Nanogap electrodes (NGEs) are a fundamental structure for the exploration of nanoscale phenomena. In this paper, we describe the fabrication and the electro-mechanical characterization of tunable tunneling NGEs on a stretchable PDMS substrate. Bottom-up capillary-assisted particle assembly (CAPA) in nano-scale traps is used to fabricate Au nanorod dimers as NGEs. The nanogap is tuned by the contraction due to the Poisson effect of the PDMS substrate. Finite element method (FEM) simulations are performed to quantify how the NGEs design affects the local Poisson contraction under applied tensile strain. The application of the proposed approach for strain sensing is discussed.