Electron Microscopy Laboratory

Microscopy provides images of the very small, down to the nanometer scale, and for analysis of molecular and elemental composition. The EML (Electron Microscopy Laboratory) offers the tools and technical expertise for research and training in microscopy with both light and electron microscopes. We maintain and operate three electron microscopes (two transmission and one scanning electron microscope), a confocal laser scanning microscope, and the ancillary equipment needed for the preparation of specimens for EM and other microscopy. Our multiple light microscopes encompass optics for bright-field, phase-contrast, differential-interference, and fluorescence imaging. Conventional electron diffraction at a range of camera lengths can be accomplished with the TEMs.

Users of the EML can opt for full technical services in microscopy, so that they are provided with whatever micrographs and analyses are needed for given specimens; or users can work independently on the EML’s microscopes and specimen-preparation equipment following appropriate training by the EML’s staff. Technical service is available for any microscopy-related tasks, such as specimen preparation, microscope operation, and photography.

Courses through the EML staff and the School of Biology and Ecology, where the EML is housed, offer graduate- and upper-undergraduate-level training in the operation of electron microscopes, techniques of microscopy, and analysis of biological ultastructure. Individual tutorials on operation of the EML’s equipment can also be arranged.

For more information contact Kelly Edwards, Electron Microscopy Lab Managerat 11 Murray Hall. Phone: 207.581.2566 Email: edwards@maine.edu.

Technical Services

  • Microscope operation—full operation of all electron and light microscopes.
  • Specimen preservation by chemical and microwave-enhanced fixation.
  • Specimen embedment in media suitable for TEM or light microscopy.
  • Critical-point-drying of specimens for SEM.
  • Metal coating of specimens by evaporative or sputter technology.
  • Consulting on techniques of microscopy.

Transmission Electron Microscopes (TEM)

Transmission Electron Microscopes (TEM) for thin, thin-sectioned and nanoparticulate specimens.

Philips/FEI CM10 a high-resolution instrument (point resolution 0.5 nm; lattice resolution 0.3 nm) suitable for studying materials-science as well as biological specimens because of its ultra-clean vac-ion pumping system and capacity for low-dose imaging. It is equipped with a eucentric goniometer specimen stage allowing tilting through 120 degrees (+/- 60 degrees), and rotation of specimens as they are viewed. A heated stage is also available. Magnification power is in the range of 20X to 510,000X; choice of accelerating potentials between 40 kV and 100 kV. Imaging can be in bright-field mode or dark-field mode (with tilting of the beam about a single plane or through a conical configuration), and electron-diffraction mode (micro-diffraction) operates with camera lengths of from 20 to 9000 mm. Images can be captured using either conventional film, or with a Gatan Orius Model 830 digital camera system.

Philips/FEI EM201a moderately high-resolution instrument for standard TEM viewing and selected-area electron-diffraction. With its conventional oil-diffusion-pumped column, it is versatile especially for conventional biological specimens. Magnifications between 1500X and 200000X are available. Users new to TEM and students in the available course are initially trained on this instrument. Image capture is via conventional photographic film.

Scanning Electron Microscope (SEM)

Scanning Electron Microscope (SEM)for imaging of bulk specimens.

AMRay 1820 has a resolution of 5 nm, a magnification range of 20 – 150,000X and an accelerating voltage range of 100 V to 30 kV. Its specimen stage is a eucentric goniometer, meaning that the specimen can be tilted and rotated about the viewing axis. Dynamic focusing accommodates imaging flat specimens. Image capture is fully digital using an iXRF digital-capture system. The microscope is fitted with a high-performance Robinson backscatter detector, and an iXRF EDS system for elemental identification and mapping, in addition to the standard secondary electron detector.

Zeiss NVision 40 FIB/SEM has a resolution of 1.2 nm, a magnification range of 20X – 600,000X and an accelerating voltage range of 100V to 30KV. It has a six axis eucentric goniometer stage, and multiple detectors including secondary electron, backscatter electron and inlens secondary electron. The microscope is equipped with an EDAX EDS system for elemental identification and mapping. 

The FIB has a SIINT zeta Ion Column with ion beam resolution of 4 nm at 30KV, an accelerating voltage range of 3KV to 30KV, and a four channel Gas Injection System. 

The NVision 40 is also equipped with;

  • Bal-Tec VCT 100 Vacuum-Cryo-Transfer System, with associated cryo-preparation/loading stage, and Bal-Tec SCD 500 sputter coater and QSG 100 Thickness Monitor
  • Kleindiek  Micromanipulator System
  • Raith ELPHY E-beam Lithography System

Confocal Laser Scanning Microscopy (CLSM)

Confocal SM Lab equipmentConfocal Laser Scanning Microscopy (CLSM) for optically sectioning thick fluorescent specimens.

Leica TCS SP2 Confocal Microscope — equipped with three lasers (Ar, green HeNE, and red HeNe) with available wavelengths of 457-477 nm, 488 nm, 514 nm, 543 nm, and 633 nm.



Microtomes and Ultramicrotomes EquipmentMicrotomes and Ultramicrotomes EquipmentMicrotomes and ultramicrotomes — for cutting specimens for both light and electron microscopy. The EML has a suite of four ultramicrotomes—a Leica EM UC6 and three Sorval MT2B ultramicrotomes—for cutting thin sections (40 to 90 nm) for electron microscopy.  Additionally, the EML maintains a Sorval JB4 equipped with a Butler trough for serially sectioning resin-embedded specimens for light microscopy (at thicknesses from ½ to 2 μm). All of the microtomes can used with either glass or diamond knives.

Light Microscopes

Light Microscopes Both compound and dissecting microscopes are available. An Olympus BX41 compound microscope is fitted for standard bright-field, phase-contrast and dark-field imaging. An Olympus SZX16 dissecting microscope is fitted for reflected light, as well as bright-field, oblique, and dark-field illumination from its integral LED stand. Both microscopes are fitted for digital micrography using Zeiss Axiocams.

Light Microscope Image

Light Microscope ImageLight Microscope Image

Specimen Drying

Critical–point dryer for drying SEM specimens without subjecting them to the distorting forces of surface tension. 


Metal Coating

Metal coating by sputter-coating and vacuum evaporating such metals as gold, gold-palladium, platinum, chromium, aluminum, and carbon. Sputter-coating is typically used for the preparation of SEM specimens, while vacuum evaporation is used for shadowing and producing conductive thin-film supports for TEM.