Figure 1

Different bioconjugation schemes. From left to right: disulphide bridge (X = S) or sulphur-metal bond (X = metal); chemical crosslinking: for example here the homo-bifunctional crosslinker glutaraldehyde binds an amine group at each end, one on the substrate surface and one on a (protein) molecule to be attached; antibodies that are themselves immobilized on a surface can recognize a specific peptide tag on a protein molecule and can thus serve to tether the protein to the surface; biotinylated bovine serum albumin (bottom dark green oval; biotin in light green) adheres non-specifically to a substrate surface and can anchor streptavidin protein molecules (grey) via receptor-ligand interactions, which in turn can bind biotinylated molecules (blue double circle); particles tagged with single stranded DNA (ssDNA) can be attached to a surface carrying the complementary ssDNA via selective DNA strand annealing.