Adaptive changes of organelles induced by gold nanoparticles

AIMS: To investigate whether non‑cytotoxic Au NPs induce reversible structural remodeling of multiple organelles, and to provide a basis for redefining biocompatibility assessment and nanocarrier design. MATERIALS AND METHODS: Citrate‑stabilized Au NPs (50 nm) were synthesized and characterized. Normal rat kidney (NRK) cells were treated with Au NPs for 24 h. Subcellular localization was assessed by transmission electron microscopy (TEM) and confocal microscopy. Lysosomal morphology, cytoskeleton, ER, and Golgi were examined using fluorescence staining and super‑resolution microscopy. Recovery was evaluated after Au NPs removal. RESULTS: Au NPs accumulated in lysosomes without affecting viability. They induced lysosomal swelling, cytoskeletal fragmentation, ER vesiculation, and Golgi disruption. These changes were fully reversible, with near‑complete recovery at 96 h, indicating a dynamic adaptive response. CONCLUSIONS: Au NPs trigger reversible multi‑organelle remodeling at non‑cytotoxic concentrations, revealing an intrinsic elastic capacity of organelles. This work establishes that biocompatibility evaluation must extend to subcellular levels and provides a foundation for nanocarriers enabling transient, controllable modulation without permanent damage.