Fig. 5

Compositional map of intracellular water pool. a Averaged minimum and maximum SREF peak frequencies of C\(\equiv\)N on Rh800 in cells. The minimum \(\bar \nu_{{\mathrm{C}} \equiv {\mathrm{N}}}\) (mean ± s.d.) is 2234.9 ± 0.6 cm⁻¹ and maximum \(\bar \nu_{{\mathrm{C}} \equiv {\mathrm{N}}}\) (mean ± s.d.) is 2242.6 ± 0.8 cm⁻¹ averaged over 21 HeLa cells. Solid line and dashed line show in vitro \(\bar \nu_{{\mathrm{C}} \equiv {\mathrm{N}}}\) in pure water (2242.4 cm⁻¹) and DMSO (2234.9 cm⁻¹), respectively. b Linear calibration curve between bound water volume percentage and the SREF peak frequency. c Intracellular map for the bound-water state: 64% in cytoplasm and 35% in nucleus on average were estimated from b. Error bars represent standard deviations for 21 cells