Which of the following is not a natural polymer?

Alumina is not a natural polymer; it is an inorganic compound primarily made of aluminum oxide. In contrast, cellulose, chitosan, and alginate are all derived from natural sources.

Cellulose is a polysaccharide found in the cell walls of plants and is the most abundant organic polymer on Earth. Chitosan is derived from chitin, which is found in the exoskeleton of crustaceans and some fungi, making it another example of a biopolymer that occurs naturally. Alginate comes from the cell walls of brown algae and is widely used in various applications, including drug delivery and tissue engineering.

Understanding the distinction between natural and synthetic materials is vital in tissue engineering, as natural polymers often exhibit better biocompatibility and bioactivity, promoting cellular interaction and tissue regeneration.