Textile fibers and other fibrous substrates functionalized with particles are provided for use in the detection of targets of interest by spectroscopic methods. In one embodiment, a substrate is provided that comprises a conformal coating on its surface, wherein the coating comprises a plurality of chemically functional particles that are spectroscopically enhancing. Methods for producing such functionalized textile fibers are also provided. These textiles can be used as platforms for spectroscopic detection, including surface-enhanced Raman scattering (SERS), surface-enhanced infrared absorption (SEIRA), and surface-enhanced fluorescence (SEF). Functionalized textile fibers for use in the signature detection methods are produced by performing layer-by-layer self-assembly of particles on natural and synthetic textile substrates.