Tribo-charge enhanced and cellulose based biodegradable nanofibrous membranes with highly fluffy structure for air filtration and self-powered respiration monitoring systems.

Recently, the demand for healthcare products especially wearable smart masks is increasing. The biosafety and degradability of smart masks are crucial for human health and environmental protection. However, the development of biodegradable and biocompatible fibrous membranes with high filtration efficiency and low pressure drop is still a challenge. How to realize the collaborative improvement between air filtration efficiency and pressure drop of the nanofibrous membrane is still a challenge. Here, a tribo-charge enhanced and biodegradable nanofibrous membranes (TCB NFMs) with highly fluffy structure for air filtration and self-powered respiration monitoring systems is reported for the first time. The filtration efficiency and pressure drop of the prepared membranes for 0.3 µm NaCl particulates is 99.971% and 41.67 Pa. The TCB NFMs based smart mask possesses a series of satisfactory and excellent characteristics, such as self-powered, biodegradable, biocompatible, high filtration efficiency, and low pressure drop, which is highly promising for application in air filtration systems and intelligent wearable respiration monitoring systems.

Xylan derived fluorescence carbon dots composite with cotton cellulose paper as 'turn-off' fluorescence platform for sensitive and selective detection Cu2+ in real samples.

The pollution of heavy metals such as Cu2+ is still serious and the discharge of sewage of Cu2+ will cause damage to soil environment and human health. Herein, a biomass-based solid-state fluorescence detection platform (CPU-CDs) was developed as fluorescent sensor for detection Cu2+ via fluorescence and colorimetric dual-model methods in real time. CPU-CDs was composed of xylan-derived CDs (U-CDs) and cotton cellulose paper, which exhibiting good reusability, non-toxicity, excellent fluorescence characteristics and high biocompatibility. Further, CPU-CDs displayed high effectiveness and sensitivity for Cu2+ with the detection limit as low as 0.14 µM, which was well below U.S. EPA safety levels (20 µM). Practical application indicated that CPU-CDs could achieve precision response of Cu2+ change in real environment water samples with good recovery range of 90 %-119 %. This strategy demonstrated a promising biomass solid-state fluorescence sensor for Cu2+ detection for water treatment research, which is of great significance in dealing with water pollution caused by heavy metal ions.

Biomass-based indole derived fluorescence sensor composited with cellulose paper: Detection of picric acid in food and environment samples.

Picric acid (PA) is highly water-soluble, the fact makes it stand out as the most hazardous environment pollutant. Therefore, accurate determination of PA is of great significance for human health and environmental protection. Herein, a novel indole-based fluorescent sensor (H1) with good water solubility and fluorescence stability was reported. H1 exhibited 'turn-off' fluorescence response for PA with fast reaction rate (<30 s), unique specificity and excellent selectivity and high sensitivity (limit of detection = 34 nM). Further, H1 was successfully applied to detect PA in real samples (tap water, Yangtze River, Xuanwu Lake, soil, food, fish and shrimp) with satisfactory recoveries at three spiking levels ranging from 98.0 to 112.0 %. In addition, H1 displayed high biocompatibility in mung beans and fresh blood. Moreover, aiming to attain portable analysis, H1 was composited with biomass cellulose paper (H1-FP) and integrated with smartphone for construction as a solid-state fluorescence platform to achieve fast and visual detection of PA in suit with significant stability, high sensitively and selectivity. The establishment of this sensing approach is expected to offer new insight into rapid, selective, and sensitive detection of major pollutants for food and environmental safety.

Xylan derived carbon dots composite with PCL/PLA for construction biomass nanofiber membrane used as fluorescence sensor for detection Cu2+ in real samples.

Water and soil pollution caused by Cu2+ is not conducive to sustainable development of environment and could cause damage to environment and even human body. Currently, fluorescent sensor solutions analysis method has been used for Cu2+ detection, but they also suffer from drawbacks including easy leakage, difficult storage, and inaccurate. Herein, a green solid-state biomass fluorescence platform (NBU-CDs) consisting of xylan-derived carbon dots (U-CDs) and polylactic acid/polycaprolactone (PLA/PCL) was designed by using in situ electrospinning technology. The prepared NBU-CDs fluorescence platform showed good fluorescence effect and can be served as fluorescence sensor for detecting Cu2+ with high sensitively, selectively and low detection limit (LOD = 0.83 µM). The practical applications of NBU-CDs exhibited high specificity for Cu2+ detection in zebrafish, water samples (school lake, Xuanwu Lake and Yangtze River) with high recovery rates of 97 %-104 % and soil (pond soil, grassland soil and bamboo soil) samples, respectively. The developed fluorescence platform was utilized to predict water and soil safety by monitoring Cu2+ concentration and provides a new strategy for Cu2+ detection.

Self-healing polymers through hydrogen-bond cross-linking: synthesis and electronic applications.

Recently, polymers capable of repeatedly self-healing physical damage and restoring mechanical properties have attracted extensive attention. Among the various supramolecular chemistry, hydrogen-bonding (H-bonding) featuring reversibility, directionality and high per-volume concentration has become one of the most attractive directions for the development of self-healing polymers (SHPs). Herein, we review the recent advances in the design of high-performance SHPs based on different H-bonding types, for example, H-bonding motifs and excessive H-bonding. In particular, the effects of the structural design of SHPs on their mechanical performance and healing efficiency are discussed in detail. Moreover, we also summarize how to employ H-bonding-based SHPs for the preparation of self-healable electronic devices, focusing on promising topics, including energy harvesting devices, energy storage devices, and flexible sensing devices. Finally, the current challenges and possible strategies for the development of H-bonding-based SHPs and their smart electronic applications are highlighted.

Optimized extraction of polysaccharide from Pinus elliottii: Characterization, antioxidant, and moisture-preserving activities.

The study on the extraction conditions, purification, and biological activity of slash pine (Pinus elliottii.) is important for the development of slash pine resources. The optimal process conditions for the extraction of slash pine polysaccharide (SPP) were determined, resulting in a liquid-solid ratio of 66.94 mL/g, extraction temperature of 83.74 °C and extraction time of 2.56 h by using the response surface methodology, and the yield of SPP was 5.99% under the optimized conditions. Following the purification of SPP, the SPP-2 component was obtained and its physicochemical properties, functional group composition, antioxidant capacity, and moisturizing capacity were determined. Structural analysis suggested that SPP-2 has a molecular weight of 118.407 kDa, and was composed of rhamnose, arabinose, fucose, xylose, mannose, glucose, and galactose in a ratio of 5.98: 14.34: 1: 1.75: 13.50: 3.43: 15.79. The antioxidant activity analysis showed that SPP-2 has good free radical scavenging activity, and it was also found to have in vitro moisturizing activity and low irritation. These results suggest that SPP-2 has the potential for applications in the pharmaceutical, food, and cosmetic industries.

Responsive and biocompatible chitosan-phytate microparticles with various morphology for antibacterial activity based on gas-shearing microfluidics.

Chitosan microparticles are frequently used for the encapsulation of ingredients, owing to their pH-responsive, renewable, biocompatible and antimicrobial properties. Herein, pH-responsive antibacterial encapsulation carriers in chitosan-phytate (CS-PA) microparticles with various morphologies were prepared by gas-shearing microfluidics. Microparticles sizes were tuned by gas flow rate in production, and the CS and PA concentration significantly dominated the morphology of microparticles. Additionally, microparticles exhibit great storage stability, lyophilizing rehydration performance, pH-responsive behavior, as well as antibacterial and biocompatible effect, indicating that CS-PA microparticles are expected to become an ideal carrier for the actives encapsulation in pharmaceutical, food and cosmetic industries.

Prussian blue composite microswimmer based on alginate-chitosan for biofilm removal.

Bacterial infections pose a serious threat to public health, causing worldwide morbidity and about 80 % of bacterial infections are related to biofilm. Removing biofilm without antibiotics remains an interdisciplinary challenge. To solve this problem, we presented a dual-power driven antibiofilm system Prussian blue composite microswimmers based on alginate-chitosan, which designed into an asymmetric structure to achieve self-driven in the fuel solution and magnetic field. Prussian blue embedded in the microswimmers given it the ability to convert light and heat, catalyze Fenton reaction, and produce bubbles and reactive oxygen species. Moreover, with the addition of Fe3O4, the microswimmers could move in group under external magnetic field. The composite microswimmers displayed excellent antibacterial activity against S. aureus biofilm with an efficiency as high as 86.94 %. It is worth mentioning that the microswimmers were fabricated with device-simple and low-cost gas-shearing method. This system integrating physical destruction, chemical damage such chemodynamic therapy and photothermal therapy, and finally kill the plankton bacteria embedded in biofilm. This approach may cause an autonomous, multifunctional antibiofilm platform to promote the present most areas with harmful biofilm difficult to locate the surface for removal.

Spatiotemporally Responsive Hydrogel Dressing with Self-Adaptive Antibacterial Activity and Cell Compatibility for Wound Sealing and Healing.

Adhesive hydrogels containing quaternary ammonium salt (QAS) moieties have shown attractive advantages in treatment for acute wounds, attributed to their high performances in wound sealing and sterilization. However, the introduction of QAS commonly leads to high cytotoxicity and adhesive deterioration. Herein, aimed to solve these two issues, a self-adaptive dressing with delicate spatiotemporal responsiveness is developed by employing cellulose sulfate (CS) as dynamic layers to coat QAS-based hydrogel. In detail, due to the acid environment of wound in the early stages of healing, the CS coating will quickly detach to expose the active QAS groups for maximum disinfectant efficacy; meanwhile, as the wound gradually heals and recovers to a neutral pH, the CS will remain stable to keep QAS screened, realizing a high cell growth-promoting activity for epithelium regeneration. Additionally, attributed to the synergy of temporary hydrophobicity by CS and slow water absorption kinetics of the hydrogel, the resultant dressing possesses outstanding wound sealing and hemostasis performance. At last, this work anticipates this approach to intelligent wound dressings based on dynamic and responsive intermolecular interaction can also be applied to a wide range of self-adaptive biomedical materials employing different chemistries for applications in medical therapy and health monitoring.

Chitosan enhanced the stability and antibiofilm activity of self-propelled Prussian blue micromotor.

The emergence, spread and difficult removal of bacteria biofilm, represent an ever-increasing persistent infections and medical complications challenge worldwide. Herein, a self-propelled system Prussian blue micromotor (PB MMs) were constructed by gas-shearing technology for efficient degradation of biofilms by combining chemodynamic therapy (CDT) and photothermal therapy (PTT). With the interpenetrating network crosslinked by alginate, chitosan (CS) and metal ions as the substrate, PB was generated and embedded in the micromotor at the same time of crosslinking. The micromotors are more stable and could capture bacteria with the addition of CS. The micromotors show excellent performance, containing photothermal conversion, reactive oxygen species (ROS) generation and bubble produced by catalyzing Fenton reaction for motion, which served as therapeutic agent could chemically kill bacteria and physically destroy biofilm. This research work opens a new path of an innovative strategy to efficiently remove biofilm.

Photothermal Nanomaterial-Mediated Photoporation.

Delivering biological effector molecules in cultured cells is of fundamental importance to any study or application in which the modulation of gene expression is required. Examples range from generating engineered cell lines for studying gene function to the engineering of cells for cell-based therapies such as CAR-T cells and gene-corrected stem cells for regenerative medicine. It remains a great challenge, however, to deliver biological effector molecules across the cell membrane with minimal adverse effects on cell viability and functionality. While viral vectors have been frequently used to introduce foreign nucleic acids into cells, their use is associated with safety concerns such as immunogenicity, high manufacturing cost, and limited cargo capacity.For photoporation, depending on the laser energy, membrane permeabilization happens either by local heating or by laser-induced water vapor nanobubbles (VNB). In our first study on this topic, we demonstrated that the physical force exerted by suddenly formed VNB leads to more efficient intracellular delivery as compared to mere heating. Next, we explored the use of different photothermal nanomaterials, finding that graphene quantum dots display enhanced thermal stability compared to the more traditionally used gold nanoparticles, hence providing the possibility to increase the delivery efficiency by repeated laser activation. To enable its use for the production of engineered therapeutic cells, it would be better if contact with cells with nondegradable nanoparticles is avoided as it poses toxicity and regulatory concerns. Therefore, we recently demonstrated that photoporation can be performed with biodegradable polydopamine nanoparticles as well. Alternatively, we demonstrated that nanoparticle contact can be avoided by embedding the photothermal nanoparticles in a substrate made from biocompatible electrospun nanofibers. With this variety of photoporation approaches, over the years we demonstrated the successful delivery of a broad variety of biologics (mRNA, siRNA, Cas9 ribonucleoproteins, nanobodies, etc.) in many different cell types, including hard-to-transfect cells such as T cells, embryonic stem cells, neurons, and macrophages.In this Account, we will first start with a brief introduction of the general concept and a historical development of photoporation. In the next two sections, we will extensively discuss the various types of photothermal nanomaterials which have been used for photoporation. We discriminate two types of photothermal nanomaterials: single nanostructures and composite nanostructures. The first one includes examples such as gold nanoparticles, graphene quantum dots, and polydopamine nanoparticles. The second type includes polymeric films and nanofibers containing photothermal nanoparticles as well as composite nanoscale biolistic nanostructures. A thorough discussion will be given for each type of photothermal nanomaterial, from its synthesis and characterization to its application in photoporation, with its advantages and disadvantages. In the final section, we will provide an overall discussion and elaborate on future perspectives.

Biomaterials based on hyaluronic acid, collagen and peptides for three-dimensional cell culture and their application in stem cell differentiation.

In recent decades, three-dimensional (3D) cell culture technologies have been developed rapidly in the field of tissue engineering and regeneration, and have shown unique advantages and great prospects in the differentiation of stem cells. Herein, the article reviews the progress and advantages of 3D cell culture technologies in the field of stem cell differentiation. Firstly, 3D cell culture technologies are divided into two main categories: scaffoldless and scaffolds. Secondly, the effects of hydrogels scaffolds and porous scaffolds on stem cell differentiation in the scaffold category were mainly reviewed. Among them, hydrogels scaffolds are divided into natural hydrogels and synthetic hydrogels. Natural materials include polysaccharides, proteins, and their derivatives, focusing on hyaluronic acid, collagen and polypeptides. Synthetic materials mainly include polyethylene glycol (PEG), polyacrylic acid (PAA), polyvinyl alcohol (PVA), etc. In addition, since the preparation techniques have a large impact on the properties of porous scaffolds, several techniques for preparing porous scaffolds based on different macromolecular materials are reviewed. Finally, the future prospects and challenges of 3D cell culture in the field of stem cell differentiation are reviewed. This review will provide a useful guideline for the selection of materials and techniques for 3D cell culture in stem cell differentiation.

Potential new material for optical fiber: Preparation and characterization of transparent fiber based on natural cellulosic fiber and epoxy.

In order to reduce the dependence on fossil energy products, natural fiber/polymer hybrid composites have been increasingly researched. The high price of the quartz optical fibers and glass optical fibers has greatly inspired researchers to engage in the research on polymer optical fibers. Herein, transparent fibers based on plant fibers were innovatively prepared for the first time by delignification and impregnating epoxy diluted with acetone. The epoxy improved the thermal stability of the fiber without deteriorating its mechanical properties, and also endowed the fiber with the property of transparency. The tensile strength of transparent fibers of three diameters were 34.5, 58.6 and 100.3 MPa, respectively and the corresponding Young's modulus reached 1.1, 1.7 and 2.3 GPa, respectively. In addition, the light-conducting properties of transparent fibers were displayed with a green laser and the fibers displayed good light transmission along the fiber growth direction. Transparent fibers are expected to be used in optical fibers because of their high thermal stability, good mechanical properties and light-conducting properties.

Blow-Spun Nanofibrous Membrane for Simultaneous Treatment of Emulsified Oil/Water Mixtures, Dyes, and Bacteria.

Membrane separation is of great significance due to its unique performance in treating wastewater. However, the simultaneous treatment of oily emulsions and other complex pollutants in water remains challenging. Herein, we have proposed a simple strategy to prepare a multifunctional titanium dioxide/silver nanoparticles/polyacrylonitrile (TiO2/AgNPs/PAN) nanofibrous membrane. The experimental results showed that the combination of the hierarchical structure composed of PAN nanofibers and Ag/TiO2 nanoprotrusions contributed to the superhydrophilicity and superoleophobicity (UOCA = 153.3 ± 2.0°). Further, the nanofibrous membrane exhibited a rapid gravity-driven permeate flux (>1829.37 ± 83.51 L m-2 h-1) and an ultrahigh separation efficiency (>99.9%) for the surfactant-stabilized oil/water emulsions. Moreover, due to the synergistic effect between the PAN fibers and TiO2/Ag heterojunction, Rhodamine B dye in water can be removed quickly and efficiently (up to 97.67% in 90 min). More importantly, the obtained nanofibrous membrane exhibited ultrahigh stability in different harsh environments. The design of superoleophobic nanofiber membrane with a high separation efficiency and high photocatalytic activity has great potential for practical applications in the purification of oily wastewater.

Potential application of natural bioactive compounds as skin-whitening agents: A review.

BACKGROUND: Melanin is a skin pigment that gives color to the skin, hair, and eyes. The accumulation or over production of melanin can lead to aesthetic problems as well as serious diseases associated with hyperpigmentation. Skin lightening is described as the procedure of using natural or synthetic products to lighten the skin tone or provide an even skin complexion by reducing the amount of melanin in the skin; therefore, skin lightening products help people to treat their skin problems. Ingredients such as hydroquinone, ascorbic acid, and retinoic acid were used as whitening agents to lighten the skin. However, they have many adverse effects on the skin and body health, such as skin irritation. AIM: In this review, firstly, discuss on the directly/indirectly target melanogenesis-related signal pathways. Secondly, summarize potential natural bioactive ingredients with skin lightening properties from plants, marine organisms, microorganisms. Finally, the remaining problems and future challenges are also discussed. METHODS: For relevant literature, a literature search was conducted using Google Scholar and Web of Science. Natural bioactive compounds, tyrosinase inhibitors, and other related topics were researched and evaluated. RESULTS: Natural products isolated from plant and animal resources are potential active cosmetic candidates for lightening the skin tone and skin whitening and protection against UV irradiation. Natural bioactive ingredients as cosmetic whitening additives have attracted increasingly attention due to their safety and cost effectiveness, with few side effects. CONCLUSION: Although natural active substances have been advocated for use in whitening cosmetics in recent years, there are still many challenges due to the fact that traditional inhibitors are used perennial in cosmetics which cannot be easily changed and the research on natural active substances is still in its infancy. In the future, by improving the extraction technique of natural extracts, it is achieved to give a qualitative and quantitative analysis of the active ingredients of the extracts, to determine the effect of the active components of action, and to find the substances that have the best possible whitening effect in natural organisms.

Biomass-based indole derived composited with cotton cellulose fiber integrated as sensitive fluorescence platform for NH3 detection and monitoring of seafood spoilage.

Herein, an indole-derived water-soluble fluorescence nanomaterial and biomass-based cellulose filter paper integrated as solid-state fluorescence platform (H2-FP) for seafood spoilage detection was prepared. H2 exhibits high fluorescence stability and good biocompatibility with green beans, onion tissues, blood and zebrafish, which proving that H2 has a wide range of application scenarios. Further, H2-FP with effective, solid-state fluorescence, portable, and reusable characteristics is nanoengineered for NH3 quantitative and qualitative detection (DOL = 2.6 ppm). Then, H2-FP has been successfully used to monitor NH3 release in the seafood spoilage process at various storage time (4 °C and 25 °C). More importantly, fluorescence color of H2-FP is integrated smartphone are converted to digital values through RGB channels and successfully used to visualize semi-quantitative recognition of NH3. This sensing fluorescence platform integrated with smartphone furnishes an effective fabrication strategy and broad prospects for explore various biomass-based materials for sensing NH3 change in biological and environmental samples.

Multicompartmental Microcapsules for Enzymatic Cascade Reactions Prepared through Gas Shearing and Surface Gelation.

Inspired by the structure of eukaryotic cells, multicompartmental microcapsules have gained increasing attention. However, challenges remain in the fabrication of "all-aqueous" (i.e., oil-free) microcapsules composed of accurately adjustable hierarchical compartments. This study reports on multicompartmental microcapsules with an innovative architecture. While multicompartmental cores of the microcapsules were fabricated through gas shearing, a shell was applied on the cores through surface gelation of alginate. Different from traditional multicompartmental microcapsules, thus obtained microcapsules have well-segregated compartments while the universal nature of the surface-gelation method allows us to finely tune the shell thicknesses of the microcapsules. The microcapsules are highly stable and cytocompatible and allow repeated enzymatic cascade reactions, which might make them of interest for complex biocatalysis or for mimicking physiological processes.

Spatial confinement of multi-enzyme for cascade catalysis in cell-inspired all-aqueous multicompartmental microcapsules.

Biocatalytic reaction networks in eukaryotic cells is realized by the immobilized and compartmental multi-enzymatic system. Inspired by the spatial localization of natural cells, multiple enzymes were confined within the multicompartmental microcapsules, which were created using a gas-shearing method coupled with surface-triggered in situ gelation strategy. Heterogeneous multicompartmental (two-, three-, four-, six-, or eight-faced) core particles, due to their capacity for positional assembly, were encapsuled in alginate hydrogel shells. The generated microcapsules integrate logic network to access complex digital design through a three-step convergent enzymatic cascade reaction as a model, and the capsules with high stability, recyclability and cytocompatibility are ideal enzymatic reactor systems to be used for biomimetic biocatalysis process.

A biomass-derived Schiff base material composited with polylactic acid nanofiber membrane as selective fluorescent 'turn off/on' platform for Pb2+ quantitative detection and characterization.

Herein, a biomass-derived compound Z1 is synthesized via 'one pot' method for detection Pb2+ using fluorescence and visual dual-mode in aqueous solution. Z1 shows good response to Pb2+ with a limit of detection (LOD) of 13.4 nM. Importantly, the coordination mode of Z1 with Pb2+ is further evaluated by UV-vis and NMR spectroscopy and a 1:1 stoichiometry is identified. Furthermore, Z1 can be applied to detection Pb2+ in practical samples with satisfactory recoveries in range of 96.0 %-112.0 % in real samples. Besides, Z1 is added into polylactic acid (PLA) solution and made as portable fluorescence nanofiber membrane for Pb2+ detection. Further, Z1 responds to Pb2+ with high selectivity and sensitivity and has been applied for tracking Pb2+ changes in soil samples, zebrafish, and plant tissues. These results indicated that Z1 had great application potential in accurate detection Pb2+.