Eunji Jang

Smart clothing, which can be manufactured based on smart textiles with electrical conductivity, can be used as a transmission line to transmit signals. The performance of the fabricated textile-based transmission line can be determined by evaluating light-emitting diode consistency. In this study, a textile-based transmission line was fabricated by impregnating two concentrations of poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT: PSS) to impart the electrical conductivity to a polyurethane (PU) nanoweb. Three conditions of thermal treatment were conducted to decrease the electrical resistance, and the thickness, electrical, surface, and chemical properties were evaluated. The thickness of the specimens tended to decrease at the low concentration, and the thermal treatment temperature increased. The linear resistances decreased from 1580 Ω/cm (PA) to 310.6 Ω/cm (PB120) as the concentration of PEDOT: PSS and thermal treatment temperature increased. Field emission scanning electron microscope images show that the PU nanoweb was uniformly and successfully impregnated with PEDOT: PSS. Raman spectra indicate an effect of the thermal treatment on the structural change of the PEDOT chains, which suggests an electrical resistance change of specimens. As a result, the optimum concentration of the PEDOT: PSS impregnated PU nanoweb as a transmission line for smart textiles is 2.6 wt%, and the thermal treatment temperature is 120℃. The performance of the textile-based transmission line (PB120) according to the length was higher as the length of the specimen was shorter. The highest consistency was 51 lm/m² (50 mm), and the lowest was 45 lm/m² (150 mm). Therefore, the PEDOT: PSS/PU nanoweb has applicability and feasibility as a transmission line.

The objectives of this study were as follows: (a) to compare two coating methods (i.e., brush painting and doctor blade coating) for applying graphene onto polyurethane nanofiber webs (PU NWs) for developing e-textiles; (b) to investigate the surface characteristics and chemical and mechanical properties of the specimens based on the coating conditions; (c) to find the relationship between the electrical resistances of the specimen and the amounts of graphene in the PU NWs; and (d) to evaluate electrical resistance changes when specimens are physically strained to calculate the gauge factors. The linear resistances of the graphene-coated PU NWs were less than 600 Ω/cm on all specimens. The PU NW linear resistances are about 1–500 Ω/cm when coated with silver nanowires and about 1000–7000 Ω/cm when coated with polypyrrole. The graphene-coated specimen linear resistances are lower than those of the polypyrrole-coated specimens and higher than those of the silver nanowire-coated specimens. As has been demonstrated in other studies, brush painting is a simple fabrication process, but the field emission scanning electron microscopy image showed that it did not produce uniform coatings compared to the doctor blade method. However, it was found that it is possible to fabricate e-textiles with linear resistances of less than 100 Ω/cm by merely using repetitive brush painting. Fourier transform infrared spectroscopy analysis confirmed the peak bands of urethane and the -NH- bending peak to investigate the graphene coating conditions. The tensile strength of the graphene-coated specimen was much lower than that of the untreated, but the elongation/strain at rupture was higher than that of the untreated specimen. This result shows that the graphene-coated specimens are strained to a smaller force than the untreated one. Furthermore, this indicates that graphene coating induced the changes of the tensile properties of the specimens. The electrical resistances are varied depending on the graphene coating uniformity. Using the doctor blade method, the electrical resistance values of the specimens were slightly lower than those for the brush painted specimens. The gauge factor values of the specimens were examined by the stretch and release test. The highest gauge factor was 97.24 (D2.6) and the lowest was 20.54 (D2.2).

Studies have shown that insertion of oleic acid into lipid bilayers can modulate the membrane properties of liposomes so as to improve their function as drug carriers. Considering that 2-hydroxyoleic acid (2OHOA), a potential antitumor agent currently undergoing clinical trials, is a derivative of oleic acid, we explored the possibility of developing 2OHOA-inserted liposomes as a multifunctional carrier of antitumor drugs in the present study. The insertion of 2OHOA into lipid bilayers was confirmed by surface charge determination and differential scanning calorimetry. 2OHOA insertion greatly decreased the order of dimyristoylphosphatidylcholine packing, produced a nanosized (in vitro anticancer activity of ATRA-incorporated/2OHOA-inserted liposomes was significantly higher than that of ATRA-incorporated conventional liposomes. In a B16-F10 melanoma syngeneic mouse model, the tumor growth rate was significantly delayed in mice treated with ATRA-incorporated/2OHOA-inserted liposomes compared with that in the control group. Immunohistochemical analyses revealed that the enhanced antitumor activity of ATRA-incorporated/2OHOA-inserted liposomes was due, at least in part, to increased induction of apoptosis. Collectively, our findings indicate that 2OHOA-inserted liposomes exhibit multiple advantages as antitumor drug carriers, including the ability to simultaneously deliver two anticancer drugs – 2OHOA and incorporated drug – to the tumor tissue.