Laser Microdissection | Laser Microdissection
Key Words: Laser, motorized microscope
Definition:Laser microdissection is a microscope-based technique that uses a laser to isolate specific groups of cells, individual cells, or cell organelles, from embedded, frozen or fresh tissue sections
With suitable software, an area, or multiple areas of interest, in a specimen under the microscope may be outlined using a mouse or screen pen, dissected using a laser, and isolated safely for further analysis in a contamination-free environment. There are a variety of laser dissection technologies commercially available, which may differ in the software-user interface, the type of laser used for dissection, and the method of tissue isolation. Key factors in selecting a microdissection system include, easy navigation and high precision definition of areas of interest, contamination-free tissue isolation, and preferably, cold laser technology to avoid exposing tissues to heat or radiation that could damage cells.
Microdissection is a well established technology in molecular pathology, cell biology, oncology, and forensic medicine, where minute samples need to be isolated from surrounding materials for contamination free analysis. For example, histological examination of tumor specimens shows that most tumors are composed of mixed cell populations: as well as cancerous cells in various forms of development there may be, for example, normal cells, inflammatory cells and blood vessels. One of the greatest problems in studying tumor development is that it has been traditionally very difficult to isolate only DNA/ RNA from cancerous cells - reducing both the sensitivity and accuracy of any genetic analyses. One solution is to pre-select and isolate only cells of interest using laser microdissection.
Automated laser microdissection requires a computer controlled microscope coupled to a video imaging system with appropriate software and drawing tools.
In this system, specimens are mounted on membrane-covered frame and a glass slide is placed on top effectively protecting the sample against contamination. Cells are cut out automatically with a high precision cold UV laser and cleanly removed using a special isolation cap that has no direct contact with the specimen. An unlimited number of different groups can be defined for cutting. A group statistics function provides information about the number of areas, size and status of the objects. Adjustable laser parameters such as focus, energy and speed allow users to choose optimum laser parameters for each application.