Microencapsulation methods and products are provided. The method includes forming, at a first temperature, a emulsion which comprises aqueous microdroplets, including the agent (e.g., a magnetic material or drug) and a cross-linkable matrix material (e.g., a protein such as albumin), dispersed in a hydrophobic continuous phase comprising an oil and an oil-soluble surfactant, the first temperature being below the temperature effective to initiate cross-linking of the matrix material, and then heating the emulsion to a temperature and for a time effective to cause the matrix material to self-crosslink, to form microparticles comprising the agent encapsulated by the crosslinked matrix material.