Nanomaterial-enabled physical rehabilitation: mechanisms, evidence, and translational pathways.

Physical rehabilitation relies on macroscopic therapeutic modalities such as ultrasound, photothermal stimulation, electrical activation, magnetic fields, and controlled mechanical loading to restore function after injury, surgery, or neurological impairment. Although these approaches are clinically established and widely used, their effects remain constrained by limited spatial precision, shallow penetration, heterogeneous tissue responses, and insufficient control over the cellular and molecular mechanisms that govern healing. Advances in nanoscience have introduced a new class of materials capable of mediating, amplifying, or refining external physical stimuli at the nanoscale. Nanomaterials exhibit tunable optical, magnetic, mechanical, and electrical properties that enable the conversion of externally applied energy into localized thermal, mechanical, or electrochemical cues, thereby influencing cellular behavior with a degree of precision not achievable by conventional modalities alone. These properties suggest potential-demonstrated primarily in preclinical models-to improve musculoskeletal repair, modulate nociceptive pathways, enhance neuromuscular activation, and integrate with regenerative scaffolds, though clinical validation remains limited. Yet, despite promising experimental findings, translation into rehabilitation practice remains limited by gaps in mechanistic understanding, variability in experimental design, safety uncertainties, and complex regulatory pathways. This review examines the fundamental properties of nanomaterials relevant to physical rehabilitation, analyzes their interactions with primary therapeutic modalities, evaluates preclinical and early clinical evidence, and outlines translational, safety, and regulatory considerations. By synthesizing mechanistic insight with empirical data, the review defines realistic opportunities and the limitations that must be resolved to advance nanomaterial-enabled physical rehabilitation toward clinical implementation.