Biomedical materials refer to a kind of materials with special properties and functions, which are used for artificial organs, surgical repair, physical therapy rehabilitation, diagnosis and treatment of diseases, and will not have adverse effects on human tissues. At present, various synthetic materials and natural polymer materials, metal and alloy materials, ceramics and carbon materials and various composite materials have been widely used in clinical and scientific research.

I. Classification of biomedical materials

Generally speaking, clinical medicine has the following basic requirements for biomedical materials: non-toxic, non-carcinogenic, non-teratogenic, non-causing the rupture of human cells and the reaction of tissue cells; It has good compatibility with human tissues and does not cause poisoning, hemolysis, blood coagulation, fever and allergy. The chemical properties are stable, and the action of antibody solution, blood and enzyme; Having physical and mechanical properties suitable for natural tissues; It has specific functions for different purposes. According to the nature of materials, biomedical materials can be roughly divided into the following categories:

1, biomedical metal materials

Biomedical metal materials are metals or alloys as biomedical materials, which have high mechanical strength and anti-fatigue characteristics, and are the most widely used load-bearing implant materials in clinic, mainly including artificial joints and artificial bones made of cobalt alloy (Co-Cr-Ni), titanium alloy (Ti-6Al-4V) and stainless steel. Nickel-titanium shape memory alloy has the intelligent characteristics of shape memory and can be used in orthopedic surgery and cardiovascular surgery.

2. Biomedical polymer materials

There are two kinds of biomedical polymers, natural and synthetic, and the fastest developing one is synthetic polymer medical materials. Many biomaterials with good physical and mechanical properties and biocompatibility can be obtained through molecular design. Among them, soft materials are often used as substitutes for human soft tissues such as blood vessels, esophagus and knuckles. Synthetic hard materials can be used as artificial dura mater, spherical valve of cage spherical artificial heart valve and so on. Liquid synthetic materials such as room temperature vulcanized silicone rubber can be used as injection tissue repair materials.

3 biomedical inorganic nonmetallic materials or bioceramics

Biomedical ceramics have stable chemical properties and good biocompatibility. Bioceramics mainly include two types: (1) inert bioceramics (such as alumina and medical carbon materials). ), high strength, good wear resistance and strong intermolecular binding force. (2) Bioactive ceramics (such as hydroxyapatite and bioactive glass) can be gradually degraded and absorbed in the physiological environment, or form stable chemical bonds with biological organisms, which has extremely broad development prospects.

4. Biomedical composite materials

Biomedical composite materials are biomedical materials composed of two or more different materials, which are mainly used to repair or replace human tissues and organs or improve their functions, and to manufacture artificial organs. Among them, titanium alloy and polyethylene prosthesis are commonly used as joint materials; Carbon-titanium synthetic material is a kind of artificial femoral head with good clinical application. Polymer materials combined with biopolymers such as enzymes, antibiotics, antibodies and hormones can be used as biosensors.

5. Biomedical derivative materials

Biomedical derivative materials are biomedical materials formed from specially treated natural biological tissues and have no biological activity. However, due to its similar structure and function to natural tissues, biomedical derived materials play an important role in the repair and replacement of human tissues, mainly used as skin masks, hemodialysis membranes, artificial heart valves and so on.

Second, the main products in the global biomedical materials market

At present, there are 20 kinds of biomedical materials widely used in medical devices (implanted devices, extracorporeal circulation systems, etc.). ), including 12 kinds of medical polymers, 4 kinds of metals, 2 kinds of ceramics and 2 kinds of others. Using the existing biomedical materials, nearly 300 kinds of medical implants and artificial organs have been developed and applied, mainly including: heart and cardiovascular system (pacemaker, heart valve, artificial blood vessel, catheter and shunt, etc.). ); Orthopedics (artificial joints, bone plates, bone screws and other internal fixation instruments, bone defect filling or repair, spinal column and spinal fusion instruments, functional neuromuscular simulation and artificial articular cartilage, etc.). ); Plastic surgery (craniofacial, ear, nose and other prostheses and artificial breasts, etc. ); Soft tissue repair (artificial urethra, artificial bladder, artificial intestine, internal and external shunt, artificial trachea, suture and tissue adhesive repair materials, etc.). ); Dentistry (dental implants, alveolar bone replacement, fillers, etc. ); Sensory nervous system (intraocular lens, contact lens, nerve conduit, middle ear prosthesis, percutaneous lead, hearing and vision reconstruction prosthesis, etc.). ), as well as controlled release carriers of drugs and bioactive substances.