Sample Preparation

Tissue processing, especially common in histology labs of any modern hospital, aims to prepare biological tissue for imaging by electron or light microscopy. Additional stains or mounting techniques can be considered once the sample has been fixed, dehydrated, embedded, and sectioned.

Standard processing (formalin fixed, paraffin embedded / FFPE) is considered for most tissue, but special consideration will be taken for projects which require alternative methods (such as fatty tissue preservation, delicate samples, or electron microscopy).

Microscopy Core Facility staff will assist in some or all tissue preparation as needed. For high volume tissue processing or alternative methods, contact us for pricing.

Chemical drying through a Hexamethyldisilizane (HMDS) series is preferred for samples to be analyzed through SEM at high magnification. As with tissue processing, MCF staff can assist in chemical protocols.

A more cost-effective alternative can be applied by MCF staff through Critical Point Drying (CPD). The physical properties of carbon dioxide (among other gases) allows for a 'supercritical fluid' to replace all liquid in the sample at high pressures, leaving a completely dry sample once returned to atmospheric pressure. For drying small samples in high volume, this is often the best option for researchers looking for replicable results, and has the added benefit of being sustainable.

Metal sputtering of samples is standard to facilitate charge distribution of an electron beam. Scanning electron microscopy typically is performed on sputtered biological tissue to prevent damage from the beam and produce high-quality images. Currently, the MCF uses both gold and silver targets to coat samples - though other metals are available on request for special purposes.

Carbon coating, a great option for elemental analysis with SEM-EDS, is also available with our neighboring Department of Environmental and Geosciences. The carbon coating provides a lesser charge distribution than the metal sputter, though necessary in cases where heavy metals will obscure resulting spectra.

Microtomy for paraffin embedded tissue (or Ultramicrotomy of resin for electron microscopy) available within the MCF. Sectioning aims to produce thin and ultra-thin sections for transmitted light microscopy and reveal intricate detail at a cellular level. Training for microtomy is also available to students on request, and may prove useful for students looking for a career in pathology or for work in a histology lab.