A centrifuge head for back-and-forth centrifugation to improve specimen infiltration by viscous plastics

Abstract

For embedding of small pieces of tissue a special centrifuge head was designed for back-and-forth centrifugation of the tissue to speed up infiltration of the tissue by a viscous plastic which is poorly miscible with the solvent used for dehydration. The centrifuge head was designed in such a way that the tube holders flip between two positions with a difference in orientation of close to 180° by varying the speed. This way the tissue moves back and forth in the centrifuge tube with the surfaces of the pieces of tissue being exposed continuously to virtually fresh plastic. This way a steep concentration gradient solvent-plastic is constantly maintained at the surface of the tissue. This centrifugation—infiltration procedure is also useful whenever plastics of high viscosity are used even when the plastic and the solvent used for dehydration are easily miscible.