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"Solvent-free tissue processing using super-critical CO2"


Aims:  Xylene is most often employed in tissue processing protocols for paraffin embedding, but poses a health hazard. Here a solvent-free processing protocol is described using supercritical carbondioxide (scCO2) as an intermediate.

Materials and Results:  Series of tests (with bovine tissues) were run evaluating the dehydration and tissue shrinkage in our new scCO2-based protocol compared with routine processing using a graded ethanol and xylene series. Then a series of tests was run to evaluate the significance of processing parameters on the outcome. Finally, a validation series was performed using optimal conditions, testing various human tissues with several staining methods. The tissue water content after paraffination was the same using our new scCO2-based and routine xylene-based protocols. Tissue shrinkage was comparable using the 2 methods, around 15%, which is also comparable with the literature. In the validation series, the human tissues showed good morphology with strong staining probably based on stronger antigenicity.

Conclusions:  This scCO2-based protocol is concluded to be a good solvent-free, alternative form of tissue processing. Although not the focus of this paper, this new protocol can process tissues within 4 hours, without the need to change macroscopy/sectioning protocols.

© 2012 Blackwell Publishing Ltd