Mapping granular structure in the biological adhesive of Phragmatopoma californica using phase diverse coherent diffractive imaging

► We demonstrate lensless imaging of the biological adhesive of the sandcastle worm. ► Phase diverse coherent diffractive imaging (CDI) provides high contrast images. ► The high sensitivity of phase diverse CDI elucidates fine structure within the sample. ► Quantitative imaging is achieved with a low X-ray dose, minimising sample damage. ► The work shows phase diverse CDI to be a useful microscopy technique for biology.