Preparation of Hollow Silica Nanoparticles Using Fluorinated Surfactant and Fluorocarbon Solvents

In this study, we used a new class of fluorinated surfactant as a soft template for the preparation of the hollow silica nanoparticles. The size of the hollow silica nanoparticles was enlarged by incorporating a variety of swelling agents (perfluorodecalin, perfluorotributylamine, perfluorooctane, and perfluorooctyl bromide) into the cores of the micelles of the fluorinated surfactant. However, once we used the perfluorinated acids (perfluorooctadecanoic acid and perfluorodecanoic acid) as swelling agents, the structure of silica nanoparticles is solid without the formation of hollow voids. The TEM analysis combined with copper elemental mapping of the hollow silica loaded with copper hexadecafluorophthalocyanine indicated that the cores of the hollow silica nanoparticles are hydrophobic. The formation mechanism of the hollow silica nanoparticles is similar to that prepared by hydrocarbon surfactant/hydrocarbon, which was supported by the zeta potential measurements. The prepared hollow silica nanoparticles had the type IV isotherm with the H3 hysteresis loop.

Hybrid Materials based on Silica Nanostructures for Biomedical Scaffolds (Bone Regeneration) and Drug Delivery

Silica nanoparticles with nanoporous nature are introduced as thermally and chemically stable nanomaterials with controllable porosity and morphology. The nanoparticles can be divided into three groups: microporous, mesoporous, and macroporous based on the porous size. The use of these materials for different applications is associated with their unique properties as disinfectants. This chapter discusses different synthesis methodologies to prepare well-dispersed mesoporous silica nanoparticles (MSNs) and hollow silica nanoparticles (HSNs) with tunable dimensions ranging from a few to hundreds of nanometers of different mesostructures. Several good characteristics of the MSNs, best biocompatibility and low toxicity, are proposed as the basis of the carrier for the controlled release of drugs, genes into living cells and bone regeneration.

Colorimetry-based System for Gaseous Carbon Dioxide Detection

The study of sensing materials to the detection of carbon dioxide (CO2) was achieved using p-nitrophenol (pNPh) as a colorimetric indicator. The sensing material was polymerized (NPLn), functionalized with 3-triethoxysilyl propyl isocyanate (IPTES) which sensitivity was tested in the form of a membrane as is and encapsulated in hollow silica nanoparticles. The sensing membranes were tested in a closed gas system comprising very precise flow controllers to deliver different concentrations of CO2 (vs. N2). The combination of the sensing membranes with multimode optical fibers and a dual-wavelength diode (LED) allows the measurement of the CO2 through the analysis of the induced absorbance changes with a self-referenced ratiometric scheme. The analysis of the sensing materials have shown significant changes in their chemical and physical properties and the results attest these materials with a strong potential for assessing CO2 dynamics in environmental, medical, and industrial applications.

Hollow silica reinforced magnesium nanocomposites with enhanced mechanical and biological properties with computational modeling analysis for mandibular reconstruction

The present study investigates Mg-SiO2 nanocomposites as biodegradable implants for orthopedic and maxillofacial applications. The effect of presence and progressive addition of hollow silica nanoparticles (0.5, 1, and 1.5) vol.% on the microstructural, mechanical, degradation, and biocompatibility response of pure Mg were investigated. Results suggest that the increased addition of hollow silica nanoparticles resulted in a progressive increase in yield strength and ultimate compressive strength with Mg-1.5 vol.% SiO2 exhibiting superior enhancement. The response of Mg-SiO2 nanocomposites under the influence of Hanks’ balanced salt solution revealed that the synthesized composites revealed lower corrosion rates, indicating rapid dynamic passivation when compared with pure Mg. Furthermore, cell adhesion and proliferation of osteoblast cells were noticeably higher than pure Mg with the addition of 1 vol.% SiO2 nanoparticle. The biocompatibility and the in vitro biodegradation of the Mg-SiO2 nanocomposites were influenced by the SiO2 content in pure Mg with Mg-0.5 vol.% SiO2 nanocomposite exhibiting the best corrosion resistance and biocompatibility when compared with other nanocomposites. Enhancement in mechanical, corrosion, and biocompatibility characteristics of Mg-SiO2 nanocomposites developed in this study are also compared with properties of other metallic biomaterials used in alloplastic mandibular reconstruction in a computational model.