Bis-peptides are analogues of peptides, but consist of bis-amino acids, which bear two carboxyl groups and two amino groups. The connection of specific bis-amino acids leads to the formation of bis-peptides with well-defined molecular shape, which is of great interest for designing nano-structures.
Possible applications that are currently investigated, include the binding and inactivation of cholera toxin and the cross linkage of surface proteins of various viruses (HIV, Ebola virus). Further the group of Christian Schafmeister developed molecular hinges, which can be used for the construction of molecular machines, such as nano-valves or data storage systems.
See also 
Levins CG, Schafmeister CE. The synthesis of curved and linear structures from a minimal set of monomers. Journal of Organic Chemistry, 70, p. 9002, 2005. doi:10.1002/chin.200605222