Gold nanoparticle-functionalized thread as a substrate for SERS study of analytes both bound and unbound to gold

The potential of thread for use as a substrate for inexpensive, disposable diagnostics for surface-enhanced Raman scattering (SERS) spectroscopy has been showed in this study. Gold-nanoparticle coated thread can be embedded into fabrics to detect chemical or biological analytes in military and medical applications through SERS. Using this inexpensive and widely available material enables reduction in the volumes of nanoparticle solution required compared to alternatives. By testing multiple analytes, it was observed that molecular structure played a significant role in SERS signal amplification, and hence, the technique is limited to the detection of a small number of analytes possessing highly polarizable structures. Although direct chemical bonding between analyte molecules and nanoparticles gives the strongest signal enhancement, it remains possible to easily discern signals generated by analytes not directly bound, provided they possess suitable structure. Amplification of SERS signal by controlling the aggregation state of the gold nanoparticles to increase the number of SERS hotspots was observed. (c) 2014 American Institute of Chemical Engineers AIChE J, 60: 1598-1605, 2014