Challenges of the movement of catalytic micromotors in blood.

Catalytic microjet bubble-propelled engines have attracted a large amount of interest for their potential applications in biomedicine, environmental sciences and natural resources discovery. One of the current efforts in this field is focused on the search of biocompatible fuels. However, only a minimal amount of effort has been made to assess the challenges facing the movement of such devices in a real world environment, especially with regards to the components of blood and their interactions with the catalytic microjets. Herein, we will show the limitations on the movement of catalytic microengines prepared via the rolled-up, as well as the templated-electrochemical deposition method, in an artificial blood sample, due to the presence of two main components of animal blood: the cellular component (red blood cells in this study) and serum. We will show that the motion of catalytic microjets is only possible in highly diluted dispersions of the red blood cells and serum. This finding has a profound implication on the development of the whole field, where the components found in real environments have to be considered carefully, and issues arising from the presence of such components have to be resolved prior to deploying these devices in real world applications.