Visual detection of cobalt(II) ion in vitro and tissue with a new type of leaf-like molecular microcrystal

A novel type of leaf-like poly (p-phenylenediamine) (PpPD) microcrystal was prepared under mild conditions, which was successfully applied to the visual detection of Co2+ in vitro and in tissue based on the extinction and light scattering features owing to the special etching effect of Co2+ on the surface of the leaf-like microcrystal.