Proton-Coupled Electron Transfer in the Aqueous Nanochannels of Lyotropic Liquid Crystals: Interplay of H-Bonding and Polarity Effects.

A molecular-level description of the aqueous nanochannels in lyotropic liquid crystals (LLCs) is crucial for their widespread utilization in diverse fields. Herein, the polarity and hydrogen bonding effects of LLC water molecules have been simultaneously explored using a single probe, 4'-N,N-dimethylamino-3-hydroxyflavone (DMA3HF), by the unique multiparametric sensitivity of the excited state proton-coupled electron transfer (PCET) phenomenon. The decreased ESIPT efficiency and the significantly retarded ESIPT dynamics (>20 times) of DMA3HF in the LLC phases suggests the dominant influence of strong hydrogen-bonded solute-solvent complexes that leads to a high activation barrier for ESIPT in the mesophases.

Peculiar hydrogen bonding behaviour of water molecules inside the aqueous nanochannels of lyotropic liquid crystals.

In spite of the widespread utilizations of lyotropic liquid crystals (LLCs) in food technology, as nanoreactors and in biomedical fields, the exact nature of their aqueous nanochannels which are deemed to dictate these applications are not completely understood. In this context, elucidation of the hydrogen bonding properties of the water molecules inside the nanochannels will contribute towards obtaining a complete picture of the LLC materials. In this study, we use two molecules exhibiting an excited state intramolecular proton transfer (ESIPT), fisetin and 3-hydroxyflavone, to determine the hydrogen bond donating and accepting parameters of the LLC water molecules.

Structural characteristics requisite for the ligand-based selective detection of i-motif DNA.

Here, we have explored the light-up property of coumarin 343 (C343) selectively towards various i-motif DNAs based on the recognition of hemi-protonated cytosine-cytosine base pairing, unlike other DNA structures. We have also demonstrated the versatile ability of this i-motif ligand, i.e.

Impact of Topology on the Characteristics of Water inside Cubic Lyotropic Liquid Crystalline Systems.

Water molecules present inside the lipid-based cubic liquid crystalline phases are found to play a major role in wide range of applications, such as protein crystallization, virus detection, delivery of drug and biomolecules, etc. In this regard, it is crucial to elucidate static and dynamic properties of the water molecules in the nanochannels and to explore the effect of geometrical topology on the nature of the water inside the different cubic phases. In the present work, we have incorporated two probes, coumarin-343 (C-343) and coumarin-480 (C-480), in two cubic phases with different symmetries, namely gyroid ( Ia3 d) and double diamond ( Pn3 m) with the same water content (22%), to probe the micropolarity, the microviscosity, and the hydration dynamics at different hydrophobic depths in the mesophases.

Silica nano-channel induced i-motif formation and stabilization at neutral and alkaline pH.

Here, we have developed a new strategy to stabilize i-motif DNA in neutral and alkaline media by incorporating C-rich sequences inside silica nano-channels. Subsequently, the reversibility of this conformational transition has been achieved using a positively charged protein. Importantly, this entire conformational transition can be performed in multiple cycles, which offers an alternative way to control i-motif formation other than pH and thermal annealing.