The importance of polymers in the preparation of medical devices for human body applications

Polymers are materials with special properties that enable them to function appropriately for a wide range of applications, such as medical devices (outside the body: hemodialysis membranes, containers; in vivo applications: urinary catheters and ureteral stents, vascular catheters, wound dressings) and packaging. Of course, there are general surgical implants made of polymers, such as tissue adhesives and sealants, suture materials, and surgical meshes. There are also orthopedic implants, such as bone cement, joint prostheses, osteosynthesis materials, and scaffolds for ligaments and tendon repairs. Other applications of polymers in clinical medicine include vascular and cardiovascular interventions, such as vascular stents, polymeric heart valves, and vascular grafts. These are in addition to the field of dentistry, in which composites (polymeric) are often utilized; ophthalmology, in which contact lenses are made of rigid poly(methyl methacrylate) (PMMA) and intraocular lenses are made of PMMA; and neurosurgery, in which tubular sheaths of polyvinyl alcohol are used in peripheral nerve guidance conduits. Resorbable polyglycolic acid sutures are often used for conduits. Other polymeric materials that are used in neurosurgery include D,L-lactide-co-ε-caprolactone, while both natural and synthetic polymers, such as natural silk, keratin, chitosan, and synthetic-poly(hydroxybutyrate) or polyurethanes, are experimental polymers for nerve guidance conduits. The properties of polymers are modifiable, according to human needs; this opens new fields in which they could be effectively employed. Polymers have started to gain in popularity in the field of medicine because of their versatility. They can be used to construct medical scaffolds, drug delivery carriers, implants, suture materials, bone cement, screws, and plates. The success of these medical devices lies in their biocompatibility. Many kinds of research are being carried out to generate biomimetic polymers for in vivo application. Extensive study is required to uncover the hidden applications of polymers for the welfare of humanity. Herein, we focus on a few polymers that are used predominantly in clinical medicine.