Luminescent iridium(III) polypyridine PEG complexes: Synthesis, photophysical, and biological properties

Steve Po-Yam Li; Johnson Lui-Lui Tsai; Kenneth Kam-Wing Lo

doi:10.1109/NANOMED.2010.5749807

Luminescent iridium(III) polypyridine PEG complexes: Synthesis, photophysical, and biological properties

Steve Po-Yam Li, Johnson Lui-Lui Tsai, Kenneth Kam-Wing Lo^*

^*Corresponding author for this work

Research output: Chapters, Conference Papers, Creative and Literary Works › RGC 32 - Refereed conference paper (with host publication) › peer-review

1 Citation (Scopus)

Abstract

We report the synthesis, characterization, and photophysical properties of a class of luminescent cyclometalated iridium(III) polypyridine poly(ethylene glycol) (PEG) complexes [Ir(N∧C)₂(bpy-CONH-PEG _n)](PF₆) (HN∧C = Hppy (1a), HN∧C = Hpq (2a), HN∧C = Hpba (3a)). The discrete PEG complexes [Ir(N∧C) ₂(bpy-CONH-dPEG₂₄)](PF₆) (HN∧C = Hppy (1b), HN∧C = Hpq (2b), HN∧C = Hpba (3b)) and the PEG-free complexes [Ir(N∧C)₂(bpy-CONH-Et)](PF₆) (HN∧C = Hppy (1c), HN∧C = Hpq (2c), HN∧C = Hpba (3c)) have also been prepared for comparison studies. The lipophilicity of the complexes has been determined by shake-flask method. We have also investigated the cytotoxicity and cellular uptake of these complexes by the 3-(4,5-dimethyl-2-thiazolyl)-2,5- diphenyltetrazolium bromide (MTT) assay and laser-scanning confocal microscopy, respectively. The results illustrated that the nondiscrete PEG complexes can act as biological imaging reagents with low cytotoxicity. Co-localization experiments using an endocytic marker Alexa Fluor 633-labeled transferrin revealed the involvement of endosomes in the uptake of the complexes by the human cervix epithelioid carcinoma (HeLa) cells. Since the aldehyde groups of the pba complexes 3a-c are reactive toward primary amines, they have been conjugated to bovine serum albumin (BSA) and the resulting conjugates have been isolated, purified, and its photophysical properties studied. Complexes 3a and 3b serve as new luminescent PEGylation reagents. © 2010 IEEE.

Original language	English
Title of host publication	2010 IEEE International Conference on Nano/Molecular Medicine and Engineering, IEEE NANOMED 2010
Pages	66-71
DOIs	https://doi.org/10.1109/NANOMED.2010.5749807
Publication status	Published - 2010
Event	4th IEEE International Conference on Nano/Molecular Medicine and Engineering (IEEE NANOMED 2010) - Hong Kong/Macau, China Duration: 5 Dec 2010 → 9 Dec 2010

Conference

Conference	4th IEEE International Conference on Nano/Molecular Medicine and Engineering (IEEE NANOMED 2010)
Country/Territory	China
City	Hong Kong/Macau
Period	5/12/10 → 9/12/10

Research Keywords

iridium
labeling
luminescence
molecular imaging
polyethylene glycol (PEG)

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@inproceedings{e19c7a0e046d44a69ac376381722ecef,

title = "Luminescent iridium(III) polypyridine PEG complexes: Synthesis, photophysical, and biological properties",

abstract = "We report the synthesis, characterization, and photophysical properties of a class of luminescent cyclometalated iridium(III) polypyridine poly(ethylene glycol) (PEG) complexes [Ir(N∧C)2(bpy-CONH-PEG n)](PF6) (HN∧C = Hppy (1a), HN∧C = Hpq (2a), HN∧C = Hpba (3a)). The discrete PEG complexes [Ir(N∧C) 2(bpy-CONH-dPEG24)](PF6) (HN∧C = Hppy (1b), HN∧C = Hpq (2b), HN∧C = Hpba (3b)) and the PEG-free complexes [Ir(N∧C)2(bpy-CONH-Et)](PF6) (HN∧C = Hppy (1c), HN∧C = Hpq (2c), HN∧C = Hpba (3c)) have also been prepared for comparison studies. The lipophilicity of the complexes has been determined by shake-flask method. We have also investigated the cytotoxicity and cellular uptake of these complexes by the 3-(4,5-dimethyl-2-thiazolyl)-2,5- diphenyltetrazolium bromide (MTT) assay and laser-scanning confocal microscopy, respectively. The results illustrated that the nondiscrete PEG complexes can act as biological imaging reagents with low cytotoxicity. Co-localization experiments using an endocytic marker Alexa Fluor 633-labeled transferrin revealed the involvement of endosomes in the uptake of the complexes by the human cervix epithelioid carcinoma (HeLa) cells. Since the aldehyde groups of the pba complexes 3a-c are reactive toward primary amines, they have been conjugated to bovine serum albumin (BSA) and the resulting conjugates have been isolated, purified, and its photophysical properties studied. Complexes 3a and 3b serve as new luminescent PEGylation reagents. {\textcopyright} 2010 IEEE.",

keywords = "iridium, labeling, luminescence, molecular imaging, polyethylene glycol (PEG)",

author = "Li, {Steve Po-Yam} and Tsai, {Johnson Lui-Lui} and Lo, {Kenneth Kam-Wing}",

year = "2010",

doi = "10.1109/NANOMED.2010.5749807",

language = "English",

isbn = "9781612841533",

pages = "66--71",

booktitle = "2010 IEEE International Conference on Nano/Molecular Medicine and Engineering, IEEE NANOMED 2010",

note = "4th IEEE International Conference on Nano/Molecular Medicine and Engineering (IEEE NANOMED 2010) ; Conference date: 05-12-2010 Through 09-12-2010",

}

Li, SP-Y, Tsai, JL-L & Lo, KK-W 2010, Luminescent iridium(III) polypyridine PEG complexes: Synthesis, photophysical, and biological properties. in 2010 IEEE International Conference on Nano/Molecular Medicine and Engineering, IEEE NANOMED 2010., 5749807, pp. 66-71, 4th IEEE International Conference on Nano/Molecular Medicine and Engineering (IEEE NANOMED 2010), Hong Kong/Macau, China, 5/12/10. https://doi.org/10.1109/NANOMED.2010.5749807

Luminescent iridium(III) polypyridine PEG complexes: Synthesis, photophysical, and biological properties. / Li, Steve Po-Yam; Tsai, Johnson Lui-Lui; Lo, Kenneth Kam-Wing.
2010 IEEE International Conference on Nano/Molecular Medicine and Engineering, IEEE NANOMED 2010. 2010. p. 66-71 5749807.

Research output: Chapters, Conference Papers, Creative and Literary Works › RGC 32 - Refereed conference paper (with host publication) › peer-review

TY - GEN

T1 - Luminescent iridium(III) polypyridine PEG complexes

T2 - 4th IEEE International Conference on Nano/Molecular Medicine and Engineering (IEEE NANOMED 2010)

AU - Li, Steve Po-Yam

AU - Tsai, Johnson Lui-Lui

AU - Lo, Kenneth Kam-Wing

PY - 2010

Y1 - 2010

N2 - We report the synthesis, characterization, and photophysical properties of a class of luminescent cyclometalated iridium(III) polypyridine poly(ethylene glycol) (PEG) complexes [Ir(N∧C)2(bpy-CONH-PEG n)](PF6) (HN∧C = Hppy (1a), HN∧C = Hpq (2a), HN∧C = Hpba (3a)). The discrete PEG complexes [Ir(N∧C) 2(bpy-CONH-dPEG24)](PF6) (HN∧C = Hppy (1b), HN∧C = Hpq (2b), HN∧C = Hpba (3b)) and the PEG-free complexes [Ir(N∧C)2(bpy-CONH-Et)](PF6) (HN∧C = Hppy (1c), HN∧C = Hpq (2c), HN∧C = Hpba (3c)) have also been prepared for comparison studies. The lipophilicity of the complexes has been determined by shake-flask method. We have also investigated the cytotoxicity and cellular uptake of these complexes by the 3-(4,5-dimethyl-2-thiazolyl)-2,5- diphenyltetrazolium bromide (MTT) assay and laser-scanning confocal microscopy, respectively. The results illustrated that the nondiscrete PEG complexes can act as biological imaging reagents with low cytotoxicity. Co-localization experiments using an endocytic marker Alexa Fluor 633-labeled transferrin revealed the involvement of endosomes in the uptake of the complexes by the human cervix epithelioid carcinoma (HeLa) cells. Since the aldehyde groups of the pba complexes 3a-c are reactive toward primary amines, they have been conjugated to bovine serum albumin (BSA) and the resulting conjugates have been isolated, purified, and its photophysical properties studied. Complexes 3a and 3b serve as new luminescent PEGylation reagents. © 2010 IEEE.

AB - We report the synthesis, characterization, and photophysical properties of a class of luminescent cyclometalated iridium(III) polypyridine poly(ethylene glycol) (PEG) complexes [Ir(N∧C)2(bpy-CONH-PEG n)](PF6) (HN∧C = Hppy (1a), HN∧C = Hpq (2a), HN∧C = Hpba (3a)). The discrete PEG complexes [Ir(N∧C) 2(bpy-CONH-dPEG24)](PF6) (HN∧C = Hppy (1b), HN∧C = Hpq (2b), HN∧C = Hpba (3b)) and the PEG-free complexes [Ir(N∧C)2(bpy-CONH-Et)](PF6) (HN∧C = Hppy (1c), HN∧C = Hpq (2c), HN∧C = Hpba (3c)) have also been prepared for comparison studies. The lipophilicity of the complexes has been determined by shake-flask method. We have also investigated the cytotoxicity and cellular uptake of these complexes by the 3-(4,5-dimethyl-2-thiazolyl)-2,5- diphenyltetrazolium bromide (MTT) assay and laser-scanning confocal microscopy, respectively. The results illustrated that the nondiscrete PEG complexes can act as biological imaging reagents with low cytotoxicity. Co-localization experiments using an endocytic marker Alexa Fluor 633-labeled transferrin revealed the involvement of endosomes in the uptake of the complexes by the human cervix epithelioid carcinoma (HeLa) cells. Since the aldehyde groups of the pba complexes 3a-c are reactive toward primary amines, they have been conjugated to bovine serum albumin (BSA) and the resulting conjugates have been isolated, purified, and its photophysical properties studied. Complexes 3a and 3b serve as new luminescent PEGylation reagents. © 2010 IEEE.

KW - iridium

KW - labeling

KW - luminescence

KW - molecular imaging

KW - polyethylene glycol (PEG)

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UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-79956010280&origin=recordpage

U2 - 10.1109/NANOMED.2010.5749807

DO - 10.1109/NANOMED.2010.5749807

M3 - RGC 32 - Refereed conference paper (with host publication)

SN - 9781612841533

SP - 66

EP - 71

BT - 2010 IEEE International Conference on Nano/Molecular Medicine and Engineering, IEEE NANOMED 2010

Y2 - 5 December 2010 through 9 December 2010

ER -

Luminescent iridium(III) polypyridine PEG complexes: Synthesis, photophysical, and biological properties

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