Carbon fiber composite materials are increasingly used in the fields of diagnosis, treatment, health care and related medical devices. With the gradual increase in demand in the medical market, relevant carbon fiber medical materials are also constantly expanding and innovating in application methods and forms.
The research on medical carbon fiber materials began as early as the 1960s. At that time, it was found that carbon fiber materials had excellent anti-coagulation properties in the research on anti-coagulation materials of artificial blood vessels. After 1970, Bokros proposed to use carbon fiber materials as biomedical devices. According to modern scientific research, carbon fiber materials have good biocompatibility, low irritation to biological tissues, non-toxicity, non-carcinogenicity, low specific gravity, and elastic modulus similar to human bones. It has the potential advantage of becoming the fourth generation of implant materials.
Advantages of carbon fiber composite materials in the medical field
1. Anisotropy and designability
Carbon fiber composite materials are anisotropic materials with different properties along the fiber direction and perpendicular to the fiber direction, which brings great freedom to design. By changing the laying method (such as laying angle, laying order) to change the elasticity and strength of the product, the specific use requirements can be met. Medical equipment components often act on different parts of the human body, and the specific performance requirements of different components are different.
2. High X-ray transmittance
The transmittance of X-rays is related to the elemental composition, atomic number, density, and thickness of the material being penetrated. The main elements that make up carbon fiber composite materials are C, H, and O, with small atomic numbers, and the X-ray mass absorption coefficient is much lower than that of general materials. The X-ray transmittance of 1mm thick aluminum plates and carbon fiber composite plates is 78% and 96% respectively, the scattering and absorption consumption of aluminum plates is 22%, and that of carbon fiber plates is only 4%.
3. Good fatigue resistance
Carbon fiber composite materials contain countless fiber/resin interfaces. When cracks are generated by excessive external forces, these interfaces can effectively prevent the cracks from further expanding and delay the occurrence of fatigue damage. Medical devices are reused every day, and the good fatigue resistance of carbon fiber composite materials ensures the service life of the instrument.
In the field of medical equipment, carbon fiber composite materials are used to manufacture mobile platforms for X-ray inspection machines by utilizing their full X-ray transmittance; CFRP is used to manufacture medical equipment such as orthopedics and organ transplantation, as well as rehabilitation products such as prostheses and orthotics by utilizing its excellent mechanical properties.
Used for CT bed plates, X-ray inspection equipment and auxiliary equipment
This type is the most widely used and most extensive carbon fiber medical case in China. The more representative ones are X-ray, CT and B-ultrasound inspection bed panels, diagnostic bed headrests, high-definition DR flat panel detector panels, and brackets.
Medical CT bed plates mostly use insulating electric plates, but their ray transmittance is low, their mechanical properties are poor, and their imaging clarity is poor. The absorption rate and scattering rate of carbon fiber composite materials are much smaller than that of them. During diagnosis, the X-ray dose can be reduced accordingly, the power of the X-ray machine can be reduced, the service life of the instrument can be extended, and electricity can be saved.
More importantly, carbon fiber composite materials have excellent X-ray transmittance, allowing the rays to be irradiated on the bed board at any angle without refraction. Only a small dose of rays is needed to obtain clear imaging, thus reducing the harm to patients and medical staff.
Carbon fiber for artificial bones and artificial joints
Currently, carbon fiber composite materials have been widely used in bone fixation plates, bone fillers, hip joint stems, artificial implant tooth roots, skull repair materials, and artificial heart materials. The bending strength of human bones is about 100Mpa, the bending modulus is 7~20Gpa, the tensile strength is about 150Mpa, and the tensile modulus is about 20Gpa. The bending strength of carbon fiber composite materials is about 89Mpa, the bending modulus is 27Gpa, the tensile strength is about 43Mpa, and the tensile modulus is about 24Gpa, which is close to or exceeds the strength of human bones.
At present, some companies have developed the use of carbon fiber composite materials to make artificial bones and joints. The bending strength of this artificial bone is closer to real human bones than artificial bones made of other biomaterials, which is of great significance to orthopedic medicine. The wear resistance of artificial joints made of it is also higher than that of ultra-high molecular weight polyethylene and metal products at the movable joint.
Another company has developed continuous carbon fiber or felt reinforced plastics for bone repair. The resin matrix uses polymethyl methacrylate and the mass fraction of carbon fiber is 20%-60%. Because the material is light, does not interfere with MRI examinations, and has good biocompatibility, long-term implantation in the body has no adverse reactions to biological tissues, blood, cerebrospinal fluid, etc., and no rejection reaction, it is suitable for use as a fracture fixation material or fracture internal fixation or bone repair material.
Tooth restoration
In Europe and the United States, non-metallic restoration-preformed fiber post system is increasingly being used in clinical practice, and is gradually being considered to be an effective alternative to the traditional metal post and core system for repairing residual roots and crowns of teeth. Studies on the physical and chemical properties and biological properties of carbon fiber posts show that carbon fiber posts have mechanical properties that are more compatible with tooth tissues. Their elastic modulus, which is similar to that of dentin, can make stress more evenly distributed along the post body, which is beneficial to protecting the tooth root; at the same time, they have many advantages such as good biocompatibility and corrosion resistance, easy removal, and convenient secondary repair.
Carbon fiber prosthesis
The link and transmission part between the prosthesis and the human body is called the receiving cavity, which mainly wraps the residual limb and transmits force. This part has high load-bearing requirements and cannot be too heavy. Carbon fiber materials can also be used as materials for making this part. The part that contains the residual limb can be made of polyethylene board, and the support body can be made of carbon fiber to make a frame structure to achieve easy support and transmission of force.
The linkage between the ankle and foot of the human body plays a key role in the balance and support of the body. The ankle joint made of carbon fiber can realize the jumping function of the human body. In addition, the connection part between the ankle and the calf prosthesis can also be realized with carbon fiber. The overall product is very exquisite and also performs well in terms of damage safety.
Carbon fiber wheelchair
The density of carbon fiber is only 1.7g/cm3. The accessories of the same specification are more than half lighter than those of aluminum alloy, but the strength is much greater. In addition, carbon fiber is also very corrosion-resistant. A considerable proportion of wheelchair patients face problems such as incontinence and frequent contact with injections and medicines. In this case, accessories made of carbon fiber composite materials show durability that is difficult to match with general metal materials.
At present, carbon fiber composite materials are mainly used in accessories such as armrests, armrests, footrests, legrests, backrests, skirts and frame tubes. Most of these accessories can be adjusted in height. Carbon fiber composite materials are easy to assemble with the wheelchair as a whole through mechanical connection. The most important thing is that after these accessories are used in carbon fiber composite materials, the overall weight of the wheelchair has been significantly reduced, and as a frequently used component, it has become stronger and more durable.
Carbon fiber composite materials have excellent performance and have been widely used in civilian daily life. They have also been verified by decades of application. They are safe and reliable for the environment and human health.
With the continuous advancement of medical technology, medical equipment is also constantly innovating and developing. The investment and application of carbon fiber in medical devices represents a new trend and direction, and will surely usher in a broader application prospect in the future.
