The　present　study　was　designed　to　examine　the　uptake,　localization,　and　the　cytotoxic　effects　of　well-dispersed　fluorescent　porous　silica　nanoparticles　(FITC-SiO2　NPs)　in　mouse　neural　stem　cells　(C　17.2,　NSCs).　NSCs　were　exposed　to　various　concentrations　of　FITC-SiO2　NPs　for　different　times　and　then　the　uptake　and　toxicity　were　assessed.　Apoptotic　cells　were　observed　and　analyzed　by　confocal　microscopy　and　flow　cytometry.　Results　of　confocal　microscopy　examination　revealed　that　silica　nanoparticles　were　taken　up　into　the　cells.　Cell　viability　decreased　significantly　as　a　function　of　both　nanoparticle　dosage　(12-240　mu　g/ml)　and　exposure　time　(12　h,　24　h　72　h).　FITC-SiO2　NPs　show　marked　toxicity　at　high　concentration　(240　mu　g/mL)　after　co-incubation　for　72　h.　There　were　clear　dose-and　time-dependent　silica-induced　cytotoxicity　and　genotoxicity　within　the　range　of　experimental　concentrations.　Interestingly,　we　have　caught　the　whole　process　of　NSCs　apoptosis　induced　by　FITC-SiO2　NPs.　The　understanding　of　such　a　mechanism　may　provide　a　scientific　basis　for　the　possible　application　of　porous　silica　in　drug　delivery　and　controlled　release.