The invention provides novel nanoparticles with tunable and multi-color afterglow emission for extended time after excitation, and compositions thereof as well as methods for their preparation and use in various applications.

A double fluorescent particle comprises: a core with a first fluorescence; and a molecularly imprinted polymer (MIP) shell with a second fluorescence; wherein the MIP is an organic polymer comprising elements selected from the group consisting of: C, H, O, N, P, and S; wherein the MIP is adapted to selectively bind to a cell surface structure; wherein the first fluorescence is generated by an entity selected from the group consisting of: a carbon nanodot, an alkaline earth metal fluoride, a dye-doped polymer, a dye-doped stabilized micelle, a P-doti.e. a -conjugated polymer, a quantum dot doped polymer, a rare earth metal ion doped polymer, a dye-doped silica, a rare-earth ion doped silica, and a rare earth ion doped alkaline earth metal fluoride nanoparticle; wherein the second fluorescence is generated by an entity selected from the group consisting of: a dye, a molecular probe, an indicator, a probe monomer, an indicator monomer, and a cross-linker, and wherein the first and second fluorescence differ at least by an emission wavelength and/or by an excitation wavelength.