Dendritic cell microrobots target spinal cord regeneration in vivo

Abstract Acute spinal cord injury (SCI) results in a significant level of disability, making neural remodeling essential for the recovery process. However, the over-activated immune response and deficiency of growth factors in post-injury significantly hinder nerve remodeling and axonal regeneration during recovery. Low targeting efficacy, delayed onset of action and side effects (e.g., infection or femoral head necrosis) are bottleneck issues associated with currently adopted approaches such as peripheral injection immunotherapy and drug delivery. Regarding these issues, vaccines based on dendritic cells (DCs) provide a promising solution for modulating immune responses while treating various central nervous system (CNS) diseases in clinical situations, due to their ability to activate antigen-specific T-cell responses. Recently, owing to their controllable motion, microrobots that are compatible with biological systems have surfaced as effective instruments for delivering drugs to specific locations and facilitating precise therapies. Magnetic microrobots can quickly and accurately target the lesion area. In this study, we developed a DC microrobot (DC robot) to serve as a DC vaccine for SCI treatment. Controlled by rotating magnetic fields, these microrobots effectively modulate immune responses and deliver neurotrophic factors, thereby facilitating axonal regeneration and enhancing functional recovery in mouse models of SCI. This approach highlights the potential of cell-based microrobots as a precise and safe strategy for treating SCI and other CNS diseases.