Real time in vivo detection of cellular senescence through the controlled release of the NIR fluorescent dye Nile Blue.

: The in vivo optical detection of cellular senescence has been accomplished by using mesoporous silica nanoparticles loaded with the NIR-FDA approved Nile Blue ( NB ) dye and capped with a galactohexasaccharide ( S3 ). Emission at 672 nm of NB is highly quenched inside S3 , yet a remarkable emission enhancement is observed upon cap hydrolysis in the presence of β-galactosidase. The efficacy of the probe to optically detect cellular senescence is tested in vitro in melanoma SK-Mel-103 and breast cancer 4T1 cells and in vivo in palbociclib-treated BALB/cByJ mice bearing breast cancer tumor. S3 nanomaterial is expected to be a potential tool to detect cell senescence in vivo for following treatment response and efficacy of senotherapies in aged related diseases.