Magnetoelectric microrobots: wireless, non-invasive actuation & stimulation for spinal cord injury repair
Severe spinal cord injury (SCI) remains a formidable clinical challenge due to the limited self-renewal capacity of endogenous nerve cells. Neural progenitor cell (NPC) therapies offer promise but are hindered by poor post-transplantation viability, unpredictable lineage commitment, and inadequate functional integration. Biochemical inducers suffer from rapid clearance and systemic side effects, while traditional electrical stimulation requires invasive electrode implantation. To address these bottlenecks, Ye and co-workers developed biohybrid microrobots termed 'NPCbots' by integrating human induced pluripotent stem cell-derived NPCs with core-shell cobalt ferrite@barium titanate (CoFe2O4@BaTiO3, CFO-BTO) magnetoelectric nanoparticles via a bidirectional microfluidic lab-on-a-chip device. The CFO-BTO nanoparticles feature a ~99.4 nm magnetostrictive core and a ~7 nm piezoelectric shell, enabling wireless magnetoelectric coupling under an alternating magnetic field (AMF) of 20 mT at 1.18 kHz. This non-invasive stimulation induces localized electrical signals that promote rapid neural differentiation and structural reconnection. The microfluidic fabrication achieved high cell viability (>85%) while preserving stem cell multipotency. In preclinical models, NPCbots accelerated functional motor recovery. This work establishes a minimally invasive paradigm for spinal cord reconstruction, unifying microfluidic biofabrication, magnetoelectric nanomaterials, precise micro-positioning, and wireless electro-stimulation, with broad implications for neuro-engineering and bioelectronic medicine.