Related topics: cells · blood vessels

Probiotic hydrogels heal gut wounds other bandages can't reach

External wounds such as skin cuts or abrasions can often be easily covered with a simple Band-Aid or a larger wound patch to protect them and facilitate their healing. When it comes to some internal surfaces like those of ...

Synthetic skin could aid wound healing

Engineers have devised a fabric dressing whose thickness and elasticity can be custom-matched to specific areas of the body.

Raising fluid walls around living cells

Cell culture plates that are in everyday use in biology can be effectively transformed into microfluidic devices, opening paths for biologists to miniaturize cell-based workflows. In a recent report, Ph.D. researcher Cristian ...

Molecular bait can help hydrogels heal wounds

Like fishermen, Rice University bioengineers are angling for their daily catch. But their bait, biomolecules in a hydrogel scaffold, lures microscopic stem cells instead of fish.

Specialized plant cells regain stem-cell features to heal wounds

If plants are injured, cells adjacent to the wound fill the gaps with their daughter cells. However, which cells divide to do the healing and how they manage to produce cells that match the cell type of the missing tissue ...

Welding with stem cells for next-generation surgical glues

Scientists at the University of Bristol have invented a new technology that could lead to the development of a new generation of smart surgical glues and dressings for chronic wounds. The new method, pioneered by Dr. Adam ...

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Wound healing

Wound healing, or wound repair, is an intricate process in which the skin (or some other organ) repairs itself after injury. In normal skin, the epidermis (outermost layer) and dermis (inner or deeper layer) exists in a steady-stated equilibrium, forming a protective barrier against the external environment. Once the protective barrier is broken, the normal (physiologic) process of wound healing is immediately set in motion. The classic model of wound healing is divided into three or four sequential, yet overlapping, phases: (1) hemostasis (not considered a phase by some authors), (2) inflammatory, (3) proliferative and (4) remodeling.

Upon injury to the skin, a set of complex biochemical events takes place in a closely orchestrated cascade to repair the damage. Within minutes post-injury, platelets (thrombocytes) aggregate at the injury site to form a fibrin clot. This clot acts to control active bleeding (hemostasis).

In the inflammatory phase, bacteria and debris are phagocytized and removed, and factors are released that cause the migration and division of cells involved in the proliferative phase.

The proliferative phase is characterized by angiogenesis, collagen deposition, granulation tissue formation, epithelialization, and wound contraction. In angiogenesis, new blood vessels are formed by vascular endothelial cells. In fibroplasia and granulation tissue formation, fibroblasts grow and form a new, provisional extracellular matrix (ECM) by excreting collagen and fibronectin. Concurrently, re-epithelialization of the epidermis occurs, in which epithelial cells proliferate and 'crawl' atop the wound bed, providing cover for the new tissue.

In contraction, the wound is made smaller by the action of myofibroblasts, which establish a grip on the wound edges and contract themselves using a mechanism similar to that in smooth muscle cells. When the cells' roles are close to complete, unneeded cells undergo apoptosis.

In the maturation and remodeling phase, collagen is remodeled and realigned along tension lines and cells that are no longer needed are removed by apoptosis.

However, this process is not only complex but fragile, and susceptible to interruption or failure leading to the formation of chronic non-healing wounds. Factors which may contribute to this include diabetes, venous or arterial disease, old age, and infection.

This text uses material from Wikipedia, licensed under CC BY-SA