title: Microenvironments and different nanoparticle dynamics in living cells revealed by a standard nanoparticle.
abstract: For quantitative analysis of nanoparticle diffusions and submicro-environments in living cells, use of newly synthesized silica-based fluorescent nanoparticle (Si-FNP) as a standard nanoprobe is successfully demonstrated. The appropriate characteristics of a standard probe were fully analyzed in vitro by single molecule detection, transmission electron microscopy, and dynamic light scattering. Using fluorescence correlation analysis in single living cells, we quantitatively compared the diffusional properties of the standard Si-FNP with a diameter of 50 nm, peptide coated Si-FNP, streptavidin coated Qdot, and GFP molecule which have different sizes and surface properties. The result demonstrates that the standard Si-FNP without coat is minimally trapped in the vesicles in the process of cellular endocytosis. Interestingly, a large proportion of Si-FNP introduced into the cells by electroporation diffuses freely in the cells during a cell cycle suggesting free diffusing NPs are hardly trapped in the vesicles. The simple but highly sensitive method will provide insight into strategies to understanding the hydrodynamic process of nanoparticle delivery into living cells as well as the cellular microenvironment in the view of submicro-size.
authors.affiliation: Cellular Informatics Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan. cback@riken.jp
authors.forename: Chan Gi
authors.initials: CG
authors.lastname: Pack
authors.forename: Mi Ryoung
authors.initials: MR
authors.lastname: Song
authors.forename: Eunju Lee
authors.initials: EL
authors.lastname: Tae
authors.forename: Michio
authors.initials: M
authors.lastname: Hiroshima
authors.forename: Kyung Hee
authors.initials: KH
authors.lastname: Byun
authors.forename: Jun Sung
authors.initials: JS
authors.lastname: Kim
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Sako
mesh_terms: D045744:Cell Line, Tumor; D018274:Electroporation; D004705:Endocytosis; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry; D045663:Quantum Dots; D012235:Rhodamines / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry* / Q000378:metabolism*; D019809:Streptavidin / Q000737:chemistry; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D010446:Peptide Fragments; D012235:Rhodamines; C485184:enhanced green fluorescent protein; D054322:tat Gene Products, Human Immunodeficiency Virus; C422951:tat peptide (48-60), Human immunodeficiency virus 1; D049452:Green Fluorescent Proteins; D012822:Silicon Dioxide; D019809:Streptavidin; C027755:rhodamine isothiocyanate; D016650:Fluorescein-5-isothiocyanate