Sers Detection of Polyaromatic Hydrocarbons on a -Cyclodextrin Containing Polymer Brush

Abstract

We have designed a new surface-enhanced Raman scattering (SERS) sensor composed of -cyclodextrin (-CD) containing poly(glycidyl methacrylate) (PGMA) brush coated silicon substrate and per-6-deoxy-(6-thio)--cyclodextrin (-CD-SH) modified gold nanoparticles for detection of polyaromatic hydrocarbons (PAHs; pyrene and anthracene). The -CD containing PGMA brushes were synthesized by the interface-mediated Reversible addition-fragmentation chain transfer (RAFT) polymerization of glycidyl methacrylate and followed an epoxide ring-opening reaction to attach -CD molecules. Some PAHs, such as pyrene and anthracene, can be introduced into the hydrophobic space of -CD, which allows them to detect the SERS of PAHs. After separating pyrene or anthracene from the solution by the -CD containing PGMA brush coated silicon substrate, they were sandwiched with the SERS substrate consisting of per-6-deoxy-(6-thio)--cyclodextrin and rhodamine 6G (Raman reporter) on gold nanoparticles. The correlation between PAH concentrations and SERS signal was found to be linear in the range of 2.5 to 10nM for anthracene and 10 and 25nM for anthracene. The limit of detection values for pyrene and anthracene are 0.8 and 2.4nM, respectively. Furthermore, the SERS sensor was also evaluated for the investigation of pyrene or anthracene specificity on different organic molecules and polyaromatic hydrocarbons.