**5. Use of different recombinant antibodies for specific applications**

To date, humans and mice remain the main source of complete antibodies for targeting diseases. However, with the aid of DNA technology, a number of new antibody fragments have been engineered as smaller single domain fragments to improve immunoassays, immunosensors and imaging probes in various applications. As described recently, the discovery of natural single heavy domain antibodies from camelids VHH and shark VNAR, and in addition lamprey VLRs offers some advantages over conventional antibodies. This range of natural antibodies is expected to open various applications: to trace molecule trafficking and to inhibit protein function inside the cell as intrabody, to apply them as therapeuticum and they can be used as detection units in biosensors or immunodiagnostics. In this section, we will review the deployment of different binders in specific diagnostic applications and to what extent these binders are used.
