Double Amino Functionalized Ag Nanoparticles as SERS Tags in Raman Diagnostic

Simona Cîntă Pînzaru,Cristian Morari,Alexandra Falamaş,Monica Venter,Cristina Dehelean

doi:10.5562/cca2067

Abstract

Surface enhanced Raman scattering (SERS) effect is currently exploited as the basis of a new type of optical labels for in vivo investigation of the tissues, especially for early medical diagnostic. Silver colloidal nanoparticles decorated with chemisorbed cresyl violet molecular species could act as hybrid SERS labels. Their Raman scattering properties have been characterized here using different SERS techniques, and probing different excitation wavelengths, even in the near infrared. Obtaining FT-SERS signal of cresyl violet is of particular importance for applying FT-Raman spectroscopy to the tissues or cells, in providing sensitive information in the close vicinity of the SERS label incubated into the biological sample. Furthermore, upon chemisorption on the silver nanoparticles, cresyl violet molecular orientation provided both amino functional groups free of interaction with the silver, resulting double aminofunctionalized Ag nanoparticles suitable for DNA tagging. SERS tests of melanoma induced in mouse using CV-Ag SERS label suggested the possibility to setup the tissue labeling procedure for skin cancer monitoring.(doi: 10.5562/cca2067)

Highlights

Many recent reported chemical, biological and medical sensing applications involve different Raman and surface-enhanced Raman scattering (SERS) techniques as powerful analytical tools.[1,2,3] Improved understanding of the mechanisms that are responsible for the effect coupled to the progresses in current technology make the use of SERS/SERRS much simpler than has been the case in the past
From the SERS spectra of cresyl violet perchlorate on Ag island films[17] collected in the 300−1800 cm−1 spectral range it was concluded that a physisorption process takes place and the molecular skeleton is adsorbed into a standing up orientation with respect to the Ag island film, both amino groups of the molecule being in the proximity of the metal surface
Based on the UV-VIS, FT-Raman, SERS and SERRS spectroscopy and on density functional theory (DFT) theoretical calculations, a complete vibrational characterization of the cresyl violet attached to Ag colloidal nanoparticles as SERS label has been performed

Summary

Introduction

Biological and medical sensing applications involve different Raman and surface-enhanced Raman scattering (SERS) techniques as powerful analytical tools.[1,2,3] Improved understanding of the mechanisms that are responsible for the effect coupled to the progresses in current technology make the use of SERS/SERRS much simpler than has been the case in the past. A critical review recently provided the latest methods for the metabolic fingerprinting using vibrational techniques as potential tools for rapid disease diagnosis, detection of dysfunction, the early intervention of therapeutic strategies, highlighting their overall conclusions that IR and Raman techniques could be successfully applied in such medical area.[4] The difficulty in producing uniform, highly sensitive, and reproducible SERS substrate has limited its use in routine biosensing. Detection and discrimination of specimens in complex biological media are a necessity, together with reproducible results, cost and time effectiveness, and ease of use under most conditions. Due to its unique ability to provide ultrasensitive detection limits, SERS has been used to detect molecular modifications involved in disease, such as cancer,[3,5] diabetes,[6] etc

Objectives

Results

Conclusion