Conjugates of an active agent such as a therapeutic, prophylactic, or diagnostic agent attached to an HSP90 targeting moiety via a linker have been designed. Nanoparticles and microparticles comprising such conjugates can provide improved temporospatial delivery of the active agent and/or improved biodistribution. Methods of making the conjugates, the particles, and the formulations thereof are provided. Methods of administering the formulations to a subject in need thereof are provided, for example, to treat or prevent cancer or other diseases.