Related topics: cells · blood vessels

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 ...

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 ...

A light-activated remote control for cells

What if doctors had a remote control that they could use to steer a patient's own cells to a wound to speed up the healing process? Although such a device is still far from reality, researchers reporting in the ACS journal ...

New polymer mixture creates ultra-sensitive heat sensor

Scientists at the Laboratory of Organic Electronics have developed an ultra-sensitive heat sensor that is flexible, transparent and printable. The results have potential for a wide range of applications – from wound healing ...

E-bandage generates electricity, speeds wound healing in rats

Skin has a remarkable ability to heal itself. But in some cases, wounds heal very slowly or not at all, putting a person at risk for chronic pain, infection and scarring. Now, researchers have developed a self-powered bandage ...

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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