Agarose, cellulose, and Sephacryl solid phases

Sephacryl S-1000 may be suitable as solid phase, since this gel is more porous and may better accommodate larger complexes. 

Large batches of activated beads may be stored at — 20°C without appreciable loss of activity over prolonged periods. For the immobilization of haptens or small antigens on a solid phase spacer molecules. 

Particulate cellulose may also be activated with NBPC by a method similar to that for the activation of paper (Section 13.3.3 Fig. 13.4). Gurvich et al. (1961) and Hales and Woodhead (1980) described a somewhat different method 5 g cellulose are suspended in a Petri dish in a mixture of 0.5 g sodium acetate in 2 ml water and 1.4 g NBPC (BDH or Sigma) in 18 ml of ethanol. The slurry is dried in an oven at 70 C and subsequently for 40 min at 125 C. The pale brown nitro-derivative is washed on a sintered glass funnel 3 times with 200 ml benzene and sucked dry. The nitro groups are reduced as in steps 5-7 of Table 13.8. The resulting cellulose is dried and pulverized in a mortar. 

Antigens bound in the interior of the cellulose are often inaccessible to IgG conjugates. 

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