Preparation of Sub-50 nm Colloidal Monodispersed Hollow Siloxane-Based Nanoparticles with Controlled Shell Structures

Abstract

Hollow siloxane-based nanoparticles (HSNs) have attracted significant attention because of their promising unique properties for various applications. For advanced applications, especially in catalysis, drug delivery systems, and smart coatings, high dispersibility and monodispersity of HSNs with precisely controlled shell structures are important. In this study, we established a simple method for preparing colloidal HSNs with a uniform particle size below 50 nm by the reaction of colloidal silica nanoparticles with bridged organoalkoxysilane [1,2-bis(triethoxysilyl)ethylene: (EtO) 3 Si-C 2 H 2 -Si(OEt) 3 , BTEE] in the presence of a cationic surfactant. Upon the formation of organosiloxane shells by hydrolysis and polycondensation of BTEE, the core silica nanoparticles were spontaneously dissolved, and a part of the silicate species was incorporated into the organosiloxane shells. The size of the colloidal silica nanoparticles, the amount of BTEE added, and the pH of the reaction mixture greatly affected the formation of HSNs. Importantly, colloidal HSNs having micropores and mesopores in the shells were successfully prepared using silica nanoparticles (20, 30, and 40 nm in diameter) at pH values of 9 and 11, respectively. These HSNs are potentially important for applications in drug delivery systems and catalysis.

Enhancing Methotrexate Delivery in the Brain by Mesoporous Silica Nanoparticles Functionalized with Cell-Penetrating Peptide using in Vivo and ex Vivo Monitoring

“…47 These results indicated successful synthesis of the silica-based materials. Complete elimination of the surfactant CTAB from the MSNs was confirmed by the disappearance of the C−H peak (CH 2 symmetric 48 and asymmetric stretches 49 ) at 2800−3000 cm −1 . The strong absorbance peaks at 3455 and 1641 cm −1 were assigned to stretching and bending modes of the silanol (Si− OH) groups on the surface of the MSNs.…”

Preparation and surface modification of porous hollow organosilica particles for biomedical applications

“…Because of the steric hindrance induced by the hydrophobicity of the ethylene bridges in BTEE, the nucleophilic attack of hydroxyl ions at the silanol groups on the core surface becomes more favorable when BTEE is utilized as the precursor. On the other hand, when the less hydrophobic TEOS is used as the precursor, the nucleophilic attack of hydroxyl ions is less favourable [96,156]. These processes have an influence on the dissolution of the inner core, which is covered in the next section.…”