“…Surface-enhanced Raman spectroscopy (SERS) has emerged as one of the most versatile tools for sensing environmental control, biomedicine analysis, security, a criminal investigation, agriculture, among others. − This technique offers an enormous enhancement factor (as high as 10 10 to 10 14 orders) over traditional Raman signal intensity issues, with high sensitivity and capability of single-molecule detection (SMD). ,,, SERS-based molecular detection can be achieved using metallic nanostructures as plasmonic nanoantennas to amplify Raman signals, mostly using silver or gold nanoparticles in colloidal suspension or nanostructured metallic films. ,− The enhanced-Raman signal using metallic nanostructures is particularly strong at nanoscopically sharp corners, tips, and mainly in interparticle gaps called hot spots. In this sense, gold nanorods (AuNRs) have attracted extensive attention and scientific interest for SERS due to their anisotropic shape and the strong coupling with the electromagnetic field. ,− Briefly, the transverse and longitudinal plasmonic resonance bands (TPR and LPR, respectively) of AuNRs bring fascinating optical properties for SERS applications. ,, Even more exciting is the LPR wavelength position finely tuned from visible to near-infrared by adjusting the nanoparticle aspect ratio. ,,− It is a fundamental characteristic since the Raman intensity is strongly dependent on the nanoparticle aspect ratio with the magnitude of SERS enhancement crucially reliant on the assembly and organization of metallic nanoparticles to obtain reproducible signals.…”