Architecture of Nanoantioxidant Based on Mesoporous Organosilica Trp-Met-PMO with Dipeptide Skeleton

Abstract

A nanoantioxidant of mesoporous organosilica (Trp-Met-PMO) based on the framework of tryptophan–methionine dipeptide was first designed and constructed by condensation between self-created dipeptide organosilica precursor (Trp-Met-Si) and tetraethyl orthosilicate (TEOS) in alkaline conditions under the template hexadecyl trimethyl ammonium bromide (CTAB). Trp-Met-Si was prepared by the reaction between dipeptide Trp-Met and conventional organosilicon coupling agent isocyanatopropyltriethoxysilane (IPTES) via a multiple-step reaction method. The material Trp-Met-PMO was confirmed by XRD, FT-IR and N2 adsorption–desorption analysis. The material Trp-Met-5-PMO with low amounts of organosilica precursor remained a mesoporous material with well-ordered 2D hexagonal (P6mm) structure. With increasing amounts of organosilica precursor, a mesoporous structure was still formed, as shown in the material Trp-Met-100-PMO with the highest amounts of organosilica precursor. Moreover, pore size distribution, surface area and porosity of Trp-Met-PMO are regulated with different amounts of organosilica precursor Trp-Met-Si. The antioxidant activity of Trp-Met-PMO was evaluated by ABTS free radical-scavenging assay. The results showed that antioxidant activity was largely enhanced with increasing contents of organosilica precusor Trp-Met-Si in the skeleton. The material Trp-Met-40-PMO exhibited maximum scavenging capacity of ABTS free radicals, the inhibition percent was 5.88%. This study provides a design strategy for nanoantioxidant by immobilizing short peptides within the porous framework of mesoporous material.

Polyoxometalates Encapsulated into Hollow Periodic Mesoporous Organosilica as Nanoreactors for Extraction Oxidation Desulfurization

“…The FT-IR spectrum of PW 2 Mo 2 exhibits some characteristic peaks in the 1100-540 cm −1 range assigned to the Venturello structure anion, and the stretching vibration characteristic peak attributed to the O-O bond appears at 870 cm −1 [28,29]. The FT-IR spectrum of HPMOS shows several strong peaks located at 1035, 773, and 454 cm −1 ascribed to antisymmetric stretching vibration and symmetric stretching vibration of Si-O-Si [30,31]. The immobilization of PW 2 Mo 2 was verified by the FT-IR spectrum, which showed some peaks that belonged to the active component at 1462, 1384, and 480-580 cm −1 .…”