Free-standing ultra-thing compliant nanocomposite membranes are good candidates for a new generation of membrane-based acoustic, pressure, and temperature sensor microarrays with high sensitivity, tremendous dynamic range, and built-in recovery ability. In this research, we fabricated compliant, highly-uniform, extremely robust, smooth, and long-living free-standing nanoscale membranes with excellent sensitivity. These membranes were fabricated from polyelectrolyte multilayers with and without an addition of a central interlayer containing gold nanoparticles. The central gold interlayer was used to enhance an optical response and detect surface plasmon resonances from membranes. These uniform nanoscale films with the thickness in the range from 30 to 80 nm for different numbers of layers were constructed with a spin-assisted LbL (SA-LbL) assembly. We exploited three different methods for characterization of membranes micro-mechanical properties. These methods allow to check membranes sensitivity in static and dynamic states and to obtain the value of elastic modulus and residual stress. From our measurements, we suggest that these compliant nanocomposite membranes can facilitate a new generation of membrane-based microsensor devices with lateral dimensions below 100 microns.