Development of a fabric-based surface-enhanced Raman spectroscopy (SERS) sensor for rapid detection of human disease biomarkers

Abstract

Currently, there is a growing demand for continuous monitoring of human disease and the development of analytical techniques capable of reliably detecting and diagnosing various illnesses. The objective of this project was the development of inexpensive, sensitive, and reproducible substrates for surface-enhanced Raman spectroscopy (SERS), from metal-coated silk fabric. Potentially, these substrates could be incorporated into clothing and other textiles for regular monitoring of biomarkers in bodily fluids or air pollutants. The main focus of this work was the roughening of the fabric samples on the nanoscale, which is a required feature of SERS substrates. This was achieved through electrochemical methods and the deposition of nanoparticles. All synthesized nanoparticles were characterized by transmission electron microscopy and ultraviolet-visible spectroscopy. The substrates were characterized by scanning electron microscopy, as well as by the SERS signal of 4,4’-bipyridine (4,4’-byp) collected on their surface. It was found that in situ synthesis of silver colloids on the fabric was most effective method for obtaining reliable and sensitive substrates, and the incubation of the fabric in gold nanoflowers provided a uniform and reproducible SERS substrate. The detection of 4,4’- byp on these surfaces was achieved with ease, whereas the biomolecules 2’-deoxyguanosine 5’-monophosphate, and guanosine could not be detected. A single band for guanine was identified in the SERS spectrum collected on a fabric substrate. Interference from the silk fibers, citrate and other reagents used in the synthesis of nanoparticles was identified as a key obstacle in the fabrication of fabric substrates for the detection of biomolecules by SERS.