A method for incorporating a biomolecule into a cell including the steps: i) production of a complex from a biomolecule and a polymer which may be obtained by reaction of an amine monomer having at least two amine groups with an epoxide monomer having at least two epoxide groups and ii) incorporation of the biomolecule into a cell bx bringing the cell into contact with the complex. The invention further relates to the transformed cell obtained by said method, the use of a particular polymer for incorporation of a biomolecule into a cell, a kit for incorporation of a biomolecule into a cell, the use of said kit, a complex made from a biomolecule and a polymer, a therapeutic composition, the use of a complex of a biomolecule and a polymer for therapeutic treatment and a method for treatment of a disease by gene therapy.
