reconstructed from polymer-crosslinked actin muscle protein (“giant-actin”) and analogously modified myosin has been built by Osada and co-workers. The “giant-actin” gel filaments (several 1000 times larger by volume than native actin) move along their myosin counterparts as fast as native F-actin. Such machines should work inside their body of origin without eliciting immunoreactions. (Y. Osada et al., August 16, Adv. Mater. 2002, 14, 1124-1126)