Abstract: The invention provides metal-chelating poly(ether amide) polymers useful in preparation of polymer compositions for delivering a variety of cargo molecules, such as bioactive agents. In solution metal ions and cargo molecules, such as vaccine epitopes, that include metal avid amino acids can be loaded into the polymer compositions and held in a non-covalent complex. Nanoparticles of such polymer compositions can also be prepared directly from the solution.

Abstract: The invention provides liposomal particle compositions, which incorporate a lipophilic biodegradable polymer, such as amino acid-containing polyester amide (PEA), polyester urethane (PEUR), and polyester urea (PEU), throughout the particles to stabilize the composition for in vivo delivery in of an incorporated biologic agent. For oral delivery, a biologic, such as insulin, is conjugated directly to the polymer. Lipids in the particle are selected to further stabilize the composition during fabrication and digestion, providing sustained delivery of the biologic with native activity. Methods of making and using the invention compositions to administer the biologic agent in vivo are also included.