The present invention relates to the use of certain microspheres, nanospheres, and other structures to provide a method of marking or masking identifying marks in individual biological hosts. Biological hosts for the present invention may include humans, other animals, or plants. Such methods may be used to sense, signal, track, mark, or identify individual biological hosts. Microspheres, nanospheres, and other structures of the present invention may be implanted, injected, ingested, or attached to individual biological hosts. Microspheres, nanospheres, and other structures of the present invention comprise poly[bis(trifluoroethoxy)phosphazene] and/or a derivative thereof which may be present throughout the particles or within an outer coating of the particles. The microspheres, nanospheres, and other structures may also comprise a core having a hydrogel which may further comprise one or more dyes or other chromophoric agents covalently bound permanently to the hydrogel core material. The microspheres, nanospheres, and other structures and/or the hydrogel core may further comprise radio frequency or other electronic chips or nanochips, capable of transmitting and/or receiving electronic signals from external transmitters and/or receivers.