Effects of polyvinylchloride microplastics on the toxicity of nanoparticles and antibiotics to aerobic granular sludge: Nitrogen removal, microbial community and resistance genes.

Copper oxide nanoparticles (CuO NPs) and ciprofloxacin (CIP) have ecological risk to humans and ecosystems. Polyvinylchloride microplastics (PVC MPs), as a representative of microplastics, may often coexist with CuO NPs and CIP in wastewater treatment systems due to their widespread application. However, the co-impact of PVC MPs in wastewater systems contained with CuO NPs and CIP on nitrogen removal and ecological risk is not clear. In this work, PVC MPs co-impacts on the toxicity of CuO NPs and CIP to aerobic granular sludge (AGS) systems and potential mechanisms were investigated. 10 mg/L PVC MPs co-addition did not significantly affect the nitrogen removal, but it definitely changed the microbial community structure and enhanced the propagation and horizontal transfer of antibiotics resistance genes (ARGs). 100 mg/L PVC MPs co-addition resulted in a raise of CuO NP toxicity to the AGS system, but reduced the co-toxicity of CuO NPs and CIP and ARGs expression. The co-impacts with different PVC MPs concentration influenced Cu2+ concentrations, cell membrane integrity, extracellular polymeric substances (EPS) contents and microbial communities in AGS systems, and lead to a change of nitrogen removal.

A Novel Mechanically Robust and Biodegradable Egg White Hydrogel Membrane by Combined Unidirectional Nanopore Dehydration and Annealing.

A homogeneous egg white obtained by high-speed shearing and centrifugation was dehydrated into a fragile and water-soluble egg white glass (EWG) by unidirectional nanopore dehydration (UND). After EWG annealing, it can become an egg white hydrogel membrane (EWHM) that is water-insoluble, flexible, biocompatible, and mechanically robust. Its tensile strength, elongation at break, and the swelling ratio are about 5.84 MPa, 50-110%, and 60-130%, respectively. Protein structure analysis showed that UND caused the rearrangement of the protein molecules to form EWG with random coil and α-helix structures. The thermal decomposition temperature of the EWG was 309.25 °C. After EWG annealing at over 100 or 110 °C for 1.0 h or 45 min, the porous network EWHM was mainly composed of ß-sheet structures, and the thermal decomposition temperature increased to 317.25-318.43 °C. Their 12-day residues in five proteases ranged from 1% to 99%, and the order was pepsin > neutral protease > papain > trypsin > alkaline protease. Mouse fibroblast L929 cells can adhere, grow, and proliferate well on these EWHMs. Therefore, the combined technology of UND and annealing for green and novel processing of EWHM has potential applications in the field of biomimetic and biomedical materials.

Green immobilization and efficient proliferation of Escherichia coli cells in polyvinyl alcohol hydrogel membranes by unidirectional nanopore dehydration.

BACKGROUND: The immobilized technology for microbial or cells has the advantages of high microbial activity, high microbial density per unit space, good tolerance, strong shock, load resistance, high processing efficiency, and high reuse rate. It is now widely used in environmental remediation, water quality treatment, biodegradation, food industry, chemical analysis, energy development, medicine and pharmaceuticals, and other fields. RESULTS: A novel Escherichia coli cell-immobilizing polyvinyl alcohol hydrogel membrane (ECI-PVAHM) was prepared by unidirectional nanopore dehydration (UND) from a 10% polyvinyl alcohol (PVA) aqueous solution containing enhanced green fluorescent protein-labeled E. coli. This bacteria-loaded film has high water stability, flexibility, transparency, and mechanical robustness. Its tensile strength, elongation rate, and swelling rate are in the ranges 0.66-0.90 MPa, 300-390%, and 330-800%, respectively. The effective bacterial load of ECI-PVAHM is 2.375 × 109-1010 CFU/g (dry weight), which does not affect the original crystal structure of the PVAHM. This biofilm has a porous network structure with pore sizes between 0.2 and 1.0 µm, and these cells are embedded in the PVAHM network. When the immobilized cells were continuously cultured for 20 days, and the medium was renewed twice daily, their relative proliferation efficiency after 40 cycles could still be maintained at ~ 91%. CONCLUSION: The above results show that the cell division, proliferation ability, and metabolic activity of immobilized E. coli were not affected by the physical barrier of the porous network structure of the hydrogel. This UND-based ECI-PVAHM has potential applications in molecular biology, biopharmaceutical expression and production, bioreactors, and fuel cells.

Silk Protein Composite Bioinks and Their 3D Scaffolds and In Vitro Characterization.

This paper describes the use of silk protein, including fibroin and sericin, from an alkaline solution of Ca(OH)2 for the clean degumming of silk, which is neutralized by sulfuric acid to create calcium salt precipitation. The whole sericin (WS) can not only be recycled, but completely degummed silk fibroin (SF) is also obtained in this process. The inner layers of sericin (ILS) were also prepared from the degummed silk in boiling water by 120 °C water treatment. When the three silk proteins (SPs) were individually grafted with glycidyl methacrylate (GMA), three grafted silk proteins (G-SF, G-WS, G-ILS) were obtained. After adding I2959 (a photoinitiator), the SP bioinks were prepared with phosphate buffer (PBS) and subsequently bioprinted into various SP scaffolds with a 3D network structure. The compressive strength of the SF/ILS (20%) scaffold added to G-ILS was 45% higher than that of the SF scaffold alone. The thermal decomposition temperatures of the SF/WS (10%) and SF/ILS (20%) scaffolds, mainly composed of a ß-sheet structures, were 3 °C and 2 °C higher than that of the SF scaffold alone, respectively. The swelling properties and resistance to protease hydrolysis of the SP scaffolds containing sericin were improved. The bovine insulin release rates reached 61% and 56% after 5 days. The L929 cells adhered, stretched, and proliferated well on the SP composite scaffold. Thus, the SP bioinks obtained could be used to print different types of SP composite scaffolds adapted to a variety of applications, including cells, drugs, tissues, etc. The techniques described here provide potential new applications for the recycling and utilization of sericin, which is a waste product of silk processing.

Dissolution and processing of silk fibroin for materials science.

In recent decades, silk fibroin (SF) from silkworm Bombyx mori has been extensively researched and applied in several fields, including: cosmetics, biomedicine and biomaterials. The dissolution and regeneration of SF fibers is the key and prerequisite step for the application of silk protein-based materials. Various solvents and dissolving systems have been reported to dissolve SF fibers. However, the dissolution process directly affects the characteristics of SF and particularly impacts the mechanical properties of the resulting silk biomaterials in subsequent processing. The purpose of this review is to summarize the common solvents, the dissolution methods for silk protein, the properties of the resulting SF protein. The suitable use of SF dissolved in the corresponding solvent was also briefly introduced. Recent applications of SF in various biomaterials are also discussed.

Murine liver damage caused by exposure to nano-titanium dioxide.

Due to its unique physiochemical properties, nano-titanium dioxide (nano-TiO2) is widely used in all aspects of people's daily lives, bringing it into increasing contact with humans. Thus, this material's security issues for humans have become a heavily researched subject. Nano-TiO2 can enter the body through the mouth, skin, respiratory tract or in other ways, after which it enters the blood circulation and is deposited in the liver, changing biochemical indicators and causing liver inflammation. Meanwhile, the light sensitivity of these nanoparticles allows them to become media-generating reactive oxygen species (ROS), causing an imbalance between oxidation and anti-oxidation that leads to oxidative stress and liver damage. Nano-TiO2 can be transported into cells via phagocytosis, where the nanoparticles bind to the mitochondrial membrane, resulting in the disintegration of the membrane and the electron transport chain within the mitochondria. Thus, more ROS are produced. Nano-TiO2 can also enter the nucleus, where it can directly embed into or indirectly affect DNA, thereby causing DNA breakage or affecting gene expression. These effects include increased mRNA and protein expression levels of inflammation-related factors and decreased mRNA and protein expression levels of IκB and IL-2, resulting in inflammation. Long-term inflammation of the liver causes HSC cell activation, and extracellular matrix (ECM) deposition is promoted by multiple signalling pathways, resulting in liver fibrosis. In this paper, the latest progress on murine liver injury induced by environmental TiO2 is systematically described. The toxicity of nano-TiO2 also depends on size, exposure time, surface properties, dosage, administration route, and its surface modification. Therefore, its toxic effects in humans should be studied in greater depth. This paper also provides useful reference information regarding the safe use of nano-TiO2 in the future.

Functional modification of silk fibroin from silkworms and its application to medical biomaterials: A review.

Silk fibroin (SF) from the silkworm Bombyx mori is a fibrous protein identified as a widely suitable biomaterial due to its biocompatibility, tunable degradation, and mechanical strength. Various modifications of SF protein can give SF fibers new properties and functions, broadening their applications in textile and biomedical industries. A diverse array of functional modifications on various forms of SF has been reported. In order to provide researchers with a more systematic understanding of the types of functional modifications of SF protein, as well as the corresponding applications, we comprehensively review the different types of functional modifications, including transgenic modification, modifications with chemical groups or biologically active substance, cross-linking and copolymerization without chemical reactions, their specific modification methods and applications. Furthermore, recent applications of SF in various medical biomaterials are briefly discussed.

Polymerization strategy for cellulose nanocrystals-based photonic crystal films with water resisting property.

Cellulose nanocrystals (CNCs) can form a liquid crystal film with a chiral nematic structure by evaporative-induced self-assembly (EISA). It has attracted much attention as a new class of photonic liquid crystal material because of its intrinsic, unique structural characteristics, and excellent optical properties. However, the CNCs-based photonic crystal films are generally prepared via the physical crosslinking strategy, which present water sensitivity. Here, we developed CNCs-g-PAM photonic crystal film by combining free radical polymerization and EISA. FT-IR, SEM, POM, XRD, TG-DTG, and UV-Vis techniques were employed to characterize the physicochemical properties and microstructure of the as-prepared films. The CNCs-g-PAM films showed a better thermo-stability than CNCs-based film. Also, the mechanical properties were significantly improved, viz., the elongation at break was 9.4 %, and tensile strength reached 18.5 Mpa, which was a much better enhancement than CNCs-based film. More importantly, the CNCs-g-PAM films can resist water dissolution for more than 24 h, which was impossible for the CNCs-based film. The present study provided a promising strategy to prepare CNCs-based photonic crystal film with high flexibility, water resistance, and optical properties for applications such as decoration, light management, and anti-counterfeiting.

Performance-enhanced regenerated cellulose film by adding grape seed extract.

Eco-friendly packaging material with intelligent colorimetric performance has been a requirement for food safety and quality. This work focused on a food packaging material from regenerated cellulose films that added the grape seed extract (GSE) and polyethylene glycol 200 (PEG). FTIR and SEM techniques were employed to prove the compatibility of GSE with cellulose matrix. The composite film showed an enhanced elongation at break (16.61 %) and tensile strength (33.09 MPa). The addition of PEG and GSE also improved the water contact angle of regenerated-cellulose film from 53.8° to 83.8°. Moreover, the composite films exhibited UV-blocking properties while maintaining adequate transparency. The GSE induced the regenerated films with a macroscopic change in color under different pH conditions. Furthermore, the loading of GSE slowed down the decomposition of strawberries and delayed the self-biodegradation compared with the control for more than 3 days and 18 days. The present study showed a regenerated cellulose film with acceptable mechanical and hydrophilia properties, pH-responsiveness, anti-decomposition, and delayed biodegradation performances, indicating a potential color sensor in food packaging.

PDMS/magnetic lignin sponge for oil/water separation.

Recyclable, non-toxic, and degradable biological substrates contribute significantly to super-wetting surfaces. In this work, we prepared magnetic micro-nano super-hydrophobic surfaces through a robust solution with magnetic modified lignin particles as the supporting structure. A novel PDMS (polydimethylsiloxane)/magnetic lignin particle (lignin@Fe3O4)/PDA sponge composite was fabricated. Through dopamine (DA) self-polymerization, covalent deposition of magnetic lignin (ML), and PDMS silane modification, the magnetic super-hydrophobic polyurethane sponge composite (Sponge-P) was synthesized so that the Fe3O4 nanoscale microspheres wrapped with microscale lignin magnetic particles adhered to the sponge surface tighter and were barely dislodged. The as-prepared Sponge-P displayed excellent flexibility and a water contact angle of up to 152.2°. The super-hydrophobic sponge prepared with the proposed method was acid-base stable (pH = 2-12), self-cleaning, and suitable for high-salinity seawater. The magnetic super-hydrophobic sponge has good oil-water separation ability and can absorb 43 times its own weight of oil. In the meantime, due to the introduction of magnetic materials into lignin, we not only constructed micro-nanostructures to improve the surface super-hydrophobicity, but also made Sponge-P have the function of magnetic recovery, which has a unique advantage in treating oily wastewater.

Controllable construction of multifunctional superhydrophobic coating with ultra-stable efficiency for oily water treatment.

Designing interfacial coating with tailored characteristics is a crucial step in regulating the wetting properties of oil/water separation materials; however, the controllable fabrication of multifunctional layer with long-term durability in harsh environments remains challenging. Fabrication of raised dots based on magnetic Fe3O4 particles on micro-nanometer units, inspired by mussel chemistry, under the adhesion behavior of dopamine (DA) self-polymerization covalent deposition of Fe3O4 particles and hydrophobic polydimethylsiloxane (PDMS) modification to synthesize magnetic superhydrophobic cotton composites (Cotton-P). Due to the unique magnetic and superhydrophobic surface composition, the synthetic Cotton-P possesses superhydrophobic (155.4°) and magnetic properties and still exhibits these excellent properties after 10 cycles. In addition, the hydrophobicity of magnetic monolithic cotton is virtually unaffected in harsh environments. The chemical/thermal stability of the Cotton-P composite is improved due to the rigid silane coating on the skeleton. Moreover, the Cotton-P revealed excellent oil/water separation efficiency of over 98 % after 10 cycles. Based on these outstanding properties, Cotton-P has the potential to develop in the treatment of oil-water mixtures.

An insight on egg white: From most common functional food to biomaterial application.

Natural egg white tis widely used as an ingredient in nutritional foods and for food processing. Due to its characteristic foaming, emulsification, adhesion, and gelation, and its heat setting, biocompatibility, and low cost, research into the application and development of egg white in biomaterials, especially medical biomaterials, have been receiving attention. The composition and characteristics of egg white protein, and the physical mixing and chemically cross-linking of egg white with other materials used to make degradable packaging films, bioceramics, bioplastics, biomimetic films, hydrogels, 3D scaffolds, bone regeneration, biopatterning, biosensors, and so forth, are reviewed in detail in this report. The novel egg white-based biomaterials in various forms and applications could be constructed mostly through physical treatments such as ultrasonic wave, ultraviolet, laser and other radiation or high-temperature calcination. Furthermore, the application and prospects for the use of egg white in biomaterials is also discussed.

Characterization of undegraded and degraded silk fibroin and its significant impact on the properties of the resulting silk biomaterials.

The silk fibroin (SF) regeneration process significantly affects the resulting biomaterials, unfortunately, there has been insufficient study regarding the most suitable regeneration method for SF. In this study, we prepared undegraded SF (uSF) and degraded SF (dSF) by common regeneration methods and studied their difference in detail. The results demonstrated that the degradation degree of SF peptide chain had little influence on the secondary structure and thermal stability of SF materials. While, uSF solution showed higher viscosity and surface tension than dSF solution. The uSF membrane (uSFM) could be elongated approximately 134%, 1.6 times the degraded SF membrane (dSFM). SEM implied that both uSF and dSF existed in aqueous solution as micelles with a diameter of approximately 30 nm. dSF could directly form SF nanoparticles (dSFNPs) when poured into acetone while uSF could only form nanoparticles (uSFNP) with the addition of SDS. Glucose oxidase embedded into dSFM and dSFNP showed high catalytic activities, but uSFNP demonstrated nearly no activity. In addition, the dSFM was more appropriate for L929 cell culture. Considering the obvious difference between the two SF proteins, our results are significant in guiding the application of appropriate SF proteins in tissue engineering materials, bioactive materials, bioink, etc.

Dissolution and regeneration of silk from silkworm Bombyx mori in ionic liquids and its application to medical biomaterials.

The dissolution and regeneration of silk fibre have long been an issue for producers of silk. The high solubility of silk fibroin (SF) in ionic liquids (ILs) is a promising new avenue in silk dissolution and regeneration as it may allow for a significant reduction in operational steps required for SF regeneration and the subsequent formation of SF biomaterials. The regenerated SF solution can be prepared by dissolving directly SF in ILs without the tedious steps of degumming, dissolution and dialysis. Besides, the regenerated SF solution can simply form different SF biomaterials with the help of coagulant, and ILs can be separated from SF biomaterials easily during SF solidification. The goal of this work is to summarize the commonly used ILs for dissolving silk protein and their dissolution methods and to present the potential application of SF/ILs mixed solution in medical biomaterials.

Six new species and a new record of Linan Hlavác in China, with a key to species (Coleoptera, Staphylinidae, Pselaphinae).

Six new species of the genus Linan Hlavác are described from central to southern China: L.arcitibialis sp. n. (Hubei), L.denticulatus sp. n. (Guizhou), L.divaricatus sp. n. (Jiangxi), L.geneolatus sp. n. (Guizhou), L.mangshanus sp. n. (Hunan), and L.mulunensis sp. n. (Guangxi), with illustrations of habitus and major diagnostic characters. Linanmegalobus Yin & Li, originally described from Guizhou, is newly recorded in Hubei. An updated key to and a distributional map of all 16 known species are provided.

A novel chitosan hydrogel membrane by an improved electrophoretic deposition and its characteristics in vitro and in vivo.

Here, we report a novel chitosan hydrogel membrane (CHM) created by an improved electrophoretic deposition. Unlike a traditional CHM by electrophoretic deposition, the CHM was formed on a nanoporous film as a barrier using a homemade device at a high DC voltage (60 VDC). The CHM maximum recovery of 81.7% could be achieved after 1h of electrophoretic deposition. The transparent CHM with an elongation of 42.46% and swelling index of 538.86% was a mixture of type I and type II crystal structures. SEM revealed that the CHM had an irregular net structure. The CHM was sufficient for L-929 mouse fibroblast cell adhesion and growth. To demonstrate immunocompatibility with host tissues, H&E and TGF-ß1 were observed and the expressions of TNF-α and NF-κB were measured up to 3weeks post-implantation. Although these scaffolds demonstrated an initial pro-inflammatory response, the amount of inflammatory cells and the expressions of TGF-ß1 returned to baseline control values at 3weeks. The expressions of TNF-α and NF-κB had no significant difference between the experimental and control groups. Animal experiments showed that the CHM did not incite serious inflammatory reactions. Thus, the CHM is a promising medical biomaterial candidate for loading appropriate cells for use as artificial skin or in transplantation.

Progress of in vivo studies on the systemic toxicities induced by titanium dioxide nanoparticles.

Titanium dioxide nanoparticles (TiO2 NPs) are inorganic materials with a diameter of 1-100 nm. In recent years, TiO2 NPs have been used in a wide range of products, including food, toothpaste, cosmetics, medicine, paints and printing materials, due to their unique properties (high stability, anti-corrosion, and efficient photocatalysis). Following exposure via various routes including inhalation, injection, dermal deposition and gastrointestinal tract absorption, NPs can be found in various organs in the body potentially inducing toxic effects. Thus more attention to the safety of TiO2 NPs is necessary. Therefore, the present review aims to provide a comprehensive evaluation of the toxic effects induced by TiO2 NPs in the lung, liver, stomach, intestine, kidney, spleen, brain, hippocampus, heart, blood vessels, ovary and testis of mice and rats in in vivo experiments, and evaluate their potential toxic mechanisms. The findings will provide an important reference for human risk evaluation and management following TiO2 NP exposure.

Processing and characterization of silk sericin from Bombyx mori and its application in biomaterials and biomedicines.

Bombyx mori silk is composed of 60-80% fibroin, 15-35% sericin and 1-5% non-sericin component including wax, pigments, sugars and other impurities. For two decades, the protein-based silk fibroin was extensively used in the research and development of medical biomaterials and biomedicines. Sericin is frequently ignored and abandoned as a byproduct or waste in the processing of traditional silk fabrics, silk floss or modern silk biomaterials. However, similar to fibroin, sericin is not only a highly useful biological material, but also a lot of biological activity. Moreover, the non-sericin component present with sericin in the cocoon shell also has a strong biological activity. In this review, the extraction and recovery methods of sericin and the non-sericin component from the cocoon layer are reported, and their composition, properties and biological activity are described to produce a comprehensive report on biomedical materials and biological drugs. In addition, related problems or concerns present in the research and development of sericin are discussed, and a potential application of sericin in sustainable development is also presented.

Synthesis, characterization and immunogenicity of silk fibroin-L-asparaginase bioconjugates.

L-asparaginase (ASNase) is one basic drug in the treatment of acute lymphoblastic leukemia (ALL). Because its half-life time is too short and it is easy to arouse allergic reaction, use in practical clinic is considerably limited. Silk fibroin (SF) with different molecular mass from 40 to 120 kDa is a natural biocompatible protein and could be used as a novel bioconjugate for enzyme modification to overcome its usual shortcomings mentioned above. When the enzyme was bioconjugated covalently with the water-soluble fibroin by glutaraldehyde, the enzyme kinetic properties and immune characteristics in vivo of the resulting silk fibroin-L-asparaginase (SF-ASNase) bioconjugates were investigated in detail. The results show that the modified ASNase was characterized by its higher residual activity (nearly 80%), increased heat and storage stability and resistance to trypsin digestion, and its longer half-life (63 h) than that of intact ASNase (33 h). The abilities of intact and modified ASNases to arouse allergic reaction are 2(4) and 2(1) antibody titers, respectively. Bioconjugation of silk fibroin significantly helps to reduce the immunogenicity and antigenicity of the enzyme. The apparent Michaelis constants of the modified ASNase (K(m(app))=0.844 x 10(-3)mol L(-1)) was approximately six times lower than that of enzyme alone, which suggests that the affinity of the enzyme to substrate l-asparagine elevated when bioconjugated covalently with silk fibroin. SF-ASNase bioconjugates could overcome the common shortcomings of the native form. Therefore, the modified ASNase coupled with silk fibroin has the potential values of being studied and developed as a new bioconjugate drug.

Processing silk hydrogel and its applications in biomedical materials.

This review mainly introduces the types of silk hydrogels, their processing methods, and applications. There are various methods for hydrogel preparation, and many new processes are being developed for various applications. Silk hydrogels can be used in cartilage tissue engineering, drug release materials, 3D scaffolds for cells, and artificial skin, among other applications because of their porous structure and high porosity and the large surface area for growth, migration, adhesion and proliferation of cells that the hydrogels provide. All of these advantages have made silk hydrogels increasingly attractive. In addition, silk hydrogels have wide prospects for application in the field of biomedical materials.