Chiral Water Strongly Couples to N−H Groups of Chiral Biomolecular Assembly but Decouples from the Nearby Achiral Interfacial Water and Bulk Water

Insights into the imprint of biomolecular chirality on the hydration water of biomolecules are crucial for comprehending biomolecular function and the molecular origin of biological homochirality in life, yet they remain poorly understood. In this study, we successfully constructed chiral water superstructures templated by a chiral biomolecular assembly under ambient conditions and performed the first investigation of its ultrafast vibrational dynamics by utilizing femtosecond time-resolved chiral sum frequency generation vibrational spectroscopy (SFG-VS). Chiral biomolecular templates were prepared by assembling achiral amphiphilic molecules into chiral superstructures with C₁ point group symmetry at the lipid membrane surface. The formation of chiral water superstructure is dictated by the amide moieties of the chiral biomolecular assembly, particularly by the N-H group with the C₁ point group. The vibrational relaxation time of chiral water (0.8 ± 0.1 ps) is identical to that of the N-H group but significantly longer than that of both bulk water and typical interfacial achiral water (≤ 0.3 ps). This indicates that chiral water strongly couples with the N-H vibrational mode but decouples from nearby achiral interfacial water and bulk water. Chiral water exhibits distinctly different behavior from achiral water. Our findings highlight the significant role of chiral water in vibrational energy redistribution and propagation within biomolecules and contribute to understanding the mechanism of chirality generation and transfer.