PLANT FIBRES USED AS SURGICAL DRESSINGS: A TEACHER’S COMPREHENSIVE GUIDE
Welcome, future pharmacists and healthcare professionals!
Surgical dressings are substances that are applied to wounds to protect and promote healing. They perform a number of purposes for the injured area. In addition to preventing infection and providing mechanical support to the supporting tissues and physical protection for the healing wound, they also remove wound exudates from the site.
As a pharmacognosy educator with years of experience teaching natural products and surgical dressings, I have observed that students often underestimate the importance of plant fibres in healthcare. Let me tell you: Plant fibres have been saving lives through surgical dressings for centuries.
In this comprehensive guide, I will walk you through the classification, properties, and uses of plant fibres used as surgical dressings—including cotton, silk, wool, and regenerated fibres. I will also cover sutures and ligatures, their classification, essential properties, and surgical catgut. By the end of this article, you will have a thorough understanding of these essential surgical materials. Let us begin!
Dpharmguru’s exam insights:
Plant fibres and surgical dressings are frequently tested in pharmacognosy exams. Remember: Cotton fibres are epidermal trichomes of Gossypium species. Silk is a protein fibre from Bombyx mori. Wool is a keratin fibre from sheep. Absorbable sutures include gut, PDS, and Vicryl. Non-absorbable sutures include silk, cotton, nylon, and metallic sutures. These are classic exam questions!
6.1. SURGICAL DRESSING
Surgical dressings are substances that are applied to wounds to protect and promote healing. They perform a number of purposes for the injured area. In addition to preventing infection and providing mechanical support to the supporting tissues and physical protection for the healing wound, they also remove wound exudates from the site.
Reusable, sterile, non-adherent to the granulating surface, and capable of being formed from loose threads and fibres are all characteristics of a high-quality dressing. Gauze, films, gels, hydrogels, hydrocolloids, foams, alginates, polysaccharide pastes, granules, and beads are examples of contemporary dressings.
Ideal Requirements of Surgical Dressing
- Should offer both bacterial and mechanical protection
- Should help in keeping the dressing/wound interface moist
- Should permit fluid and gaseous exchange
- Should not adhere to the wound
- Should be non-toxic, non-sensitising, and non-allergic
- Should be cost-effective
6.2. PLANT FIBRES USED AS SURGICAL DRESSINGS
Fibres are elongated cells having thick walls and pointed ends. The cell walls consist of cellulose but the presence of lignin is not confirmed, i.e., it may or may not be present.
Fibrous, pliable, and green leaves are the source of fibres. A leaf which can be curled around a finger without breaking is a potential source of fibres. The natural fibre-reinforced polymer composite materials are rapidly being used in industries as well as in fundamental researches. Fibres are also chemically synthesised from various materials.
6.2.1. Classification of Fibres
| Sources | Fibres |
|---|---|
| Plant Fibres | Jute, Flax, Banana, Cotton, Hemp |
| Animal Fibres | Silk, Wool |
| Regenerated and Synthetic Fibres | Nylon, Terylene, Orlon |
| i) Fibres regenerated from carbohydrate materials | Alginate yarn, Artificial silk or Rayon |
| ii) Fibres regenerated from protein materials | Aridil (from groundnut protein), Fibrolin (from milk casein) |
| iii) Synthetic fibres | Nylon, Terylene, Orlon |
| Mineral Fibres | Glass, Asbestos |
6.2.2. Uses of Fibres
- They are used for making ligatures, oiled silk, and surgical dressings
- They are used for making lint and gauze
- They are used in textile industries for weaving clothes
- They are used as filtering medium and straining medium
- They are used for insulation purpose
6.2.3. Study of Fibres
Following are the few examples of fibres which are used in pharmacy for different purposes:
- Cotton
- Silk
- Wool
- Regenerated fibres (Rayon)
6.2.4. Cotton
Cotton fibres are soft, fluffy, and staple. Cotton grows in a ball, or protective case, around the seeds of cotton plants. It is one of the world’s leading agricultural crops which are produced economically in huge quantities. Large scale production of cotton is also making cotton products inexpensive.
Synonyms: Raw cotton, Cotton wool, Purified cotton, Absorbent cotton, Surgical cotton
Source: Cotton is the epidermal trichomes or hair of the seeds of cultivated species of Gossypium (Gossypium herbaceum and Gossypium barbadense). It belongs to the family Malvaceae.
Chemical Constituents: Raw cotton contains cellulose (about 90%), moisture (7-8%), and natural impurities (4-6%) such as wax, fat, and protoplasm remnants. Purified cotton or absorbent cotton contains mostly cellulose and 6-7% of moisture.
Uses:
- Used as a filtering medium
- Used as an insulating material
- Absorbent cotton is used in surgical dressings to absorb blood, mucus, pus and prevent wounds from infections
6.2.5. Silk
Silk is a natural protein fibre which can be woven into textiles. The protein present in silk is fibroin and is produced by certain insect larvae to form cocoons.
Synonyms: Mantua, Pongee, Samite, Sendal
Source: Silk is the fibre obtained from the cocoons of Bombyx mori (Mulberry silkworm) and other species of Bombyx and also from Antheraea species. It belongs to the family Bombycidae.
Chemical Constituents: Natural silk consists of fibroin protein which hydrolyses into glycine (44%), alanine (27%), serine (11%), tyrosine (5%), and other amino acids. The molecule exhibits a chain-like structure. It does not contain sulphur.
Uses: Silk fibres are used for preparing special types of sutures, sieves, and ligatures.
6.2.6. Wool
Wool is a specific type of hair of some mammals. It is mainly obtained from sheep and goats and sometimes also comes from other animals.
Synonym: Sheep wool
Source: Wool is obtained from the fleece of Ovis aries, belonging to the family Bovidae.
Chemical Constituents: Wool fibres are made up of keratin protein. They show elasticity, in contrast to the cellulose and silk fibres. The elasticity arises from a reversible intramolecular transformation of the fibre substance.
Uses:
- Used in manufacturing dressings, like domette and crepe bandages and flannel
- Used as a filtering and straining medium
6.2.7. Regenerated Fibres (Rayon)
Regenerated fibre is made by dissolving the cellulose fraction of plant fibre in chemicals and then again making it a fibre by viscose method. It is also termed as regenerated cellulose fibre as it consists of cellulose, like cotton and hemp.
Synonyms: Regenerated cellulose, Viscose rayon
Source: Rayon is an artificial fibre, composed of regenerated cellulose in which not more than 15% of hydrogen of hydroxyl groups have been replaced by the substituents.
Uses: It is used for making fabrics, surgical dressings, and viscose rayon absorbent wool.
6.3. SUTURES AND LIGATURES
Sutures, commonly called stitches, are sterile surgical threads that are used to repair cuts (lacerations). They also are used to close incisions from surgery. Some wounds (from trauma or from surgery) are closed with metal staples instead of sutures. A ligature is a thread or string without a needle which is used to tie blood vessels and other tissues together.
6.3.1. Classification of Sutures and Ligatures
Sutures and ligatures can be classified on the basis of their absorbency:
1) Types of Absorbable Sutures
- Gut: Natural monofilament suture for internal soft tissue wounds. Not used for cardiovascular or neurological procedures.
- Polydioxanone (PDS): Synthetic monofilament suture for soft tissue wound repair and pediatric cardiac procedures.
- Poliglecaprone (Monocryl): Synthetic monofilament suture for general soft tissue repair. Commonly used to close skin invisibly.
- Polyglactin (Vicryl): Synthetic braided suture for hand or facial lacerations. Not used for cardiovascular or neurological procedures.
2) Types of Non-absorbable Sutures/Ligatures
- Silk Sutures: Prepared by spinning or twisting silk fibres. Smooth, strong, braided. Sterilised and boiled in water to soften.
- Cotton Sutures: Uniform size, recommended in critical parts where strength is required for long time.
- Nylon Sutures: Made by microfilaments of nylon braiding. Strong, water resistant, used in skin and plastic surgery.
- Linen Sutures: Cheap, very strong under moist condition but not uniform in diameter.
- Metallic Sutures: Comprise of metallic wires of silver or stainless steel. Available as mono-filaments, twists, and braids.
6.3.2. Essential Properties of Sutures and Ligatures
- They must be sterile
- Their strengths must be adequate for the purpose
- They must not cause any irritation as far as practicable
- Their gauge should be as fine as possible
- Those that undergo rapid degradation in tissues losing tensile strength within 60 days are considered absorbable sutures
- Those that retain tensile strength for longer than 60 days are non-absorbable sutures/ligatures
6.3.3. Surgical Catgut
Catgut is best used for wounds in areas where the tissue regenerates rapidly. A disadvantage of using this suture material is that a higher level of tissue reaction is incited in the surrounding tissue due to the foreign protein nature of the catgut suture.
Synonyms: Kit gut, Violin gut, Surgical gut, Collagen fibre
Source: Catgut suture is made by twisting together strands of purified collagen taken from the serosal or submucosal layer of the small intestine of healthy ruminants (cattle, sheep, and goats) or from beef tendon.
Properties:
- Absorbs within 60-90 days for chromic suture and 60-70 days for plain gut suture
- Allows for smooth passage through tissue
- Packed in IPA to retain memory and increase pliability
- Uniform chrome content provides required wound support and absorption
- Available from U.S.P Sizes 5-0 to 2
Types of Catgut
- Boilable Catguts: Comprise of anhydrous tubing
- Non-boilable Catguts: Comprise of alcohol and small water containing tubing which avoids heat sterilisation
Standards for Surgical Catgut
- All catguts for surgical use are indicated or described under British Pharmaceutical Codex
- Sterility Tests: Must be considered due to bactericides likely to be present in tubing fluid
- Gauge: Measured by means of a dial reading micrometer
- Tensile Strength: Measured by machine on “straight” and “knotted” samples
Advantages of Catgut
- Less likely to form sinuses if the wound turns septic
- Valuable in situations where a non-absorbable suture might act as a nidus (nest) for a foreign body
- Used for suturing the mucosa of gastrointestinal tract where a non-absorbable suture might cause chronic ulceration or haemorrhage
- Used as a skin suture in scrotum, vulva, perianal region where removing a non-absorbable suture might be painful
Dpharmguru’s exam insights:
Sutures and ligatures are frequently tested. Remember: Absorbable sutures include gut, PDS, Monocryl, and Vicryl. Non-absorbable sutures include silk, cotton, nylon, linen, and metallic sutures. Catgut is made from purified collagen from ruminant intestines. It absorbs within 60-90 days. These are classic exam questions!
COMPARISON: ABSORBABLE VS NON-ABSORBABLE SUTURES
| Feature | Absorbable Sutures | Non-Absorbable Sutures |
|---|---|---|
| Degradation | Degrade within 60 days | Retain tensile strength >60 days |
| Removal | Not required | Removed after wound healing |
| Examples | Gut, PDS, Monocryl, Vicryl | Silk, Cotton, Nylon, Linen, Metallic |
| Tissue Reaction | Higher (foreign protein) | Lower |
| Use | Internal soft tissue repair | Skin, cardiovascular, neurological |
FREQUENTLY ASKED QUESTIONS (FAQs)
1. What is the biological source of cotton fibres?
Cotton fibres are the epidermal trichomes or hair of the seeds of cultivated species of Gossypium (Gossypium herbaceum and Gossypium barbadense). Family: Malvaceae.
2. What is the chemical composition of silk?
Natural silk consists of fibroin protein which hydrolyses into glycine (44%), alanine (27%), serine (11%), tyrosine (5%), and other amino acids. It does not contain sulphur.
3. What is the difference between absorbable and non-absorbable sutures?
Absorbable sutures degrade in tissues within 60 days and do not require removal. Non-absorbable sutures retain tensile strength for longer than 60 days and must be removed after wound healing.
4. What is surgical catgut made from?
Surgical catgut is made by twisting together strands of purified collagen taken from the serosal or submucosal layer of the small intestine of healthy ruminants (cattle, sheep, and goats) or from beef tendon.
5. What are the ideal requirements of surgical dressing?
A good surgical dressing should: offer bacterial and mechanical protection, keep the wound interface moist, permit fluid and gaseous exchange, not adhere to the wound, be non-toxic and non-allergic, and be cost-effective.
6. What are the types of absorbable sutures?
The types of absorbable sutures are: Gut (natural monofilament), Polydioxanone (PDS), Poliglecaprone (Monocryl), and Polyglactin (Vicryl).
SUMMARY
Plant fibres and surgical dressings are essential components of modern healthcare. This guide covered:
- Surgical Dressings: Substances applied to wounds to protect and promote healing—ideal requirements include sterility, permeability, and non-adherence
- Classification of Fibres: Plant (cotton, jute, flax), Animal (silk, wool), Regenerated/Synthetic (rayon, nylon, terylene), and Mineral (glass, asbestos)
- Cotton: Epidermal trichomes of Gossypium species; contains 90% cellulose; used as filtering medium and absorbent cotton in surgical dressings
- Silk: Protein fibre (fibroin) from Bombyx mori; contains glycine (44%); used for sutures, sieves, and ligatures
- Wool: Keratin protein from sheep; used in bandages, flannel, and filtering medium
- Regenerated Fibres (Rayon): Artificial fibre made by viscose method; used in fabrics and surgical dressings
- Sutures and Ligatures: Absorbable (gut, PDS, Monocryl, Vicryl) and non-absorbable (silk, cotton, nylon, linen, metallic)
- Surgical Catgut: Purified collagen from ruminant intestines; absorbs within 60-90 days
As I always tell my students: “Understanding plant fibres and surgical dressings connects the natural world to surgical care—these materials save lives every day in operating rooms worldwide.”
REFERENCES AND FURTHER READING
- Pharmacy Council of India (PCI). (2022). Pharmacognosy Syllabus. New Delhi: PCI.
- Tyler, V. E., Brady, L. R., & Robbers, J. E. (2020). Pharmacognosy and Pharmacobiotechnology (9th ed.). Wolters Kluwer.
- Trease, G. E., & Evans, W. C. (2019). Trease and Evans’ Pharmacognosy (16th ed.). Elsevier.
- Kokate, C. K., Purohit, A. P., & Gokhale, S. B. (2020). Pharmacognosy (50th ed.). Nirali Prakashan.
- British Pharmacopoeia Commission. (2020). British Pharmacopoeia. London: BP Commission.
Disclaimer: This article is for educational purposes only and does not constitute medical advice. Always consult qualified healthcare professionals for medical concerns. Pharmaceutical regulations and guidelines may vary by region—always refer to your local regulatory authorities for specific requirements.
written by:
Dr. N. Sujith Kumar
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