Surface Navigation of Alginate Artificial Cells in Mucus Solutions

Alginate hydrogels are widely researched in phar-maceutical applications for their abilities to encapsulate and dis-perse therapeutics in response to stimuli. While effective, their utility can be greatly improved once converted into artificial cell soft-microrobots, allowing them to actively navigate through complex in vivo environments and facilitate targeted drug deliv-ery. In this study, artificial cells were fabricated by crosslinking alginate with magnetic nanoparticles and then deployed within mucus solutions to characterize their propulsion capabilities. The goal of this study was to understand how variations in simplified gastrointestinal fluid, artificial cell properties, and magnetic field characteristics could affect surface locomotion. A comparison between automatic feedback control and manual “open-loop” operation was also quantitatively explored. Under feedback control, individual artificial cells were navigated with automatically generated waypoints and a PID controller. Simu-lations were used to verify controller performance and accuracy. User operation was carried out using an Xbox controller, where the joystick could directly change navigation direction. We conclude in this study that the surface navigation of artificial cells is highly predictable within mucus concentrations and that both feedback and open-loop control are equally successful in navigation.