Objectives and results of the second project year (01 Mar 2005 – 28 Feb 2006)

Whereas the first year of the CellPROM project was mostly dedicated to setting up an operational framework and deriving detailed specifications for the devices, the second year was characterised by first technical implementations of tools and modules and proof of principle experiments for the biological hypothesises. Suitable cell models had to be selected and evaluated ranging from cell lines easily to be handled - even by non-biologists -  (Caco-2 endothelial cells and fibroblasts) over primary cells with distinct differentiation and activation capabilities (monocytes and T-cells) up to adult stem cells with high differentiation potential (mesenchymal stem cells and pancreatic stellate like cells). Starting with simplified procedures to immo-bilise differentiation factors on standard surfaces, experiments have been carried out to clearly show that surface bound signal factors are able to stimulate differentiation.

For the further processing in the CellPROM device, both the cells and the immobilised factors had to be manipulated in a technological framework. Since suspension and adherent cells imply different handling strategies, two device concepts have been derived.

For the suspension cells, a fluidic lab-on-chip like system in combination with di-electrophoretic forces acting on both the cells and signal-factor-coated beads has been set up. The main focus of this period was the integration of a mechanical framework combining micro-fluidic periphery, electrical field generators, suitable high quality optical inspection and a new generation of chips with imprinting facilities. This is the first implementa-tion of the prototype capable to perform experiments to finally access some of the unknown parameters directly related to the cell models under study. The second step is the up-scaling of the chip and integration in the demonstrator. The design currently under realisation features six inlet channels and six outlets enabling the parallel processing of three cell types together with three differently coated beads.

The other approach is taking advantage of the tendency of the majority of cell types to adhere to suitable surfaces. It is based on flat carriers carrying the cells and being manipulated magnetically in a meso-fluidic channel system. The triggering of the differentiation process is done either by direct immobilisation of the signal factor on the carrier surface or by temporary contact of the cells with another flat surface carrying the factors. To prove the concept magnets and suitable manipulation systems had to be designed and built. It could be shown that complex trajectories can be followed by the carriers inside the system. The current focus is on the integration of periphery developed by different partners and the up-scaling of the system. In parallel biological experiments concerning the cultivation of cells on those carriers has been conducted ensuring the right combination of materials and production processes.