A characterisation of dark-field imaging of colloidal gold labels in a scanning transmission X-ray microscope

Using scanning transmission X-ray microscope, high-angle dark-field images of cells with colloidal gold labels, with and without silver enhancement, are characterized. The high density of the colloidal gold particles, or the silver particles seeded by the gold, leads to a large scattering signal, and the fact that the particle diameters are comparable to the width of the microscope point spread function results in good localization of the label with high contrast. The dark-field images can have greater signal to noise ratio that bright-field images acquired with the same incident X-ray dose.