Journal: bioRxiv

Article Title: Multivalency controls the growth and dynamics of a biomolecular condensate

doi: 10.1101/2025.02.01.636084

Figure Lengend Snippet: (a) Schematic of PopZ protein condensate formation in the presence of magnesium ions (Mg 2+ ), shown alongside a DIC microscopy image of PopZ condensates. The image highlights their spherical morphology. Scale bar: 5 µm. (b) Diagram of the holographic characterization setup for condensate analysis, which employs a microfluidic channel to flow samples through a laser-based holographic microscope. The objective lens captures the scattered light to produce holograms that are subsequently analyzed to extract physical parameters, including diameter d p , and refractive index, n p . The scatter plot illustrates the measured n p and d p values for 4383 condensate droplets, with colors representing the probability density, P ( n p , d p ). The horizontal dashed line indicates the mean refractive index, n p = 1.359 21 ± 0.000 03. (c) Violin plots of PopZ condensate size distributions across a range of Mg 2+ concentrations (50 µM to 250 µM) at two initial PopZ concentrations (50 µM and 10 µM). Holographic microscopy provides consistent size measurements without substrate effects, outperforming traditional DIC microscopy.

Article Snippet: Imaging was performed using a confocal laser scanning microscope (Abberior), and at least three 80 μm × 80 μm ROIs were collected per condition.

Techniques: Microscopy, Refractive Index