Molecular analysis of animal and plant cells is facilitated by their attachment to collodion (cellulose nitrate) films.

A procedure for the efficient transfer of cell monolayers, cultured on glass coverslips, to microscopy slides has been developed. This technique involves the coating of the upper surface of an ethanol-fixed cultured cell layer with a film of collodion dissolved in n-amyl acetate. The dry collodion-coated cell layer can then be detached by rehydrating it for 1 h under water or phosphate-buffered saline and then carefully peeling it away from the coverslip using a pair of tweezers. Once a cell layer has been so mounted, it can be subjected to rough treatment such as proteolytic degradation (which greatly improves the signal-to-noise ratio in procedures like in situ hybridization [ISH] or primed in situ synthesis [PRINS]) without running the risk of cell detachment because of the partial or total degradation of the extracellular matrix. As an example of its application, we show a PRINS of telomeres from mouse fibroblasts. The high mechanical strength of collodion ensures that the structural integrity and morphology of the cell layer is maintained under experimental conditions where the collodion itself is insoluble. In addition to its use on cell layers, collodion can be used for the production of support films for (i) attaching suspension cell cultures, (ii) immobilizing cells normally cultured in suspension (such as tobacco BY2 cells or germinating tobacco pollen grains) or (iii) planting cryostat sections to microscopy slides. The value of this technique lies in its ease of use and the large number of different applications, in both the plant and animal fields of research, to which it may be applied.