Development of an antibody-binding modular nanoplatform for antibody-guided targeted cell imaging and delivery

A polyvalent antibody-binding lumazine synthase protein cage nanoparticle (ABD-AaLS) is constructed by genetically fusing lumazine synthase and antibody-binding domains. ABD-AaLS effectively captures targeting antibodies in an orientation-controlled manner by selectively binding to the Fc region of antibodies derived from a variety of species, such as rabbits, rats, and mice, on demand by simple molecular recognition. The resulting antibody/ABD-AaLS non-covalent complexes specifically recognize and bind to their target cells in vitro, guided by antibodies displayed on the surface of ABD-AaLS. ABD-AaLS has an additional internal cavity and exterior sites for encapsulation and attachment of cargo molecules such as drugs and diagnostic probes. ABD-AaLS effectively serves as a universal antibody-binding nanoplatform to display various targeting antibodies on demand through molecular recognition as well as to acquire additional functionalities without altering the essential properties of the targeting antibodies. ABD-AaLS may provide new opportunities to develop versatile target-dependent nanoscale theranostic systems.