Core-shell particles have a hydrophobic core and a shell formed of o containing hyperbranched polymers (HP). The HP can be covalently bound to the one or more materials that form the core or coated thereon. The HP coating can be modified to adjust the properties of the particles. For example, unmodified HP coatings resist non-specific protein absorption. Alternatively, the hydroxyl groups on the HP coating can be chemically modified to form functional groups that react with functional groups on tissue to adhere the particles to the tissue, cells, or extracellular materials, such as proteins. Such functional groups include, but not limited to, aldehydes, amines, and O-substituted oximes. Topical formulation for application to the skin contain these HP coated nanoparticles. In some embodiments, the particles include cosmetic, therapeutic, diagnostic, nutraceutical, and/or prophylactic agents, such as those used as sunblock compositions.