Nanobodies are recombinantly produced antigen binding domains derived from heavy-chain-only antibodies that naturally occur in camelid species and some cartilaginous fish. Physicochemical properties of these small, single-domain antibodies made them a useful tool for researchers in various disciplines of biology. The nanobody technology has revolutionised the field of protein structural biology assisting structure determination of important membrane transport proteins, like G-protein-coupled receptors (GPCRs). Nanobodies are ideally suited for non-invasive cancer imaging and some are currently in phase III clinical trials for various human diseases.
The main advantages over conventional antibodies is in much smaller size and solubility that reflects in superior tissue penetration, excellent thermal stability, and ease of expression and selection in vitro, whilst maintaining the same binding affinities as conventional antibodies. In addition, nanobodies are often able to recognise epitopes which are not accessible to conventional antibodies.
Nanobodies can be produced and manipulated in vitro to suit the needs of many different applications which range from immunohistochemistry, live imaging, pull-down assays, functional analysis of protein-protein interactions, modulation of protein functions in the cell, or as mediators of specific protein knock-out. Highly diverse nanobody libraries also offer a powerful high-throughput tool for development of diagnostic tests.