Synthesis of hierarchically nanoporous silica films for controlled drug loading and release

Hierarchically Porous Silica Prepared with Anionic Polyelectrolyte-Nonionic Surfactant Mesomorphous Complex as Dynamic Template

Hierarchically porous silica KIT-6 and SBA-15 mesostructures were successfully synthesized by using a mesomorphous complex of a nonionic triblock copolymer (pluronic P123) and an anionic polyelectrolyte (polyacrylic acid) as the dynamic template. The obtained mesoporous silica materials possessed both ordered mesopores (∼7 nm) and nanopores (∼15-50 nm), and the long-range order of the mesophase was not perturbed by the embedded larger secondary nanopores. Moreover, hierarchically porous silica KIT-6 exhibited enhanced adsorption capacity in enzyme and protein immobilization, which was attributed to the hierarchically porous structure.

Voltage-Responsive Controlled Release Film with Cargo Release Self-Monitoring Property Based on Hydrophobicity Switching

Herein, voltage-responsive controlled release film was constructed by grafting ferrocene on the mesoporous inverse opal photonic crystal (mIOPC). The film achieved free-blockage controlled release and realized the monitoring of cargo release without external indicator. Free-blockage was attributed to the voltage switchable nanovalves which undergo hydrophobic-to-hydrophilic transition when applying voltage. Monitoring of cargo release was attributed to the optical property of mIOPC, the bandgap of mIOPC had a red shift when the solution invaded in. The film was hydrophobic enough to stop solution intrusion. Once the voltage was applied, the film became hydrophilic, leading to invasion of the solution. As a result, the cargos were released and the bandgap of mIOPC was red-shifted. Therefore, in this paper both a free-blockage controlled release film and a release sensing system was prepared. The study provides new insights into highly effective controlled release and release sensing without indicator.

On demand electrochemical release of drugs from porous reduced graphene oxide modified flexible electrodes

Despite the advantages of an electrochemical control of drug release, only a handful of electrochemical-based release systems have been developed so far.

Emulsion droplets as a dynamic interface for the direct and large-scale synthesis of ultrathin free-standing mesoporous silica films as well as 2D polymeric and carbon nanomaterials

The efficient synthesis of free-standing mesostructured two-dimensional (2D) nanofilms with high-yield as well as good control of composite, mesophase structure, orientation of the pore channel and thickness represents a big challenge. In this work, it was serendipitously found that microemulsion droplets of tetraethylorthosilicate (TEOS) could serve as a novel dynamic interface for continuous growth of nanofilms. Based on this finding, a general, efficient strategy for the direct and large-scale synthesis of free-standing mesoporous silica films (FSMSFs) was developed. Remarkably, with the careful control of the synthesis conditions, the FSMSFs with high-yield as well as good control of composite, mesophase structure, orientation of the pore channel and thickness could be efficiently achievable. More importantly, by using polymerizable surfactants the preorganized monomers in the nanochannels of the resultant silica films could be further converted into 2D polymers and carbon nanomaterials as well as metal particle-decorated forms, as exemplified by using pyrrole-terminated surfactants, demonstrating a powerful method to create 2D inorganic, organic or hybrid functional nanomaterials.

Applications of hierarchically structured porous materials from energy storage and conversion, catalysis, photocatalysis, adsorption, separation, and sensing to biomedicine

A comprehensive review of the recent progress in the applications of hierarchically structured porous materials is given.

pH-Responsive nano sensing valve with self-monitoring state property based on hydrophobicity switching

pH-Responsive free-blockage nanovalves with self-monitoring state property were constructed based on the hydrophobicity switching of mesoporous photonic crystal.

Dip-in Indicators for Visual Differentiation of Fuel Mixtures Based on Wettability of Fluoroalkylchlorosilane-Coated Inverse Opal Films

We have developed the dip-in indicator based on the inverse opal film (IOF) for visual differentiation of organic liquid mixtures, such as oil/gasoline or ethanol/gasoline fuel mixtures. The IOF consists of a three-dimensional porous structure with a highly ordered periodic arrangement of nanopores. The specularly reflected light at the interface of the nanopores and silica walls contributes to the structural color of the IOF film. This color disappears when the nanopores are infiltrated by a liquid with a similar refractive index to silica. The disappearance of the structural color provides a means to differentiate various liquid fuel mixtures based on their wettability of the nanopores in the IOF-based indicators. For differentiation of various liquid mixtures, we tune the wettability threshold of the indicator in such a way that it is wetted (color disappears) by one liquid but is not wetted by the other (color remains). Although colorimetric differentiation of liquids based on IOF wettability has been reported, differentiation of highly similar liquid mixtures require complicated readout approaches. It is known that the IOF wettability is controlled by multiple surface properties (e.g., oleophobicity) and structural properties (e.g., neck angle and film thickness) of the nanostructure. Therefore, we aim to exploit the combined tuning of these properties for differentiation of fuel mixtures with close compositions. In this study, we have demonstrated that, for the first time, the IOF-based dip-in indicator is able to detect a slight difference in the fuel mixture composition (i.e., 0.4% of oil content). Moreover, the color/no-color differentiation platform is simple, powerful, and easy-to-read. This platform makes the dip-in indicator a promising tool for authentication and determination of fuel composition at the point-of-purchase or point-of-use.

Controlling drug delivery kinetics from mesoporous titania thin films by pore size and surface energy

The osseointegration capacity of bone-anchoring implants can be improved by the use of drugs that are administrated by an inbuilt drug delivery system. However, to attain superior control of drug delivery and to have the ability to administer drugs of varying size, including proteins, further material development of drug carriers is needed. Mesoporous materials have shown great potential in drug delivery applications to provide and maintain a drug concentration within the therapeutic window for the desired period of time. Moreover, drug delivery from coatings consisting of mesoporous titania has shown to be promising to improve healing of bone-anchoring implants. Here we report on how the delivery of an osteoporosis drug, alendronate, can be controlled by altering pore size and surface energy of mesoporous titania thin films. The pore size was varied from 3.4 nm to 7.2 nm by the use of different structure-directing templates and addition of a swelling agent. The surface energy was also altered by grafting dimethylsilane to the pore walls. The drug uptake and release profiles were monitored in situ using quartz crystal microbalance with dissipation (QCM-D) and it was shown that both pore size and surface energy had a profound effect on both the adsorption and release kinetics of alendronate. The QCM-D data provided evidence that the drug delivery from mesoporous titania films is controlled by a binding-diffusion mechanism. The yielded knowledge of release kinetics is crucial in order to improve the in vivo tissue response associated to therapeutic treatments.

Enhanced Catalytic Efficiency of Pt Nanoparticles Supported on 3D Ordered Macro-/Mesoporous Ce0.6 Zr0.3 Y0.1 O2 for Methane Combustion

Highly dispersed Pt nanoparticles supported on high-surface-area 3D ordered macroporous (3DOM) Ce0.6 Zr0.3 Y0.1 O2 (CZY) are synthesized via a bubbling cetyltrimethyl ammonium bromide/P123-assisted reduction route. The 1.1 wt% Pt/3DOM CZY catalyst shows supercatalytic activity for methane combustion, which is attributed to a higher oxygen adspecies amount, larger surface area, better low-temperature reducibility, and unique nanovoid-walled 3DOM structure.

Self-assembled coffee-ring colloidal crystals for structurally colored contact lenses

A circlular structural-colored contact lens is reported, which is fabricated by replicating self-assembled colloidal photonic crystal templates. The structural-colored contact lenses not only display variable and brilliant color under light illumination, but also avoid the addition of any colorants to the hydrogel lenses and prevent the potential harm posed by traditional colored contact lenses.

Facile incorporation of aggregation-induced emission materials into mesoporous silica nanoparticles for intracellular imaging and cancer therapy

Aggregation-induced emission (AIE) materials were facilely incorporated into mesoporous silica nanoparticles (MSNs) via one-pot surfactant templated method. Cell imaging and cancer therapy applications of such fluorescent MSNs were further explored. We demonstrated that AIE-MSN nanocomposites showed strong fluorescence and uniform morphology, making them promising for both cell imaging and cancer therapy.

Template free synthesis of crystallized nanoporous F-Ta2O5 spheres for effective photocatalytic hydrogen production

Crystallized and fluorinated nanoporous Ta(2)O(5) spheres were prepared by a combination of co-precipitation and hydrothermal methods in a NH(4)F-containing water solution. The as-prepared porous spheres, with a pore-size of around 7 nm and a large specific surface area of 132 m(2) g(-1), show superior photocatalytic hydrogen production activity over P25 and commercial-Ta(2)O(5).

Synthesis of hydrothermally stable, hierarchically mesoporous aluminosilicate Al-SBA-1 and their catalytic properties

Hydrothermally stable mesoporous aluminosilicates Al-SBA-1 with hierarchical pore structure have been successfully synthesized under alkaline condition at 120 °C by employing organic mesomorphous complexes of polyelectrolyte (poly(acrylic acid) (PAA)) and cationic surfactant (hexadecyl pyridinium chloride (CPC)) as template. The Si/Al ratio could be as high as 5 and the incorporation of Al into the silica framework did not disturb the well-ordered cubic Pm ̅3n mesostructure. Meanwhile, the incorporation of Al could greatly increase the specific surface area and pore volume of the samples. The Al-SBA-1 materials exhibited a high hydrothermal stability and remained stable even after being treated in boiling water for 10 days. The catalytic activity of the Al-SBA-1 materials was investigated by employing the Friedel-Crafts alkylation of toluene with benzyl alcohol as a model reaction and they exhibited excellent catalytic property due to the incorporated acid sites and the hierarchically mesoporous structure.