Correlative contrast agents -visible in multiple imaging modalities are limited. Semiconductor quantum dots are visible in X-ray CT, fluorescence, and electron microscopy, but tools to localize QDs to specific biomolecules, revealing their location in multiple length scales/resolutions are not stoichiometrically quantitative (e.g., QDantibody conjugates, VIPER. An overarching goal of bio-imaging is to integrate and understand biological processes from length scales ranging from meters to angstroms. Correlative contrast agents that are visible in X-ray, optical, and electron-based images do not yet exist. Such agents could facilitate correlative visual studies across all biologically relevant length scales. This arises both from the ability to correlate images from different modalities and also simply to locate in a meter-scale images the proteins of interest to image in mm and nm scale imaging modalities.