The arthropod cuticle has been in existence for well over 500 million years. The cuticle is mostly composed of two types of polymers, proteins and chitin. Chitin is a polysaccharide that provides structural support for the cuticle. Chitin is the second most abundant natural polymer on planet earth, after cellulose (produced by plants).
Chitin is also a waste product from the seafood industry. The muscular tissues of shrimp and other shellfish are consumed by humans but the cuticle is typically removed in processing. Most of the cuticle is discarded as waste. However, there are some important new uses for arthropod cuticle in medical products.
The arthropod cuticle must contain the liquid of the arthropod open circulatory system. If an arthropod is wounded, cells in its hemolymph (arthropod blood) will attach to the cuticle, coagulate and harden to patch the wound. This process has some similarities to blood clotting and scab formation to close wounds in humans. The cuticle of arthropods provides a much better surface for blood cell adhesion than many other polymers such as cellulose. Can arthropod cuticle be used for human blood clotting?
It can. However, the proteins that can cause shellfish allergies are removed by processing to produce a material called chitosan. The chitosan is a modified chitin that tightly binds cells and charged particles. When used as a compress, it stops bleeding more rapidly and effectively than the traditional cotton gauze bandage. Chitosan bandages are more expensive than traditional gauze and are used in special situations such as severe trauma or in dental applications where the wound area is relatively small. Chitosan powder can be used directly in wounds to stop bleeding and is being tested as a material for use in minimizing long term damage to the spinal chord after trauma. Chitosan has important antibacterial properties. Pathogens will adhere to the chitosan and be prevented from circulating throughout the body.
Chitosan is also finding use in environmental protection. The properties of chitosan that bind cells will also bind soil particles. Chitosan can be used as a flocculant, a substance that causes soil particles to more rapidly sediment. In areas where the soil has been disturbed and is ‘muddying the waters’ chitosan can clear the water and improve conditions for aquatic plants and animals.
Chitosan is even used as a food additive to provide additional fiber to the diet. While marketed for weight loss, chitosan is marginally effective. In weight loss, the primary mechanism would be replacing nutrients, with the non-digetstible chitosan fiber. People who want to lose weight still need to consume less and exercise more.
The study of biomolecules of insects and other arthropods can lead to important advances in human health and environmental protection.