Slender
protein microtube motors with a catalase interior surface
are self-propelled in aqueous H2O2 by jetting
O2 microbubbles from the open-end terminus. Immobilization
of a catalase biocatalyst on the internal wall is achieved using avidin–biotin
complexation. It is particularly interesting that the migration of
O2 bubbles in the 1D channel and their subsequent expulsions
were clearly visible because the tube walls are transparent. The microtube
motor velocity reached a maximum at the optimum pH and temperature
of the catalase. Furthermore, the microtubes were digested completely
by proteases, showing sufficient biodegradability