Nanoparticles that Distinguish Chemical and Supramolecular Contexts of Lysine for Single-Site Functionalization of Protein.

Lysine is one of the most abundant residues on the surface of proteins and its site-selective functionalization is extremely challenging. The existing methods of functionalization rely on differential reactivities of lysine on a protein, making it impossible to label less reactive lysines selectively. We here report polymeric nanoparticles that mimic enzymes involved in the posttranslational modifications of proteins that distinguish the chemical and supramolecular contexts of a lysine and deliver the labeling reagent precisely to its ε amino group. The nanoparticles are prepared through molecular imprinting of cross-linkable surfactant micelles, plus an in situ, on-micelle derivatization of the peptide template prior to the imprinting. The procedures encode the polymeric nanoparticles with all the supramolecular information needed for sequence identification and precise labeling, allowing single-site functionalization of a predetermined lysine on the target protein in a mixture.

High-Performance Bioinspired Microspheres for Boosting Dental Adhesion.

Dental adhesives are widely used in daily practice for minimally invasive restorative dentistry but suffer from bond degradation and biofilm attack. Bio-inspired by marine mussels having excellent surface-adhesion capability and high chemical affinity of polydopamine (PDA) to metal ions, herein, experimental zinc (Zn)-containing polydopamine-based adhesive formulation, further being referred to as "Zn-PDA@SiO2"-incorporated adhesive is proposed as a novel dental adhesive. Different Zn contents (5 and 10 mm) of Zn-PDA@SiO2 are prepared. Considering the synergistic effect of Zn and PDA, Zn-PDA@SiO2 not only presents excellent antibacterial potential and notably inhibits enzymatic activity (soluble and matrix-bound proteases), but also exhibits superior biocompatibility and biosafety in vitro/vivo. The long-term bond stability is substantially improved by adding 5 wt% 5 mm Zn-PDA@SiO2 to the primer. The aged bond strength of the experimentally formulated dental adhesives applied in self-etch (SE) bonding mode is 1.9 times higher than that of the SE gold-standard adhesive. Molecular dynamics calculations indicate the stable formation of covalent bonds, Zn-assisted coordinative bonds, and hydrogen bonds between PDA and collagen. Overall, this bioinspired dental adhesive provides an avenue technology for innovative biomedical applications and has already revealed promising perspectives for dental restorative dentistry.

Regulation of Photophysical Behaviors in Hyperbranched Aggregation-Induced Emission Polymers for Reactive Oxygen Species Scavenging.

Developing nonconjugated materials with large Stokes shifts is highly desired. In this work, three kinds of hyperbranched aggregation-induced emission (AIE) polymers with tunable n/π electronic effects were synthesized. HBPSi-CBD contains alkenyl groups in the backbone and possesses a promoted n-π* transition and red-shifted emission wavelength with a large Stokes shift of 186 nm. Experiments and theoretical simulations confirmed that the planar π electrons in the backbone are responsible for the red-shifted emission due to the strong through-space n···π interactions and restricted backbone motions. Additionally, the designed HBPSi-CBD could be utilized as an ROS scavenger after coupling with l-methionine. The HBPSi-Met exhibits remarkable ROS scavenging properties with a scavenging capacity of 77%. This work not only gains further insight into the structure-property relationship of nonconjugated hyperbranched AIE polymers but also provides a promising ROS-scavenging biomaterial for the treatment of ROS-related diseases.

Gene therapy by virus-like self-spooling toroidal DNA condensates for revascularization of hindlimb ischemia.

Peripheral arterial diseases (PAD) have been reported to be the leading cause for limb amputations, and the current therapeutic strategies including antiplatelet medication or intervene surgery are reported to not clinically benefit the patients with high-grade PAD. To this respect, revascularization based on angiogenetic vascular endothelial growth factor (VEGF) gene therapy was attempted for the potential treatment of critical PAD. Aiming for transcellular delivery of VEGF-encoding plasmid DNA (pDNA), we proposed to elaborate intriguing virus-like DNA condensates, wherein the supercoiled rigid micrometer-scaled plasmid DNA (pDNA) could be regulated in an orderly fashion into well-defined nano-toroids by following a self-spooling process with the aid of cationic block copolymer poly(ethylene glycol)-polylysine at an extraordinary ionic strength (NaCl: 600 mM). Moreover, reversible disulfide crosslinking was proposed between the polylysine segments with the aim of stabilizing these intriguing toroidal condensates. Pertaining to the critical hindlimb ischemia, our proposed toroidal VEGF-encoding pDNA condensates demonstrated high levels of VEGF expression at the dosage sites, which consequently contributed to the neo-vasculature (the particularly abundant formation of micro-vessels in the injected hindlimb), preventing the hindlimb ischemia from causing necrosis at the extremities. Moreover, excellent safety profiles have been demonstrated by our proposed toroidal condensates, as opposed to the apparent immunogenicity of the naked pDNA. Hence, our proposed virus-like DNA condensates herald potentials as gene therapy platform in persistent expressions of the therapeutic proteins, and might consequently be highlighted in the management of a variety of intractable diseases.

A pH-triggered N-oxide polyzwitterionic nano-drug loaded system for the anti-tumor immunity activation research.

Triple negative breast cancer (TNBC) has the characteristics of low immune cell infiltration, high expression of tumor programmed death ligand 1 (PD-L1), and abundant cancer stem cells. Systemic toxicity of traditional chemotherapy drugs due to poor drug selectivity, and chemotherapy failure due to tumor drug resistance and other problems, so it is particularly important to find new cancer treatment strategies for TNBC with limited treatment options. Both the anti-tumor natural drugs curcumin and ginsenoside Rg3 can exert anti-tumor effects by inducing immunogenic cell death (ICD) of tumor cells, reducing PD-L1 expression, and reducing cancer stem cells. However, they have the disadvantages of poor water solubility, low bioavailability, and weak anti-tumor effect of single agents. We used vinyl ether bonds to link curcumin (Cur) with N-O type zwitterionic polymers and at the same time encapsulated ginsenoside Rg3 to obtain hyperbranched zwitterionic drug-loaded micelles OPDEA-PGED-5HA@Cur@Rg3 (PPH@CR) with pH response. In vitro cell experiments and in vivo animal experiments have proved that PPH@CR could not only promote the maturation of dendritic cells (DCs) and increase the CD4+ T cells and CD8+ T cells by inducing ICD in tumor cells but also reduce the expression of PD-L1 in tumor tissues, and reduce cancer stem cells and showed better anti-tumor effects and good biological safety compared with free double drugs, which is a promising cancer treatment strategy.

The Effecting Mechanisms of 100 nm Sized Polystyrene Nanoplastics on the Typical Coastal Alexandrium tamarense.

Due to the increase in nanoplastics (NPs) abundance in aquatic environments, their effects on phytoplankton have aroused large research attention. In this study, 100 nm sized polystyrene NPs were chosen to investigate their effecting performance and mechanisms on a typical dinoflagellates Alexandrium tamarense. The results indicated the population growth and photosynthetic efficiencies of A. tamarense were significantly inhibited by NPs exposure, as well as the increase in cellular total carotenoids and paralytic shellfish toxins (PSTs). Meanwhile, the cellar ROS levels increased, corresponding to the increased activities or contents of multiple antioxidant components, including SOD, CAT, GPX, GR, GSH and GSSG. The transcriptional results support the physiological-biochemical results and further revealed the down-regulation of genes encoding the light reaction centers (PSI and PSII) and up-regulation of genes encoding the antioxidant components. Up-regulation of genes encoding key enzymes of the Calvin cycle and glycolytic pathway together with the TCA cycle could accelerate organic carbon and ATP production for A. tamarense cells resistant to NPs stress. Finally, more Glu and acetyl-CoA produced by the enhanced GSH cycle and the glycolytic pathway, respectively, accompanied by the up-regulation of Glu and Arg biosynthesis genes supported the increase in the PST contents under NPs exposure. This study established a data set involving physiological-biochemical changes and gene information about marine dinoflagellates responding to NPs, providing a data basis for further evaluating the ecological risk of NPs in marine environments.

Temporal gene expression profiling during early-stage traumatic temporomandibular joint bony ankylosis in a sheep model.

BACKGROUND: Investigating the molecular biology underpinning the early-stage of traumatic temporomandibular joint (TMJ) ankylosis is crucial for discovering new ways to prevent the disease. This study aimed to explore the dynamic changes of transcriptome from the intra-articular hematoma or the newly generated ankylosed callus during the onset and early progression of TMJ ankylosis. METHODS: Based on a well-established sheep model of TMJ bony ankylosis, the genome-wide microarray data were obtained from samples at postoperative Days 1, 4, 7, 9, 11, 14 and 28, with intra-articular hematoma at Day 1 serving as controls. Fold changes in gene expression values were measured, and genes were identified via clustering based on time series analysis and further categorised into three major temporal classes: increased, variable and decreased expression groups. The genes in these three temporal groups were further analysed to reveal pathways and establish their biological significance. RESULTS: Osteoblastic and angiogenetic genes were found to be significantly expressed in the increased expression group. Genes linked to inflammation and osteoclasts were found in the decreased expression group. The various biological processes and pathways related to each temporal expression group were identified, and the increased expression group comprised genes exclusively involved in the following pathways: Hippo signaling pathway, Wnt signaling pathway and Rap 1 signaling pathway. The decreased expression group comprised genes exclusively involved in immune-related pathways and osteoclast differentiation. The variable expression group consisted of genes associated with DNA replication, DNA repair and DNA recombination. Significant biological pathways and transcription factors expressed at each time point postoperatively were also identified. CONCLUSIONS: These data, for the first time, presented the temporal gene expression profiling and reveal the important process of molecular biology in the early-stage of traumatic TMJ bony ankylosis. The findings might contributed to identifying potential targets for the treatment of TMJ ankylosis.

[Molding matrix formulation of hot-melt pressure-sensitive adhesive plaster of personalized traditional Chinese medicine preparations].

This study aims to optimize the matrix formulation for the hot-melt pressure-sensitive adhesive plaster of personalized traditional Chinese medicine(TCM) preparations and verify the applicability of the formulation. The central composite design in JMP Pro 16.1.0 was employed to optimize the dosages of styrene-isoprene-styrene triblock copolymer(SIS), hydrogenated petroleum resin, and lightweight liquid paraffin, with the fine powder of Yipifang as the model drug(drug loading of 10%) and the sensory score and objective evaluation as the comprehensive evaluation indicators. The quality evaluation system of hot-melt pressure-sensitive adhesive plaster of personalized TCM preparations was established. The applicability of the optimized matrix formulation of hot-melt pressure-sensitive adhesive plaster was verified with 16 TCM preparations for external application. Furthermore, the applicability of the matrix formulation was investigated with different drug loadings. The general molding matrix formulation was SIS∶hydrogenated petroleum resin∶lightweight liquid paraffin 3∶3∶5. The optimized matrix formulation showed good molding properties and high quality scores for 16 TCM preparations and were suitable for the plastering of finely powdered decoction pieces with a loading capacity of 10% to 30%. The results suggest that the optimized matrix formulation has good applicability and is suitable for TCM preparations. The findings lay a foundation for the application and promotion of the hot-melt pressure-sensitive adhesive plasters of personalized TCM preparations.

Bacterial diversity and community characteristics of the sinus and dental regions in adults with odontogenic sinusitis.

BACKGROUND: The microbiome plays a crucial role in odontogenic sinusitis (OS); however, the bacterial characteristics of the sinuses and connected dental regions in OS are poorly understood. In this study, nasal secretion samples were collected from 41 OS patients and 20 simple nasal septum deviation patients, and oral mucosa samples from dental regions were collected from 28 OS patients and 22 impacted tooth extraction patients. DNA was extracted, and 16S rRNA sequencing was performed to explore the characteristics and structure of the microbiome in the sinuses and dental regions of OS patients. RESULTS: The alpha diversity of the oral and nasal microbiomes in OS patients was higher than that in controls. Principal coordinate analysis (PCoA) showed that oral samples clustered separately from nasal samples, and the beta diversity of oral and nasal samples in OS patients was higher than that in controls. The dominant phylum was Bacteroidetes in OS patients and Firmicutes in controls in both the oral and nasal cavity. The dominant genera in the oral microbiome and nasal microbiome of OS patients were similar, including Fusobacterium, Porphyromonas and Prevotella. Co-occurrence network analysis showed decreased microbial connectivity in the oral mucosa and nasal secretion samples of OS patients. CONCLUSIONS: Odontogenic infection promotes structural and functional disorders of the nasal microbiome in OS. The interaction of dominant pathogens in the nasal and oral regions may promote the development of OS. Our study provides the microbiological aetiology of the nasal and connected dental regions in OS and is expected to provide novel insights into the diagnosis and therapeutic strategies for OS.

pH-Activatable Charge-Reversal Polymer-Based Nanocarriers for Targeted Delivery of Antihepatoma Compound.

Chemotherapy is one of the available cancer treatments which has been successfully employed to prolong the survival of cancer patients. However, it remains a major challenge to develop effective chemotherapeutic agents by reducing off-target toxicity, improving bioavailability, and effectively prolonging blood circulation. The pH profile of tumor cells is abnormal to that of normal cells, making it a potential breakthrough for designing effective chemotherapeutic drug agents. Here, the pH-activatable charge-reversal supramolecular nanocarriers, named MI7-ß-CD/SA NPs, were prepared through a simple and "green" constructive process. MI7-ß-CD/SA NPs possess both pH-induced charge-reversal and disassembly properties that were exploited to investigate the loading, delivery, and pH-responsive controlled release of the antitumor compound celastrol (CSL). CSL@MI7-ß-CD/SA NPs displayed low hemolysis, good biocompatibility, and targeted uptake. Furthermore, CSL@MI7-ß-CD/SA NPs exhibited superior apoptosis rates against SMMC-7721 cell lines compared with CSL, when CSL@MI7-ß-CD/SA NPs and CSL were administered at a mass concentration of 5.0 µg/mL, i.e., the CSL content in CSL@MI7-ß-CD/SA NPs was relatively lower than that of intact CSL. We expected that MI7-ß-CD/SA NPs featuring pH-triggered charge reversal could offer a promising controlled release strategy that would then facilitate the clinical conversion of antitumor drugs.

Tuning the Emission of a Nonconventional Aggregation-Induced Emission Polymer via Silicon-Bridged Twisted Intramolecular Charge Transfer for Targeted Delivery and Visualized Drug Release.

The design of tunable luminescent biomaterials with large Stokes shifts is usually pursued by a twisted intramolecular charge transfer (TICT) effect with switchable emission colors in response to various external stimuli. However, such a strategy is usually realized in conjugated molecules containing benzene or its derivatives and consequently suffers from poor biocompatibility. In this work, a hyperbranched polysiloxane (HBPSi)-based non-conjugated fluorescent polymer with TICT and aggregation-induced emission (AIE) features is developed, and its luminescent properties, fluorescence mechanism, and potential applications are investigated. Initially, the non-conjugated HBPSi exhibits remarkable AIE characteristics due to the formation of through-space conjugation. With the introduction of the sulfur atom, a non-conjugated D-A type AIE material, HBPSi-Cys, that exhibits a dual-state emission with a large Stokes shift of 213 nm, is obtained. The correlation of the lower-energy emission band with solvent polarity suggests the existence of the TICT state. TICT and AIE characteristics direct different properties of HBPSi-Cys, with TICT regulating solvatochromic emission wavelengths and AIE manipulating the emission intensity with a compensation effect. Density functional theory calculations reveal that the non-conjugated D-A structure in HBPSi-Cys was formed across the silicon bridge, with auxochromic sulfhydryl groups and adjacent amide groups as acceptor units and amine and hydroxyl groups as donor units. Additionally, the AIE-active HBPSi could be utilized as a fluorescent probe for the analysis of metal ions. After grafting the AS1411 aptamer to HBPSi-Cys as the recognition motif, HBPSi-Apt possesses excellent targeted bioimaging, drug loading, pH/GSH dual-responsive drug release, and visualized drug delivery performance. This work provides a new way to design functional AIE polymers with tunable optical properties, and the synthesized HBPSi-Cys shows great potential as a smart fluorescent biomaterial.

Restructuring the Interface of Silk-Polycaprolactone Biocomposites Using Rigid-Flexible Agents.

Natural fiber-reinforced biocomposites with excellent mechanical and biological properties have attractive prospects for internal medical devices. However, poor interfacial adhesion between natural silk fiber and the polymer matrix has been a disturbing issue for such applications. Herein, rigid-flexible agents, such as polydopamine (PDA) and epoxy soybean oil (ESO), were introduced to enhance the interfacial adhesion between Antheraea pernyi (Ap) silk and a common medical polymer, polycaprolactone (PCL). We compared two strategies of depositing PDA first (Ap-PDA-ESO) and grafting ESO first (Ap-ESO-PDA). The rigid-flexible interfacial agents introduced multiple molecular interactions at the silk-PCL interface. The "Ap-PDA-ESO" strategy exhibited a greater enhancement in interfacial adhesion, and interfacial toughening mechanisms were proposed. This work sheds light on engineering strong and tough silk fiber-based biocomposites for biomedical applications.

The adsorption and absorption kinetics of BDE-47 by Chlorella sp. and the role of extracellular polymer substances influenced by environmental factors.

Microalgae act as the entrance of polybrominated diphenyl ethers (PBDEs) from abiotic to biotic environments, which controlled the environmental fate of PBDEs in aquatic environments. Combing with typical coastal environmental characteristics including extracellular polymer substances (EPS) enrichment, light limitation and nitrogen starvation, the changes of adsorption and absorption kinetics of BDE-47 by Chlorella sp. and the role of EPS therein were investigated. The results quantified the adsorption and absorption kinetics of BDE-47 by Chlorella sp. cells and fitted it by the Lagergren pseudo first order model. Furthermore, we found the adsorption and absorption kinetics could be changed by the above mentioned environmental factors. To be specific, the total BDE-47 adsorption amounts per microalgal cell were increased as the increase of ambient EPS (proteins or carbohydrates), attributing to the increase of soluble (SL)-EPS contents; increased total BDE-47 adsorption amounts but decreased absorption rates were found under light limitation and nitrogen starvation, which were attributed to increased bound (B)-EPS contents and protein/carbohydrates (P/C) ratios therein, respectively. Therefore, our study elucidated the adsorption and absorption kinetics of PBDEs by microalgae could be influenced by ambient environmental changes, clarified the roles of SL-EPS, B-EPS contents and P/C ratios, providing a solid basis for evaluating the environmental fate of PBDEs in the marine environments.

Diagnostic accuracy of fused CBCT images in the evaluation of temporomandibular joint condylar bone resorption.

OBJECTIVES: To evaluate the diagnostic accuracy of fused CBCT images for patients with condylar bone resorption of temporomandibular joint (TMJ) osteoarthrosis. MATERIALS AND METHODS: Forty-two TMJs from twenty-one patients were included. Bone resorption of condyles evaluated by three experts was used as the reference standard. Three oral and maxillofacial radiology residents evaluated the resorption of condyles with a five-point scale for the four sets of images (two consecutive CBCT images without fusion, fused 2D cross-sectional images, fused 3D images, and combining fused 2D cross-sectional images and fused 3D images) randomly and independently. Each set of images was evaluated at least 1 week apart, and a second evaluation was performed 4 weeks later. Intraclass correlation coefficients were calculated to assess the intra- and inter-observer agreement. The areas under the ROC curves (AUCs) were compared among the four image sets using the Z test. RESULTS: Twenty-four TMJs were determined as condylar bone resorption, and eighteen were determined as no obvious change. The average AUC values from the three observers for the three fused image sets (0.94, 0.93, 0.93) were significantly higher than the image set without fusion (p < 0.01). The intra- and inter-observer agreement on the three fused image sets (0.70-0.89, 0.91-0.92) was higher than the image set without fusion (0.37-0.63, 0.75). CONCLUSIONS: Fused CBCT images of TMJ osteoarthrosis patients can intuitively display the condylar bone resorption and significantly improve the diagnostic accuracy. CLINICAL RELEVANCE: Fused CBCT images can help clinicians intuitively observe bone changes of the condyle in TMJ osteoarthrosis patients.

Exploration of ß-glucosidase-producing microorganisms community structure and key communities driving cellulose degradation during composting of pure corn straw by multi-interaction analysis.

Poor management of crop residues leads to environmental pollution and composting is a sustainable practice for addressing the challenge. However, knowledge about composting with pure crop straw is still limited, which is a novel and feasible composting strategy. In this study, pure corn straw was in-situ composted for better management. Community structure of ß-glucosidase-producing microorganisms during composting was deciphered using high-throughput sequencing. Results showed that the compost was mature with organic matter content of 37.83% and pH value of 7.36 and pure corn straw could be composted successfully. Cooling phase was major period for cellulose degradation with the highest ß-glucosidase activity (476.25 µmol·p-Nitr/kg·dw·min) and microbial diversity (Shannon index, 3.63; Chao1 index, 500.81). Significant compositional succession was observed in the functional communities during composting with Streptomyces (14.32%), Trichoderma (13.85%) and Agromyces (11.68%) as dominant genera. ß-Glucosidase-producing bacteria and fungi worked synergistically as a network to degrade cellulose with Streptomyces (0.3045**) as the key community revealed by multi-interaction analysis. Organic matter (-0.415***) and temperature (-0.327***) were key environmental parameters regulating cellulose degradation via influencing ß-glucosidase-producing communities, and ß-glucosidase played a key role in mediating this process. The above results indicated that responses of ß-glucosidase-producing microorganisms to cellulose degradation were reflected at both network and individual levels and multi-interaction analysis could better explain the relationship between variables concerning composting cellulose degradation. The work is of significance for understanding cellulose degradation microbial communities and process during composting of pure corn straw.

Quadruple H-Bonding and Polyrotaxanes Dual Cross-linking Supramolecular Elastomer for High Toughness and Self-healing Conductors.

Tough and self-healable substrates can enable stretchable electronics long service life. However, for substrates, it still remains a challenge to achieve both high toughness and autonomous self-healing ability at room temperature. Herein, a strategy by using the combined effects between quadruple H-bonding and slidable cross-links is proposed to solve the above issues in the elastomer. The elastomer exhibits high toughness (77.3 MJ m-3 ), fracture energy (≈127.2 kJ m-2 ), and good healing efficiency (91 %) at room temperature. The superior performance is ascribed to the inter and intra crosslinking structures of quadruple H-bonding and polyrotaxanes in the dual crosslinking system. Strain-induced crystallization of PEG in polyrotaxanes also contributes to the high fracture energy of the elastomers. Furthermore, based on the dual cross-linked supramolecular elastomer, a highly stretchable and self-healable electrode containing liquid metal is also fabricated, retaining resistance stability (0.16-0.26 Ω) even at the strain of 1600 %.

Synergistic Hydrolysis of Cellulose by a Blend of Cellulase-Mimicking Polymeric Nanoparticle Catalysts.

Enzyme-like catalysts by design have been a long sought-after goal of chemists but difficult to realize due to the challenges in the construction of multifunctionalized active sites with accurately positioned catalytic groups for complex substrates. Hydrolysis of cellulose is a key step in biomass utilization and requires multiple enzymes to work in concert to overcome the difficulty associated with hydrolyzing the recalcitrant substrate. We here report methods to construct synthetic versions of these enzymes through covalent molecular imprinting and strategic postmodification of the imprinted sites. The synthetic catalysts cleave a cellulose chain endolytically at multiple positions or exolytically from the nonreducing end by one or three glucose units at a time, all using the dicarboxylic acid motif found in natural cellulases. By mimicking the endocellulase, exocellulase, and ß-glucosidase, the synthetic catalysts hydrolyze cellulose in a synergistic manner, with an activity at 90 °C in pH 6.5 buffer more than doubled that of Aspergillus niger cellulase at pH 5 and 37 °C and 44% of that of a commercial cellulase blend (from Novozyme). As robust cross-linked polymeric nanoparticles, the synthetic catalysts showed little changes in activity after preheating at 90 °C for 3 days and could be reused, maintaining 76% of activity after 10 reaction cycles.

Recovery of Fluoride-Rich and Silica-Rich Wastewaters as Valuable Resources: A Resource Capture Ultrafiltration-Bipolar Membrane Electrodialysis-Based Closed-Loop Process.

Traditional technologies such as precipitation and coagulation have been adopted for fluoride-rich and silica-rich wastewater treatment, respectively, but waste solid generation and low wastewater processing efficiency are still the looming concern. Efficient resource recovery technologies for different wastewater treatments are scarce for environment and industry sustainability. Herein, a resource capture ultrafiltration-bipolar membrane electrodialysis (RCUF-BMED) system was designed into a closed-loop process for simultaneous capture and recovery of fluoride and silica as sodium silicofluoride (Na2SiF6) from mixed fluoride-rich and silica-rich wastewaters, as well as achieving zero liquid discharge. This RCUF-BMED system comprised two key parts: (1) capture of fluoride and silica from two wastewaters using acid, and recovery of the Na2SiF6 using base by UF and (2) UF permeate conversion for acid/base and freshwater generation by BMED. With the optimized RCUF-BMED system, fluoride and silica can be selectively captured from wastewater with removal efficiencies higher than 99%. The Na2SiF6 recovery was around 72% with a high purity of 99.1%. The aging and cyclic experiments demonstrated the high stability and recyclability of the RCUF-BMED system. This RCUF-BMED system has successfully achieved the conversion of toxic fluoride and silica into valuable Na2SiF6 from mixed wastewaters, which shows great application potential in the industry-resource-environment nexus.

Adipose-derived mesenchymal stem cell-loaded ß-chitin nanofiber hydrogel promote wound healing in rats.

Because of stem cells are limited by the low efficiency of their cell homing and survival in vivo, cell delivery systems and scaffolds have attracted a great deal of attention for stem cells' successful clinical practice. ß-chitin nanofibers (ß-ChNF) were prepared from squid pens in this study. Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy proved that ß-ChNFs with the diameter of 5 to 10 nm were prepared. ß-ChNF dispersion became gelled upon the addition of cell culture medium. Cell culture experiments showed that ß-ChNFs exhibited negligible cytotoxicity towards ADSCs and L929 cells, and it was found that more exosomes were secreted by the globular ADSCs grown in the ß-ChNF hydrogel. The vivo experiments of rats showed that the ADSCs-loaded ß-ChNF hydrogel could directly cover the wound surface and significantly accelerate the wound healing and promote the generation of epithelization, granulation tissue and collagen. In addition, the ADSCs-loaded ß-ChNF hydrogel clearly regulated the expressions of VEGFR, α-SMA, collagen I and collagen III. Finally, we showed that ADSCs-loaded ß-ChNF hydrogel activated the TGFß/smad signaling. The neutralization of TGFß markedly reduced Smad phosphorylation and the expressions of TIMP1, VEGFR and α-SMA. Taken together, these findings suggest that ADSCs-loaded ß-ChNF hydrogel promises for treating wounds that are challenge to heal via conventional methods. Graphical abstract.

Different effecting mechanisms of two sized polystyrene microplastics on microalgal oxidative stress and photosynthetic responses.

Increasing marine microplastics (MPs) pollution potentially threatens the stability of phytoplankton community structures in marine environments. MPs toxicities to microalgae are largely determined by particle size, while the size-dependent mechanisms are still not fully understood. In this study, two sizes (0.1 µm and 1 µm) of polystyrene (PS) MPs were used as experimental targets to systemically compare their different effecting mechanisms on the marine model diatom Thalassiosira pseudonana with respect to oxidative stress and photosynthesis. The results indicated the toxicity of 1 µm sized MPs was higher than 0.1 µm sized MPs regarding to population growth. In condition of similar microalgal population inhibition rates, we found more enhanced cellular oxidative stress and cell death happened in the 1 µm MPs treatments, which could be linked to higher zeta potential of 1 µm MPs and more severe cell surface damage; microalgal surface light shading and cellular pigments decline were more obvious in the 0.1 µm MPs treatment, which could be linked to high aggregation abilities of 0.1 µm MPs. Gene expressions supported the morphological and physiological findings on the transcriptional level. Environmental related MPs concentrations (5 µg L-1) also aroused gene expression changes of T. pseudonana while more changing genes were found under 0.1 µm MPs than 1 µm MPs. These results provide novel insights into the size-dependent mechanisms of MPs toxicity on marine microalgae, as well as their potential influence on the marine environment.