Using plasma discharges to chemically functionalise 3-D tissue engineeering scaffolds

Using low-pressure radio frequency sustained plasmas struck in allylamine and hexane monomers it has been possible to produce gradients in surface chemistry inside the matrix of porous polymer scaffolds (pore size from 10 to 250 microns). The deposition of hydrophobic hexane (ppHex) close the outer edge of the scaffold and hydrophilic allylamine (ppAAm) surfaces up to 10 mm inside have been used to guide biological cells (e.g. 3T3 fibroblasts) inwards, where they adhere and proliferate (D. Howard, et. al., 2006). The plasma diffusion processes leading to the penetration of chemical groups inside the scaffold are interpreted using a Knudsen diffusion model. Herein, we discuss the details of this plasma polymerisation technique and its usefulness in the development of 3-D engineering scaffolds for applications in cartilage and muscle regeneration.