Deciphering Density Fluctuations in the Hydration Water of Brownian Nanoparticles via Upconversion Thermometry.

ABSTRACT: We investigate the intricate relationship among temperature, pH, and Brownian velocity in a range of differently sized upconversion nanoparticles (UCNPs) dispersed in water. These UCNPs, acting as nanorulers, offer insights into assessing the relative proportion of high-density and low-density liquid in the surrounding hydration water. The study reveals a size-dependent reduction in the onset temperature of liquid-water fluctuations, indicating an augmented presence of high-density liquid domains at the nanoparticle surfaces. The observed upper-temperature threshold is consistent with a hypothetical phase diagram of water, validating the two-state model. Moreover, an increase in pH disrupts the organization of water molecules, similar to external pressure effects, allowing simulation of th

SUBMITTER: Maturi FE 

PROVIDER: S-EPMC10926164 | biostudies-literature | 2024 Mar

REPOSITORIES: biostudies-literature