Fig. 3: Diffusiophoresis enhances the transport of biomolecules.

Diffusion experiments for individual biomolecules where either only (a, b) [dT]₄₀ or (c, d) [RGRGG]₅ are introduced to the side channel in the (a, c) absence (c₁ = c₂ = 20 mM) or (b, d) presence or NaCl gradients (c₁ = 20 mM, c₂ = 1 mM). For these experiments, we used Cy5-labeled [dT]₄₀ (1.2 mol% of the total [dT]₄₀) and Alexa488-labeled [RGRGG]₅ (3.7 mol% of the total [RGRGG]₅). The top panels are the fluorescence images and the bottom panels are width-averaged intensity profiles. The dashed curves are generated using Eq. 1. e The time-averaged diffusiophoretic mobility <M> for [dT]₄₀ (yellow circles) and [RGRGG]₅ (blue triangles) molecules in monovalent chloride salts of diffusivity contrast β. The dash lines represent the best linear fitting of the mobility and β. The mobility tends to zero as β approaches zero, indicating a negligible effect of chemiphoresis. Source data are provided as a Source Data file.