Provided are polymers (e.g., polymeric materials), nanoparticles comprising one or more of the polymers, and compositions. A polymer may be in the form of a nanoparticle. A polymer can be linear or branched. A polymer includes one or more poly(ester urea) segment, optionally, one or more poly(urethane) segment, optionally, one or more diol segment, optionally, one or more poly(ethylene glycol) segment, and, optionally, one or more terminal/end group. A polymer (e.g., a polymeric material) may include a branching moiety. For example, a composition includes one or more polymer. In an example, polymers and nanoparticles can be used to deliver a drug (e.g., gambogic acid) to an individual (e.g, who has been diagnosed with or is suspected of having cancer and/or a viral infection).
