Abstract: Compositions, methods and kits are provided for altering the properties of a biological surface using particles such as, for instance, calcium based particles in combination with an agent that binds to the biological surface. Properties such as color, sheen, texture, strength, and odor of biological surfaces such as teeth and bone are alterable.

Abstract: The present invention generally relates to polymers and macromolecules, in particular, to polymers useful in particles such as nanoparticles. One aspect of the invention is directed to a method of developing nanoparticles with desired properties. In one set of embodiments, the method includes producing libraries of nanoparticles having highly controlled properties, which can be formed by mixing together two or more macromolecules in different ratios. One or more of the macromolecules may be a polymeric conjugate of a moiety to a biocompatible polymer. In some cases, the nanoparticle may contain a drug. Other aspects of the invention are directed to methods using nanoparticle libraries.