Smart Hydrogels

Skin substitutes have been widely used to close wounds and to encourage wound healing. A number of such products are commercially available and they usually maintain a biologically balanced moist wound environment, structural support for tissue regeneration and supply of beneficial biomolecules to the wound.

Among these devices, cellular skin substitutes most closely mimic skin tissue. They are made of a scaffold structure that is seeded with living cells. These cells make proteins and other molecules to stimulate the person’s own cells and promote the healing process.

As a material to be used in wound closure and healing, Dr Wenxin Wang has developed a series of in situ cross-linking hydrogels with different mechanisms and physical properties including: 

1. Photo-crosslinking hydrogel
A PEG-based hyperbranched polymer made using in situ DE-ATRP (Deactivation-Enhanced Atom Transfer Radical Polymerisation). This hyperbranched polymer exhibited a lower critical solution temperature (LCST) close to body temperature - meaning it forms a gel when it is put on a wound - and it can be further cross-linked and strengthened using light (figure 1).

2. ECM Chemical-crosslinking hydrogels
A well-defined PEG based hyperbranched thermo-responsive copolymer made with high content of acrylate vinyl groups using the situ DE-ATRP approach. This gave an injectable and in situ crosslinked system (via Michael-type thiol-ene reaction with a thiol-modified hyaluronan extracellular matrix (figure 2, references 1,2,3). 

Adipose-derived stem cells (ADSCs) embedded into this hydrogel system survived well (figure 3). The Wang group are now carrying out preclinical studies to determine how the ADSCs embedded hydrogel system behave and to analyse their therapeutic potential for wound healing. The primary results suggest that this hybrid in situ crosslinking wound-dressing system prevented wound contraction and increased the production of blood vessels.