Measurement of Uptake and Release Capacities of Mesoporous Silica Nanoparticles Enabled by Nanovalve Gates

Abstract

The uptake and release capacities of mesoporous silica particles are measured on nanovalve-gated stimulated release systems, using a water soluble biological stain, Hoechst 33342, as the cargo model. Five different types of mesoporous silica nanoparticles: 2D-hexagonal MCM-41, swollen pore MCM-41, rod-like MCM-41, hollow mesoporous nanoparticles and radial mesoporous nanoparticles are studied and compared. Solid silica nanoparticles are used as the control. Because of the presence of the nanovalves, the loaded and capped particles can be washed thoroughly without losing the content of the mesopores. The quantity of Hoechst 33342 molecules trapped within the nanoparticles and released upon opening the nanovalves are systematically studied for the first time. The loading conditions are optimized by varying the Hoechst concentration in the loading solutions. Surprisingly, increasing the Hoechst concentration in the loading solution does not always result in a larger amount of Hoechst being trapped and released. Among the five types of mesoporous silica nanoparticles, the radial mesoporous nanoparticles and the swollen pore MCM-41 particles show the highest and lowest release capacity, respectively. The uptake capacities is correlated with the specific surface area of the materials rather than their internal volume. The uptake and release behaviors are also affected by charge and spatial factors.

Photoexpulsion of Surface-Grafted Ruthenium Complexes and Subsequent Release of Cytotoxic Cargos to Cancer Cells from Mesoporous Silica Nanoparticles

“…The uptake and release capacity of the MSNPs 2 loaded with the different fluorescent cargo molecules are summarized in Table 1. The trapped and releasable amounts of the cargo, in agreement with previous release experiments on nanovalve-gated MSNPs, 33 would provide a better control over the delivery process for both in vitro and in vivo applications.…”

pH-Responsive Dual Cargo Delivery from Mesoporous Silica Nanoparticles with a Metal-Latched Nanogate

“…The observed 2% weight of Hoechst is a typical delivery capacity of MSN loaded with Hoechst. 41 Additionally, a 0.2% weight release of cobalt was observed. In terms of molar concentration, this amount is on the order of Hoechst released; 5 mg of gated particles can release ∼0.2 μmols of Hoechst and cobalt, demonstrating that the system is capable of delivering comparable molar quantities of both cargo types (Figure 3b1).…”

A reversible light-operated nanovalve on mesoporous silica nanoparticles

“…4 To be an effective drug delivery system, MSNs must be able to retain cargo molecules while in storage and in circulation, but capable of delivering their payload upon arriving at its target. A variety of methods have been employed to prepare MSN to meet these criteria; researchers have exploited hydrophobicity as a method of passive cargo retention, 5 and/or engineered nanomachines based on supramolecular nanovalves, 6a–c snap-tops, 6d metal nanocrystals,6 e–f nanoimpellers,6 g supported lipid bilayers,6 h biomolecules,6 i and reversible chelation6 j towards the goal of retaining cargo inside the pores of MSN. These systems have been designed to deliver their payload in response to a variety of stimuli; some of which may already be present inside the cell, or is externally applied in the form of magnetic fields 7 and light.…”