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ISSN:1616-3028 ISSN:1616-301X

Rapid and affordable detection of analytes is critical in diagnostic technologies, but current methods are typically expensive and unsuitable for field detection. Lipidic cubic phases are optically isotropic, transparent lyotropic liquid crystals (LC), containing highly confined water nanochannels in-between percolating lipid bilayers following defined space groups. Due to this nanoconfinement, the water in these systems provides a unique environment for chemical and enzymatic reactions. Here, it is shown that during the in meso peroxidase enzymatic reaction, the converted product crystallizes within the mesophase domains, generating a detectable birefringence signal and a new general assay principle is presented for the detection of an unprecedented vast class of analytes using such birefringence as sole optical output signal. By exploiting bienzymatic cascade reactions or introducing an enzyme-linked immunosorbent assay based on birefringence (Birefringent-ELISA), this approach is used for real-time detection of exemplary analytes, such as glucose and cholesterol, model pathogenic microorganisms, Escherichia coli, and viruses such as Ebola and HIV. It is also shown how the same technology enables the rapid, naked-eye screening of malaria infection via in meso detection of hemozoin crystallites. This new technology is general and readily adaptable to the rapid detection of virtually any type of analyte, such as disease biomarkers, viruses, bacteria, and parasites.

Due to their porous structure, angora rabbit fi bers make for some of the highest quality wool. The application of these fi bers on a technical scale is not feasible due to their limited availability and high price. Here, a robust fi ber preparation method is reported based on an unusual spinning process, where a non-equilibrated, ternary system of protein, solvent, and non-solvent is continuously processed into strong fi bers with minimal energy input and harmless solvents. Gelatin—the degradation product of collagen—is chosen as the protein component because of its immense availability from slaughterhouse waste. Due to the sponge-like structure of the ternary gelatin/ water/2-propanol spinning mixture, fi bers with internal cavities are produced. The porous nature of these fi bers resembles the morphology of angora rabbit fi bers. Despite their high porosity, the here-obtained gelatin fi bers show clear re-orientation of the fi brous protein and attain a mechanical performance similar to other bio- (e.g., wool, tendon collagen) and synthetic polymers (e.g., polytetrafl uoroethylene, polyamide 6). These promising results motivate for broader investigations on the spinning of non-equilibrium protein mixtures and suggest the use of porous gelatin fi bers in textiles.

This paper reports β-lactoglobulin amyloid protein fibrils directed synthesis of Titanium Dioxide (TiO2) hybrid nanowires. Protein fibrils act as templates to generate closely packed TiO2 nanoparticles on the surface of the fibrils using titanium (IV) bis (ammonium lactato) dihydroxide (TiBALDH) as precursor, resulting in the TiO2–coated amyloid hybrid nanowires. These amyloid fibrils also exhibit complexation with a luminescent water-soluble semiconductive polythiophene (P3HT). TiO2 nanowires behave as electron acceptor while, P3HT as electron donor. In this way, amyloid-TiO2 hybrid nanowires can serve in heterojunction photovoltaic devices. To demonstrate this, a photovoltaic active layer is prepared by spin coating the blended mixture of polythiophene-coated fibrils and amyloid-TiO2 hybrid nanowires. The current–voltage characteristics of these photovoltaic devices exhibit excellent fill factor of 0.53, photovoltaic current density of 3.97 mA·cm−2 and power conversion efficiency of 0.72%, highlighting a possible future role for amyloid-based templates in donor–acceptor devices, organic electronics and hybrid solar cells.

Novel donor-acceptor rod-coil diblock copolymers of regioregular poly(3-hexylthiophene) (P3HT)-block-poly(2-phenyl-5-(4-vinylphenyl)-1,3,4-oxadiazole) (POXD) are successfully synthesized by the combination of a modified Grignard metathesis reaction (GRIM) and atom transfer radical polymerization (ATRP). The effects of the block ratios of the P3HT donor and POXD pendant acceptor blocks on the morphology, field effect transistor mobility, and memory device characteristics are explored. The TEM, SAXS, WAXS, and AFM results suggest that the coil block fraction significantly affects the chain packing of the P3HT block and depresses its crystallinity. The optical absorption spectra indicate that the intramolecular charge transfer between the main chain P3HT donor and the side chain POXD acceptor is relatively weak and the level of order of P3HT chains is reduced by the incorporation of the POXD acceptor. The field effect transistor (FET) hole mobility of the system exhibits a similar trend on the optical properties, which are also decreased with the reduced ordered P3HT crystallinity. The low-lying highest occupied molecular orbital (HOMO) energy level (-6.08 eV) of POXD is employed as charge trap for the electrical switching memory devices. P3HT-b-POXD exhibits a non-volatile bistable memory or insulator behavior depending on the P3HT/POXD block ratio and the resulting morphology. The ITO/P3HT 44 -b-POXD 18 /Al memory device shows a non-volatile switching characteristic with negative differential resistance (NDR) effect due to the charge trapped POXD block. These experimental results provide the new strategies for the design of donor-acceptor rod-coil block copolymers for controlling morphology and physical properties as well as advanced memory device applications.

Remotely controlled actuation with wireless sensorial feed-back is desirable for smart materials to obtain fully computer-controlled actuators. A light-controllable polymeric material is presented, in which exposure to light couples with a change in magnetic properties, allowing light signal conversion into non-volatile magnetic memory. The same material can serve, additionally, both as actuator and transducer, and allows the monitoring of its two-way elastic shape-changes by magnetic read-out. In order to tune the macroscopic magnetic properties of the material, both the reorientation of i) shape anisotropic ferrimagnetic nano-spindles and ii) a mechanically and magnetically coupled liquid-crystalline elastomer (LCE) matrix are controlled. These materials are envisioned to have great potential for the development of innovative functional objects, for example, computer-controlled smart clothing, sensors, signal encoding, micro-valves, and robotic devices.