Homobifunctional Crosslinkers

Homobifunctional reagents represent some of the most common and fundamental crosslinkers available for bioconjugation. This chapter describes the properties and reactivities of crosslinking compounds that contain identical reactive groups on both ends. The chapter is divided into sections based upon the functional group reactivities of each reagent type, such as amine-reactive, thiol-reactive, carbonyl-reactive, and nonspecific photoreactive compounds. The crossbridges of these reagents also can be designed to provide permanent or cleavable bonds or, hydrophilic or hydrophobic properties, or to make available long or short linkages between molecules. Homobifunctional crosslinkers have been used for decades to form protein conjugates, capture protein interactions within cells, and to immobilize affinity molecules onto solid-phase supports.