Various coupling agents are disclosed to form lap joints between metallic and polymeric surfaces within catheters and other medical devices. The coupling agents disclosed in the present invention can be applied directly to a metallic surface, or the coupling agents may be incorporated within a polymeric material. In certain circumstances, the mere application of the coupling agent between the two dissimilar materials provides sufficient adhesive strength to form a fatigue-free lap joint bond. Alternative methods utilize coupling agents as primers for later thermal bonding and laser welding procedures that form lap joint bonds.