Nano-Mechatronic Systems and Smart Imaging for Non-Invasive Nanorobot Tracking in Damaged Tissue Regeneration: A Rehabilitation Medicine Perspective

Background and Aims: Traumatic spinal cord injuries, peripheral nerve trauma, and severe osteochondral defects present formidable bottlenecks in physical medicine and rehabilitation. Conventional macroscopic interventions (e.g., robotic exoskeletons and physical therapy) cannot manipulate cellular-level biological processes, whereas passive nanomedicine suffers from biophysical barriers and poor target bioavailability (<2%).This structured narrative review synthesizes the integration of active nano-mechatronic propulsion systems and artificial intelligence (AI)-driven smart imaging for non-invasive in vivo tracking and targeted tissue regeneration.

Materials and Methods: Employing a structured literature search strategy informed by PRISMA principles and the PICO framework, comprehensive searches were executed across PubMed, Scopus, Web of Science, and IEEE Xplore for benchmark studies published between 2020 and 2026. From 348 unique identified records, 96 full-text articles were evaluated, and 36 interdisciplinary studies were selected for qualitative and narrative synthesis.

Results: External rotating magnetic fields and acoustic micro-streaming enable robust propulsion and reconfigurable swarm morphing in complex biofluids. Deep learning architectures (U-Net, YOLOX, and YOLOv8) integrated with high-frequency Doppler ultrasound and photoacoustic imaging effectively suppress acoustic speckle noise and motion artifacts, achieving sub-millimeter localization accuracy (RMS error <0.18 mm) within an end-to-end closed-loop control sampling budget of 100 ms (core AI inference and control latency <20 ms). Preclinical in vivo animal models confirmed that targeted microrobotic delivery suppresses glial scar formation (decreased GFAP), facilitates axonal regrowth (increased NeuN and GAP-43), and statistically improves functional hindlimb motor scores (BBB/BMS).

Conclusion: The convergence of nano-mechatronic actuation, machine vision tracking, and physical medicine establishes an adjuvant microscale paradigm for targeted cellular restoration, bridging deep-tissue engineering with functional movement recovery.