A key challenge to the creation of chemically responsive electro-functionality of nonconductive, hydrophobic, and free-contacted textile or fibrous network materials is how to impart the 3D structure with functional filaments to enable responsive structure sensitivity, which is critical in establishing the fibrous platform technology for sensor applications. We demonstrate this capability using an electrospun polymeric fibrous substrate embedded with nano-filaments defined by size-tunable gold nanoparticles and structurally sensitive dendrons as crosslinkers. The resulting interparticle properties strongly depend on the assembly of the nano-filaments, enabling an interface with high structure sensitivity to molecular interactions. This is demonstrated with chemiresistive responses to vaporous alcohol molecules with different chain lengths and isomers, which is critical in breath and sweat sensing involving a high-moisture or -humidity background. The sensitivity scales with the chain length and varies with their isomers. This approach harnesses the multifunctional tunability of the nano-filaments in a sensor array format, showing high structure sensitivity to the alcohol molecules with different chain lengths and isomers. The high structure sensitivity and its implications for a paradigm shift in the design of textile sensor arrays for multiplexing human performance monitoring via breath or sweat sensing and environmental monitoring of air quality are also discussed.