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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

SERS active self-assembled diphenylalanine micro/nanostructures: A combined experimental and theoretical investigation

Full text
Author(s):
Kogikoski, Jr., Sergio ; Khanra, Soma ; Alves, Wendel A. ; Guha, Suchismita
Total Authors: 4
Document type: Journal article
Source: Journal of Chemical Physics; v. 147, n. 8 AUG 28 2017.
Web of Science Citations: 5
Abstract

Enhancing Raman signatures of molecules by self-assembled metal nanoparticles, nanolithography patterning, or by designing plasmonic nanostructures is widely used for detection of low abundance biological systems. Self-assembled peptide nanostructures provide a natural template for tethering Au and Ag nanoparticles due to its fractal surface. Here, we show the use of L, L-diphenylalanine micro-nanostructures (FF-MNSs) for the organization of Ag and Au nanoparticles (Nps) and its potential as surface-enhanced Raman scattering (SERS)-active substrates. The FF-MNSs undergo an irreversible phase transition from hexagonally packed (hex) micro-nanotubes to an orthorhombic (ort) structure at similar to 150 degrees C. The metal Nps form chains on hex FF-MNSs as inferred from transmission electron microscopy images and a uniform non-aggregated distribution in the ort phase. The high luminescence from the ort FF-MNS phase precludes SERS measurements with AgNps. The calculated Raman spectra using density-functional theory shows a higher intensity from rhodamine 6G (R6G) molecule in the presence of an Ag atom bound to ort FF compared with hex FF. The SERS spectra obtained from R6G bound to FF-MNSs with AuNps clearly show a higher enhancement for the ort phase compared with hex FF, corroborating our theoretical calculations. Our results indicate that FF-MNSs both in the hex and ort phases can be used as substrates for the SERS analysis with different metal nanoparticles, opening up a novel class of optically active bio-based substrates. Published by AIP Publishing. (AU)

FAPESP's process: 15/24018-1 - Polymer-Peptide Conjugates for hydrogel formulation and its usage in detection
Grantee:Wendel Andrade Alves
Support type: Regular Research Grants
FAPESP's process: 16/14507-8 - Structural and Electrochemical Studies of Nanostructures films based on DNA
Grantee:Sergio Kogikoski Junior
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 12/01933-8 - Biomimetic electrospun matrixes: possible application in NO detection
Grantee:Sergio Kogikoski Junior
Support type: Scholarships in Brazil - Doctorate (Direct)