Laser Capture Microdissection is defined as the precise cutting of microscopic tissue area using a laser and the subsequent separation of the dissected area from surrounding tissue. Importantly, laser dissection microscopes differ in the particular method to isolate target cells after cutting. MMI for example isolates cut tissue by employing adhesive isolation caps, which gently and reliably take up the sample of any size and shape.
What is laser capture microdissection?
Laser Capture Microdissection
is defined as the precise cutting of microscopic tissue area using a laser, and the subsequent separation of the dissected area from surrounding tissue. Terms such as Laser Microdissection, Laser-assisted Microdissection, Microdissection, Laser Capture or Laser Dissection are used synonymously and describe the same method.
The first commercial laser microdissection microscopes have been developed and built in the late 1990s to early 2000s, based on the research by Michael R. Emmert-Buck and his colleagues at the National Institutes of Health and the National Cancer Institute (Bethesda, Maryland, USA). The following years, the technology has been further improved to allow for more flexible and automated workflows, for easier handling as well as for more reliable and precise cell isolation. Therefore, also the isolation of single cells from samples such as tissue sections, smears or live cell culture is now possible. Intriguingly, single cell sequencing technologies have emerged over the last decade which now enable molecular analyses of single cells isolated by laser capture microdissection. Single cell transcriptomics or proteomics methods have been established and improved to shed light on various molecular mechanisms in individual cells.
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This video shows a typical laser microdissection workflow:
How does laser capture microdissection work?
Typically, laser capture microdissection systems are based on research microscopes. Lasers are required to precisely cut tissue on this microscopic scale, and they are coupled into the optical paths of the dissection microscopes. For cutting, the sample is mounted on membrane slides to enable both for precise cutting and for subsequent cell isolation procedures.
The laser microdissection microscopes on the market today mainly differ in the laser types they use and how the laser is applied to cut the sample. The MMI CellCut
uses a low-damage laser with low power but high pulse frequency to allow for efficient and precise cutting and to not compromise tissue integrity. Moreover, the laser is fixed during the cutting process to ensure that the laser is always in focus and the sample is efficiently cut.
Importantly, the laser dissection microscopes differ in the particular method to isolate target cells after cutting. MMI for example isolates cut tissue by employing adhesive isolation caps, which gently and reliably take up the sample of any size and shape.
1. Sample Preparation: The tissue sample is first prepared for microdissection by fixing, embedding, and sectioning it into a membrane slide that is inert and has negligible autofluorescence. Afterwards, the membrane slide is inverted and placed onto a glass slide for protection against contamination.
2. Cell Selection: The cells of interest can be selected on the computer screen using either the mouse, by freehand or by predefined geometrical shapes. Any number of cells across the slide can be identified as targets within one screening process.
3. Laser Cutting: Once the region/cells of interest have been identified, the laser is focused on the selected area. The thin laser cutting path enables a precise and gentle extraction at an outstanding speed.
4. Collection & Inspection: The isolated target cell is collected by an adhesive cap. The orientation and morphology will be maintained. After cutting the cell can be visualized on the cap.
5. Ready for Downstream Processing: After microdissection, the collected cells can be processed further for any downstream application (e.g. gene expression analysis, RNA isolation and much more)
What applications does laser capture microdissection have?
Laser Capture Microdissection offers a huge range of applications since a plethora of different sample types can be processed. Several applications are originating from pathology where diseased tissue is separated from healthy tissue for molecular analysis to be able to make a better diagnosis, as this is often the case for highly heterogeneous tumor tissue. Since any type of human tissue, even bone tissue, can be cut by laser dissection, laser capture microdissection is widely applied in cancer research, oncology, neurology, infection research, immunology, stem cell research, developmental biology and many other research areas in biomedicine. Importantly, laser microdissection adds spatial information to the molecular data of individual cells thus providing an extra dimension to omics research.
Moreover, laser capture microdissection is also a valuable tool in crop science and plant research as this technology is able to cut different types of plant tissue. In addition to basic and clinical research, laser capture microdissection is applied in diagnostics and also in forensics. Thus, laser capture microdissection is a very versatile technology with a tremendous range of applications.
How efficient is laser capture microdissection for single cells?
The laser capture microdissection technology has improved over the last year to make the cutting process more reliable and more precise. Thus, also single and rare cells can be excised from tissue sections, living cells or smears and swabs.
Interestingly, the MMI CellCut microdissection microscope is highly optimized to specifically cut single cells. The low-damage laser allows to cut single target cells without impairing their DNA or RNA quality, or the integrity of living cells. To be able to cut single living cells, MMI also offers a range of dedicated consumables. Thus, physiological conditions and contamination-free handling is supported throughout the experiment.
Intriguingly, the patented adhesive cap technology used by the MMI CellCut allows to keep the tissue in position during cutting. Thus, excised tissue cannot drop off because of airflow or static forces, a phenomenon that often occurs with dry sample of very small sizes such as single cells. Moreover, the different objectives and fluorescence filters implemented in the laser dissection microscope can be combined and optimally employed to identify and select single target cells. Image analysis tools integrated into the MMI CellTools software package allow to find even very rare cells in the sample.
Which laser capture microdissection solutions does MMI offer?
The MMI CellCut dissection microscope by MMI is a very flexible tool to isolate single cells from various sources. The MMI CellCut system is integrated on inverse microscopes such as the Nikon Ti2E or the Olympus IX83 and can use all objectives and fluorescence filters compatible with the microscope.
The MMI CellCut is employing a fixed, low-damage laser to precisely cut even single living cells without compromising their integrity and viability. To reliably and gently isolate single cells from tissue sections in a contamination-free way, the MMI CellCut applies adhesive isolation caps. This unique and patented laser “CapSure” dissection technology is able to prevent excised tissue from flipping away due to static forces or air flow induced by air condition or open doors.
Intriguingly, the MMI CellCut can be integrated with all MMI systems (MMI CellScan, MMI CellEctor, MMI CellManipulator) onto a single microscope platform to build a unique and versatile set up to combine single cell isolation, micromanipulation and imaging.
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