title: Pyrenebutyrate Leads to Cellular Binding, Not Intracellular Delivery, of Polyarginine-Quantum Dots.
abstract: The intracellular, cytosolic, delivery of quantum dots is an important goal for cellular imaging. Recently, a hydrophobic anion, pyrenebutyrate had been proposed to serve as a delivery agent for cationic quantum dots as characterized by confocal microscopy. Using an extracellular quantum dot quencher, QSY-21, as an alternative to confocal microscopy, we demonstrate that quantum dots remain on the cell surface and do not cross the plasma membrane following pyrenebutyrate treatment, a result that is confirmed with transmission electron microscopy. Pyrenebutyrate leads to increased cellular binding of quantum dots rather than intracellular delivery. These results characterize the use of QSY-21 as a quantum dot quencher and highlight the importance of the use of complementary techniques when using confocal microscopy.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139; School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332.
authors.forename: Amy E
authors.initials: AE
authors.lastname: Jablonski
authors.forename: Takashi
authors.initials: T
authors.lastname: Kawakami
authors.forename: Alice Y
authors.initials: AY
authors.lastname: Ting
authors.forename: Christine K
authors.initials: CK
authors.lastname: Payne