Periodic Mesoporous Organosilica Nanoparticles with BOC Group, towards HIFU Responsive Agents

Abstract

Periodic Mesoporous Organosilica Nanoparticles (PMONPs) are nanoparticles of high interest for nanomedicine applications. These nanoparticles are not composed of silica (SiO2). They belong to hybrid organic–inorganic systems. We considered using these nanoparticles for CO2 release as a contrast agent for High Intensity Focused Ultrasounds (HIFU). Three molecules (P1–P3) possessing two to four triethoxysilyl groups were synthesized through click chemistry. These molecules possess a tert-butoxycarbonyl (BOC) group whose cleavage in water at 90–100 °C releases CO2. Bis(triethoxysilyl)ethylene E was mixed with the molecules Pn (or not for P3) at a proportion of 90/10 to 75/25, and the polymerization triggered by the sol-gel procedure led to PMONPs. PMONPs were characterized by different techniques, and nanorods of 200–300 nm were obtained. These nanorods were porous at a proportion of 90/10, but non-porous at 75/25. Alternatively, molecules P3 alone led to mesoporous nanoparticles of 100 nm diameter. The BOC group was stable, but it was cleaved at pH 1 in boiling water. Molecules possessing a BOC group were successfully used for the preparation of nanoparticles for CO2 release. The BOC group was stable and we did not observe release of CO2 under HIFU at lysosomal pH of 5.5. The pH needed to be adjusted to 1 in boiling water to cleave the BOC group. Nevertheless, the concept is interesting for HIFU theranostic agents.

Acetone Factor in the Design of Cu4-, Cu6-, and Cu9-Based Cage Coppersilsesquioxanes: Synthesis, Structural Features, and Catalytic Functionalization of Alkanes

“…Taking into attention the well-described affinity of trialkoxysilanes to form condensed derivatives (e.g., nanostructured materials and catalysts − ), a similar approach was chosen for the self-assembly of the target Cu­(II)-CLMS: alkaline (NaOH in ethanol) hydrolytic condensation of PhSi­(OMe) 3 , followed by an exchange reaction with CuCl 2 and complexation with ethylenediamine. Different reaction media were tested for the subsequent crystallization procedures (Scheme ).…”

Sol-Gel Chemistry: From Molecule to Functional Materials

“…Durand et al reported the synthesis and characterization of framework-functionalized mesoporous silica nanoparticles with the aim of CO 2 release which acted as a contrast agent for high intensity focused ultrasounds (HIFU) [13]. In this study, several multi-silylated precursors containing tert-butoxycarbonyl (BOC) group were synthesized.…”

Preparation and Characterization of Novel Mixed Periodic Mesoporous Organosilica Nanoparticles

“…The 13 C-CP-MAS solid state NMR spectra (Les Ullis, France), the BET surface areas (Mérignac, France), Dynamic Light Scattering (DLS, Pessac, France) and Zeta potential values (Orsay, France) were obtained from equipments of University of Montpellier [39]. The 1 H-and 13 C-NMR spectroscopy (Bruker Biospin, Rheinstetten, Germany), Mass-Spectrometry (MS, Bruker Biosciences Española, Madrid, Spain), elemental analysis, Infra-Red spectroscopy (IR, Bruker Biosciences Española, Madrid, Spain), Powder X-Ray diffraction (P-XRD, Almelo, Netherlands) and Transmission Electron Microscopy (TEM, JEOL Ltd., Akishima, Tokyo, Japan) were performed at the Universitat Autònoma de Barcelona (UAB) [39].…”

“…The samples were then extracted with a solution of NH 4 NO 3 (6 g/L in 96% EtOH) for three times and washed successively with 96% ethanol, Mili-Q water, 96% ethanol. The E-Pn PMO NPs were obtained as white solids [39]. E-P1 90/10 PMO NPs: 13…”

“…The micellar solution was prepared at 80 • C for 50 min with a stirring speed adjusted at 1000 rpm. Then, the stirring speed was enhanced to 1400 rpm, a mixture of (E)-BTSE (or E) and different amounts of the corresponding disilylated precursor Pn was quickly added and the mixture was left to react for 120 min at 80 • C [39]. E-Pn PMO NPs were collected by centrifugation.…”