Biodegradable polymer which, edible films have gained more attention due to their environmentally-friendly characteristics, vast variety and availability, non-toxicity, and low cost. Biodegradable polymers have a long history, and since many are natural products, the precise timeline of their discovery and use cannot be accurately traced. One of the first medicinal uses of a biodegradable polymer was the catgut suture, which dates back to at least 100 AD. The first catgut sutures were made from the intestines of sheep, but modern catgut sutures are made from purified collagen extracted from the small intestines of cattle, sheep, or goats. The concept of synthetic
Setar Setar The Setar (, from ', meaning "three" and ', meaning "string") is an Iranian musical instrument. It is a member of the lute family, which is played with the index finger of the right hand. Two and a half centuries ago, a fourth string was added to the Setar which most of the time has the same tone of the bass string. It has 25–27 moveable frets which are usually made of animal intestines or silk. Setar covers about 2 and a half scale (depending on the length the handle). some musicians even use its different strings like chords