Skin Tissue Mass Production
Wound healing is a systemic biochemical response to tissue injury and occurs in 4 main steps – homeostasis, inflammation, proliferation, and maturation. These four overlapping stages involve interaction of many different biological entities such as platelets, extracellular matrix (ECM) components, cells such as keratinocytes, macrophages, neutrophils, fibroblasts, and endothelial cells. Wounds can be acute or chronic. Acute wounds typically undergo the natural wound healing process and show signs of healing within four weeks, while chronic wounds are “stalled” at a stage of the wound healing process due to various physiological reasons such as poor oxygen supply, tissue swelling, infections, and poor immune system.
Wound treatments vary depending on the type and severity of the wound; moreover, wound healing is affected by individual conditions such as age, body type, diet, and medications. The following are some examples of wounds that need special treatments, as they can be difficult to treat.
- Partial and full thickness wounds: Partial thickness wounds are wounds where the dermis and epidermis are destroyed, while full thickness wounds are wounds where the dermis, epidermis, subcutaneous tissue and/or even deeper tissues are destroyed.
- Tunnelled/undermined wounds: Tunnelled wounds (also known as sinus tracts) are wounds that create ‘passages’ underneath the skin in different directions, snaking through layers of skin; tunnelled wounds can be difficult to heal. On the other hand, undermining wounds are large wounds that have small openings, caused by the erosion of the wound edge.
- Draining wounds: Draining wounds are wounds that have exudates. The different types of drainages include serous (thin, clear, watery plasma), sanguineous (fresh blood), serosanguineous (thin, watery, pink), seropurulent (thin, watery, cloudy, yellow to tan), and purulent (thick, opaque, can be green, yellow or brown).
- Trauma wounds: Trauma wounds are injuries on the soft tissue of the skin, which includes abrasions, lacerations, second-degree burns, and skin tears.
- Surgical wounds: Surgical wounds are cuts or incisions done during a surgery. These include donor sites/grafts, post-Mohs surgery, and wound dehiscence.
- Diabetic foot ulcers: Diabetic foot ulcers or DFU’s are open wounds commonly found on the bottom of the food and affects about 15% of diabetes patients.
- Venous skin ulcer: Venous skin ulcers result from the poor blood circulation in the legs and are typically found on below the calf, on the sides of the lower leg, and above the ankle.
- Pressure ulcers: Pressure ulcers (also known as pressure sores, bed sores, decubitus ulcers) develop from staying in the same position for too long. They normally occur in areas of the skin close to the bones such as the elbows, heels, ankles, hips, and back.
- Vascular ulcers: Vascular ulcers are ulcers on the lower extremities for people older than 65 years of age. They are often chronic or recurrent and can cause infections and increase the risk of lower extremity amputations.
One of the current wound treatments available is the use of special wound patches, which stimulate or repair the extracellular matrix (ECM). There is a variety of special wound patches available in the market, these products may be biologically inert (acellular) or contain live cells (cellular); they can be human-, animal- (usually porcine or bovine) or plant-derived, and they can be naturally found (biologic), synthetic or composite (combination of biologic and synthetic products). Some of these wound patches maybe cadaveric human skin allografts, cryopreserved human skin allografts, patches composed of the human living cells and collagen, acellular human dermis product, patches solely composed of animal (porcine or bovine) collagen, and patches with both human and animal components.
Esco VacciXcell offers a skin bioreactor system, ideal for the automated production of specialized wound patches. The patches, made from collagen or other materials, are placed in individual bags, where the cell growth takes place, and a single system can accommodate up to 25 bags of patches. Esco VacciXcell’s skin bioreactor system features automated cell seeding and medium exchange simultaneously of all 25 bags; it also has an optimized design for the even distribution of cells over the patch during cell seeding and level control of the medium during medium exchange. For larger scales, up to 400 bags can be manufactured simultaneously using a single control system.