Nuclear Quantum Effects on the Dynamics of Bulk Water and Supercooled Aqueous Solutions

≈ 1.3, consistent with quantum simulations attributing this difference to NQEs. At supercooled temperatures (200 K), the isotope ratio ρ increases moderately to ≈2 in neutral poly(vinyl methyl ether) solutions, and reaches ≈4 for fast-water relaxation in basic lysine solutions, revealing a 3-fold enhancement of NQEs. These findings demonstrate that biological environments can amplify the magnitude of NQEs on water dynamics, with implications for biochemistry and quantum-accurate aqueous modeling.