title: Non-specific cellular uptake of surface-functionalized quantum dots.
abstract: We report a systematic empirical study of nanoparticle internalization into cells via non-specific pathways. The nanoparticles were comprised of commercial quantum dots (QDs) that were highly visible under a fluorescence confocal microscope. Surface-modified QDs with basic biologically significant moieties, e.g. carboxyl, amino, and streptavidin, were used, in combination with surface derivatization with polyethylene glycol (PEG) for a range of immortalized cell lines. Internalization rates were derived from image analysis and a detailed discussion about the effect of nanoparticle size, charge and surface groups is presented. We find that PEG derivatization dramatically suppresses the non-specific uptake while PEG-free carboxyl and amine functional groups promote QD internalization. These uptake variations displayed a remarkable consistency across different cell types. The reported results are important for experiments concerned with cellular uptake of surface-functionalized nanomaterials, both when non-specific internalization is undesirable and when it is intended for material to be internalized as efficiently as possible.
authors.affiliation: MQ Photonics Centre, Faculty of Science, Macquarie University, Sydney, Australia.
authors.forename: T A
authors.initials: TA
authors.lastname: Kelf
authors.forename: V K A
authors.initials: VK
authors.lastname: Sreenivasan
authors.forename: J
authors.initials: J
authors.lastname: Sun
authors.forename: E J
authors.initials: EJ
authors.lastname: Kim
authors.forename: E M
authors.initials: EM
authors.lastname: Goldys
authors.forename: A V
authors.initials: AV
authors.lastname: Zvyagin
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D004705:Endocytosis; D006863:Hydrogen-Ion Concentration; D008856:Microscopy, Fluorescence; D010316:Particle Size; D045663:Quantum Dots; D051381:Rats; D013499:Surface Properties