Unique Energy Transfer in Fluorescein-Conjugated Au22 Nanoclusters Leading to 160-Fold pH-Contrasting Photoluminescence

Kyunglim Pyo; Nguyen Hoang Ly; Sang Myeong Han; Mohammad Bin Hatshan; Abubkr Abuhagr; Gary Wiederrecht; Sang Woo Joo; Guda Ramakrishna; Dongil Lee

doi:10.1021/acs.jpclett.8b02130

Unique Energy Transfer in Fluorescein-Conjugated Au₂₂ Nanoclusters Leading to 160-Fold pH-Contrasting Photoluminescence

Kyunglim Pyo, Nguyen Hoang Ly, Sang Myeong Han, Mohammad Bin Hatshan, Abubkr Abuhagr, Gary Wiederrecht, Sang Woo Joo, Guda Ramakrishna, Dongil Lee

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

21 Citations (Scopus)

Abstract

Accurate measurements of intracellular pH are of crucial importance in understanding the cellular activities and in the development of intracellular drug delivery systems. Here we report a highly sensitive pH probe based on a fluorescein-conjugated Au₂₂ nanocluster. Steady-state photoluminescence (PL) measurements have shown that, when conjugated to Au₂₂, fluorescein exhibits more than 160-fold pH-contrasting PL in the pH range of 4.3-7.8. Transient absorption measurements show that there are two competing ultrafast processes in the fluorescein-conjugated Au₂₂ nanocluster: the intracore-state relaxation and the energy transfer from the nonthermalized states of Au₂₂ to fluorescein. The latter becomes predominant at a higher pH, leading to dramatic PL enhancement of fluorescein. In addition to the intrinsically low toxicity, fluorescein-conjugated Au₂₂ nanoclusters exhibit high pH sensitivity, wide dynamic range, and excellent photostability, providing a powerful tool for the study of intracellular processes.

Original language	English
Pages (from-to)	5303-5310
Number of pages	8
Journal	Journal of Physical Chemistry Letters
Volume	9
Issue number	18
DOIs	https://doi.org/10.1021/acs.jpclett.8b02130
Publication status	Published - 2018 Sept 20

Bibliographical note

Funding Information:
D.L. acknowledges support by the Korea CCS R&D Center (KCRC) Grant (NRF-2014M1A8A1074219) and NRF Grants NRF-2017R1A2B3006651 and NRF-2009-0093823. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of science, office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

Publisher Copyright:
© 2018 American Chemical Society.

All Science Journal Classification (ASJC) codes

Materials Science(all)
Physical and Theoretical Chemistry

Access to Document

10.1021/acs.jpclett.8b02130

Cite this

@article{7796d2f594a64369b53e9a2210805889,

title = "Unique Energy Transfer in Fluorescein-Conjugated Au22 Nanoclusters Leading to 160-Fold pH-Contrasting Photoluminescence",

abstract = "Accurate measurements of intracellular pH are of crucial importance in understanding the cellular activities and in the development of intracellular drug delivery systems. Here we report a highly sensitive pH probe based on a fluorescein-conjugated Au22 nanocluster. Steady-state photoluminescence (PL) measurements have shown that, when conjugated to Au22, fluorescein exhibits more than 160-fold pH-contrasting PL in the pH range of 4.3-7.8. Transient absorption measurements show that there are two competing ultrafast processes in the fluorescein-conjugated Au22 nanocluster: the intracore-state relaxation and the energy transfer from the nonthermalized states of Au22 to fluorescein. The latter becomes predominant at a higher pH, leading to dramatic PL enhancement of fluorescein. In addition to the intrinsically low toxicity, fluorescein-conjugated Au22 nanoclusters exhibit high pH sensitivity, wide dynamic range, and excellent photostability, providing a powerful tool for the study of intracellular processes.",

author = "Kyunglim Pyo and Ly, {Nguyen Hoang} and Han, {Sang Myeong} and Hatshan, {Mohammad Bin} and Abubkr Abuhagr and Gary Wiederrecht and Joo, {Sang Woo} and Guda Ramakrishna and Dongil Lee",

note = "Funding Information: D.L. acknowledges support by the Korea CCS R&D Center (KCRC) Grant (NRF-2014M1A8A1074219) and NRF Grants NRF-2017R1A2B3006651 and NRF-2009-0093823. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of science, office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Publisher Copyright: {\textcopyright} 2018 American Chemical Society.",

year = "2018",

month = sep,

day = "20",

doi = "10.1021/acs.jpclett.8b02130",

language = "English",

volume = "9",

pages = "5303--5310",

journal = "Journal of Physical Chemistry Letters",

issn = "1948-7185",

publisher = "American Chemical Society",

number = "18",

}

TY - JOUR

T1 - Unique Energy Transfer in Fluorescein-Conjugated Au22 Nanoclusters Leading to 160-Fold pH-Contrasting Photoluminescence

AU - Pyo, Kyunglim

AU - Ly, Nguyen Hoang

AU - Han, Sang Myeong

AU - Hatshan, Mohammad Bin

AU - Abuhagr, Abubkr

AU - Wiederrecht, Gary

AU - Joo, Sang Woo

AU - Ramakrishna, Guda

AU - Lee, Dongil

N1 - Funding Information: D.L. acknowledges support by the Korea CCS R&D Center (KCRC) Grant (NRF-2014M1A8A1074219) and NRF Grants NRF-2017R1A2B3006651 and NRF-2009-0093823. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of science, office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Publisher Copyright: © 2018 American Chemical Society.

PY - 2018/9/20

Y1 - 2018/9/20

N2 - Accurate measurements of intracellular pH are of crucial importance in understanding the cellular activities and in the development of intracellular drug delivery systems. Here we report a highly sensitive pH probe based on a fluorescein-conjugated Au22 nanocluster. Steady-state photoluminescence (PL) measurements have shown that, when conjugated to Au22, fluorescein exhibits more than 160-fold pH-contrasting PL in the pH range of 4.3-7.8. Transient absorption measurements show that there are two competing ultrafast processes in the fluorescein-conjugated Au22 nanocluster: the intracore-state relaxation and the energy transfer from the nonthermalized states of Au22 to fluorescein. The latter becomes predominant at a higher pH, leading to dramatic PL enhancement of fluorescein. In addition to the intrinsically low toxicity, fluorescein-conjugated Au22 nanoclusters exhibit high pH sensitivity, wide dynamic range, and excellent photostability, providing a powerful tool for the study of intracellular processes.

AB - Accurate measurements of intracellular pH are of crucial importance in understanding the cellular activities and in the development of intracellular drug delivery systems. Here we report a highly sensitive pH probe based on a fluorescein-conjugated Au22 nanocluster. Steady-state photoluminescence (PL) measurements have shown that, when conjugated to Au22, fluorescein exhibits more than 160-fold pH-contrasting PL in the pH range of 4.3-7.8. Transient absorption measurements show that there are two competing ultrafast processes in the fluorescein-conjugated Au22 nanocluster: the intracore-state relaxation and the energy transfer from the nonthermalized states of Au22 to fluorescein. The latter becomes predominant at a higher pH, leading to dramatic PL enhancement of fluorescein. In addition to the intrinsically low toxicity, fluorescein-conjugated Au22 nanoclusters exhibit high pH sensitivity, wide dynamic range, and excellent photostability, providing a powerful tool for the study of intracellular processes.

UR - http://www.scopus.com/inward/record.url?scp=85053290237&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85053290237&partnerID=8YFLogxK

U2 - 10.1021/acs.jpclett.8b02130

DO - 10.1021/acs.jpclett.8b02130

M3 - Article

C2 - 30165739

AN - SCOPUS:85053290237

SN - 1948-7185

VL - 9

SP - 5303

EP - 5310

JO - Journal of Physical Chemistry Letters

JF - Journal of Physical Chemistry Letters

IS - 18

ER -