Smart Drug Delivery Strategies Based on Porous Nanostructure Materials

The control of drug delivery can have a great effect on its efficacy. An optimum concentration range of drugs can play a significant role in the human body, and it can cause harm to humans when it exceeds the range of the drug concentration. Recently, a variety of drug deliveries and their targeted systems have been studied to minimize drug loss and maximize the amount of drug accumulated in the required area, thus increasing drug bioavailability. In addition, we should especially consider the prevention of its harmful side-effects in the human body. Innovative drug delivery systems based on biodegradable, natural or synthetic polymers, micro- or nano-particles, lipoproteins, micelles, TiO2 nanotube arrays (TNTs), nanoporous anodic aluminum oxide (AAO), and so on were developed, which combined magnetic targeting and stimulus-responsive in drug delivery systems. The composition of delivery carriers and the stimulus-responsive elements proved stimulus-responsive drug release as a smart drug delivery system

Enhanced photoelectrochemical activities of a nanocomposite film with a bamboo leaf-like structured TiO(2) layer on TiO(2) nanotube arrays

A novel nanocomposite TiO(2) film consisting of a bamboo leaf-like nano TiO(2) layer on a nanotubular TiO(2) arrays surface is synthesized by electrochemical anodization with wet chemical pretreatment; it shows almost three times higher activity as compared to that of nanotubular TiO(2) arrays alone.National Natural Science Foundation of China[51072170, 20773100, 20620130427]; National Basic Research Program of China[2007CB935603]; National High Technology Research and Development Program of China[2009AA03Z327

Sonoelectrochemical synthesis of highly photoelectrochemically active TiO2 nanotubes by incorporating CdS nanoparticles

Self-organized anodic TiO2 nanotube arrays (TiO2NTs) are functionalized with CdS nanoparticle based perfusion and deposition through a single-step sonoelectrodeposition method. Even controlled at 50 degrees C, CdS nanoparticles with smaller size and more homogeneous distribution are successfully synthesized in dimethyl sulfoxide (DMSO) under ultrasonic irradiation. Moreover, TiO2 nanotubes can be filled with nanoparticles because of the ultrasonic effect. The CdS incorporated TiO2NTs (CdS-TiO2NTs) effectively harvest solar light in the UV as well as the visible light (up to 480 nm) region. Compared with pure TiO2NTs, a more than ninefold enhancement in photocurrent response is observed using the CdS-TiO2NTs. Maximum incident photon to charge carrier efficiency (IPCE) values of 99.95% and 9.85% are observed respectively for CdS-TiO2 nanotubes and pure TiO2NTs. The high value of IPCE observed with the CdS-TiO2NTs is attributed to the increased efficiency of charge separation and transport of electrons. A schematic diagram is proposed to illustrate the possible process of CdS formation in nanotubes under sonochemical and electrochemical conditions.Natural Science Foundation of China and Fujian Province [20773100, U0750015]; Technical Program of Fujian Province and Xiamen City, China [2007H0031, 3502Z20073004

Efficiently texturing hierarchical superhydrophobic fluoride-free translucent films by AACVD with excellent durability and self-cleaning ability

Translucent and superhydrophobic glass surfaces were fabricated by one-step deposition of a composite from the precursors, polydimethylsiloxane (PDMS) and tetraethyl orthosilicate (TEOS), via aerosol-assisted chemical vapour deposition. A raspberry-like hierarchical structure was obtained due to the nanoparticles being decomposed by the TEOS precursor and deposited around the micro-scale particles formed by the hydrolysis of the PDMS precursor. In this work, a translucent and superhydrophobic film was prepared by using optimized parameters (T: 290–330 °C, deposition time: 15–30 min) and the resulting water contact angle and sliding angle were >160° and <1°, respectively. It was found that there were 9 bounce cycles when water droplets were dropped onto such surfaces. Superior robustness was observed against tape-peeling, and on exposure to UV light (365 nm, 3.7 mW cm−2, 72 h) and to a large pH range (pH = 1–14, 72 h). The mechanical robustness was also examined and the results demonstrated that the film loses its superhydrophobicity when abraded for 5 meters with coarse sandpaper. The self-cleaning test demonstrated that the superhydrophobic surface could shed various contaminants and aqueous dyes, leaving a clear surface behind. This novel method can be applied to various substrates, including flexible (fabric and copper mesh) and rigid materials (copper block). This can provide a new, rapid and facile route for producing large-scale samples with multifunctional applications

Fabrication of uniform Ag/TiO2 nanotube array structures with enhanced photoelectrochemical performance

In the current work, pulse current deposition has been used to prepare evenly distributed and uniformly sized Ag nanoparticles on a TiO2 nanotube array photoelectrode. The Ag particle size and loading were controlled by the pulse deposition time. The Ag/TiO2 nanotube arrays were characterized by SEM, TEM, XRD, XPS and UV-vis diffuse reflection absorption. The resulting electrode contained intimately coupled, three-dimensional Ag/TiO2 structures with greatly improved photocurrent generation and charge transfer compared to a two-dimensional random Ag particle layer deposited directly on top of the nanotube array by the regular photoinduction method. A model mechanism is proposed to illustrate the uniform Ag nanoparticle deposition via the new deposition technique developed in the current work that promotes the uniform distribution of the Ag particles whilst minimizing their deposition at tube entrances, thus effectively preventing the pores from becoming clogged.National Research Foundation of Singapore Government [MEWR 651/06/160]; National Nature Science Foundation of China [20773100, 20620130427]; National Basic Research Program of China (973 Program) [2007CB935603]; R&D of Fujian and Xiamen [2007H0031, 3502Z20073004

Multi-functional hybrid protonated titanate nanobelts with tunable wettability

We present the preparation of millimetre-sized liquid marbles with strong mechanical strength and good deformability using self-assembled fluoroalkylsilane functionalized titanate nanobelt powder. The strength and deformability of the marbles are adjustable by changing the intrinsic wetting state of the titanate nanoparticles. The excellent chemical stability of surface layer on the liquid marbles consisting of the titanate nanobelts provides the possibility for qualitative and quantitative chemical sensing under a wide range of pH values.Environment and Water Industry Programme Office (EWI) under the National Research Foundation of Singapore[MEWR651/06/160]; National Nature Science Foundation of China[20773100, 51072170, 20620130427]; National Basic Research Program of China (973 Program)[2007CB935603]; Technical Program of Fujian Province, China[2007H0031

Hierarchical layered titanate microspherulite: formation by electrochemical spark discharge spallation and application in aqueous pollutant treatment

An ultrafast and template-free method to synthesize three-dimensional (3D) hierarchical layered titanate microspherulite (TMS) particles with high surface area is reported. The synthesis makes use of an electrochemical spark discharge spallation (ESDS) process, during which a fast anodic reaction on the titanium surface creates a layer of titanium dioxide that instantly breaks down by the applied electrical field into the solution in the form of titanium oxide particles. The spalled particles readily react with the heated NaOH electrolyte to form the titanate particles. A typical as-prepared TMS with a diameter of 0.4 similar to 1.5 mu m is synthesized by ESDS of Ti foils in 10 M NaOH solution under an applied current density of 0.5 A cm(-2), leading to a reaction yield of approximately 0.10 similar to 0.15 g per square centimetre of exposed Ti foil within 20 min. After hydrogen ion exchange, the surface area can reach as high as similar to 406 m(2) g(-1). On the Ti surface, a crystalline rutile TiO2 nanosheet structure is formed, which is attributed to the local exothermic heat caused by the spark discharge. A formation mechanism of the TMS is discussed based on field emission scanning electron microscopy (FESEM), a transmission electron microscopy (TEM) study and Raman scattering spectroscopy analysis. The as-prepared TMS shows excellent adsorption performance compared with a titanate micro-particle (TMP), nanowire (TNW) and nanotube (TNT) when methylene blue (MB) and Pb-II ions are used as representative organic and inorganic pollutants. The mechanism of adsorption has also been discussed.National Research Foundation of Singapore Government [MEWR651/06/160

Self-organized TiO2 nanotube arrays with uniform platinum nanoparticles for highly efficient water splitting

Highly efficient water splitting electrode based on uniform platinum (Pt) nanoparticles on self-organized TiO2 nanotube arrays (TNTAs) was prepared by a combination of multi-step electrochemical anodization with facile photoreduction process. Uniform platinum (Pt) nanoparticles with an average diameter of 8 nm are distributed homogeneously on nanoporous top layer and underneath TiO2 nanotube wall. In comparison to pristine TNTAs, Pt@TNTAs show substantially enhanced photocurrent density and the incident photon-to-current conversion efficiency (IPCE) in the entire wavelength window. The maximum photocurrent density and IPCE from the optimized Pt@TNTAs photoelectrode (Pt, similar to 1.57 wt%) were about 24.2 mA cm(-2) and 87.9% at 350 nm, which is much higher than that of the pure nanotubes sample (16.3 mA cm(-2) and 67.3%). The resultant Pt@TNTAs architecture exhibited significantly enhanced photoelectrochemical activities for solar water splitting with hydrogen evolution rate up to 495 mu mol h(-1) cm(-2) in 2 M Na2CO3 + 0.5 M ethylene glycol under the optimal external bias of -0.3 V-SCE. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.National Natural Science Foundation of China [51072170, 21021002]; National Basic Research Program of China [2012CB932900]; Alexander von Humboldt (AvH) Foundation of German