Fast, Ratiometric FRET from Quantum Dot Conjugated Stabilized Single Chain Variable Fragments for Quantitative Botulinum Neurotoxin Sensing

Joonseok Lee, Melissa B. Brennan, Rosemarie Wilton*, Clare E. Rowland, Elena A. Rozhkova, Sara Forrester, Daniel C. Hannah, Julia Carlson, Elena V. Shevchenko, Daniel S. Schabacker, Richard Daniel Schaller

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Botulinum neurotoxin (BoNT) presents a significant hazard under numerous realistic scenarios. The standard detection scheme for this fast-acting toxin is a lab-based mouse lethality assay that is sensitive and specific, but slow (2 days) and requires expert administration. As such, numerous efforts have aimed to decrease analysis time and reduce complexity. Here, we describe a sensitive ratiometric fluorescence resonance energy transfer scheme that utilizes highly photostable semiconductor quantum dot (QD) energy donors and chromophore conjugation to compact, single chain variable antibody fragments (scFvs) to yield a fast, fieldable sensor for BoNT with a 20-40 pM detection limit, toxin quantification, adjustable dynamic range, sensitivity in the presence of interferents, and sensing times as fast as 5 min. Through a combination of mutations, we achieve stabilized scFv denaturation temperatures of more than 60 °C, which bolsters fieldability. We also describe adaptation of the assay into a microarray format that offers persistent monitoring, reuse, and multiplexing.

Original languageEnglish (US)
Pages (from-to)7161-7167
Number of pages7
JournalNano letters
Volume15
Issue number10
DOIs
StatePublished - Oct 14 2015

Keywords

  • FRET
  • botulinum neurotoxin
  • microarray
  • protein sensor
  • quantum dot
  • scFv

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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