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.

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.

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.

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.

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 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.

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.

Encapsulated Microstructures of Beneficial Functional Lipids and Their Applications in Foods and Biomedicines.

Beneficial functional lipids are essential nutrients for the growth and development of humans and animals, which nevertheless possess poor chemical stability because of heat/light-sensitivity. Various encapsulation technologies have been developed to protect these nutrients against adverse factors. Different microstructures are exhibited through different encapsulation methods, which influence the encapsulation efficiency and release behavior at the same time. This review summarizes the effects of preparation methods and process parameters on the microstructures of capsules at first. The mechanisms of the different microstructures on encapsulation efficiency and controlled release behavior of core materials are analyzed. Next, a comprehensive overview on the beneficial functional lipids capsules in the latest food and biomedicine applications are provided as well as the matching relationship between the microstructures of the capsules and applications are discussed. Finally, the remaining challenges and future possible directions that have potential interest are outlined. The purpose of this review is to convey the construction of beneficial functional lipids capsules and the function mechanism, a critical analysis on its current status and challenges, and opinions on its future development. This review is believed to promote communication among the food, pharmacy, agronomy, engineering, and nutrition industries.

Toxic reactive oxygen species enhanced chemodynamic therapy by copper metal-nanocellulose based nanocatalysts.

When compared with traditional petroleum-based materials, bio-based materials show greater application potential in the field of biomedicine owing to the good biocompatibility, in specifical, the application of natural macromolecular polymers in chemotherapeutics has become a hot topic in anticancer treatment. In this study, cellulose nanocrystals (CNCs) were selected as carriers, and Au nanoparticles (NPs) were directly conjugated on their surface, with the highly reactive Cu2+ ions serving as an ion-ligand bridge, to construct a multifunctional nanocatalyst. These findings suggest that the nanosystem delivers a large amount of highly reactive Cu2+ ions (3.75 wt%) and DOX (7.71 wt%) by the surface loading of cellulose nanocrystals, which greatly improves ROS yield and promotes the application of the Fenton reaction system in cancer therapy.

A Prussian blue alginate microparticles platform based on gas-shearing strategy for antitumor and antibacterial therapy.

Prussian blue (PB) with distinct hollow mesoporous structure and favorable properties has captured the attention of extensive biomaterial researchers. However, there is an unmet need for biocompatible PB microparticles with recyclability fabricated by a facile method. Herein, a size-controlled PB alginate microparticles (PBAMs) generated by a one-step and large batch production gas-shearing strategy. With the characteristic of porous and surface-modifiable, PBAMs used as vehicles may effectively load and release drug to improve the therapeutic efficacy. Meanwhile, Fe2+ in PBAMs exerts a catalyze for chemodynamic therapy (CDT) to produce reactive oxygen species (ROS), which synergizes with the photothermal therapy (PTT) induced by PB particles with effective photothermal conversion, achieving active tri-modality combination antitumor and antibacterial. The new concept for the low-cost and facile preparation of biocompatible PBAMs here illustrated opens a novel pathway toward the effective multifunctional platform.

Quaternized chitin/tannic acid bilayers layer-by-layer deposited poly(lactic acid)/polyurethane nanofibrous mats decorated with photoresponsive complex and silver nanoparticles for antibacterial activity.

Chronic wounding treatment based on bacterially infected diabetes suffers an essential limitation in persistent skin injuries due to the resistance of progressive antibiotics, which inhibits the process of healing with wound tissue. Therefore, biologically friendly and nontoxic bio-based mats without antibiotics are taken for granted as a versatile platform for biomedical dressing, but urgently necessitates further functional diversification. Herein, a novel tannic acid (TA)/silver (Ag)-modified poly(lactic acid) (PLA)/Polyurethane (PU) antibacterial hybrid nanofibers were successfully constructed by electrospinning technology. Layer-by-layer (LBL) self-assembly technique was utilized to produce membranes via deposited biocompatible quaternized chitin (QC) and TA. The mats are enabled with outstanding flexibility, antibacterial activity, great hemocompatibility, and good ROS-scavenger in a wounding environment. Consequently, the basis of morphology and structure of electrospun membranes was verified by SEM and FT-IR. Besides, the LBL-structured surface was proved to impart improved wettability and hydrophilic via the test of water contact angle. Additionally, antimicrobial experiments demonstrate the effective broad-spectrum antibacterial ability of as-prepared hybrids, inhibiting infection of gram-positive microbial (S. aureus) as well as gram-negative microbial. Finally, the anti-oxidation performance holds great promise in conducive to the formation favorable physiological environment for wound healing. In conclusion, this work establishes a feasible but effective pathway to construct a multifunctional antibacterial dressing for the skin infection.

Blow-spun nanofibrous composite Self-cleaning membrane for enhanced purification of oily wastewater.

Membrane separation is one of the most effective strategies for water treatment. However, problems such as poor emulsion separation performance, single function and easy membrane fouling limit its application in dealing with complex wastewater. The synergistic treatment technology of adsorption and visible light catalysis is an efficient and environment-friendly method to degrade organic pollutants. Here, we report a simple method to fabricate Zeolitic Imidazolate Framework-8/Graphene oxide/Polyacrylonitrile (ZIF-8/GO/PAN) nanofibrous membranes and their multifunctional treatment capacity for complex wastewater. The construction of superhydrophilic and underwater superoleophobic surface structure has achieved excellent emulsion separation performance (with a maximum flux of 6779.66 L m-2h-1), visible light photocatalytic degradation (with an efficiency of 96.5% in 90 min) and antibacterial properties. Moreover, the fibrous membrane also shows good biosafety, and will not have toxic effects on aquatic organisms. These excellent performances endow this membrane with great potential in complex wastewater purification.

Core-shell microparticles: From rational engineering to diverse applications.

Core-shell microparticles, composed of solid, liquid, or gas bubbles surrounded by a protective shell, are gaining considerable attention as intelligent and versatile carriers that show great potential in biomedical fields. In this review, an overview is given of recent developments in design and applications of biodegradable core-shell systems. Several emerging methodologies including self-assembly, gas-shearing, and coaxial electrospray are discussed and microfluidics technology is emphasized in detail. Furthermore, the characteristics of core-shell microparticles in artificial cells, drug release and cell culture applications are discussed and the superiority of these advanced multi-core microparticles for the generation of artificial cells is highlighted. Finally, the respective developing orientations and limitations inherent to these systems are addressed. It is hoped that this review can inspire researchers to propel the development of this field with new ideas.

"Turn-on" ratiometric fluorescent probe: Naked-eye detection of acidic pH and citric acid (CA) by using fluorescence spectrum and its application in real food samples and zebrafish.

Rapid, accurate and efficient detection of acidic pH and citric acid (CA) changes is of great significance for predicting environmental and food safety problems by fluorescence analysis technique. Herein, a small molecule ratiometric fluorescent probe (BICL) based on benzoindole derivatives is successfully synthesized and characterized and used for quantitatively and qualitatively "turn-on" detection acid pH and CA changes in solution and environment by ultraviolet spectrum and fluorescence emission spectrum. On the one hand, the probe has a good linear relation to acidic pH in the pH range 3.1-4.5 (I604/I550 = 13.088-2.3878pH, R2 = 0.9986). On the other hand, the probe has a good linear relationship in the range of CA concentration of 14.0-23.0 µM (I604/I550 = 0.5324 [CA]-5.2628, R2 = 0.9993) and a low detection limit of 2.967 µM. BICL has a good recovery rate in the range of 114.6 ~ 101.0% and a low relative standard deviation (RSD) (0.0011 ~ 0.0092) in the determination of CA in real samples (water, drinks and fruits), which holds great potential for application in determination of CA in real samples. Importantly, the probe has good blood compatibility, and it has been successfully applied to detect exogenously induced changes in acidic pH and CA in zebrafish with great time-stability by using fluorescence imaging technology, respectively.

Multifunctional Applications of Blow-Spinning Setaria viridis Structured Fibrous Membranes in Water Purification.

With increasing water pollution and human health problems caused by oily wastewater, the fabrication of oil-water separation materials has become an urgent task. However, most of the reported materials have a single function and poor performance. In this paper, a multifunctional zinc oxide/polyaniline/polyacrylonitrile (ZnO/PANI/PAN) nanofibrous membrane with needle-like ZnO nanorods was prepared by in situ synthesis of PANI and a hydrothermal reaction on a highly stable self-standing PAN blow-spinning fibrous membrane. Due to the electronic synergistic effect of ZnO and PANI, the fibrous membrane exhibits excellent antibacterial activity and visible-light degradation ability of organic dyes. Moreover, the micro-/nanosized pores of the ZnO/PANI/PAN fibrous membranes also guarantee its excellent emulsion separation performance, including an ultrahigh surfactant-free emulsion permeate flux (∼8597.40 L/(m2 h)), ultrahigh surfactant-stabilized emulsion permeate flux (∼2253.50 L/(m2 h)), and excellent separation efficiency (above 99%). Furthermore, the composite membrane maintains stable underwater superoleophobicity and hydrophilicity under adverse conditions, shows good biological safety, and is harmless to the water environment. These excellent properties endow the ZnO/PANI/PAN nanofibrous membranes with great potential in treating oily wastewater.

Multistructured Electrospun Nanofibers for Air Filtration: A Review.

Air filtration materials (AFMs) have gradually become a research hotspot on account of the increasing attention paid to the global air quality problem. However, most AFMs cannot balance the contradiction between high filtration efficiency and low pressure drop. Electrospinning nanofibers have a large surface area to volume ratio, an adjustable porous structure, and a simple preparation process that make them an appropriate candidate for filtration materials. Therefore, electrospun nanofibers have attracted increased attention in air filtration applications. In this paper, first, the preparation methods of high-performance electrospun air filtration membranes (EAFMs) and the typical surface structures and filtration principles of electrospun fibers for air filtration are reviewed. Second, the research progress of EAFMs with multistructures, including nanoprotrusion, wrinkled, porous, branched, hollow, core-shell, ribbon, beaded, nets structure, and the application of these nanofibers in air filtration are summarized. Finally, challenges with the fabrication of EAFMs, limitations of their use, and trends for future developments are presented.

Faithful Fabrication of Biocompatible Multicompartmental Memomicrospheres for Digitally Color-Tunable Barcoding.

Barcodes have attracted widespread attention, especially for the multiplexed bioassays and anti-counterfeiting used toward medical and biomedical applications. An enabling gas-shearing approach is presented for generating 10-faced microspherical barcodes with precise control over the properties of each compartment. As such, the color of each compartment could be programmatically adjusted in the 10-faced memomicrospheres by using pregel solutions containing different combinations of fluorescent nanoparticles. During the process, three primary colors (red, green, and blue) are adopted to obtain up to seven merged fluorescent colors for constituting a large amount of coding as well as a magnetic compartment, capable of effective and robust high-throughput information-storage. More importantly, by using the biocompatible sodium alginate to construct the multicolor microspherical barcodes, the proposed technology is likely to advance the fields of food and pharmaceutics anti-counterfeiting. These remarkable properties point to the potential value of gas-shearing in engineering microspherical barcodes for biomedical applications in the future.

Self-Healing and Superwettable Nanofibrous Membranes with Excellent Stability toward Multifunctional Applications in Water Purification.

Considering the complexity of toxic ingredients in practical polluted water, the development of energy- and labor-saving and environmentally friendly multifunctional materials to decontaminate wastewater is of great necessity. Herein, a multifunctional branched poly(ethylenimine) (bPEI) and poly(acrylic acid) (PAA)/tungsten oxide/polyacrylonitrile (PP/WO3/PAN) composite membrane was fabricated by the combination of blow spinning and layer-by-layer methods. The incorporated WO3 in generated in hydrophilic PAN fibers by spinning the precursor method, which simultaneously reveals remarkable photodegradation performance towards mimetic organic pollutions and excellent antibacterial activity due to their electron synergetic effect. In addition, the micro/nanoporous structure of the PP/WO3/PAN composite membrane also ensures its good oil-water separation performance. Moreover, the reduction reaction of W atoms in the WO3 network upon solar irradiation endows the membrane with superior heavy metal ion removal capability. Significantly, the membrane exhibits water-enabled self-healing performance due to the coated polyelectrolyte layer. More importantly, the membrane could be easily scaled-up; was free-standing, durable, and biocompatible; and exhibited no additional toxic effect on the surrounding environments. These outstanding properties make the membrane to have significant potential applications in wastewater treatment.