The search continues for a safe and cost-effective ideal temporary skin substitute that functions as well as, or better than, the gold standard (cadaver allograft). Minimal functional requirements are as follows: (a) protect excised deep wound surfaces until autografting takes place, resulting in equal or greater autograft and equal or fewer complications (infection or dressing changes due to rejection, nonadherence, etc); (b) protect excised wounds covered with widely meshed autograft until the interstices heal; and (c) limit conversion of mid-dermal burns to full-thickness wounds
Novel and meaningful terminology1
was proposed for wound-dressing products referred to as bioengineered skin
, tissue-engineered skin
, and bioengineered skin equivalents
. “Bioengineered Alternative Tissue” applies to products like Biobrane, Integra, TransCyte, Alloderm, Apligraft, Orcell, Oasis, Epicel, Gamma Graft, Laser skin, AW
BAT, and AW
BAT Plus. Composition may include biologicals, such as collagen (various types and forms), chondroitin 4 and/or 6 sulfate, vitamin C or E, growth factors and cytokines, and living cells. AW
BAT Plus was cleared by the Food and Drug Administration (FDA) in January 2010 and declared to be a “Combination Product” wound dressing device containing properties of both a drug and a device.
Desirable properties of an ideal temporary skin substitute or bioengineered alternative tissue2,3
include adherence, moisture permeability control, safety, pain management, flexibility, transparency, stability, cost-effectiveness, and ease of application and removal. Greenwood et al4
have shown Biobrane to possess these properties. The desirable properties are expanded for AW
BAT Plus: stimulate fibroblast proliferation, increase collagen synthesis, provide better drapability, and can be preformed into anatomically shaped gloves, which enable efficient and precise fit to the hand wound surface, reducing time for wound closure and anesthesia.
Six biological components are added to the 3D matrix of AW
BAT Plus to increase its hydrophilic and hygroscopic properties enabling a moist, but not wet environment, to heal more rapidly. Vitamin C and E are natural antioxidants. Hypoallergenic type I collagen peptide and chondroitin 4 and 6 sulfate contribute hydrophilic properties.3
Immuno-10 is a purified carbohydrate fraction of Aloe vera, which increases the hydrophilic and hygroscopic nature of the 3D matrix. Different porosities (5.5% or 7.5%) accommodate wounds with varying exudative characteristics.
AWBAT product configurations are described later. The distinction between AWBAT and AWBAT Plus is that the former contains collagen peptide as the sole biological component, same as Biobrane; AWBAT Plus contains 6 biological components. The S, D, and M configurations distinguish the level of porosity and adherence needed for the type of wound managed.