The best-known examples for controlled, molecular-scale motion are biological motor proteins.

Experimental studies of biological molecular motors combine methods from molecular biology with protein structure analysis, and with single-molecule force measurements and advanced microscopy techniques. In recent years, these combined efforts have led to substantial progress towards the understanding of the workings of specific motors. Important biological questions have been answered, and a small number of motors is now understood in impressive detail. However, many other motors systems are yet to be explored, and it is not yet clear whether a unified description of the fundamental mechanisms of biological force generation will be possible.

Stimulated in part by these developments in biology and biophysics, in the past decade a new sub-field of statistical physics has developed that is concerned with directed motion in a stochastic, nonequilibrium environment. Models for the mechanism of molecular motors have been developed and help solving biophysical questions. In addition, this research impacts far beyond biophysics. A wealth of novel phenomena has been predicted, and some of these phenomena have been observed in areas as diverse as synthetic chemistry, bio-molecular colloids, self-organizing systems, quantum electronics, microfluidics, and materials science. Applications, such as novel actuators and molecular separation techniques, are evolving quickly.

Fueled by rapid advances in nanotechnology, this truly interdisciplinary research field has potential for significant developments in the near future. The solid theoretical basis, in combination with controlled and self-organized molecular assembly techniques, should allow the construction of artificial, bio-mimetic motors of nanometer dimensions in the near future.

In addition, solid understanding of the physics of controlled nanoscale motion is expected to feed back to biology and help answering biological questions. Researchers are also beginning to integrate biological motors with artificial nano-mechanical structures. Biological or synthetic motors may be used to power artificial devices, and artificial structures can guide and control the natural function of bio-motors. Areas of potential applications include lab-on-chip technology, drug delivery, and biotechnology.