Nano Research

, Volume 2, Issue 2, pp 121–129

Improved peptidyl linkers for self-assembly of semiconductor quantum dot bioconjugates

Authors

  • Lorenzo Berti
    • CNR-INFMNational Research Center on nanoStructures and bioSystems at Surfaces (S3)
    • University of California Davis Medical Center
  • Paola Serena D’Agostino
    • CNR-INFMNational Research Center on nanoStructures and bioSystems at Surfaces (S3)
  • Kelly Boeneman
    • Center for Bio/Molecular Science and Engineering Code 6900U.S. Naval Research Laboratory
    • Center for Bio/Molecular Science and Engineering Code 6900U.S. Naval Research Laboratory
Open AccessResearch Article

DOI: 10.1007/s12274-009-9008-9

Abstract

We demonstrate improved peptide linkers which allow both conjugation to biomolecules such as DNA and self-assembly with luminescent semiconductor quantum dots. A hexahistidine peptidyl sequence was generated by standard solid phase peptide synthesis and modified with the succinimidyl ester of iodoacetamide to yield a thiol-reactive iodoacetyl polyhistidine linker. The reactive peptide was conjugated to dye-labeled thiolated DNA which was utilized as a model target biomolecule. Agarose gel electrophoresis and fluorescence resonance energy transfer analysis confirmed that the linker allowed the DNA to self-assemble with quantum dots via metal-affinity driven coordination. In contrast to previous peptidyl linkers that were based on disulfide exchange and were thus labile to reduction, the reactive haloacetyl chemistry demonstrated here results in a more stable thioether bond linking the DNA to the peptide which can withstand strongly reducing environments such as the intracellular cytoplasm. As thiol groups occur naturally in proteins, can be engineered into cloned proteins, inserted into nascent peptides or added to DNA during synthesis, the chemistry demonstrated here can provide a simple method for self-assembling a variety of stable quantum dot bioconjugates.

https://static-content.springer.com/image/art%3A10.1007%2Fs12274-009-9008-9/MediaObjects/12274_2009_9008_Fig1_HTML.jpg

Keywords

Semiconductor quantum dot peptide DNA nanocrystal bioconjugation iodoacetyl sulfhydryl polyhistidine metal-affinity fluorescence fluorescence resonance energy transfer (FRET)

Copyright information

© Tsinghua University Press and Springer Berlin Heidelberg 2009