Yes, sodium polyacrylate is used in both expansion microscopy and baby diapers.
However you also need a few other ingredients to ensure isotropic expansion, or otherwise the expanded sample isn't scaled uniformly in all axis and you get a skewed view of the sample.
However you also need a few other ingredients to ensure isotropic expansion, or otherwise the expanded sample isn't scaled uniformly in all axis and you get a skewed view of the sample.