Low-Cost Surface Enhanced Raman Scattering for Bio-Probes

Abstract

Raman Spectroscopy is a well-known method for identifying molecules by their spectroscopic “fingerprint”. In Surface Enhanced Raman Scattering (SERS), the presence of nanometallic surfaces in contact with the molecules enormously enhances the spectroscopic signal. Raman enhancing surfaces are often fabricated lithographically or chemically, but the throughput is low and the equipment is expensive. In this work a SERS layer was formed by the self-assembly of silver nanospheres from a hexane suspension onto an imprinted thermoplastic sheet (PET). In addition, the SERS layer was transferred and securely bonded to other surfaces. This is an important attribute for probes into solid specimen. Raman spectra were obtained with Rhodamine 6G (R6G) solution concentrations ranging from 1 mm to 1 nm. The methods described here produced robust and sensitive SERS surfaces with inexpensive equipment, readily available materials, and with no chemical or lithographic steps. These may be critical concerns to laboratories faced with diminishing funding resources.

Recent Progress in Nanotechnology-Based Approaches for Food Monitoring

“…The Raman spectrum provides information about the rotation and vibration of the analyzed molecules, opening a novel fingerprint for molecular recognition. However, the Raman scattering effect is generally 10 10 –10 14 times lower than infrared and fluorescent signals, making the Raman scattering effect not applicable for the recognition of contaminants at low concentrations [ 125 , 126 , 127 ]. Scientists discovered that when the analyzed samples are located in close proximity or adsorbed to a nanostructured metal (such as gold and silver), the incident light passing through the sample produces a massive intensification of Raman scattering, also known as SERS [ 128 , 129 , 130 ].…”