Quantum dots encapsulated within phospholipid membranes: Phase-dependent structure, photostability, and site-selective functionalization

Weiwei Zheng, Yang Liu, Ana West, Erin E. Schuler, Kevin Yehl, R. Brian Dyer, James T. Kindt, Khalid Salaita

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

Lipid vesicle encapsulation is an efficient approach to transfer quantum dots (QDs) into aqueous solutions, which is important for renewable energy applications and biological imaging. However, little is known about the molecular organization at the interface between a QD and lipid membrane. To address this issue, we investigated the properties of 3.0 nm CdSe QDs encapsulated within phospholipid membranes displaying a range of phase transition temperatures (Tm). Theoretical and experimental results indicate that the QD locally alters membrane structure, and in turn, the physical state (phase) of the membrane controls the optical and chemical properties of the QDs. Using photoluminescence, ICP-MS, optical microscopy, and ligand exchange studies, we found that the Tm of the membrane controls optical and chemical properties of lipid vesicle-embedded QDs. Importantly, QDs encapsulated within gel-phase membranes were ultrastable, providing the most photostable non-core/shell QDs in aqueous solution reported to date. Atomistic molecular dynamics simulations support these observations and indicate that membranes are locally disordered displaying greater disordered organization near the particle-solution interface. Using this asymmetry in membrane organization near the particle, we identify a new approach for site-selective modification of QDs by specifically functionalizing the QD surface facing the outer lipid leaflet to generate gold nanoparticle-QD assemblies programmed by Watson-Crick base-pairing.

Original languageEnglish (US)
Pages (from-to)1992-1999
Number of pages8
JournalJournal of the American Chemical Society
Volume136
Issue number5
DOIs
StatePublished - Feb 5 2014

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