Applied Neuroscience
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Microdialysis Probes Assembler (SS-model)
Supplementary instructions to diagrams

This device is designed to reduce drastically the time required to prepare microdialysis probes. Optimum time-saving is achieved when the Assembler is used with our partially-assembled probes (see corresponding section).

The following instructions are intended for the preparation of a batch of 5 probes. However, we recommend that you prepare one or two probes at a time to start with, until you have become familiar with the system, in which case it is advisable to wait 5 to 10 minutes after each application of epoxy glue to allow it to set.

Most of the following steps should be performed under a stereomicroscope (we recommend x 20 magnification).

1.  Insert the supplied probes into the slots in the silicon rubber, as shown in Fig.1 (step 1) of the accompanying diagrams.
    2.  Place the metal spine (probe holder) supporting the silicon rubber into the slot on the base as shown in Fig.2.

    3.  Snip off the excess silica tubing (single silica tubing corresponding to the dialysis fibre end).
    Note: If you plan to use only one length of dialysis fibre (e.g. 2 mm), please specify it in your order. Supplying you with specific silica tubing circumvents this step. We normally allow an extra 0.25 to 0.5 mm silica tube length to compensate for the part covered by the epoxy (see step 4).

    4.  Slide the dialysis fibre over the silica tube and into the stainless steel tube. Push in gently until you meet resistance (Fig. 3).

    5.  Dispense two small equal quantities of epoxy adhesive and hardener, and mix thoroughly. Using the white needle, apply a small amount of the epoxy to the point of entry of the dialysis fibre into the stainless steel tube (Fig. 4). As the needle will be reused, wipe immediately the remaining epoxy off the needle with disposable tissue.

    6.  Slip the stainless steel tubes over the silica tubes. First slip the short stainless steel tube over the short silica tube (outlet), then secure it in position by pressing into the blue tack. Repeat this procedure with the long stainless steel tube (inlet). Leave about 1 mm between the ends of the stainless steel tubes; this should reduce the risk of 'shunts' (Fig. 5).

    7.  Mix another small quantity of epoxy and, using the white needle, apply a small amount of glue to the tips of the stainless steel tubes to make sure that the entry points of the silica tubes are completely sealed (Fig. 6). Then wipe the epoxy off the needle.

    8.  Mix a larger amount of epoxy and apply over the junction of the stainless steel tubes with the orange needle (Fig. 7). Then wipe the epoxy off the needle.

    9.  Lift the metal rectangle (i.e. the probe holder) and place it upside down on the perspex base.

    10.  Repeat step 5 to ensure that the entry point of the dialysis fibre into the stainless steel tube is sealed all around the tube.

    11.  Repeat step 8 so that the junction of the stainless steel tubes is completely sealed.

    12.  Turn the probe holder right-side up, and slot it back into position on the base.

    13.  Trim the dialysis fibre with the spring scissors, so that there is only 0.5 -0.75 mm sticking beyond the tip of the silica tube (Fig. 8).

    14.  Mix a small amount of epoxy and, using the white needle, apply a drop to the tip of the dialysis fibre. Capillary action will draw the epoxy into the fibre. Pull the needle away when the epoxy has gone nearly 0.25 mm into the fibre (Fig. 9). Wipe the remaining epoxy off the needle.

    15.  Leave overnight for the epoxy to set. Then, using the straight forceps with the round tip, grip the stainless steel body strongly, and lift out of the slot in the silicon rubber. The inlet and outlet tubes will automatically detach from the blue tack.

    With practice, 5 probes can be prepared easily within 35 min.