Bioinspired One-Step Synthesis of Pomegranate-like Silica@Gold Nanoparticles with Surface-Enhanced Raman Scattering Activity

Abstract

Gold-silica (Au-SiO2) nanohybrids are of great technological importance, and it is crucial to develop facile synthetic protocols to prepare Au-SiO2 nanohybrids with novel structures. Here we report the bioinspired synthesis of pomegranate-like SiO2@Au nanoparticles (P-SiO2@Au NPs) via one-step aqueous synthesis from chloroauric acid and tetraethyl orthosilicate mediated by a basic amino acid, arginine. Effects of chloroauric acid, tetraethyl orthosilicate, and arginine on the morphology and optical property of the products are investigated in detail. The P-SiO2@Au NPs achieve tunable plasmon resonance depending on the amount of chloroauric acid, which affects the size and shape of the P-SiO2@Au NPs. Finite-difference time-domain simulations are performed, revealing that the plasmon peak red-shifts with increasing particle size. Arginine serves as the reducing and capping agents for Au as well as the catalyst for SiO2 formation, and also promotes the combination of Au and SiO2. Formation process of the P-SiO2@Au NPs is clarified through timecourse analysis. The P-SiO2@Au NPs show good sensitivity for both colloidal and paper-based surface-enhanced Raman scattering measurements. They achieve enhancement factor of 4.3✕10 7-8.5✕10 7 and a mass detection limit of ca. 1 ng using thiophenol as the model analyte.

Polythiolactone‐Decorated Silica Particles: A Versatile Approach for Surface Functionalization, Catalysis and Encapsulation

“…Our precursor particles at hand, we wanted to further illustrate the versatility of our post‐modifiable particles by immobilizing metal NP into the polymer brushes. Attaching metal NP to a support material can feature synergistic properties and can be important to improve their colloidal stability, handling and their utility in a range of applications [4,7,35] . In addition, clusters or controlled assemblies of metallic and inorganic NP are able to enhance the relevant physical properties and cooperative functions as compared to the individual particles [36] .…”

“…Attaching metal NP to a support material can feature synergistic properties and can be important to improve their colloidal stability, handling and their utility in a range of applications. [4,7,35] In addition, clusters or controlled assemblies of metallic and inorganic NP are able to enhance the relevant physical properties and cooperative functions as compared to the individual particles. [36] Here, we used dodecylamine (DDA) stabilized gold NP (AuNP), oleylamine (OlAm) stabilized palladium NP (PdNP) and 3aminopropyltriethoxysilan (APTES) functionalized magnetic CoFe 2 O 4 NP (MNP) for the immobilization experiments.…”

“…[1,2] Especially the surface chemistry is a dominant factor, as it allows to finely tune the surface properties of particles and therefore the interaction with their environment. [3][4][5] In this way it is possible to endow the surface of colloidal silica with new functionalities, thus expanding the applicability into new fields like drug delivery, [1,6] imaging agents, [1,7,8,9] catalytic supports, [1,10] biosensors, [11] templates for polymer capsules [12,13] or self-assembly. [14][15][16] The functionalization of silica particles is usually achieved by two main strategies.…”

Biomolecule-mimetic nanomaterials for photothermal and photodynamic therapy of cancers: Bridging nanobiotechnology and biomedicine

“…In addition, the formed AuNPs presented low toxicity and good biocompatibility; therefore, they could be utilized as the nanoprobes of SERS for in-situ cell imaging. In another similar study, Zhou et al employed the AA-mediated reduction strategy to synthesize AuNPs using the basic amino acid (arginine) as both reducing and encapsulating agent for AuNPs [ 48 ]. Figure 5 a shows the biomimetic synthesis process, in which a one-step hydrothermal reaction is utilized to create pomegranate-like SiO 2 @Au hybrid nanomaterials.…”

“…Reprinted with permission from Ref. [ 48 ], Copyright 2020, American Chemical Society. b Plant extract-induced formation of ZnO NFs with antibacterial activity and photochemical properties.…”