The invention relates to a method for the preparation of porous polymeric fibres comprising functionalised or active particles. By extruding a mixture of one or more dissolved polymers with particulate material a porous fibre is obtained in which the particulate material is entrapped. Extrusion of the fibre occurs under two-step phase inversion conditions. In particular the porous fibres can be used for the isolation of macromolecules such as peptides, proteins, nucleic acids or other organic compounds from complex reaction mixtures, in particular from fermentation broths. Another application is the immobilisation of a catalyst in a reaction mixture.
