Reversible Pore‐Structure Evolution in Hollow Silica Nanocapsules: Large Pores for siRNA Delivery and Nanoparticle Collecting

Abstract

The effective modulation of pore sizes for nanoporous silica nanoparticles still remains a great challenge not satisfactorily solved. In this paper, the pore sizes in the shell of hollow silica nanocapsules are well-tuned by a reversible Si-O bond breakage and reformation process under mildly alkaline conditions (e.g., Na(2) CO(3) solution). The pores in nanosized hollow silica capsules can be modulated from 3.2 nm to larger than 10 nm by a novel, surfactant-directing alkaline-etching (SDAE) strategy. Interestingly, the pores can be fully filled through the regrowth of the dissoluted silicates by bonding to silanols (Si-OH) on the wall surface to generate the nonporous hollow silica nanocapsules. The large-sized pore hollow silica nanocapsules exhibit excellent siRNA-loading capabilities and intracellular transfection efficiencies in vitro. In addition, the large pores in the shell of hollow silica nanocapsules are explored as channels for collecting superparamagnetic, small-sized Fe(3) O(4) nanoparticles as contrast agents for magnetic resonance imaging, initiating a special approach towards pore-size modulation and multifunctionalization of silica-based nanostructural materials for nanobiomedical applications.

Fabrication of high specificity hollow mesoporous silica nanoparticles assisted by Eudragit for targeted drug delivery

“…This will create particles with a surface difficult for further modifications such as conjugating with functional peptides or targeting ligands that are crucial for in vitro and in vivo applications. Similarly, silica can also be used as core template [31,32] and then etched away with either Na 2 CO 3 or HF solution to fabricate HMSNs. However, hollow-rattle mesoporous silica nanoparticles [7,31,33] as a byproduct of HMSNs could decrease the drug loading of final products to some extent because of the existence of the solid cores.…”

Mesoporous carbon biomaterials

“…The well-defined mesoporous structures with large surface area, high pore volume, and tunable pore sizes provide large reservoirs for guest molecules and show sustained drug-release profiles [29][30][31]. Mesoporous silica nanoparticles (MSNs) are one of the most representative and explored mesoporous biomaterials in biomedicine due to their high biocompatibility, tunable biodegradation, sustained drug-releasing performance, and easy surface modifications ( Fig.…”

Nanosheet transfection: effective transfer of naked DNA on silica glass

“…Nanoporous silica NPs (but not the nonporous ones) increase the transfection. 22 Silica NPs decorated with~300 spikes 6.4 nm in diameter to mimic the enveloped virus can enhance gene binding and delivery, although they have higher cytotoxicity. 23 Based on these arguments, the surface structures or textures, particularly in the form of spikes or upright nanosheets, may promote gene delivery.…”