The present invention relates to a method for the preparation of polymer shells, preferably composed of cellulose or hemicellulose, comprising the steps of dissolving the polymer component in a first solvent, preferably an organic solvent and precipitating the polymer component by contacting the first solution with a second solvent, which second solvent has a polar character, and in which second solvent the polymer component is essentially insoluble, thereby obtaining polymer shells. Moreover, the invention refers to the polymer shells as such, having permeable and responsive properties, as well as various applications comprising such polymer shells within the fields of drug delivery, separation techniques, and inter alia filling material.
