Gold exhibits catalytic activities in many reactions. The activity depends on the specific surface of the material. For practical use, an immobilisation of gold nanoparticles (AuNP) is essential. We present a method for the immobilisation using embedding between a thermoplastic material and a functional polymer cover while retaining the catalytic activity. The AuNP were synthesized by a method of Turkevich and Frens. The particles had a diameter of 20 nm according to DLS measurements. Layers on substrates (glass or PTFE film) were formed with this solution and with a solution of polyethylenimine (PEI) by electrostatic deposition, beginning with a PEI layer. Up to three dipping cycles were applied. REM images of substrates after one dipping cycle showed a statistical lateral distribution of single particles over the surface with a degree of coverage of 50%. Additional AuNP of following dipping cycles attached in the vicinity of the pre-adsorbed under formation of a planar monolayer of AuNP. Through the substrate in the mould, AuNP were transferred to PC after injection moulding. Structure and function of these layers were characterised. REM images showed the same distribution as on the substrate. AFM investigations revealed a partly embedding of each AuNP in the PC. This picture was confirmed by TEM images. Moreover, the particles are partly covered by PEI according to EFTEM investigations and PEI was chemically bonded to PC due to melt temperature. The accessibility of AuNP on PC was proven with a catalytic reduction of methylorange, catalyzed by AuNP. The pure mixture of dye and sodium borohydride was stable over a long period of time. The optical absorbance decreased after the dipping of PC plates with AuNP in the solution what suggested, that AuNP on the surface were accessible to small molecules. The investigations demonstrated a method to produce thermoplastic parts with AuNP. The concept can be extended to other nanoparticles for a broad range of applications.