Functionalized Silica Nanoparticles by Nanometallic Ag Decoration for Optical Sensing of Organic Molecule

Abstract

Sensing technologies based on metallic nanoparticles, known as Ag, Au, and so on, have raised enormous interest for their extraordinary sensing resolution and sensitivity to analytes of chemical or biological importance under optical detection have received wide attention in recent decades. Currently, a discrete nanoparticle in a free-standing form, either being organically or biologically modified on the nanoparticle surface, on a given substrate surface region has been employed for photosensing purpose. However, metallic nanoparticles suffering from physical and chemical instability such as oxidation, interparticle coupling, agglomeration, and so on during the processing stages may render undesirable outcomes, which further results in poorer performance than the theoretical expectation. Here we propose a facile and elegant concept to prepare an Ag-decorated silica nanoparticle (hereinafter termed core-shell SiO 2 @Ag nanosphere) based on the modified Sto ¨ber method. The Ag nanoparticles with an average size controlled at about 1, 3, and 5 nm deposited over the surface of the silica nanocarrier were well separated, making the resulting SiO 2 @Ag nanospheres. The nanospheres showed physically and optically stable surface plasmon resonance spectra and also demonstrated a relatively high Ag-sized dependent sensitivity to ppb level for the detection of analyte molecule, that is, melamine. Theoretical model fitting has been well managed to correlate the optical behavior of the nanosensors, and the outcomes strongly indicated a promising potential of the Ag-decorated SiO 2 core-shell nanospheres for sensory applications.

Noble metal/silica “raspberry” type hybrids: Synthesis and functionalization

“…S2. The same result was detected in all the cases and similar metal decorated SiO 2 NPs have been observed before [6,36,37] but not so far for Ru NPs. Although there are some Ru NPs seen in the TEM that are not adsorbed on the SiO 2 particles (which could also be an artefact of the preparation, for instance due to shear forces).…”

A Series of Monodisperse Silver Nanoparticles by a One-Pot Synthesis

“…14 Moreover, the size of Ag NPs synthesized by Tagad group, in the range of 18-51 nm, depended on the concentration of locust bean gum and AgNO 3 . 24 In the research of the size-dependent e®ect of Ag NPs, apparently, these multipots fabrication approaches are incompetent and toilsome.…”

“…[1][2][3][4][5][6][7][8] Among the metal nanoparticles, silver nanoparticles (Ag NPs) is one of the most notable materials because of its unique properties such as good conductivity, chemical stability, catalysis and antimicrobial activity. 9 These properties of Ag NPs strongly depend on their sizes and morphologies.…”

Electroanalysis of nitrobenzene derivatives and nitrite ions using silver nanoparticles deposited silica spheres modified electrode

“…The development of different synthetic methods for the preparation of metal NPs encapsulated by silicate sol-gel (SSG) matrix is an emerging field since they exhibit a wide range of applications in catalysis and sensors [10,11,28]. The metal NPs supported on silica (SiO 2 ) spheres are used for optical [29,30] [31,32] applications due to the higher active surface area provided by the SiO 2 spheres. In particular, Ag NPs embedded with SSG matrix or supported on SiO 2 find interesting applications in catalysis and sensors [10,11,29,30,33].…”

“…The metal NPs supported on silica (SiO 2 ) spheres are used for optical [29,30] [31,32] applications due to the higher active surface area provided by the SiO 2 spheres. In particular, Ag NPs embedded with SSG matrix or supported on SiO 2 find interesting applications in catalysis and sensors [10,11,29,30,33]. For the detection of toxic molecules, Ag NPs based modified electrodes are promising due to its low cost when compared to Au, Pt and Pd.…”