Plasmonic features of free-standing chitosan nanocomposite film with silver and graphene oxide for SERS applications

Abstract

A scalable procedure of SERS substrates design was developed using a novel plasmonic structure based on a freestanding chitosan film, silver nanoparticles, and graphene oxide. Chitosan provides a uniform distribution of silver nanoparticles from a colloidal suspension and, therefore, a reproducible Raman signal from local areas of measurements of several tens of microns. The addition of graphene oxide (GO) to the colloidal solution of silver nanoparticles suppresses the tortuous background fluorescence signal from the analyte and leads to an increase in the signal-to-fluorescence background intensity ratio by up to 6 times as compared to structures without GO. The manufactured plasmonic polymer nanocomposite provides a detection limit of down to 100 pM for R6G using a laser wavelength of 532 nm through a portable ×10 objective. The high colloidal stability of GO in water and the use of an aqueous colloid of silver nanoparticles simplify the procedure for creating a substrate by applying the GO-silver composite on the surface of a chitosan film without a need to form a GO film. Therefore, our approach paves a promising avenue to provide more sensitive detection even for the fluorescent analytes with short-wavelength lasers (532, 633 nm) instead of IR (785, 1024 nm) and foster the practical application of the developed plasmonic composites on portable Raman spectrometers.

Simulation Calculation Verification of Graphene Oxide-Decorated Silver Nanoparticles Growing on Titania Nanotube Array as SERS Sensor Substrate

“…It was also reported that the graphene-modified SERS substrate is able to generate the SERS chemical enhancement effect [19,20]. An Ag/TiO 2 composite is suitable for SERS substrate application since both Ag and GO composites have SERS activity [21,22]. Our previous works had proven that GO modification of Ag/TiO 2 NTA could be used for SERS-sensing detection of organic aromatic ring molecules [23].…”

Functionalized Silver Nanocubes for the Detection of Hazardous Analytes through Surface-Enhanced Raman Scattering: Experimental and Computational Studies

“…The details of composites, concentration of Ag loading, and LOD of MB reported in the literature and present work are compared and tabulated in Table in the Results and Discussion. Other substrates synthesized for SERS application with higher loadings of nanostructures were observed. ,, From the literature, it is observed that the loading of high concentrations of nanomaterials onto support materials results in enhanced performance. The use of high-concentration nanomaterials is not economical.…”

“…Other substrates synthesized for SERS application with higher loadings of nanostructures were observed. 22,24,25 From the literature, it is observed that the loading of high concentrations of nanomaterials onto support materials results in enhanced performance. The use of high-concentration nanomaterials is not economical.…”

Model of the SARS-CoV-2 Virus for Development of a DNA-Modified, Surface-Enhanced Raman Spectroscopy Sensor with a Novel Hybrid Plasmonic Platform in Sandwich Mode

“…Thus, the natural reed leaves, without any special pretreatment, coated by silver, have been utilized as a self-assembled plasmonic structure for ultra-sensitive crystal violet trace detection with sensitivity as low as 10 −13 M using a novel natural surface-enhanced fluorescence [ 2 ]. Recently, a scalable design of SERS substrate based on a biopolymer of free-standing chitosan film, silver nanoparticles, and graphene oxide has been demonstrated [ 3 ]. The developed plasmon hybrid structures were assessed by their SERS-sensitivity, reproducibility, stability, and quenching capability.…”