Fig. 2.

a) TEM micrograph showing the IgG within the solid silica matrix and b) APT reconstruction of a single IgG molecule showing the spatial distribution of ${\mathrm{C}\mathrm{N}\mathrm{H}}_2^{+}$ and $\mathrm{C}{\mathrm{O}}_{\mathrm{2}}^{+}$ c) carbon isodensity heat maps derived from two different techniques 1 and 2: human IgG derived from X-ray diffraction [59] and 3 and 4 rabbit IgG derived from APT [60].