title: A new technique for reversible permeabilization of live cells for intracellular delivery of quantum dots.
abstract: A major challenge with the use of quantum dots (QDs) for cellular imaging and biomolecular delivery is the attainment of QDs freely dispersed inside the cells. Conventional methods such as endocytosis, lipids based delivery and electroporation are associated with delivery of QDs in vesicles and/or as aggregates that are not monodispersed. In this study, we demonstrate a new technique for reversible permeabilization of cells to enable the introduction of freely dispersed QDs within the cytoplasm. Our approach combines osmosis driven fluid transport into cells achieved by creating a hypotonic environment and reversible permeabilization using low concentrations of cell permeabilization agents like Saponin. Our results confirm that highly efficient endocytosis-free intracellular delivery of QDs can be accomplished using this method. The best results were obtained when the cells were treated with 50 μg ml⁻¹ Saponin in a hypotonic buffer at a 3:2 physiological buffer:DI water ratio for 5 min at 4 °C.
authors.affiliation: Department of Electrical and Computer Engineering, Speed School of Engineering, University of Louisville, Louisville, KY 40208, USA.
authors.forename: Krishnakiran
authors.initials: K
authors.lastname: Medepalli
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Alphenaar
authors.forename: Robert S
authors.initials: RS
authors.lastname: Keynton
authors.forename: Palaniappan
authors.initials: P
authors.lastname: Sethu
mesh_terms: D000818:Animals; D002021:Buffers; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects* / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects; D003584:Cytological Techniques / Q000379:methods*; D003593:Cytoplasm / Q000737:chemistry / Q000378:metabolism*; D004337:Drug Carriers / Q000737:chemistry / Q000493:pharmacokinetics; D004705:Endocytosis; D007038:Hypotonic Solutions / Q000494:pharmacology*; D008856:Microscopy, Fluorescence; D009995:Osmosis; D045663:Quantum Dots; D051381:Rats; D012503:Saponins / Q000737:chemistry / Q000493:pharmacokinetics
chemical_list: D002021:Buffers; D004337:Drug Carriers; D007038:Hypotonic Solutions; D012503:Saponins