Spatially confined cell growth for biological experiments

Dipl.-Phys. Ronald Werner

Cell-cell communication (Bystander effects) after low dose irradiations is mostly unknown. There are two possibilities: direct cell-cell-communication via gap junctions and cell-cell communication via media. For the investigation of these effects the compartment- alization of Petri dishes is a good way to exclude the direct communication. AGAR, a water-insoluble, cell repellent polysaccharide was applied to the surface of Petri dishes, silicon nitride (Si3N4) irradiation windows, and multi-electrode-arrays. The compart- mentalization was achieved by proton beam writing. This irradiation destroys the polysaccharide into water-soluble monosaccharides. Irradiated parts were developed in PBS solution. Seeded cells could only adhere in the areas were the AGAR was removed. The rest is removed via cleaning with PBS or medium. With a new exit nozzle we can irradiate the Petri dishes in air. This allows us to increase the production of structured Petri dishes per hour signifi- cantly. Now we are able to produce structured Petri dishes with a maximum size of 2 x 2 mm2 with an accuracy of <2 µm.

Figure 1: Confined cell growth on a multi electrode array in four areas, of which the two left are connected (image size 1.8 x 1.8 mm2).

With proton beam writing we are able to create any possible two dimensional structure. For further biological research, multi-electrode-arrays were structured (see Fig.1). This allows impedance spectroscopy of the cells in the four areas after a selective targeted irradiation of cells in just one area. We want to study whether the cellular response of unirradiated cells depends on the signaling via direct cell-cell-communication.

We gratefully acknowledge the finacial support by the NOTE IP 036465 (FI6R), Euratom specific programme for research and training on nuclear energy, 6th FP of the EC.

Literature:
S. Rohr et al.: Eur. J. Physiol. 446, 125 (2003)