Using magnetic nanoparticles to map cellular senescence

A hallmark of aging is the accumulation of senescent cells. Senescence is a cell-fate decision characterized by permanent proliferation arrest, resistance to apoptosis, and secretion of inflammatory cytokines, chemokines, and proteases collectively termed senescence-associated secretory phenotype (SASP). However, gaps remain in understanding senescent cell load, as a unique molecular profile for senescence—specific gene or protein markers—has yet to be identified, with these cells exhibiting varied features like larger size, increased mitochondrial and lysosomal mass, and iron accumulation. To address these challenges and to potentially map senescence, magnetic force microscopy (MFM) measurements were performed on fibroblasts treated with magnetic nanoparticles (MNPs). Three types of MNPs: nanocrystalline maghemite (Mh) with cobalt doping were synthesized. Characterization techniques, including FT-IR, X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM), confirmed the MNPs' nanocrystalline structure. MNPs did not impact cell viability or induce senescence, confirmed by senescence-associated galactosidase activity, suggesting cellular compatibility. Rhodamine isothiocyanate-conjugated MNPs revealed MNP location within cells. This talk will present results from our ongoing MFM measurements to distinguish senescent, quiescent, and proliferating cells, which may serve as a 'one-stop-shop platform' for detecting senescence.