Abstract
Medical microrobots have strong potential for targeted therapeutic delivery; however, current systems achieve only physical targeting, and once at the target site, they are unable to distinguish healthy cells from cancerous ones because of the lack of biological selectivity. Here, we present a biohybrid microrobot system that combines magnetic targeting with biological selectivity. The microrobots are derived from human embryonic kidney cells genetically engineered to produce tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a molecule that induces cancer cell death in multiple tumor types without damaging healthy cells. Engineered cells are then conjugated to biocompatible magnetic Janus particles-silica beads half-coated with FePt nanofilms-to enable external magnetic control. With magnetic fields, the microrobots accumulate around the tumor spheroids and continuously release TRAIL for several days, leading to selective cancer cell death while avoiding damage to healthy cells. This study combines microrobotics with genetically engineered cell therapies to achieve a targeted, prolonged, and cancer-selective therapeutic delivery.