the invention provides polymer particles that are obtainable by a method selected from emulsion methods , diffusion methods and evaporation methods carried out in the presence of surface - engineering surfactant which is one or more polymer that displays a lower critical solution temperature , in aqueous media , that is between 10 to 90 ° c ., this polymer being the polymerisation product of one or more monomer selected from polymerisable alkyleneglycol acrylate monomers and polymerisable alkyleneglycol methacrylate monomers . the polymer particles can be used in controlled release applications , such as flavour release applications , fragrance release applications and biomedical applications . the invention also provides a cell support matrix comprising the polymer particles .