Volume 5, Issue 6 - Special issue: 4th Asia-Pacific Chemical and Biological Microfluidics Conference (APCBM 2015), Part 2 / Issue editors: Tran Dai Lam, Dong Pyo Kim and Holger Löwe

In this study, in order to enhance the aqueous solubility and to overcome the limitation of curcumin (Cur) in free form, as well as to develop a carrier for transdermal delivery of hydrophobic pharmaceutical agents such as Cur, a sonicated synthetic process of nanocurcumin (nCur) in thermally responsive Chitosan-g-Pluronic (CP) copolymer is disclosed herein. The use of CP copolymer solution as a dispersant medium is a very attractive method to avoid the use of toxic organic solvent and non-biocompatible surfactant. The obtained Cur nanoparticles had a fairly narrow distribution of 8–23 nm. nCur-dispersed CP solution showed good stability with no change in color characteristic and no phase separation after 1 month of storage. Rheological characterization of CP hydrogels had indicated sol-gel transition at the same temperature (35°C). Interestingly, the rate of Cur release for this system can be conveniently modulated as transdermal drug delivery.

Porous nanosilica (PNS) has been attracting much attention in fabrication of nanocarriers for a drug delivery system (DDS). However, the unmodified PNS-based carriers exhibited a significant initial burst release of drug, which may limit their potential clinical application. In this study, PNS was surface conjugated with cyclodextrin (CD) which was functionalized with adamantylamine-polyethylene glycol (APEG) for 5-fluorouracil (5-FU) delivery, in which case CD was used due to its ability to form a stable inclusion complex with 5-FU and APEG. The conjugated PNS (PNSC@APEG) was successfully prepared with spherical shape and diameter around 50 nm, determined by transmission electron microscopy (TEM). In addition, 5-FU was efficiently trapped in PNSC@APEG particles, which were around 63.4%±3.8% and was slowly released up to 3 days in phosphate buffer saline (PBS). Furthermore, the cell proliferation kit I (MTT) assay data showed that PNSC@APEG was a biocompatible nanocarrier. These results indicated that PNSC@APEG nanoparticles have a great potential as novel carriers for anticancer drug delivery.

Antimony-doped tin oxide (ATO) nanoparticles (NPs) (Sb-doped content 3%, 10%, and 15%) were synthesized by the (2 l autoclave, medium-scale) solvothermal method followed by sintering at various temperatures (500°C, 800°C, 900°C and 1000°C) so they would crystallize. The particle size increased from several to tens of nanometers with the increase of sintered temperature from 500°C to 1000°C, sharply from 800°C to 1000 °C; ~30 g of final product was received for each experiment. More interestingly, the crystallinity of the as-synthesized ATO was also increased with the increasing Sb doped content from 3% to 15%. The ATO NPs were coated onto glass substrates and then sintered at 500°C, which effectively prevented transmittance of infrared (IR) wavelengths (>800 nm) with 10% wt Sb-doped content, which is useful for thermal insulated glass coating application.

A metal organic framework (MOF) material based on Cu-BTC, which is formed from Cu and benzene-1,3,5-tricarboxylic acid (H 3 BTC), with 1D and 3D structures was synthesized under potential control. Cu-BTC 3D was electrodeposited at an applied potential of 5 V using tetrabutylammonium tetrafluoroborate (TBATFB) as electrolyte during 10–60 min. Hydration showed that the phase structure of Cu-BTC 3D did not change after a short time of immersing in water and that the specific surface area increased from 48 m 2 /g to 371 m 2 /g. In contrast, with a long time of hydration (more than 4 h), Cu-BTC was destroyed and a dehydration process could not recover the Cu-BTC structure.

Polyaniline titanium dioxide (PANi-TiO 2 ) composite had improved electrochemical behavior by intercalation of varied carbon nanotubes (CNTs): from 0 wt% to 30 wt%, compared to aniline. Those composites were coated on the titanium substrate to form PANi-TiO 2 -CNTs/Ti by using a binder agent. Material properties were characterized by IR spectra, X-ray diffraction and thermal analysis. The scanning electron microscope (SEM) images explained that the composite existed in uniform fibers with diameter of about 100 nm if content of CNT was 20–30 wt%. Electrical conductivity measurement, electrochemical impedance spectroscopy (EIS) and cyclic voltammograms showed their excellent electrical performance: electrical conductivity reached approximately 10 −1 S/cm, and the resistances of those composite layers were reduced from 18 to 27 times compared to that without CNTs. Warburg diffusion was found by EIS analysis with coefficient data ranging from 10 −15 to 10 −16 cm 2 /s only for composites containing CNTs on which also no adsorption resistance occurred. The potentiodynamic and galvanodynamic polarizations explained that the composite contained 20% CNTs, exhibiting a better cyclic voltammetry (CV) diagram because of higher responding current density and a better performance because of yielding a higher current density (300 μA/cm 2 ) at 250 mV versus silver/silver chloride reference electrode in comparison with the other obtained composites in this study, respectively.

Silica nanoparticles (SNPs) were modified by different amounts of 3-aminopropyltriethoxysilane (APTES). Nanocomposites based on ethylene vinyl acetate copolymer (EVA) and modified SNP (m-SNP) were prepared by the melt mixing method. They were characterized by Haake torque measurement, differential scanning calorimetry (DSC), horizontal burning test, scanning electron microscopy. Accelerated weather testing of the nanocomposites was performed according to ASTM D4329 (cycle A) for 168 h. The Haake torque indicates that the relative melt viscosity of EVA/m-SNPs is slightly higher than that of EVA/SNP nanocomposites. The DSC and burning test results show that m-SNPs decrease crystallinity degree and flammability of EVA. After accelerated weather testing, the relative amount of C=O groups in EVA/m-SNP nanocomposites is lower than that in EVA/SNP nanocomposites. Micro crack of EVA/m-SNP nanocomposite is smaller than that of EVA/SNP nanocomposite. In our study, the EVA/m-SNP nanocomposites with good tensile properties, flame and weather resistance can be used as sustainable materials in some technique fields.