Civil Engineering Reference
In-Depth Information
of material necessary for wound healing, as well as reduce the frequency of dressing
changes, which lead to overall cost reduction.
h e most traumatic and complex of all skin injuries are caused by burns, which result
in extensive damage to the various skin layers. Burns are generally classii ed according
to depth and identii ed by three degrees: i rst-degree burn - usually superi cial, af ects
only the outer layer of skin (epidermis); second-degree burn - either superi cial, with
damage to the epidermis layer of the skin (second-degree A), or deep when penetrat-
ing into the dermis (second-degree B); third-degree burn - a total destruction of all
the epidermis and dermis, extending into subcutaneous tissue (skin grat ing is rec-
ommended). h e process of healing of burn tissues involves both regeneration of the
epidermis and repair of the dermis resulting in formation of scar tissue. Burn wound
dressing can be classii ed into two major categories according to usage. h ey are (i)
short-term application (dressings) which requires replacement at regular intervals, and
(ii) long-term applications (skin substitutes). h ey can be further subdivided into tem-
perory (applied on fresh partial thickness wounds until complete healing is ensure),
and semi-permanent (applied on full thickness wounds until autograt ing). However,
the most frequently used classii cation of dressing is based on the nature of dressing
material rather than the mode of application. Based on the type of materials used for
the preparation of wound care dressings, they may be classii ed as conventional, bio-
logical and synthetic dressings. Within each category, the dressings may be further clas-
sii ed into (i) primary dressing - a dressing in physical contact with the wound bed; (ii)
secondary dressing - a dressing that covers the primary dressing; and (ii) island dress-
ing - a dressing that is constructed with a central absorbent portion surrounded by an
adhesive portion. h e standard protocol of burn management highlights several factors
which accelerate the process of optimal healing [52]: (i) control of l uid loss, (ii) barrier
to wound infection, (iii) fast and ef ective wound closure, optimally with skin grat s or
skin substitutes, and (iv) signii cant pain relief.
Czaja
et al.
[53] clinically investigated a new wound healing system based on micro-
bial cellulose for the treatment of large area second-degree A/B skin burns. In their
study never-dried microbial cellulose produced by the vinegar fermentation bacterium
A. xylinum
is synthesized in the form of twisting ribbons, which in stationary culture
forms a thick, gelatinous membrane on the surface of a liquid medium. h e membrane
formed in such conditions is characterized by the 3D structure made of an ultrai ne
network of cellulose nano- and microi brils. h is particular structure of the never-
dried microbial cellulose pellicle determines the remarkable and unique physical and
mechanical properties of the wound dressing material, which can hold a large amount
of liquid and displays high mechanical strength. In this study the authors compared
the wound healing ef ects of never-dried microbial cellulose membranes and conven-
tional gauze wound dressings. h e results showed that the skin of the patients whose
burns were covered with never-dried microbial cellulose membranes healed faster
(faster re-epithelialization) than the wounds of patients who received a conventional
wound dressing (such as wet gauze and ointments). h e study of Czaja
et al.
[53,54] also
found that microbial cellulose membranes actually performed better than conventional
wound dressings in (i) conforming to the wound surface (excellent molding to all facial
contours and a high degree of adherence even to the contoured parts such as nose,
mouth, etc., were observed), (ii) maintaining a moist environment within the wound,
