Chiroptical property enhancement of chiral Eu(III) complex upon association with DNA-CTMA

Haruki Minami,Wataru Watanabe,Ziying Li,Natsumi Itamoto,Kazuki Nakamura,Norihisa Kobayashi

doi:10.1038/s41598-020-75808-w

Haruki Minami, Wataru Watanabe + Show 4 more

Open Access

https://doi.org/10.1038/s41598-020-75808-w

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Journal: Scientific Reports	Publication Date: Nov 3, 2020
Citations: 9	License type: open-access

Affiliation: Chiba University

Abstract

DNA-based materials have attracted much attention due to their unique photo-functional properties and potential applications in various fields such as luminescent and biological systems, nanodevices, etc. In this study, the photophysical properties of a chiral Eu(III) complex, namely (Eu(D-facam)3), within DNA films were extensively investigated. The enhancement of photoluminescence (more than 25-folds increase of luminescence quantum yield) and degree of circularly polarization in luminescence (glum = − 0.6) was observed upon interaction with DNA. Various photophysical analyses suggested that the emission enhancement was mainly due to an increase of the sensitization efficiency (high ηsens) from the ligands to Eu(III) and suppression of the vibrational deactivation upon immobilization onto the DNA molecule. From CD and VCD measurements, it was suggested that the coordination structure of Eu(D-facam)3 was affected by the interaction with DNA, suggesting that the structural change of Eu(D-facam)3 contributed to the improvement of its luminescent properties.

Highlights

DNA-based materials have attracted much attention due to their unique photo-functional properties and potential applications in various fields such as luminescent and biological systems, nanodevices, etc
From circular dichroism (CD) and Vibrational circular dichroism (VCD) measurements, it was suggested that the coordination structure of Eu(D-facam)[3] was affected by the interaction with DNA, suggesting that the structural change of Eu(D-facam)[3] contributed to the improvement of its luminescent properties
Since DNA is soluble only in water whereas Eu(D-facam)[3] is insoluble in water, DNA is modified with CTMA, which is one of the most typical surfactants utilized for biomolecules

Summary

Introduction

DNA-based materials have attracted much attention due to their unique photo-functional properties and potential applications in various fields such as luminescent and biological systems, nanodevices, etc. DNA possesses the unique ability to incorporate various types of functional materials like metal complexes[4,5], organic dyes[6,7], and conductive polymers[8], leading to an enhancement of their photo-functional properties. This ability can be mainly attributed to the electrostatic properties of the phosphate group, selective affinity for small molecules by intercalation and binding of specific molecules into its g rooves[9,10,11]. Aiming to develop improved DNA-based photo-functional materials, this study focuses on DNA/Eu(III) complexes in view of their characteristic optical properties. Chiral Eu(III) complexes exhibit chiral optical properties like circular dichroism (CD) and circularly polarized luminescence (CPL)[29,30]. A higher luminescence intensity and |glum| of CPL were achieved from Eu(D-facam)[3] compared with the conventional polymer upon interaction with DNA

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