Amphiphilic constructs with accessible, nanometer-size cavities can enable selective encapsulation, separation, and purification of nanomaterials and biomacromolecules on a similar length scale. We have developed a new method for the fabrication of amphiphilic organic nanotubes from multicomponent bottlebrush copolymers with triblock terpolymer side chains. The obtained nanotubes were demonstrated to be very effective and highly selective carriers for positively charged molecules and nanometer-size macromolecules by means of liquid liquid extractions. Unprecedented discrimination between dendrimers with about 2 nm size differential was achieved.