Two-Color Emitting Colloidal Nanocrystals as Single-Particle Ratiometric Probes of Intracellular pH

Francesco Bruni, Jacopo Pedrini, Caterina Bossio, Beatriz Santiago-Gonzalez, Francesco Meinardi, Wan Ki Bae, Victor I Klimov, Guglielmo Lanzani, Sergio Brovelli

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Intracellular pH is a key parameter in many biological mechanisms and cell metabolism and is used to detect and monitor cancer formation and brain or heart diseases. pH-sensing is typically performed by fluorescence microscopy using pH-responsive dyes. Accuracy is limited by the need for quantifying the absolute emission intensity in living biological samples. An alternative with a higher sensitivity and precision uses probes with a ratiometric response arising from the different pH-sensitivity of two emission channels of a single emitter. Current ratiometric probes are complex constructs suffering from instability and cross-readout due to their broad emission spectra. Here, we overcome such limitations using a single-particle ratiometric pH probe based on dot-in-bulk CdSe/CdS nanocrystals (NCs). These nanostructures feature two fully-separated narrow emissions with different pH sensitivity arising from radiative recombination of core- and shell-localized excitons. The core emission is nearly independent of the pH, whereas the shell luminescence increases in the 3–11 pH range, resulting in a cross-readout-free ratiometric response as strong as 600%. In vitro microscopy demonstrates that the ratiometric response in biologic media resembles the precalibralation curve obtained through far-field titration experiments. The NCs show good biocompatibility, enabling us to monitor in real-time the pH in living cells.

Original languageEnglish
Article number1605533
JournalAdvanced Functional Materials
Volume27
Issue number12
DOIs
Publication statusPublished - Mar 24 2017

Fingerprint

Nanocrystals
nanocrystals
Color
color
probes
Fluorescence microscopy
Titration
Biocompatibility
Metabolism
Excitons
Luminescence
Nanostructures
Brain
Microscopic examination
Coloring Agents
Dyes
Cells
readout
sensitivity
microscopy

Keywords

  • bioimaging
  • colloidal quantum dots
  • pH sensing
  • ratiometric sensing
  • two-color emission

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Condensed Matter Physics
  • Electrochemistry

Cite this

Bruni, F., Pedrini, J., Bossio, C., Santiago-Gonzalez, B., Meinardi, F., Bae, W. K., ... Brovelli, S. (2017). Two-Color Emitting Colloidal Nanocrystals as Single-Particle Ratiometric Probes of Intracellular pH. Advanced Functional Materials, 27(12), [1605533]. https://doi.org/10.1002/adfm.201605533

Two-Color Emitting Colloidal Nanocrystals as Single-Particle Ratiometric Probes of Intracellular pH. / Bruni, Francesco; Pedrini, Jacopo; Bossio, Caterina; Santiago-Gonzalez, Beatriz; Meinardi, Francesco; Bae, Wan Ki; Klimov, Victor I; Lanzani, Guglielmo; Brovelli, Sergio.

In: Advanced Functional Materials, Vol. 27, No. 12, 1605533, 24.03.2017.

Research output: Contribution to journalArticle

Bruni, F, Pedrini, J, Bossio, C, Santiago-Gonzalez, B, Meinardi, F, Bae, WK, Klimov, VI, Lanzani, G & Brovelli, S 2017, 'Two-Color Emitting Colloidal Nanocrystals as Single-Particle Ratiometric Probes of Intracellular pH', Advanced Functional Materials, vol. 27, no. 12, 1605533. https://doi.org/10.1002/adfm.201605533
Bruni, Francesco ; Pedrini, Jacopo ; Bossio, Caterina ; Santiago-Gonzalez, Beatriz ; Meinardi, Francesco ; Bae, Wan Ki ; Klimov, Victor I ; Lanzani, Guglielmo ; Brovelli, Sergio. / Two-Color Emitting Colloidal Nanocrystals as Single-Particle Ratiometric Probes of Intracellular pH. In: Advanced Functional Materials. 2017 ; Vol. 27, No. 12.
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