Soft microfluidic systems that capture, store, and perform biomarker analysis of microliter volumes of sweat, in situ, as it emerges from the surface of the skin, represent an emerging class of wearable technology with powerful capabilities that complement those of traditional biophysical sensing devices. Recent work establishes applications in the real-time characterization of sweat dynamics and sweat chemistry in the context of sports performance and healthcare diagnostics. This paper presents a collection of advances in biochemical sensors and microfluidic designs that support multimodal operation in the monitoring of physiological signatures directly correlated to physical and mental stresses. These wireless, battery-free, skin-interfaced devices combine lateral flow immunoassays for cortisol, fluorometric assays for glucose and ascorbic acid (vitamin C), and digital tracking of skin galvanic responses. Systematic benchtop evaluations and field studies on human subjects highlight the key features of this platform for the continuous, noninvasive monitoring of biochemical and biophysical correlates of the stress state.

Bioassay-directed chromatographic fractionation of an ethyl acetate extract of Gardenia jasminoides (Gardeniae Fructus) afforded a new vanillic acid 4-O-beta-d-(6'-sinapoyl)glucopyranoside (1) and five new quinic acid derivatives, methyl 5-O-caffeoyl-3-O-sinapoylquinate (2), ethyl 5-O-caffeoyl-3-O-sinapoylquinate (3), methyl 5-O-caffeoyl-4-O-sinapoylquinate (4), ethyl 5-O-caffeoyl-4-O-sinapoylquinate (5), and methyl 3,5-di-O-caffeoyl-4-O-(3-hydroxy-3-methyl)glutaroylquinate (6), together with three known quinic acid derivatives, two flavonoids, two iridoids, and two phenolic compounds. The structures of new compounds were elucidated by the aid of spectroscopic methods. These compounds were assessed for antioxidant activity using three different cell-free bioassay systems and for HIV-1 integrase inhibitory activity. Five new quinic acid derivatives showed potent DPPH radical scavenging, superoxide anion scavenging, and lipid peroxidation inhibition activities. These new quinic acid derivatives also exhibited HIV-1 integrase inhibitory activity.

Efficient dye-sensitized solar cells (DSCs) were realized by using multiwalled carbon nanotubes (CNTs) as the counter-electrode catalyst. The catalytic layers were produced from an aqueous paste of mass-produced raw CNTs with carboxymethylcellulose polymer by low-temperature (70 degrees C) drying. We found that the highly disordered CNTs played the important role of increasing the fill factor of DSCs with electrolytes including large molecules and that the presence of Li(+) as the counter charges for I(3)(-)/I(-) redox couples reduced the chemical stability when using the CNT catalyst. Our experiments showed that by replacing the conventional Pt catalyst and Li(+)-based electrolyte with the proposed CNT catalyst and an electrolyte containing 1-butyl-3-methylimidazolium cations instead of Li(+), the energy conversion efficiency increased from 6.51% to 7.13%. This result suggests that highly defective CNT catalysts prepared by low-temperature drying are viable cost-effective alternatives for DSCs, as long as the electrolytes composition is optimized.

Dye-sensitized solar cells (DSSCs) are considered a suitable photovoltaic system for urban applications and highly bendable DSSCs can be expanded to applications such as dispensable DSSCs for commercial advertising and small portable power sources. However, although many reports have shown flexible or highly bendable photoelectrodes using TCO-coated polymeric substrates or metal meshes, until now, few have shown highly bendable DSSCs using electrodes because the flexibility of a single electrode is not a critical issue for highly bendable DSSCs. Here, we report a new DSSC design, inspired by the traditional Korean door structure consisting of a paper-bonded wooden frame, and a process for TCOfree highly bendable DSSCs utilizing glass paper and metal mesh. In the new DSSC design, constituents such as stainless steel mesh and mesoporous TiO 2 loaded with a Ru-complex dye were bonded on the glass paper, which was sputter-coated with Pt on one side and filled with electrolyte. The glass-paper-based flexible DSSCs showed 2% energy-conversion efficiency, which was maintained under bending until the radius of curvature reached 2 cm. The new glass-paperbased flexible DSSCs may have potential applications as low-cost highly bendable solar cells to overcome the limitations of conventional sandwich-type DSSCs.Dye-sensitized solar cells (DSSCs) have attracted attention due to their low production cost and relatively high energy-conversion efficiency even under weak illumination. Owing to these advantages, DSSCs are considered a suitable photovoltaic system for urban applications, including building-integrated photovoltaics (BIPV) and electronics-integrated photovoltaics (EIPV). 1-3 Flexible DSSCs can be attached to buildings or integrated into electronics for mechanical reliability and light-weight structures/devices. 4-9 Additionally, highly bendable DSSCs can be expanded to applications such as dispensable DSSCs for commercial advertising and small portable power sources.Generally, DSSCs have a sandwich-type structure consisting of two transparent conductive oxide (TCO)-coated substrates that face each other and an inserted spacer or gasket to provide space for electrolyte filling between the electrodes and to prevent electrical shorts. 1-9 The structure is produced as follows. A photoelectrode layer containing mesoporous TiO 2 and the loaded dye is deposited onto one transparent conductive substrate. An electrochemical catalytic counter electrode, such as Pt, is deposited on the other conductive substrate. The two separately prepared electrodes are assembled by inserting a spacer and gasket into the sandwich-type structure and filling the space between the two electrodes with an electrolyte. The sandwich-type structure has been the dominant design for DSSCs, and there are few alternatives.A new dye sensitized solar cell (DSSC) design, modeled on traditional Korean door structures and utilizing porous glass paper, suitable for bendable DSSCs is proposed. In the new design, all device components, including the photoelectrod...

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Increasing demands for wearable energy sources and highly flexible, lightweight photovoltaic devices have stimulated the development of textile-structured solar cells. However, the former approach of wire-type solar cell fabrication, followed by weaving of these devices, has had limited success, due to device failure caused by high friction forces and tension forces during the weaving process. To overcome this limitation, we present a new approach for textile solar cell fabrication, in which dye-sensitized solar cell (DSSC) electrodes are incorporated into the textile during the weaving process, using the textile warp as a spacer to maintain the DSSC structure. Porous, dye-loaded TiO2-coated holed metal ribbon and Pt nanoparticle-loaded carbon yarn were used as the photoanode and counterelectrode, respectively. The highly flexible textile-based solar cell was fabricated using a common weaving process with a loom. The inserted DSSCs in the textile demonstrated an energy conversion efficiency of 2.63% (at 1 sun, 1.5 A.M.). Our results revealed that additional performance enhancement was possible by considering other electrode materials and textile structures, as well as where and how the DSSC electrodes are inserted. In addition, we demonstrated that the inserted DSSCs could be electrically connected using a parallel configuration.

Crystal splitting and enhanced photocatalytic activities caused by implied dislocations were observed in hierarchical TiO(2) nano-architectures prepared by one-pot hydrothermal synthesis in concentrated HCl. Microstructural observation revealed that the nanowires formed by continuous splitting of TiO(2) nano-belts, which is caused by a lattice misorientation of about 6°, were generated by an array of dislocations. In addition, the larger amount of dislocations implied in TiO(2) nano-architectures induces higher photocatalytic activities under ultra-violet illumination.

Textile forms of solar cells possess special advantages over other types of solar cells, including their light weight, high flexibility, and mechanical robustness. Recent demand for wearable devices has promoted interest in the development of high-efficiency textile-based solar cells for energy suppliers. However, the weaving process occurs under high-friction, high-tension conditions that are not conducive to coated solar-cell active layers or electrodes deposited on the wire or strings. Therefore, a new approach is needed for the development of textile-based solar cells suitable for woven fabrics for wide-range application. In this report, we present a highly flexible, efficient DSSC, fabricated by sewing textile-structured electrodes onto casual fabrics such as cotton, silk, and felt, or paper, thereby forming core integrated DSSC structures with high energy-conversion efficiency (~5.8%). The fabricated textile-based DSSC devices showed high flexibility and high performance under 4-mm radius of curvature over thousands of deformation cycles. Considering the vast number of textile types, our textile-based DSSC devices offer a huge range of applications, including transparent, stretchable, wearable devices.