The PALM MicroBeam System from P.A.L.M. Microlaser Technologies AG, enables the microdissection and microablation of cells and tissue fragments on a microscopic scale and with single micrometer resolution. The system allows for the non-contact capture of large cell areas, small cell clusters, single cells and chromosomes. Basically, the whole procedure consists of two stages, laser microbeam microdissection (LMM) followed by laser pressure catapulting (LPC). Once the desired region is dissected from the surrounding tissue by nitrogen laser beam (LMM), another strong laser is used to catapult (LPC) the microdissected material directly into the tube cap used as a collection vessel.
Together with our collaborators at the Free University in Berlin, we aimed to apply a microgenomics approach to investigate alterations of gene expression profiles in the glomeruli of rat kidney during the course of hypertension development. To achieve this goal, the isolation of pure glomeruli tissue was necessary. We decided to use the PALM system due to a number of technical advantages it possesses compared to other devices on the market. The PALM system allows for the microdissection of tissue without allowing the biological material to contact the device, thus preserving the tissue integrity. In our case this feature was extremely important since we used isolated tissue for RNA isolation and subsequent microarray hybridisation. Another important element was an option for the automation of the dissection and ablation process. In order to obtain enough material for RNA recovery, we had to isolated hundreds of glomeruli, which would be extremely tedious using manual processing. In addition, in contrast to other manufacturers, no special tube caps are necessary for collection of dissected tissue. This in turn allowed us to decrease the costs of large-scale experiments. The software for operating of the system is user-friendly and does not require weeks of training. It allows, for example, a user to define a number of different tissues areas, which are then automatically dissected and ablated in a defined sequence. So far we have not encountered any technical problems with the system, partially because of the good technical support from P.A.L.M., which has helped us several times by phone.
The only real disadvantage of the PALM system, which is inherent to this kind of device, is its price. Therefore the best way to acquire such a system is to create a central microdissection facility where several groups or departments financially contribute to the endeavour.
For those researchers who plan to enter the field of microdissection or microgenomics, I would suggest to considering the PALM system. It has a number of micromanipulation possibilities, some of which are unique. For example, it allows for the manipulation of living cells and chromosomes. Moreover, the non-contact dissection technique and its automation greatly facilitates cell-type specific gene expression studies.
Michal Janitz, M.D.
Max Planck Institute for Molecular Genetics
Berlin, Germany