Development of magnetically driven microrobot covered with a time-dependent film for colon drug delivery

Abstract

Oral administration is an ideal method, while achieving targeted drug delivery to the colon remains a challenge. In this study, a magnetic microrobot incorporating a colon-specific method has been developed, featuring both time-dependent and magnetically driven functions. With the help of commercial enteric-coated capsules, this microrobot can function like a pH- and time-dependent sequential trigger system in an in vitro gastrointestinal (GI) simulation environment, a common approach for colon-targeted drug delivery. This design allows the microrobot also to have the ability to target drug delivery without control in vitro. However, the complexity and variability of the GI tract may lead to ineffectiveness in colon-specific methods. With internally sealed neodymium-iron-boron (NdFeB) N52 magnets, the microrobot can tumble on the intestinal surface in vitro, demonstrating good controllability and speed. This means the microrobot can be controlled by the rotating magnetic field when the colon-specific method fails, providing the possibility of in vitro intervention. The in vitro results indicate that this magnetic microrobot, which incorporates the colon-specific method, holds promise as a platform that can reduce control costs and enhance targeting capabilities.