Nanotechnology-enabled strategies to improve stem cell therapy for erectile dysfunction

Erectile dysfunction (ED) is a common male sexual disorder that substantially affects quality of life and psychosocial well-being, with an increasing global burden. Although conventional therapies such as phosphodiesterase-5 inhibitors provide symptomatic relief, they are often inadequate for patients with severe pathological conditions, including diabetes, cavernous nerve injury, aging, and advanced vascular disease, because they do not reverse the underlying neurovascular and smooth muscle damage. Stem cell therapy has therefore attracted attention because of its paracrine, pro-angiogenic, anti-apoptotic, anti-fibrotic, and neuroprotective effects. However, its clinical translation remains constrained by rapid washout after intracavernous injection, poor local retention, low survival in the hostile penile microenvironment, and inconsistent therapeutic efficacy. Nanotechnology provides a set of practical tools for addressing these barriers. In this review, we summarize recent advances in nanotechnology-enhanced stem cell therapy for ED, with particular emphasis on strategies that improve stem cell delivery, tracking, homing, retention, and survival. We further discuss nanotechnology-assisted genetic engineering and preconditioning approaches that enhance the regenerative potency of stem cells. We also discuss acellular strategies, particularly stem cell-derived extracellular vesicles (EVs) and exosomes, which can be engineered and delivered using nanoplatforms to improve safety, targeting, and therapeutic durability. We also outline the emerging application of nanostructured scaffolds and multifunctional biomaterials for tissue engineering and structural repair in severe ED. Overall, available preclinical evidence suggests that nanotechnology can improve the precision, stability, and regenerative efficacy of stem cell therapy for ED. Nevertheless, important challenges remain, including biosafety evaluation, standardization of nanomaterials and extracellular vesicle production, large-animal validation, and clinical-grade manufacturing. Addressing these issues will be necessary before nano-enhanced regenerative strategies can be translated into clinically usable therapies for ED.