Construction of a DNA‐Based Supramolecular Nanosheet That Emits Bluish‐White Light from Charge‐Transfer Excited States of the Nucleobases

Abstract

1,ω‐Inosinic acid‐bearing bolaamphiphiles dI(18), dI(19), and dI(20) with a 3′‐phosphorylated inosine as a universal base connected to each end of an oligomethylene chain were synthesized for the first time. Single‐component self‐assemblies of these bolaamphiphiles and their binary self‐assemblies with salmon sperm DNA were studied by AFM; temperature‐dependent UV absorption, fluorescence, and circular dichroism spectroscopy; and gel electrophoresis. The binary self‐assembly of dI(20) and salmon sperm DNA (dI(20)‐DNA) had a nanosheet structure with a homogeneous thickness of about 6 nm and widths of several micrometers. Interestingly, an aqueous solution of the nanosheets showed a broad absorption band originating from the charge‐transfer (CT) states of the nucleobase in the long‐wavelength region (>300 nm), and the molar absorptivity per nucleobase was calculated to be approximately 150 times that of single‐stranded (dT20 and dA20) and double‐stranded (dT20‐dA20) oligonucleotides. In addition, a continuous and broad emission band originating from CT excited states of the nucleobases was observed in the visible region. These observations indicate that CT states of the nucleobases were formed and stabilized in the supramolecular nanosheet and that bluish white light was emitted from CT excited states of the nucleobases.

Photoswitchable architecture transformation of a DNA-hybrid assembly at the microscopic and macroscopic scale

“…1A). 2,45,46 However, the dynamical regulation of these supramolecular architectures and their properties necessitate an external control element to grant an additional level of functionality. Several stimuli have been explored in the context of DNAstructure regulation and DNA hybrid architectures.…”

Probing metal-dependent G-quadruplexes using the intrinsic fluorescence of DNA

“…420 nm. 16,19 On the other hand, fluorescence in the red visible region has been observed in 20-mer strands of all compositions, which was applied for biological imaging. 20 Due to the weak nature of this fluorescence, studies have mainly focused on characterizing its origins rather than exploring biochemical or analytical applications.…”