube

l Hypotube

The hypotube refers to the metal tube at the proximal end (the end closer to the operator) of the balloon dilatation catheter, which enters the human body during the interventional operation. The material is generally medical grade 304 stainless steel. In stent implantation, the hypotube is part of the delivery system. The superior performance of the hypotube directly affects the success rate of the operation, because it is the only force application site for the operator to push the entire balloon dilatation catheter into the patient, and it is also the strongest component of the entire balloon dilatation catheter.

Hybotube

l Minimally invasive expansion and drainage

At present, minimally invasive surgery is widely used in the field of clinical surgery. Percutaneous kidney or choledochoscope can enter the human body through a minimally invasive dilation and drainage device to complete the operation. Minimally invasive dilatation and drainage devices are the most common medical consumables in clinical medicine. Human tissues are punctured through a puncture needle to reach the surgical site (such as gallbladder, kidney and other organs), and then different types of minimally invasive dilation and drainage devices are inserted through the puncture needle. Enter 22 minimally invasive dilation and drainage device to complete the operation. At present, the minimally invasive dilatation and drainage device is generally a single-lumen cannula. The minimally invasive surgical instrument is operated in the single-lumen cannula. If sampling or drainage is required, the operating scope must be withdrawn and drained through the same channel. The stones or pus are flushed from the channel by liquid Rush out. This operation method is not conducive to specimen collection, the operation process is complicated, the operation process is not a closed system, and it is easy to cause contamination of the operation area or operation samples.

PTFE coating

l Intravascular balloon dilatation catheter

Balloon dilatation catheter, as the main medical device in interventional therapy, is bound to be widely used. Its pros and cons have a direct impact on the quality of surgery and the health of patients. The transition section is in the middle part of the entire catheter. Due to the large difference in hardness between the end catheter and the proximal catheter, the transition section plays a smooth transition in hardness and ensures the normal use and various necessary performance of the balloon dilatation catheter. Therefore, the design of the transition section directly affects the overall performance of the balloon dilatation catheter.

At present, there are many brands of balloon dilatation catheters on the market. Each brand of balloon dilatation catheters has its own characteristic transition section design. However, the design of the transition section of some products causes the overall flexibility of the balloon to be poor, which strongly stimulates blood vessels. , And the design of the transition section is not perfect, which affects the pushing effect of the balloon. Interventional cardiologists pay more attention to the following points in the process of using balloons: passability, release time, tracking, pushing force and other characteristics.

ptfe coating