From molecular shuttles to directed procession of nanorings

Synthetic molecular shuttles prove that controllable nanoscale translation is possible in the curious shape of molecular rings encircling a linear track. However, a shuttle ring’s movement is limited between a pair of binding sites. Ring-locking may provide a molecular mechanism for implementing a major requirement for inchworm nanowalkers. Here we propose a nanowalker in the form of track-encircling molecular rings that is capable of directed procession along an unlimited track beyond molecular shuttles. A detailed molecular design for the walker is obtained by properly exploiting molecular mechanisms already realized in shuttle systems. A computer simulation using realistic parameters predicts major walker–track parameters for optimal performance of the walker. Several unique features of the proposed walker are discussed in comparison with previously suggested or realized motor systems.