In this article, we present the exploration of a facile synthetic tactic incorporating delay-photo-oxidation to recover the loss in emission frequently encountered after encapsulating quantum dots (QDs) inside a silica shell. This facile synthesis procedure reproducibly increases emissive intensity of QDs (core)-SiO2 (shell) (60 nm) nanomaterials by >5 fold (QY from 3% to >15%). The resulting QDs (core)- SiO2 proved to be a single quantum dot in single SiO2, homogeneous and highly monodispered; their emissions have been successfully fine-tuned from visible to the near infrared region. We then demonstrate their power in biological imaging by labeling human mesenchymal stem cells under two-photon confocal microscopy. The results of low cytotoxicity, efficient labeling, and specific location nearby the nucleus characters of these nanoparticles should spark an intensive relevant research within a living system. ; 附設醫院影像醫學部 ; 醫學院附設醫院 ; 期刊論文