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Inhibition of Beta-Amyloid Fibrillation by Luminescent Iridium(III) Complex Probes.

Lu L, Zhong HJ, Wang M, Ho SL, Li HW, Leung CH, Ma DL - Sci Rep (2015)

Bottom Line: We report herein the application of kinetically inert luminescent iridium(III) complexes as dual inhibitors and probes of beta-amyloid fibrillogenesis.These iridium(III) complexes inhibited Aβ1-40 peptide aggregation in vitro, and protected against Aβ-induced cytotoxicity in neuronal cells.Furthermore, the complexes differentiated between the aggregated and unaggregated forms of Aβ1-40 peptide on the basis of their emission response.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.

ABSTRACT
We report herein the application of kinetically inert luminescent iridium(III) complexes as dual inhibitors and probes of beta-amyloid fibrillogenesis. These iridium(III) complexes inhibited Aβ1-40 peptide aggregation in vitro, and protected against Aβ-induced cytotoxicity in neuronal cells. Furthermore, the complexes differentiated between the aggregated and unaggregated forms of Aβ1-40 peptide on the basis of their emission response.

No MeSH data available.


Related in: MedlinePlus

Luminescence response of 2 μM of (a) 13 and (b) 14 in the absence or presence of 25 μM Aβ1–40 monomers or fibrils.λEx = 360 nm.
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f4: Luminescence response of 2 μM of (a) 13 and (b) 14 in the absence or presence of 25 μM Aβ1–40 monomers or fibrils.λEx = 360 nm.

Mentions: Encouraged by the promising activity of 13 and 14 against Aβ aggregation, we investigated that the luminescence behaviour of 13 and 14 towards different forms of Aβ1–40. The results showed that both complexes displayed a significantly enhanced luminescence response in the presence of the Aβ1–40 monomers or fibrils (Fig. 4). 13 exhibited ca. 6- and 12-fold emission enhancements at λmax = 540 nm in the presence of comparable mass concentrations of Aβ1–40 monomers and fibrils, respectively. On the other hand, 14 showed ca. 11- and 18-fold emission enhancements at λmax = 540 nm in the presence of Aβ1–40 monomers and fibrils. Taken together, these two Ir(III) complexes showed luminescence enhancement to the presence of Aβ1–40 monomers and fibrils to different extents. We presume that this behaviour of the Ir(III) complexes towards the Aβ1–40 peptide may be due to the ability of the complexes to bind to a hydrophobic region within the peptide, thus protecting the complexes from non-radiative decay by solvent quenching and thereby giving rise to an enhanced luminescence response. The differential luminescence response of the complexes towards Aβ1–40 monomers and fibrils may be due to the different microenvironments experienced by the Ir(III) complexes upon binding to the Aβ1–40 monomers or the fibrils.


Inhibition of Beta-Amyloid Fibrillation by Luminescent Iridium(III) Complex Probes.

Lu L, Zhong HJ, Wang M, Ho SL, Li HW, Leung CH, Ma DL - Sci Rep (2015)

Luminescence response of 2 μM of (a) 13 and (b) 14 in the absence or presence of 25 μM Aβ1–40 monomers or fibrils.λEx = 360 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4588514&req=5

f4: Luminescence response of 2 μM of (a) 13 and (b) 14 in the absence or presence of 25 μM Aβ1–40 monomers or fibrils.λEx = 360 nm.
Mentions: Encouraged by the promising activity of 13 and 14 against Aβ aggregation, we investigated that the luminescence behaviour of 13 and 14 towards different forms of Aβ1–40. The results showed that both complexes displayed a significantly enhanced luminescence response in the presence of the Aβ1–40 monomers or fibrils (Fig. 4). 13 exhibited ca. 6- and 12-fold emission enhancements at λmax = 540 nm in the presence of comparable mass concentrations of Aβ1–40 monomers and fibrils, respectively. On the other hand, 14 showed ca. 11- and 18-fold emission enhancements at λmax = 540 nm in the presence of Aβ1–40 monomers and fibrils. Taken together, these two Ir(III) complexes showed luminescence enhancement to the presence of Aβ1–40 monomers and fibrils to different extents. We presume that this behaviour of the Ir(III) complexes towards the Aβ1–40 peptide may be due to the ability of the complexes to bind to a hydrophobic region within the peptide, thus protecting the complexes from non-radiative decay by solvent quenching and thereby giving rise to an enhanced luminescence response. The differential luminescence response of the complexes towards Aβ1–40 monomers and fibrils may be due to the different microenvironments experienced by the Ir(III) complexes upon binding to the Aβ1–40 monomers or the fibrils.

Bottom Line: We report herein the application of kinetically inert luminescent iridium(III) complexes as dual inhibitors and probes of beta-amyloid fibrillogenesis.These iridium(III) complexes inhibited Aβ1-40 peptide aggregation in vitro, and protected against Aβ-induced cytotoxicity in neuronal cells.Furthermore, the complexes differentiated between the aggregated and unaggregated forms of Aβ1-40 peptide on the basis of their emission response.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.

ABSTRACT
We report herein the application of kinetically inert luminescent iridium(III) complexes as dual inhibitors and probes of beta-amyloid fibrillogenesis. These iridium(III) complexes inhibited Aβ1-40 peptide aggregation in vitro, and protected against Aβ-induced cytotoxicity in neuronal cells. Furthermore, the complexes differentiated between the aggregated and unaggregated forms of Aβ1-40 peptide on the basis of their emission response.

No MeSH data available.


Related in: MedlinePlus