Download - Biomaterial science presentation
Skin Repair/Wound Dressing
Huzaifa Umar 20142894
Bioengineering Department Cyprus International University
“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.
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