Skin Repair/Wound Dressing

Huzaifa Umar 20142894

Bioengineering Department Cyprus International University

Synopsis

Skin Repair

Wound Healing

Wound Dressings

Chitosan

Alginate

Summary

Conclusion

“God heals, and the doctor takes the

fees”Benjamin Franklin (American Satetesman, Scientist, Philosoper)

Skin RepairSkin is an important cover that protect

the internal body from mechanical

injury and  chemical hazards, and

bacterial invasion.

Skin epidermis is relatively thick and

covered with keratin.

Keratin is family of fibrous structural

proteins that make up the outer layer

of human skin (hair and nails).

Monomers are join to form

intermediate filament that provide

necessary strength and toughness for

masticatory organs.

Microscopy of keratin filaments inside cells.

Wound HealingWound is specifically refers to a sharp injury which

damages the dermis of a skin.

Wound healing is an intricate process where the skin or

other body tissue repairs itself after injury.

The factors that lead to the injury are; Incision, Laceration,

Abrasion, Puncture, Gunshot, Contusion, Crush Injury etc.

wikipedia.org/wiki/Wound_healing

Approximate days since injury0 3 17 30

Classification of Wound Healing

Primary Intention (1st): It occur when the edges are clean and held

together with ligatures (little gap).

Healing by occur very fast.

Secondary Intention (2nd): The edges of the wound are wide and allowed

to close by contraction and epithelization.

Healing usually take longer time.

Tertiary Healing (3rd) : Contaminated and left open to prevent infection.

Healing by host defenses.

Phases of Wound HealingHemostasis (blood clotting): Clotting factors are activated by blood,

exposed basement membrane proteins and collagen.

Inflammation: Platelets Activate cytokines and growth factors. Growth

factors stimulate cells to speed their rate of division.

Histamine

Phases of Wound Cont….Proliferation (growth of new tissue) :

After 2-3 days, fibroblasts begin to enter the wound site. Proliferative phase start before the inflammatory phase has ended.

Angiogenesis: Necessary to support a wound environment that can repair the injury. Supplies Oxygen and nutrients for fibroblast proliferation and

production of wound matrix.Fibroplasia: Fibroblasts migrate into wound on fibrin skeleton left behind

from hemostasis. Macrophage derived growth factors stimulate proliferation of

fibroblasts. Even as fibroblasts are producing new collagen, collagenases and other

factors degrade it. Fibroblasts begin to commit apoptosis to balance synthesis and

degradation of collagen

Phases of Wound Cont…Epithelialization :

The formation of granulation tissue into an open wound allows the re-

epithelialization phase to take place.

Basal keratinocytes from the wound edges and dermal appendages (such as hair

follicles, sweat glands and sebacious (oil) glands) are the main cells responsible

for the epithelialization phase of wound healing.

It take place within days to week.

Remodeling of tissues (Maturation) :

Collagen production = degradation equalize.

The maturation phase of tissue repair is said to have begun.

The onset of maturation depend on the size of the wound.

As the phase progresses, the tensile strength of the wound increases.

PHASES OF WOUND HEALING

Factors Affecting HealingLocal Factors Systemic Factors

Wound SepsisBlood SupplyWound TensionIrradiation

HypervascularityHypercellularityHypoxia

Foreign Bodies InfectionProlong Inflamatory Reaction

Nutritional Deficiency

Vitamin A

Vitamin C

Systemic Disease

Diabetes Mellitus

Uremia

Jaundice

Therapeutics

Wound DressingA dressing is a sterile pad, applied to

a wound to promote healing and

prevent further harm.

Removes exudate and toxic

components.

Allows gaseous exchange.

Insulates thermally & humidity.

Protects from secondary infection.

Allows removal without trauma. wikipedia.org/wiki/Dressing_(medical)

AlginateNaturally occurring anionic and

hydrophilic polysaccharide, derived from

brown seaweed.

It absorb water quickly

Biocompatible

Biodegradable

Alginate is used in various

pharmaceutical preparations (Drug

delivery, wound dressing, dental

impression, tissue engineering.

www.comfortsplints.com

www.wound-treatment

ChitosanChitosan is a linear polysaccharide

composed of randomly distributed

Its obtained by treating shrimps and

crustacean shells with NaOH.

It has haemostatic properties

It prevent blood clothing

It has pharmacological

applications: Bandage, Artificial

blood vessels, contact lenses, drug

delivery etc..

www.swicofil.com

www.everychina.com

SummarySkin is a protective cover composed of three layers

(Epidermis, dermis, hypodermis).

Wound healing means repairing of tissue after injury.

Wound healing is classified into: 1o, 2o and 3o intention.

Phases of wound healing are: Heamostasis, Inflammation,

Proliferation and Maturation.

Dressing is use in a wound to promote healing and prevent

further harm. The dressing is usually carried out by polymers

(Alginate, Chitosan, Polyurethane etc.)

ConclusionDressing promote wound healing activity and

it also prevent further harm.

Some polymer such as chitosan, alginate

plays an important role in healing and other

pharmaceutical activities.

ReferencesRieger, S.; Zhao, H.; Martin, P.; Abe, K.; Lisse, T.S. (2014). "The role

of nuclear hormone receptors in cutaneous wound repair". Cell biochemistry and function 33 (1): 1–13.

Stadelmann, WK; Digenis, AG; Tobin, GR (1998). "Physiology and healing dynamics of chronic cutaneous wounds". American journal of surgery 176 (2A Suppl): 26S–38S.

Rasche, H (2001). "Haemostasis and thrombosis: an overview". European Heart Journal Supplements 3 (Supplement Q): Q3–Q7.

Midwood, K.S.; Williams, L.V.; Schwarzbauer, J.E. (2004). "Tissue repair and the dynamics of the extracellular matrix". The International Journal of Biochemistry & Cell Biology 36 (6): 1031–1037.

 Rosenberg L., de la Torre J. (2006). Wound Healing, Growth Factors. Emedicine.com. Accessed January 20, 2008.

Dealey C. (1999). The care of wounds: A guide for nurses. Oxford ; Malden, Mass. Blackwell Science. Electronic book.

Mumcuoglu et al. Int. J. Dermatology, 1999

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OBSERVATION