Tuesday 25 February 2014

Wound Care with Photo-active Collagen

More from the EDANA NIA 2013 Conference in Roubaix...

Giuseppe Tronci of Leeds University School of Dentistry described advanced wound care as a $2bn market currently led by hydrogel dressings such as Convatec Aquacel .  These dressings absorb wound exudate to form a protective gel but have several limitations.  They have poor strength when wet and any attempt to increase their strength reduces exudate absorbency.  
They are also based on cellulose which does not promote the healing process as well as collagen.  Unfortunately collagen loses its integrity on extraction from tissues and needs stabilising.  

This is done as follows:

  •         Isolate type 1 collagen from rat’s tails.
  •          Functionalise it using either 4-vinylbenzyl chloride (4VBC) or glycidyl methacrylate (GMA).  These functional groups attach to the surface of the collagen triple helix structure.
  •          UV irradiation of the functionalized collagen causes cross-links to form between the triple helices stabilising the polymer, preventing dissolution and allowing gel formation.
These superabsorbent collagen gels have proved to have better swelling and compression properties than carboxymethyl celluloses, compression at a micro-level having been measured using an atomic force microscope. 

Cytotoxity according to ISO 10993-5 showed that mouse fibroblasts thrived on the gel. For fibre or nonwoven manufacture, the functionalised but unstabilised collagen can be dissolved in water at 40C, wet spun into yarn in a coagulation bath of acetone or methanol, UV-irradiated and stabilized, washed and dried.

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