In tissue engineering, gel-like ‘scaffold’ materials are sometimes used as implants or dressings to deliver therapeutic agents such as drugs or other important biomolecules.
It is a big challenge to find the correct balance between biofunctional molecules and the physical properties of the scaffold materials. The approach being taken by the Wang group to meet this challenge represents an important step-change for the treatment of wounds.
They combine extracellular matrix biomolecules with a polymer-based system and have optimised the hydrogel microenvironment for supporting cells.
A molecule called hyaluronan (HA) plays a major role in the growth of cells and their extracellular matrix (ECM) in wounds. The Wang group have combined HA with their hyperbranched/knot polymer system (figure 1), leading the way for a new generation of hybrid hydrogels for tissue engineering.
Currently, they are using another technique to control polymerisation - reversible addition-fragmentation chain transfer (RAFT) - to make a poly(ethylene)glycol (PEG)-based highly functional hyperbranched copolymer (figure 2). PEG is often recognised as the gold standard for fabrication synthetic hydrogels and the team expect it to perform well in vivo.
This co-polymer is quite versatile and could be applied to numerous applications in tissue engineering. The Wang group have cross linked the polymer with a modified HA encapsulating adipose derived stem cells (ADSCs) to make a hydrogel network within a few minutes. They found that cells remained viable in the HA hydrogel (figure 3), suggesting that their multifunctional hyperbranched copolymer can be used as a backbone in constructing a 3-dimensional hydrogel scaffold for tissue engineering purposes.