Biomedical Engineering Reference
In-Depth Information
method to produce this i bre without the use of organic solvents [96]. h e
production of chitosan-based textiles is important for the manufacture of
antimicrobial apparel.
During the period 2011 - 2013, there were a large number of patents
i led, at least 58 were attributed to the biomedical applications of this ver-
satile polymer. [97]. h e majority of these patents were i led by the Chinese
since China is the largest producer of chitosan worldwide. In addition, the
Chinese government has employed an incentive policy which privileges
inventors and applicants [98]. With a polymer as diverse as chitosan, the
number of potential applications increases as new technology is developed.
h e patented technologies can be divided into the following sections: bone
composite, platforms for cell growth, scaf olds for delivery of cell growth
factors, delivery agents and antimicrobial studies.
5.7.2
Wound Healing/Tissue Regeneration
Tissue engineering or wound healing comprise of three main components,
biomaterials, cells and growth factors [99]. One of chitosans most widely
studied applications is that of wound healing or tissue generation. It has
been shown that chitosan can contribute to wound healing in dif erent
ways such as enhancing the i ltration of polymorphonuclear neutrophils
and macrophages into the injured tissue, activating the complement and
normal i brolasts, increasing granulation, vascularisation and promot-
ing re-growth of the epithelium. In the market there are currently quite
a few examples of chitosan-based wound dressings, examples include:
HemCon , ChitoFlex , Chitopack C and Chitodine . h ese dressings
range from bandages to sponges and i lms of chitosan [100]. Wound heal-
ing or tissue regeneration generally comprises platforms for cell growth
(tissue engineering), scaf olds for delivery of cell growth factors or bone
composites. Chitosan-based scaf olds can be produced using a variety of
techniques these include, solvent casting and particulate leaching, phase
separation and freeze drying, solution spinning, microsphere sintering,
hydrogel formation and other less commonly used techniques such as solid
free-form fabrication and rapid prototyping integrated with computer-
aided design. When designing a scaf old for tissue regeneration, certain
requirements should be met; the scaf old should ideally be biodegradable
and mimic the native tissue extracellular matrix thereby providing an ideal
environment for cellular activities and tissue regeneration. Chitosan meets
these requirements and it has functional groups present on the backbone
which can be modii ed with a variety of biological agents with advanta-
geous properties. To date, chitosan has been used in the regeneration of
