Aluminium and mica azide surface functionalization

Abstract

Aluminium and mica (muscovite) plates have been functionalized with azide groups by a protocol which includes (3-chloropropyl) trichlorosilane modification followed by chlorine atom nucleophilic substitution by azide. The azide groups have been transformed to dimethoxytrityl (DMT) ones by [3+2] azide-alkyne cycloaddition reaction. This made it possible to determine their number per surface unit photometrically, based on the absorption of the DMT cation. The functionalization method allowed to achieve high surface load of the materials by azide groups, which was 2.2 and 2.7 nm-2 for mica and aluminium, respectively. The mica plates have been additionally functionalized by 25 kDa branched polyethylenimine. The samples have shown a capability for adsorptive nanoand microobjects immobilization. The feature could be useful for atomic force microscopy, which have been demonstrated with erythrocytes and exosomes.