202405221743

• Source: [[ @spackova2022 Label-free nanofluidic scattering microscopy of size and mass of single diffusing molecules and nanoparticles ]]
• Tags: #nanoparticle-sizing #molecular-weigth #nanoparticle-tracking-analysis #nanoparticle-tracking-in-channels

The principle of operation of 202405221125 Nanofluidic Scattering Microscopy (NSM) is very similar to that of the NanoCET (and the challenges are similar.) However, since they use an interferometric detection scheme, they can increase the dynamic range (in essence, the signal scatters as $d^3$ instead of $d^6$). See: nanoparticle tracking in hollow optical fibers , and also see: increase the number of frames for tracking by confining the movement of a nanpoarticle .

To prove the usefulness of the method, they focused on smaller proteins:

Two things are very interesting to note: they are able to detect dimers of proteins, since they scale linearly with molecular weight (and they prove the relationship between molecular weight and $iOC$, or interferometric optical contrast).

On the other hand, the size distribution they get from measuring the diffusion coefficient is very broad (check for smaller $R$, the uncertainty in $D$ is almost 100%).