Metabolic and proliferative cells activity on different substrates

Scaffolds for tissue engineering can be either natural or synthetic materials. The latter allow control of chemical, physical and mechanical properties and also provide support and shape, however they are not of biological origin, and therefore could not promote cell adhesion. This problem does not occur in natural materials however, they have the drawback of having non-suitable mechanical properties and tend to deteriorate too fast. In this work we study the influence of different substrate on the metabolic as well as proliferative cells activity. In particular 4 substrates have been considered: (i) medical grade StageFlexer (silicone elastomer), (ii) Polydimethylsiloxane (PDMS), (iii) PDMS with a layer of carbon nanotubes (CNT’s) and (iv) PDMS with a layer of ceramic whiskers. The results of both tests (metabolic and proliferative capacity) showed that the PDMS without any surface treatment, is the worst of the tested substrates. The reason is to be found in the fact that the PDMS is highly hydrophobic and therefore cells have low adhesion to the substrate. This represents a major limitation of PDMS and its functionalization is necessary to improve cell adhesion. Cells placed on PDMS samples with CNT’s show higher metabolic activity and proliferative capacity, compared to the PDMS and PDMS treated with fibronectin. However, the best outcomes have occurred with the PDMS substrate coated with ceramic whiskers.