Surface-enhanced molecular spectroscopy (SEMS) based on perfect-absorber metamaterials in the mid-infrared

Abstract

Surface-enhanced infrared absorption spectroscopy has attracted increased attention for direct access to molecular vibrational fingerprints in the mid-infrared. Perfect-absorber metamaterials (PAMs) with multi-band spectral responses and significant enhancement of the local near-field intensity were developed to improve the intrinsic absorption cross sections of absorption spectrum to identify the vibrational spectra of biomolecules. To verify its performance, the proposed infrared PAM array was used to identify the molecular stretches of a Parylene C film. The resonant responses of the infrared PAMs were accurately tuned to the vibrational modes of the C = C target bonds. The vibrational stretches of the C = C moiety were observed and the auto-fluorescence mechanisms of the Parylene C film were monitored. The unique properties of the PAMs indicate that this approach is a promising strategy for surface-enhanced molecular absorption spectroscopy (SEMS) in the mid-infrared region and for the tracking of characteristic molecular vibrational modes.

Versatile Direct Laser Writing Lithography Technique for Surface Enhanced Infrared Spectroscopy Sensors

“…Compared to the fabrication methods listed above, like EBL, DLW benefits from practically ultimate freedom in the positioning and the design of the shape of the nano-structures: it obviates the need for manufacturing of pre-defined masks (which are required for stencil lithography and UV photolithography), and the resulted nano-structures are independent of the size of the spheres as in the case of colloidal and spherical-lens lithography. With recently emerged new designs of SEIRA nano-structures which depart from simple bar-shaped antennas, the introduction of a flexible and fast fabrication method that can serve as an alternative to EBL is of great interest 13,14,[17][18][19] . In this work we report the fabrication and testing of SEIRA chemical sensor based on an alternative approach for using TPP-DLW to fabricate large arrays of nano-structures.…”

Periodic array-based substrates for surface-enhanced infrared spectroscopy

“…Another cross structure, however, symmetric and in a hexagonal lattice, was investigated by Li et al [135]. The arrays of gold crosses on Al 2 O 3 and gold showed two absorptions, the fundamental mode between 6 and 7 μm and a higher-order mode at around 2.5 μm.…”

High-density 3D pyramid-shaped microelectrode arrays for brain-machine interface applications

“…Hydrogels are excellent scaffolding materials for repairing and regenerating a variety of tissues due to their highly swollen 3D structure similar to soft tissues [168]. PEG hydrogel and parylene-C are biocompatible polymers that are widely used for coating MEAs in both in vitro and in vivo studies [131,[169][170][171]. Mo and molybdenum oxide thin films are highly conductive, resistance to corrosion, and biocompatible [172,173].…”

“…Fourier transform infrared spectroscopy (FTIR) was performed in order to characterize the chemical composition of the parylene-C/PDL coatings [171,176]. A Thermo Scientific model Nicolet 6700 spectrometer, with a SMART iTR attenuated total reflectance probe, was used to record spectra in the 500-4000 cm -1 range, using a 4 cm -1 resolution.…”