A General pH‐Responsive Supramolecular Nanovalve Based on Mesoporous Organosilica Hollow Nanospheres

Abstract

Smart release on demand: A general pH‐responsive supramolecular nanovalve operating in aqueous media has been designed by using mesoporous organosilica hollow nanospheres as nanocontainers (see picture). The nanovalve is capable of storing guest molecules within the hollow core and mesopore shell and releasing them on demand by acid/base triggering of the capping molecule, demonstrating a delicate vehicle for controlled release.

A pH-responsive drug delivery system based on ethylenediamine bridged periodic mesoporous organosilica

“…The ionisation of surface-attached drug molecules will occur only after the release of unattached free flowing drug molecules in the pore channels. Because of the presence of imino and carbonyl functionality in 5-Fu, a weak interaction (hydrogen bond) will be created between the drug molecule and surface diamine functionality [7,27,37]. This interaction plays a key role in making the second stage of 5-Fu release will be more controlled from both nano containers.…”

“…Controlled drug release systems based on PMOs were first reported in 2009 [11]. Although many reports in the synthesis of PMOs with various types and numbers of bridged silane precursors have been [12,13]. The principal driving forces in the adsorption of drugs or biomolecules onto porous hosts are electrostatic, hydrophobic and hydrogen-bonding.…”

“…This nanovalve can store guest molecules within the hollow core and mesopore shell, and release M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 5 them on demand through the acid/base triggering of the capping molecule, demonstrating a delicate vehicle for controlled release [27]. An earlier communication reported a combination of receptor groups and conductivity promoter functionalities in a mesoporous silica hybrid network to work as a double drug delivery system for both anti-inflammatory (IBU) and anticancer (5-FU) drugs loaded together in a single entity with precise control over the sequence of release [28].…”

Preparation of frustule-like 1,2-ethylene-silica nanospheres through a chiral amphiphile/organic solvent dual-templating approach

“…The structural transition of the chiral amphiphile/silica oligomer assemblies in the reaction mixture played an important role in the formation of this hierarchical structure. However, the reports on hollow organosilica nanospheres that can be widely functionalized are few [23][24][25][26][27][28][29].…”

Heterogeneous Organocatalysis at Work: Functionalization of Hollow Periodic Mesoporous Organosilica Spheres with MacMillan Catalyst

“…[6b, 15] The first example of the preparation of PMO materials with hollow nanospheres was reported by Lus group, in which a dual-templating approach was explored. [16] Ha and co-workers [17] also prepared mesoporous ethane-silica hollow nanospheres through a hardtemplating route using polystyrene latex spheres. Frçba and co-workers [18] reported the synthesis of core-shell PMO materials with a solid silica core and a phenylene PMO shell.…”