Degradation of aniline: sodium alginate/modified pomelo cellulose double cross-linking system as a bacterial immobilization carrier.

Pectin cellulose grafted with glycidyltrimethylammoniochloride (GTMAC) was successfully obtained following the processes of depectinfibrillation and cellulose cationization using ordinary Shatian pomelo peel produced in Yongzhou, Hunan, as the raw material. This is the first report on a new type of functionalized sodium alginate-immobilized material prepared from the fibers of pomelo peel. The material was prepared by combining modified pomelo peel cellulose and sodium alginate following the processes of physical and chemical double cross-linking. The prepared material was used to embed the target bacteria to achieve the biodegradation of p-aniline. The concentration of CaCl2 was adjusted when the alginate gelled, and the alginate to yuzu peel cellulose ratio was tuned. The immobilized material-embedded bacteria help achieve the best degradation effect. Bacteria are embedded during the process of the degradation of aniline wastewater, and the functionalization of the cellulose/sodium alginate-immobilized material results in unique surface structure performance. The performance of the prepared system is better than that of the single sodium alginate-based material characterized by a large surface area and good mechanical properties. The degradation efficiency of the system is improved significantly for the cellulose materials, and the prepared materials can potentially find applications in the field of bacteria-fixed technology.

Bubble-Enabled Underwater Motion of a Light-Driven Motor.

This work reports the photothermally driven horizontal motion of a motor as well as the suspending and vertical movements underwater. A motor is designed by attaching two polydimethylsiloxane-coated oxidized copper foams (POCF) to the two opposite sides of an oxidized copper foam (OCF). When the hydrophobic POCF is immersed in water, it serves as both an air bubble trapper and a light-to-heat conversion center. As bubbles grow under photothermal heating, they provide lifting force and result in the revolving motion of the motor. With removal of light illumination, bubbles are cooled by the surrounding water and shrink, and the buoyance is lowered. The resultant force of gravitational force, buoyance, and fluid resistance drives the motor to move forward horizontally. Furthermore, the motors are utilized as oil collectors and oil/water separation is achieved successfully. To effectively control the suspending motion, a polydimethylsiloxane foam doped with carbon black (C-foam) is designed under the photothermal principle. It is maintained at a certain position underwater by controlling the on/off of light. The vertical motion is also studied and utilized to generate electricity. It is expected that different types of underwater motion will open up new opportunities for various applications including drug delivery, collection of heavy oil underwater, and electricity generation.

Magnetic Induction Heating in a Conducting Polymer for Biomedical Applications.

In this study, we investigate the magnetic induction heating induced in a conducting polymer (CP) under alternative magnetic fields (AMFs). Experimental results and numerical simulations have proved that the magneto-thermal conversion of the CP is caused by the induced eddy current, which is related to the shape and intensity of the applied external AMF, and the intrinsic electrical conductivity, macrostructure and microstructure of the CP. By employing various fabrication methods, specific temperature distribution and control of thermal field within conducting polymer films and aerogels could be achieved. To exploit the potential of magnetic induction heating in CP for biomedical applications, we designed a conducting polymer aerogel-based self-adaptive heat patch and demonstrated its AMF-enabled localized heating of skin. In addition to the thermal ablation of tumor cells via magneto-thermal conversion of the CP, the promotion of neuronal differentiation at mild temperature by noninvasive magneto-electrical stimulation has also been demonstrated to be an effective strategy for tissue engineering.

Preparation and thermal stability evaluation of cellulose nanofibrils from bagasse pulp with differing hemicelluloses contents.

In this work, cellulose nanofibrils (CNFs) are produced from bagasse pulps with differing hemicelluloses contents by ultrafine grinding and high-pressure homogenization. The results showed that hemicelluloses content in the range of 9.7-21.7 wt.% led to nanofibrils with average diameter. A decrease in hemicelluloses content can enhance the crystallinity and improve the thermal stability of the CNFs. The activation energy of the CNF samples with hemicelluloses contents of 9.7 wt.%, 12.72 wt.%, 15.7 wt.%, 18.76 wt.%, and 21.7 wt.% are 713.03, 518.93, 462.62, 421.78, and 211.11 kJ/mol, respectively, when the conversion rate is increased from 30%-90%. These results demonstrate that hemicelluloses content has a considerable influence on the properties of CNFs. This work provides a theoretical basis for high-value utilization of CNFs, and enriches useful information on the application of CNF materials.

A Dual-Emissive Phosphorescent Polymeric Probe for Exploring Drug-Induced Liver Injury via Imaging of Peroxynitrite Elevation In Vivo.

Drug-induced liver injury (DILI) is a widespread clinical problem. The pathophysiological mechanisms of DILI are complicated, and the traditional diagnostic methods for DILI have their limitations. Owing to its convenient operation, high sensitivity, and high specificity, luminescent sensing and imaging as an indispensable tool in biological research and clinical trials may provide an important means for DILI study. Herein, we report the rational design and preparation of a near-infrared dual-phosphorescent polymeric probe (P-ONOO) for exploring the DILI via specific imaging of peroxynitrite (ONOO-) elevation in vivo, which was one of early markers of DILI and very difficult to be detected due to its short half-life and high reactive activity. With the utilization of P-ONOO, the raised ONOO- was visualized successfully in the drug-treated hepatocytes with a high signal-to-noise ratio via ratiometric and time-resolved photoluminescence imaging. Importantly, the ONOO- boost in the acetaminophen-induced liver injury in real time was verified, and the direct observation of the elevated ONOO- production in ketoconazole-induced liver injury was achieved for the first time. Our findings may contribute to understanding the exact mechanism of ketoconazole-induced hepatotoxicity that is still ambiguous. Notably, this luminescent approach for revealing the liver injury works fast and conveniently.

Enzymatic pretreatment for cellulose nanofibrils isolation from bagasse pulp: Transition of cellulose crystal structure.

In this work, cellulase, low-concentration cold alkali and cellulase combined with cold alkali were used to pretreat unbleached bagasse pulp from which cellulose nanofibrils (CNFs), about 30 nm in diameter, were successfully prepared through ultrafine grinding and high-pressure homogenization. X-ray diffraction analysis showed that cellulase pretreatment increased the crystallinity of CNFs. After low-concentration cold alkali pretreatment, the crystallinity of CNFs significantly reduced and the crystal structure of the cellulose changed from type I to type II. Thermogravimetric analysis showed that CNFs prepared by cellulase combined with cold alkali treatment produced more regenerated cellulose and had lower thermal stability. The use of cellulase and low-concentration cold alkali pretreatments combined with ultrafine grinding and high-pressure homogenization is an environment-friendly method for preparing CNFs. The use of low-concentration cold alkali reduces the consumption of alkali and clean water.

Nanocellulose-graphene composites: A promising nanomaterial for flexible supercapacitors.

With the increasing consumption of global fossil energy and environmental pollution, the development of green renewable energy and efficient energy storage technology become an urgent problem to solve. Supercapacitors have drawn a great interest for use in wearable electronic devices due to their portability and stable performance. The electrode is very important when preparing a high-performance flexible supercapacitor, which requires good electrochemical performance and flexibility. Graphene and nanocellulose are excellent flexible electrode material for supercapacitors, and nanocellulose is often used as a substrate material for electronic devices because of its good biodegradability, mechanical flexibility and chemical reactivity. In this work, the structure design and assembly method of the nanocellulose-graphene composite materials used for flexible supercapacitors are reviewed. The mechanical flexibility, specific capacitance, electrochemical performance, cyclic stability, renewability and biodegradability are taken into account, so as to evaluate the performance of the composite materials and to better assess the merits of this material with respect to real applications.

Photomodulated chiral induction in helical azobenzene oligomers.

Appending L-alanine to the terminal positions of a helical azobenzene oligomer produced a P helical bias, which increased with oligomer length. Irradiation gave rise to E-->Z isomerization of the terminal azo linkages, which displaced the stereogenic center of L-Ala from the helix backbone and suppressed chiral induction. Theoretical simulations of the CD spectrum of the P helical conformation are in qualitative agreement with the experimental spectra.

Hyperbranched Phosphorescent Conjugated Polymer Dots with Iridium(III) Complex as the Core for Hypoxia Imaging and Photodynamic Therapy.

Real-time monitoring of the contents of molecular oxygen (O2) in tumor cells is of great significance in early diagnosis of cancer. At the same time, the photodynamic therapy (PDT) could be realized by highly toxic singlet oxygen (1O2) generated in situ during the O2 sensing, making it one of the most promising methods for cancer therapy. Herein, the iridium(III) complex cored hyperbranched phosphorescent conjugated polymer dots with the negative charges for hypoxia imaging and highly efficient PDT was rationally designed and synthesized. The incomplete energy transfer between the polyfluorene and the iridium(III) complexes realized the ratiometric sensing of O2 for the accurate measurements. Furthermore, the O2-dependent emission lifetimes are also used in photoluminescence lifetime imaging and time-gated luminescence imaging for eliminating the autofluorescence remarkably to enhance the signal-to-noise ratio of imaging. Notably, the polymer dots designed could generate the 1O2 effectively in aqueous solution, and the image-guided PDT of the cancer cells was successfully realized and investigated in detail by confocal laser scanning microscope. To the best of our knowledge, this represents the first example of the iridium(III) complex cored hyperbranched conjugated polymer dots with the negative charges for both hypoxia imaging and PDT of cancer cells simultaneously.

Bioinspired Bifunctional Membrane for Efficient Clean Water Generation.

Solving the problems of water pollution and water shortage is an urgent need for the sustainable development of modern society. Different approaches, including distillation, filtration, and photocatalytic degradation, have been developed for the purification of contaminated water and the generation of clean water. In this study, we explored a new approach that uses solar light for both water purification and clean water generation. A bifunctional membrane consisting of a top layer of TiO2 nanoparticles (NPs), a middle layer of Au NPs, and a bottom layer of anodized aluminum oxide (AAO) was designed and fabricated through multiple filtration processes. Such a design enables both TiO2 NP-based photocatalytic function and Au NP-based solar-driven plasmonic evaporation. With the integration of these two functions into a single membrane, both the purification of contaminated water through photocatalytic degradation and the generation of clean water through evaporation were demonstrated using simulated solar illumination. Such a demonstration should also help open up a new strategy for maximizing solar energy conversion and utilization.

Preparation and optical properties of indium tin oxide/epoxy nanocomposites with polyglycidyl methacrylate grafted nanoparticles.

Visibly highly transparent indium tin oxide (ITO)/epoxy nanocomposites were prepared by dispersing polyglycidyl methacrylate (PGMA) grafted ITO nanoparticles into a commercial epoxy resin. The oleic acid stabilized, highly crystalline, and near monodisperse ITO nanoparticles were synthesized via a nonaqueous synthetic route with multigram batch quantities. An azido-phosphate ligand was synthesized and used to exchange with oleic acid on the ITO surface. The azide terminal group allows for the grafting of epoxy resin compatible PGMA polymer chains via Cu(I) catalyzed alkyne-azide "click" chemistry. Transmission electron microscopy (TEM) observation shows that PGMA grafted ITO particles were homogeneously dispersed within the epoxy matrix. Optical properties of ITO/epoxy nanocomposites with different ITO concentrations were studied with an ultraviolet-visible-near-infrared (UV-vis-NIR) spectrometer. All the ITO/epoxy nanocomposites show more than 90% optical transparency in the visible light range and absorption of UV light from 300 to 400 nm. In the near-infrared region, ITO/epoxy nanocomposites demonstrate low transmittance and the infrared (IR) transmission cutoff wavelength of the composites shifts toward the lower wavelength with increased ITO concentration. The ITO/epoxy nanocomposites were applied onto both glass and plastic substrates as visibly transparent and UV/IR opaque optical coatings.