When working with biological material, homogenisation is frequently a prerequisite for analysis. To homogenise minute amounts of tissue samples, e.g. isolated cells or very small core cylinders or biopsy samples, homogenisation by repeated freezing and thawing is frequently employed. Since this is often insufficient for the complete disintegration of the tissues, micro homogenisers must be used. Eichner (1966) has devised the micro-homogeniser shown in Fig. 1, made from a loop of Nikrothal wire (AB Kanthal, Halsthammer, Sweden); the wire has a diameter of 60 or 35 μm. To make the homogeniser, a piece of wire is bent into a loop, inserted into a thin polyethylene tube, and fixed there with quick-setting cement (e.g. Harvard glass wax1). The top of the loop is then bent to a fine point using a fine watchmaker’s forceps, and the whole loop is twisted once round in the process. The loop is connected to a motor (dentist’s drill) by two polyethylene tubes which fit suitably into each other. One is pushed firmly onto a small milling cutter in the handle of the drill to form a mounting, and the wire loop is inserted into the other (see Fig. 1). Homogenisation is performed under a strong lens or a stereomicroscope, so that the hand piece of the homogeniser can be fixed to a firm support in the position desired. The sample of tissue in the capillary can be held firmly on the stereomicroscope table by means of a simple holder (e.g. plasticine). The high elasticity of the wire makes centering of the individual components unnecessary.
KeywordsPolyethylene Tube Wire Loop Repeated Freezing Hand Piece Pyrex Glass Tube
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