A porous polymer scaffold for tissue engineering, which has tuneable cell adhesion, has been developed by Swedish and Belgian scientists.

The researchers, led by Filip Du Prez at Ghent University, Belgium, used a porous polymer gel that is compatible with biological systems and modified the pores with another polymer to which cells can easily attach and detach. The scaffold is very elastic and can restore its shape by up to 90 per cent after deformation.

According to Du Prez, pores are very important in a tissue engineering scaffold 'to provide room for the cells to grow and for transport of oxygen and nutrition'. The cells need to be able to invade the scaffold and bind strongly.

Using a method called cryogelation, Du Prez's team made poly(2-hydroxyethyl methacrylate) (pHEMA) in the form of a macroporous hydrogel at sub-zero temperatures. pHEMA is a biocompatible polymer and has been used as a cell scaffold in the past. 

Du Prez and colleagues made the surface even more biocompatible by modifying the pores with another polymer, poly(N-isopropylacrylamide) (PNIPAM). Using a technique called atom transfer radical polymerisation to graft PNIPAM to the inside of the cryogel pores allows the amount of deposited polymer to be controlled. Du Prez's group chose PNIPAM because it is thermoresponsive. Cells can attach and detach with changes in temperature making it a tool for tuning cell adhesion to the cryogel.

Du Prez hopes to extend the technique further to make 'cryogels with controllable porous structure and mechanical properties, using biopolymers such as collagen, fibrinogen and gelatine'. 

Sophia Anderton