Sericin is a protein derived from silk. It is a natural biopolymer secreted by the silkworm (Bombyx mori) during the production of silk. Sericin acts as a protective and adhesive coating around fibroin, the structural core protein of silk fibers.
Key Characteristics:
1. Composition:
- Sericin is a glycoprotein composed of amino acids, with serine, glycine, and aspartic acid as major components.
- It contains hydrophilic groups like hydroxyl, carboxyl, and amino groups, making it water-soluble.
2. Structure:
- The molecular weight of sericin varies depending on the extraction process, generally ranging between 10–400 kDa.
- It exhibits a random coil or β-sheet structure.
3. Solubility:
- Sericin is soluble in hot water or dilute alkali solutions, facilitating its extraction from silk cocoons.

Functions in Nature:
- Acts as a glue binding the fibroin fibers to form a cocoon.
- Provides protection to the fibroin core from environmental factors like moisture and UV radiation.
Extraction Methods:
- Degumming: Sericin is commonly extracted during silk processing through boiling the silk in water, alkali, or detergent solutions.
- Enzymatic Extraction: Uses proteases or other enzymes to separate sericin from fibroin.
Applications of Sericin:
1. Cosmetics:
- Used as a moisturizing agent and anti-aging ingredient due to its hydrophilic properties.
- Promotes skin elasticity and reduces inflammation.
2. Biomedical:
- Wound healing: Stimulates cell proliferation and promotes skin repair.
- Drug delivery: Acts as a carrier for bioactive molecules due to its biocompatibility.
3. Textile Industry:
- Enhances the smoothness and strength of fabrics.
- Used in functional textiles with antibacterial and UV-protective properties.
4. Food Industry:
- Acts as a natural antioxidant and stabilizer in food products.
5. Pharmaceuticals:
- As a biopolymer for fabricating scaffolds, hydrogels, and membranes for medical applications.

Benefits of Sericin:
- Non-toxic, biocompatible, and biodegradable.
- Rich in amino acids that provide antioxidant and anti-inflammatory effects.
- Promotes hydration and protection for skin and hair.
Challenges:
- Potential allergenicity in some individuals.
- Extraction efficiency and molecular stability can vary based on the method used.
Let me know if you want to explore sericin is applications in detail!