title: Optical coding of mammalian cells using semiconductor quantum dots.
abstract: Cell-based assays are widely used to screen compounds and study complex phenotypes. Few methods exist, however, for multiplexing cellular assays or labeling individual cells in a mixed cell population. We developed a generic encoding method for cells that is based on peptide-mediated delivery of quantum dots (QDs) into live cells. The QDs are nontoxic and photostable and can be imaged using conventional fluorescence microscopy or flow cytometry systems. We created unique fluorescent codes for a variety of mammalian cell types and show that our encoding method has the potential to create > 100 codes. We demonstrate that QD cell codes are compatible with most types of compound screening assays including immunostaining, competition binding, reporter gene, receptor internalization, and intracellular calcium release. A multiplexed calcium assay for G-protein-coupled receptors using QDs is demonstrated. The ability to spectrally encode individual cells with unique fluorescent barcodes should open new opportunities in multiplexed assay development and greatly facilitate the study of cell/cell interactions and other complex phenotypes in mixed cell populations.
authors.affiliation: Quantum Dot Corp., 26118 Research Road, Hayward, CA 94545, USA. lmattheakis@cytokinetics.com
authors.forename: Larry C
authors.initials: LC
authors.lastname: Mattheakis
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Dias
authors.forename: Yun-Jung
authors.initials: YJ
authors.lastname: Choi
authors.forename: Jing
authors.initials: J
authors.lastname: Gong
authors.forename: Marcel P
authors.initials: MP
authors.lastname: Bruchez
authors.forename: Jianquan
authors.initials: J
authors.lastname: Liu
authors.forename: Eugene
authors.initials: E
authors.lastname: Wang
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D003543:Cysteamine / Q000031:analogs & derivatives; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D005434:Flow Cytometry; D007545:Isoproterenol / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism; D010455:Peptides; D021382:Protein Sorting Signals; D045663:Quantum Dots; D043643:Receptor, Muscarinic M1 / Q000378:metabolism; D044402:Receptor, Serotonin, 5-HT2A / Q000378:metabolism; D044403:Receptor, Serotonin, 5-HT2B / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D012666:Semiconductors
chemical_list: D009842:Oligopeptides; C503924:Pep-1 peptide; D010455:Peptides; D021382:Protein Sorting Signals; D043643:Receptor, Muscarinic M1; D044402:Receptor, Serotonin, 5-HT2A; D044403:Receptor, Serotonin, 5-HT2B; D043562:Receptors, G-Protein-Coupled; D003543:Cysteamine; D007545:Isoproterenol; D002118:Calcium