Table 2.
Summary of the most common methods of activation for inorganic supports.
| Activation Method | Support Reactive Group | Protein Reactive Group | Type of Bond | Bond Stability | Cost of the Reagents | Molecular Spacer |
|---|---|---|---|---|---|---|
| Cyanogen bromide | -OH
-NH2 |
-NH2 | Isourea or imido-carbonate | Low | Moderate | Very short |
| Cyanuric chloride | -OH
-NH2 |
-NH2 | Secondary amine | High | Low | Medium length |
| Sulfonyl halides | -OH | -NH2
-SH |
Secondary amine or thioether | High | Moderate/high | None |
| Acyl halides | -OH | -NH2 | Carbamate | High | Moderate/high | Very short |
| Thionyl chloride | -COOH | -NH2
-SH |
Amide/thioester | High | Low | None |
| Metal halides | -OH | -SH | Metal bridge | Moderate | Moderate | Very short |
| Glutaraldehyde | -NH2 | -NH2 | Secondary amine | High | Low | Long |
| Carbodiimides | -COOH/
-NH2 |
-NH2/
-COOH |
Amide | High | High | None |
| Divinylsulfone | -OH
-NH- |
-SH
-NH2 |
Ether/Secondary amine/thioether | Good (at neutral pH) | Moderate | Medium length |
| Benzoquinone | -OH
-NH2 |
-NH2
-SH |
Anilinyl | High | Low | Medium length |
| Disuccinimidyl suberate | -NH2 | -NH2 | Amide | High | High | Long |
| Succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate | -NH2 | -SH | Amide
Thioether |
High | High | Long |
| 2-2'- and 4,4'-Dipyridyldisulfide | -SH | -SH | Disulfide | Moderate | High | Very short |
| 1,6-Bismaleimidohexane | -SH | -SH | Thioether | High | High | Long |
| Carbonyl diimidazole | -OH | -NH2 | Carbamate | Moderate | Low | Very short |
| Diazotization | Aromatic-NH2 | Aromatic -OH | Azo bond | High | Moderate | Medium |
| Epichlorohyridin | -OH
-NH2 |
-NH2 | Secondary amine | High | Low | Short |