Zwitterionic 3D- Printed Non- Immunogenic Stealth Microrobots

Abstract

Microrobots offer transformative solutions for non- invasive medical interventions due to their small size and untethered operation inside the human body. However, they must face the immune system as a natural protection mechanism against foreign threats. Here, non- immunogenic stealth zwitterionic microrobots that avoid recognition from immune cells are introduced. Fully zwitterionic photoresists are developed for two- photon polymerization 3D microprinting of hydrogel microrobots with ample functionalization: tunable mechanical properties, anti- biofouling and non- immunogenic properties, functionalization for magnetic actuation, encapsulation of biomolecules, and surface functionalization for drug delivery. Stealth microrobots avoid detection by macrophage cells of the innate immune system after exhaustive inspection (>90 hours), which has not been achieved in any microrobotic platform to date. These versatile zwitterionic materials eliminate a major roadblock in the development of biocompatible microrobots, and will serve as a toolbox of non- immunogenic materials for medical microrobot and other device technologies for bioengineering and biomedical applications.Zwitterionic stealth microrobots avoid detection and capture by immune cells. Zwitterionic microrobots with anti- biofouling, stealth, and non- immunogenic properties are 3D- printed via two- photon- polymerization, and are functionalized for magnetic actuation, encapsulation of biomolecules, and drug delivery. The microrobots remain undetected by macrophages and other immune cells for at least 90 hours, overcoming a major roadblock in medical microrobotics.