This letter demonstrates that a novel, highly efficient enzyme electrode can be directly obtained using covalent attachment between carboxyl acid groups of graphene oxide sheets and amines of glucose oxidase. The resulting biosensor exhibits a broad linear range up to 28 mM x mm(-2) glucose with a sensitivity of 8.045 mA x cm(-2) x M(-1). The glucose oxidase-immobilized graphene oxide electrode also shows a reproducibility and a good storage stability, suggesting potentials for a wide range of practical applications. The biocompatibility of as-synthesized graphene oxide nanosheets with human cells, especially retinal pigment epithelium (RPE) cells, was investigated for the first time in the present work. Microporous graphene oxide exhibits good biocompatibility and has potential advantages with respect to cell attachment and proliferation, leading to opportunities for using graphene-based biosensors for the clinical diagnosis.

We report the preparation of a furan polymer, poly(2,5-furandimethylene succinate) by means of a condensation reaction between bio-based monomers. A reversible Diels–Alder reaction between furan and maleimide groups allowed the formation of network polymers cross-linked by a bismaleimide. By controlling the amount of the bismaleimide, mechanical properties were varied widely. These network polymers healed well when their broken surfaces were activated by bismaleimide solutions or solvent. The polymers also displayed excellent self-healing ability without external stimulus. This polymer class offers a wide range of possibilities to produce materials from biomass that have both practical mechanical properties and healing ability. These materials have the potential to bring great benefits to our daily lives by enhancing the safety, performance, and lifetime of products.

Multi-wavelength lasers have widespread applications (e.g. fiber telecommunications, pump-probe measurements, terahertz generation). Here, we report a nanotube-mode-locked all-fiber ultrafast oscillator emitting three wavelengths at the central wavelengths of about 1540, 1550, and 1560 nm, which are tunable by stretching fiber Bragg gratings. The output pulse duration is around 6 ps with a spectral width of ~0.5 nm, agreeing well with the numerical simulations. The triple-laser system is controlled precisely and insensitive to environmental perturbations with <0.04% amplitude fluctuation. Our method provides a simple, stable, low-cost, multi-wavelength ultrafast-pulsed source for spectroscopy, biomedical research and telecommunications.

Fabrics with automatic one‐way water transport ability are highly desirable for applications in daily life, industry, health, and defense. However, most of the studies on one‐way water transport fabrics only report the qualitative water transport results. The lack of quantitative measure makes it hard to assess the directional transport quality. Here, it is proved that a hydrophilic fabric after being electrosprayed with a thin layer of hydrophobic coating on one side shows one‐way water transport ability. By using moisture management tester, the water transport property is qualitatively characterized and the effect of hydrophobic fabric layer thickness on one‐way water transport feature is examined. The hydrophobic fabric layer thickness is found to play a key role in deciding the one‐way transport ability. When a plain woven fabric with an overall thickness of 420 μm and average pore size of 33 μm is used as fabric substrate, a hydrophobic fabric layer thickness between 22 and 62 μm allows the treated fabric to show a one‐way droplet transport feature. A one‐way transport index as high as 861 can be attained. The one‐way water transport is durable enough to withstand repeated washing. This novel fabric may be useful for development of “smart” textiles for various applications.

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Finding new ways to control and slow down the group velocity of light in media remains a major challenge in the field of optics. For the design of plasmonic slow light structures, graphene represents an attractive alternative to metals due to its strong field confinement, comparably low ohmic loss and versatile tunability. Here we propose a novel nanostructure consisting of a monolayer graphene on a silicon based graded grating structure. An external gate voltage is applied to graphene and silicon, which are separated by a spacer layer of silica. Theoretical and numerical results demonstrate that the structure exhibits an ultra-high slowdown factor above 450 for the propagation of surface plasmon polaritons (SPPs) excited in graphene, which also enables the spatially resolved trapping of light. Slowdown and trapping occur in the mid-infrared wavelength region within a bandwidth of ~2.1 μm and on a length scale less than 1/6 of the operating wavelength. The slowdown factor can be precisely tuned simply by adjusting the external gate voltage, offering a dynamic pathway for the release of trapped SPPs at room temperature. The presented results will enable the development of highly tunable optoelectronic devices such as plasmonic switches and buffers.

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As graphene becomes one of the most exciting candidates for multifunctional biomedical applications, contact between eyes and graphene-based materials is inevitable. On the other hand, eyes, as a special organ in the human body, have unique advantages to be used for testing new biomedical research and development, such as drug delivery. Intraocular biocompatible studies on graphene-related materials are thus essential. Here, we report our recent studies on intraocular biocompatibility and cytotoxicity of graphene oxide (GO) both in vitro and in vivo. The successful preparation of GO nanosheets was confirmed using atomic force microscopy, contact angle analyzer, Fourier transform infrared spectroscopy, and Raman spectroscopy. The influence of GO on human retinal pigment epithelium (RPE) cells in terms of the cell morphology, viability, membrane integrity, and apoptosis was investigated using various techniques, including optical micrography, cell counting kit-8 (CCK-8) assay, lactate dehydrogenase (LDH) assay, and apoptosis assay. The addition of GO had little influence on cell morphology, but the change was visible after long-time culturing. RPE cells showed higher than 60% cell viability by CCK-8 assay in GO solutions and less than 8% LDH release, although a small amount of apoptosis (1.5%) was observed. In vitro results suggested good biocompatibility of GO to RPE cells with slight adverse influence, on the cell viability and morphology in long-time periods, along with aggregation of GO. Thus, some further studies are needed to clarify the cytotoxicity mechanism of GO. GO intravitreally injected eyes showed few changes in eyeball appearance, intraocular pressure (IOP), eyesight, and histological photos. Our results suggested that GO did not cause any significant toxicity to the cell growth and proliferation. Intravitreal injection of GO into rabbits' eyes did not lead to much change in the eyeball appearance, IOP, electroretinogram, and histological examination.