Figure 6.

Anti-infective activity of the antimicrobial motors in vivo. (a) Mice had their dorsal region shaved, scratched (1-cm-long wound), and infected with A. baumannii AB177. After 1 h, functionalized and nonfunctionalized micro- and nanomotors or peptides were added to the infection site. Mice were euthanized, the tissue from the infection site was harvested, and the bacterial cells of treated and untreated samples were counted by plating. (b) Schematic representation of the wound site infected and the addition of urea before the treatment with (i) micro- and nanomotors or (ii) peptides free is solution. Antimicrobial micro- and nanomotors self-propelled, driven by urea, through a distance of 1 cm to enable the autonomous treatment of the target infected area. On the other hand, peptides by themselves exhibited antimicrobial activity only within the area they were administered and did not clear the infection at a distance. Briefly, after the infection was established, urea was spread over the entire length of the wound (1 cm). Next, the micro- and nanomotors coated with peptides and the peptides alone were inoculated to one of the extremities of the infected wound. (c) Four days postinfection, 1 cm² of the infected area was excised and the ability of the micro- and nanomotors to travel throughout the wound alone and when functionalized with peptides was assessed. (d) Treatment with peptides alone decreased bacterial counts only in the extremity where they were administered (light yellow background), as revealed by similar bacterial counts detected in areas at a distance from the administration site (dark yellow background) and those of untreated control groups. (e) Mouse weight was monitored throughout the experiments, serving as a proxy to assess the toxicity of both micro- and nanomotors and (f) peptides in solution. None of the treatment groups led to toxicity in mice. Eight animals were used per group. This figure was created with BioRender.com.