title: Large-area, uniform and low-cost dual-mode plasmonic naked-eye colorimetry and SERS sensor with handheld Raman spectrometer.
abstract: We demonstrated a highly-sensitive, wafer-scale, highly-uniform plasmonic nano-mushroom substrate based on plastic for naked-eye plasmonic colorimetry and surface-enhanced Raman spectroscopy (SERS). We gave it the name FlexBrite. The dual-mode functionality of FlexBrite allows for label-free qualitative analysis by SERS with an enhancement factor (EF) of 10(8) and label-free quantitative analysis by naked-eye colorimetry with a sensitivity of 611 nm RIU(-1). The SERS EF of FlexBrite in the wet state was found to be 4.81 × 10(8), 7 times stronger than in the dry state, making FlexBrite suitable for aqueous environments such as microfluid systems. The label-free detection of biotin-streptavidin interaction by both SERS and colorimetry was demonstrated with FlexBrite. The detection of trace amounts of the narcotic drug methamphetamine in drinking water by SERS was implemented with a handheld Raman spectrometer and FlexBrite. This plastic-based dual-mode nano-mushroom substrate has the potential to be used as a sensing platform for easy and fast analysis in chemical and biological assays.
authors.affiliation: Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. xuzhida1108@gmail.com loganliu@illinois.edu.
authors.forename: Zhida
authors.initials: Z
authors.lastname: Xu
authors.forename: Jing
authors.initials: J
authors.lastname: Jiang
authors.forename: Xinhao
authors.initials: X
authors.lastname: Wang
authors.forename: Kevin
authors.initials: K
authors.lastname: Han
authors.forename: Abid
authors.initials: A
authors.lastname: Ameen
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Khan
authors.forename: Te-Wei
authors.initials: TW
authors.lastname: Chang
authors.forename: Gang Logan
authors.initials: GL
authors.lastname: Liu