Biotin PEG2 amine is used as a linker or cross linker. This allows to attach specific compounds to proteins or to antibodies.
A common use of biotin PEG2 amine is to use EDC and crosslink the amine in the biotin PEG2 amine to carboxyl groups on protein residues that are either aspartate or glutamate or the carboxy-terminus of proteins.
A particular example of use is labeling red cells, which in turn allows for the detection of these labeled cells in small samples using flow cytometry.