Paclitaxel (PTX) is one of the most widely used anticancer agents for chemotherapy. However, the solubility of PTX in water is poor, which results in the occurrence of side effects. In this study, the PTX concentration in aqueous solution was improved by naturally derived biocompatible materials, such as phospholipids (dipalmitoyl-sn-glycero-3-phosphotydilcholine, DPPC) and amino acids (AAs). The PTX concentration in phosphate-buffered saline (PBS) was increased by complexes consisting of PTX/DPPC/AAs, and glycine was found to be the most effective AA for this method. The molar ratio of PTX/DPPC/Gly was important. The ratio of DPPC to PTX was more important in increasing the concentration of PTX in PBS than the ratio of Gly to PTX. The cytotoxic effects in cancer cells were evaluated. After incubation with the PTX/DPPC/Gly complex, the viability of HeLa cells decreased. These results suggested that the PTX/DPPC/Gly complex is an efficient system for the delivery of PTX to cancer cells.

The present study introduces a simple and inexpensive microdevice for the reduction of nitrate ions using copper micro-tubular carriers with outer and inner diameters of 0.5 and 0.2 mm, respectively. Three units consisting of seven pieces of carriers of lengths 35 mm were layered in a series in a square channel with side 2 mm in the microdevice. The performance of the microdevice was evaluated by measuring the reduction of nitrate ions in aqueous nitric acid solutions of 2.5×10⁻³, 5×10⁻³, 1×10⁻², and 2×10⁻² mol/m³ using naphthylethylenediamine absorptiometry. The reduction efficiency in a solution of 2.5×10⁻³ mol/m³ nitric acid achieved 100% at reduction times longer than 22.7 min. The Langmuir adsorption isotherm suggests that the adsorption of the nitrate ions on the copper surfaces follows the Langmuir adsorption model. Adopting copper micro-tubular carriers without cadmium as a reductant could reduce environmental loads and easily optimize the channel structure of the microdevice.