Flower-shaped gold nanoparticles: synthesis, characterization and their application as SERS-active tags inside living cells

Abstract

The detection of Raman signals inside living cells is a topic of great interest in the study of cell biology mechanisms and for diagnostic and therapeutic applications. This work presents the synthesis and characterization of flower-shaped gold nanoparticles and demonstrates their applicability as SERS-active tags for cellular spectral detection. The particles were synthesized by a facile, rapid new route that uses ascorbic acid as a reducing agent of gold salt. Two triarylmethane dyes which are widely used as biological stains, namely malachite green oxalate and basic fuchsin, were used as Raman-active molecules and the polymer mPEG-SH as capping material. The as-prepared SERS-active nanoparticles were tested on a human retinal pigment epithelial cell line and found to present a low level of cytotoxicity and high chemical stability together with SERS sensitivity down to picomolar particle concentrations.

Green Synthesis of Asymmetrically Textured Silver Meso-Flowers (AgMFs) as Highly Sensitive SERS Substrates

“…The ascorbic acid is a mild reducing agent, known as a vitamin C, which is widely used in the synthesis of various complex nanostructures. 15,24,33 Chitosan is a biocompatible polymer containing primary amine and hydroxyl groups which have high affinity to Ag nanoparticles. Chitosan unraveled the ability in fabricating complex nanostructures as a capping and shape-controlling agent.…”

Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

“…541 Recently this was done by Astilean and co-workers with a novel synthesis method for flower-shaped Au nanoparticles functionalized with a thiol-modified poly(ethylene) glycol (PEG) polymer. 542 Intracellular detection with the multibranched flower-shaped nanoparticles was successfully tested in the cytosol of human epithelial cells with two Raman reporters: the dyes malachite green oxalate and basic fuchsin.…”

Designing Gold Nanoparticle-Ensembles as Surface Enhanced Raman Scattering Tags inside Human Retinal Cells

“…More recently an increased attention was given to the implementation of improved substrates for SERS nanoprobes such as anisotropic or multibranched nanoparticles, which exhibit strong plasmon resonances close to the NIR window of biological transparency and, particularly, high electromagnetic field localized at their protrusions [14][15][16]. Our group succeeded to demonstrate the efficiency of such dye-encoded multi-branched flowershaped nanoparticles as SERS tags inside living cells [17]. The SERS nano-tags were designed using malachite green oxalate and basic fuchsin as Raman-active molecules and protected against aggregation with thiol-modified poly(ethylene) glycol polymer.…”