Fig. 2: Diffusivity-time traces, histograms, and state lifetimes for an oligonucleotide sandwich assay using particles with a diameter of 1 and 2.8 μm.

a Diffusivity D measured over a 5-min period showing unbound states (blue) and bound states (orange). b Distributions of D derived from the single-particle traces in panel a. The characteristic D of 1 and 2.8 μm particles differ by approximately a factor 4. c D distributions for hundreds of particles. d Distribution of unbound state lifetimes plotted as survival curves (1 - CDF, with CDF = Cumulative Distribution Function), for 1 and 2.8 μm particles with similar biofunctionalization and target concentration ([T] = [ssDNA target], Supplementary Table 2). Larger particles show shorter unbound state lifetimes than smaller particles for comparable conditions. The inset shows a zoom in of the data on linear scales. e Survival plot as in panel d, for bound state lifetimes. Curve segments are attributed to short-lived monovalent bonds and longer-lived multivalent bonds. The inset shows a zoom in of the data on linear scales, highlighting that the bound state lifetime of single-molecular bonds does not depend on the size of the particles. Source data are provided as a Source Data file.