Ultrabright Fluorescent Silica Mesoporous Silica Nanoparticles: Control of Particle Size and Dye Loading

Abstract

The synthesis of ultrabright fl uorescent mesoporous silica nanoparticles (UFSNPs) of various sizes loaded with different amounts of fl uorescent dye (Rhodamine 6G) is reported here. The dye is physically entrapped inside the nanochannels of the silica matrix created during templated sol-gel self assembly. Due to the specifi c nanoenvironment, the fl uorescence of the encapsulated dye molecules remains unquenched up to very high concentrations, which results in relatively high fl uorescence. The particle size (ranging from 20-50 nm) and dye loading (0.8-9.3 mg dye per g particles) are controlled by the timing of the synthesis and the concentration of several organotriethoxysilanes, which are coprecursors of silica. The quantum yields of the encapsulated dye range from 0.65 to 1.0. The relative brightness of a single particle is equivalent to the fl uorescence of 30-770 free nondimerized R6G dye molecules in water, or to that of 1.5-39 CdSe/ZnS quantum dots. Despite the presence of some hydrophobic groups on the particles' surfaces, colloidal suspensions of the particles are relatively stable (as monitored for 120 days).

Organic–Inorganic Hybrid Functional Carbon Dot Gel Glasses

“…[ 40 ] Immobilization of many types of luminescent substances on a rigid support can lead an enhancement of the emission, [ 40 ] except that one of the costs of silane covalent functionalization is also a typical decrease in the QY of dye-silica composites. [ 36 ] But the chemical bonding of SiCDs to silicate matrix can enhance both the QY and lifetime of CDs herein. This can be ascribed to ''in situ'' silane pre-functionalization, chemical dispersion on the molecular level, completely preventable movement [ 41 ] and agglomeration of high PL SiCD 1 , [ 25 ] and the excellent protective environment of the Ormosil host.…”

Nanoconfinement of pyrene in mesostructured silica nanoparticles for trace detection of TNT in the aqueous phase

“…It is important to note that although similar surfactant assisted methods to load water-soluble dyes (e.g. R6G) into the pores of MCM-41 type MSNs have been reported, 33,34 in this study surfactant assisted loading of a water-insoluble molecule into the pores of MCM-41 type MSNs is reported, to our knowledge, for the first time. Nano-confinement of pyrene inside these mesostructures resulted in a bright and visible excimer emission.…”

Colloidal and spherical mesoporous silica particles: synthesis and new technologies for delivery applications

“…Emphasis is made in the requirements to achieve an ideal carrier, a perfect monodispersed sphere, and therefore, a qualitative evaluation of the shape and size dispersion of the particles is provided. Although many authors claimed to synthesize nanoparticles, only those showing proof of nanosized diameters [13,[15][16][17][18][19][20][21] are labeled as MSN (if no proof of crystal structure is shown by XRD). While some MCM-41 materials are listed [12,[22][23][24], only one was found for SBA-15 particles [24] in the submicron range, although resembling more an hexagonal shape, as it will be discussed later.…”