Response of aerobic granular sludge under polyethylene microplastics stress: Physicochemical properties, decontamination performance, and microbial community.

Microplastics are widely detected in sewage and sludge in wastewater treatment plants and can thereby influence biological processes. In this study, the overall impacts of polyethylene microplastics (PE MPs) and their toxicity mechanisms on aerobic granular sludge (AGS) were investigated. Particle structure, settling properties, particle size distribution, and extracellular polymeric substance characteristics of AGS were significantly affected by PE MPs with concentrations of 20 and 200 n/L. Increased relative contents of reactive oxygen species (ROS) (146.34% and 191.43%) and lactate dehydrogenase (LDH) (185.71% and 316.67%) under PE MPs (20 and 200 n/L) exposure resulted in disruption of cellular structure. The activities of enzymes related to denitrification and phosphorus removal were greatly decreased, while ammonia monooxygenase (AMO) was stable, supporting the high efficiency removal of ammonia nitrogen. High-throughput sequencing demonstrated that the relative abundance of nitrifying and denitrifying bacteria (Nitrospira, Thermomonas, Flavobacterium), and PAOs (Comamonas and Rhodocyclus) were significantly reduced from 4.47%, 3.57%, 2.02%, 9.38%, and 5.45%-2.95%, 2.88%, 1.77%, 8.01%, and 4.86% as the concentration of PE MPs increased from 0 to 200 n/L, respectively. Those findings were consistent with the deterioration in decontamination capability.

HA2-FimA DNA Vaccine Treats Experimental Periodontitis.

PURPOSE: To study the therapeutic effect of hemagglutinin-2 and fimbrial (HA2-FimA) vaccine on experimental periodontitis in rats. MATERIALS AND METHODS: The first batch of rats was divided into two groups and immunised with pure water or pVAX1-HA2-FimA at the age of 6, 7, and 9 weeks. After sacrificing the animals, total RNA was extracted from the spleens for RNA high-throughput sequencing (RNA-Seq) analysis. The second batch of rats was divided into four groups (A, B, C, D), and an experimental periodontitis rat model was established by suturing silk thread around the maxillary second molars of rats in groups B, C, and D for 4 weeks. The rats were immunised with pure water, pVAX1-HA2-FimA vaccine, empty pVAX1 vector, and pure water at 10, 11, and 13 weeks of age, respectively. Secretory immunoglobulin A (SIgA) antibodies and cathelicidin antimicrobial peptide (CAMP) levels in saliva were measured by enzyme-linked immunosorbent assay (ELISA). All rats were euthanised at 17 weeks of age, and alveolar bone loss was examined using micro-computed tomography (Micro-CT). RESULTS: Through sequencing analysis, six key genes, including Camp, were identified. Compared with the other three groups, the rats in the periodontitis+pVAX1-HA2-FimA vaccine group showed higher levels of SIgA and CAMP (p < 0.05). Micro-CT results showed significantly less alveolar bone loss in the periodontitis+pVAX1-HA2-FimA vaccine group compared to the periodontitis+pVAX1 group and periodontitis+pure water group (p < 0.05). CONCLUSION: HA2-FimA DNA vaccine can increase the levels of SIgA and CAMP in the saliva of experimental periodontitis model rats and reduce alveolar bone loss.

Response mechanisms of Chlorella sorokiniana to microplastics and PFOA stress: Photosynthesis, oxidative stress, extracellular polymeric substances and antioxidant system.

Co-pollution of microplastics and per- and polyfluoroalkyl substances (PFAS) is prevailing in the aquatic environment. However, the risks of coexisting microplastics and PFAS on organisms remain unknown. This study investigated the response mechanisms of Chlorella sorokiniana (C. sorokiniana) under polystyrene microplastics (PS-MPs) and perfluorooctanoic acid (PFOA) stress, including toxicity and defense mechanisms. C. sorokiniana was exposed to PS-MPs (10 mg/L) and PFOA (0.05, 0.5, and 5 mg/L) and their mixtures for 96 h, respectively. We found that the dominant toxicity mechanism of PFOA and PS-MPs to C. sorokiniana was dissimilar. PS-MPs mainly inhibited photosynthesis through shading effect, while PFOA mainly induced oxidative stress by reactive oxygen species. The co-exposure of PFOA and PS-MPs aggravated biotoxicity (maximum inhibition rate: 27.27 ± 2.44%), such as photosynthesis inhibition, physical damage, and oxidative stress, compared with individuals. To alleviate toxicity, C. sorokiniana activated defense mechanisms. Extracellular polymeric substances were the first barrier to protect cells, the effect on its secretion was ordered PS-MPs+5PFOA > PS-MPs > 5PFOA, and IBRv2 values were 2.37, 1.35, 1.11, respectively. Antioxidant system was thought of second defense pathway, the influence order of treatment groups was PS-MPs+5PFOA > 5PFOA > PS-MPs, and its IBRv2 values were 2.89, 1.69, 0.25, respectively. Our findings provide valuable information on the complex impacts of PFOA and PS-MPs, which facilitate the ecological risk assessment of multiple pollutants.

One-pot preparation of a multi-functional enzymatically generated gelatin hydrogel with controllable antibacterial and hemorheological properties.

The creation of multi-functional bio-hydrogels with tunable properties that meet in vivo demands is significant but remains challenging. Inspired by host-guest chemistry, a novel multi-functional gelatin-based bio-hydrogel with tunable antibacterial and hemorheological properties (TAH-GEL) is synthesized via an in situ one-pot strategy. TAH-GEL not only exhibits excellent mechanical properties but also shows promising self-healing and bio-compatibility features. For the first time, this biomaterial presents controllable antibacterial and hemorheological properties by controlling the TAH-GEL polypseudorotaxane motif. The resulting bio-hydrogel is easy to prepare and delivers superior performance, making it a powerful tool for bio-applications, such as hemostatic materials.

Effect of polystyrene microplastics on the volatile fatty acids production from waste activated sludge fermentation.

Anaerobic fermentation is crucial to resource utilization of waste activated sludge (WAS). However, accumulated microplastics (MPs) in sludge could not be ignored. Here, a typical MP, polystyrene (PS), was selected to study the effects of different concentrations of PS on anaerobic fermentation under the optimal volatile fatty acids (VFAs) production. Compared to the control, low PS concentrations (30 particles/g total solid) significantly (p = 0.002) increased the production of VFAs to 112.8 ± 2.4% due to solubilization enhancement and enzymatic activity. High concentrations of PS (90 particles/g total solid) significantly (p = 0.000) decreased VFAs production to 83.01 ± 0.76% because of the inactive related microbial activities, although organic matter release was enhanced in the initial stage. Mechanism studies showed that the toxicity of high PS concentration could be attributed to reactive oxygen species (ROS) production, excess sodium dodecyl sulfate (SDS), and synergistic toxicity of aged MPs with external pollutants.

RBC membrane camouflaged boron nitride nanospheres for enhanced biocompatible performance.

Boron nitride nanospheres (BNNS) have attracted increasing attention in many fields due to their unique physicochemical properties. Biomedical application of BNNS has also been explored recently. However, limited by the hydrophobicity and poor dispersity of BNNS, their biocompatible performance especially the in vivo biosafety has rarely been reported and is still unclear now. In this work, BNNS were firstly camouflaged with red blood cell membrane by physical extrusion (CM-BNNS). CM-BNNS were then incubated with cells as well as intravenously injected into the mice to uncover their potential in vitro and in vivo toxicity. Results were promising as CM-BNNS exhibited better dispersion and stability compared with pristine BNNS. In vitro data demonstrated the relatively enhanced biosafety of CM-BNNS. The red blood cell membrane coating endowed BNNS with markedly prolonged blood circulation and decreased accumulation in the lung. In addition, CM-BNNS showed no adverse effects on all the evaluated hematic parameters and tissues of treated mice at a dose of 10 mg/kg. Taken together, our work demonstrated the optimal biocompatibility of CM-BNNS and pave the way for their future biomedical applications.

Autophagy and Hsp70 activation alleviate oral epithelial cell death induced by food-derived hypertonicity.

Stable intracellular and intercellular osmolarity is vital for all physiological processes. Although it is the first organ that receives food, the osmolarity around the mouth epithelium has never been systematically investigated. We found that oral epithelial cells are a population of ignored cells routinely exposed to hypertonic environments mainly composed of saline, glucose, etc. in vivo after chewing food. By using cultured oral epithelial cells as an in vitro model, we found that the hypotonic environments caused by both high NaCl and high glucose induced cell death in a dose- and time-dependent manner. Transcriptomics revealed similar expression profiles after high NaCl and high glucose stimulation. Most of the common differentially expressed genes were enriched in "mitophagy" and "autophagy" according to KEGG pathway enrichment analysis. Hypertonic stimulation for 1 to 6 h resulted in autophagosome formation. The activation of autophagy protected cells from high osmolarity-induced cell death. The activation of Hsp70 by the pharmacological activator handelin significantly improved the cell survival rate after hypertonic stimulation. The protective role of Hsp70 activation was partially dependent on autophagy activation, indicating a crosstalk between Hsp70 and autophagy in hypertonic stress response. The extract of the handelin-containing herb Chrysanthemum indicum significantly protected oral epithelial cells from hypertonic-induced death, providing an inexpensive way to protect against hypertonic-induced oral epithelial damage. In conclusion, the present study emphasized the importance of changes in osmolarity in oral health for the first time. The identification of novel compounds or herbal plant extracts that can activate autophagy or HSPs may contribute to oral health and the food industry.

Transgenic PDGF-BB/sericin hydrogel supports for cell proliferation and osteogenic differentiation.

Sericin has been exploited as a biomaterial due to its biocompatibility, biodegradability, and low-immunogenicity as an isolated polymer and support for cell adhesion. In the present study, human platelet-derived growth factor (PDGF-BB)-functionalized sericin hydrogels were generated using transgenic silkworms, where the as-spun silk incorporated engineered PDGF-BB (termed PDGFM) in the sericin layers of the cocoons. Sericin and PDGFM were simultaneously extracted from the silk fibroin cocoon fibers, and the soluble extract was then formed into a hydrogel via thermal exposure. The PDGFM sericin hydrogels exhibited increased ß-sheet content and a compressive modulus of 74.91 ± 2.9 kPa comparable to chemically crosslinked sericin hydrogels (1.68-55.53 kPa) and a porous microstructure, which contributed to cell adhesion and growth. A 13.1% of total extracted PDGFM from the initial silk fibers was incorporated and immobilized in the sericin hydrogels during material processing, and 1.33% of PDGFM was released over 30 days from the hydrogels in vitro. The remaining PDGFM achieved long-term storage/stability in the sericin hydrogels for more than 42 days at 37 °C. In addition, the PDGFM sericin hydrogels were not immunogenic, were biocompatible and bioactive in promoting the support of cell proliferation. When combined with BMP-9, the PDGFM sericin hydrogels provided synergy to support the osteoblastic differentiation of mesenchymal stem cells (hMSCs) in vitro and in vivo. This study demonstrates that genetically functionalized PDGFM sericin hydrogels can provide useful biomaterials to support cell and tissue outcomes, here with a focus on osteogenesis.

Designing heparan sulfate-based biocompatible polymers and their application for intracellular stimuli-sensitive drug delivery.

Heparan sulfate (HS) is a kind of natural polysaccharides with good biocompatibility. And as drug carriers, it has some advantages compared to heparin. However, the preparation of HS is cumbersome and difficult, which limits its application in drug delivery. Here, we use modern separation technique combined with chromatography to establish a new preparation method of HS. The molecular weight and degree of dispersion of HS were (1.03 × 104 ±â€¯107) kDa and 1.106, respectively. HS also showed low anticoagulation activity in comparison with heparin. Subsequently, novel redox-sensitive heparan sulfate-cystamine-vitamin E succinate (HS-SS-VES, HSV) micelles were designed to increase tumor selectivity and improve the therapeutic effect of doxorubicin (DOX). DOX-loaded HSV micelles (DOX/HSV) with spherical morphology had average particle size of 90-120 nm and good redox-triggered release behavior. The cell viabilities of blank micelles were >90% in both human breast cancer (MCF7) cells and African green monkey SV40-transformed kidney fibroblast (COS7) cells. However, the cytotoxicity of DOX/HSV in MCF7 cells was higher than that of COS7 cells. Flow cytometry analyses and confocal laser scanning microscopy observation indicated that DOX/HSV micelles were internalized by endocytosis, and then the drug was released quickly and entered the nuclei of tumor cells. The results demonstrate that high-purity HS can be prepared and has the potential to be further used for drug delivery in antitumor applications.

Nasal absorption enhancement of insulin using PEG-grafted chitosan nanoparticles.

The objective of this work was to explore the potential of polyethylene glycol-grafted chitosan (PEG-g-chitosan) nanoparticles as a system for improving the systemic absorption of insulin following nasal administration. Insulin-loaded PEG-g-chitosan nanoparticles were prepared by the ionotropic gelation of PEG-g-chitosan solution using tripolyphosphate ions as the crosslinking agent. The nanoparticles were in the size range 150-300 nm, had a positive electrical charge (+16 to +30 mV) and were associated with insulin (loading efficiency 20-39%). The physicochemical properties of nanoparticles were affected by the composition of the copolymer. In vitro insulin release studies showed an initial burst followed by a slow release of insulin. Intranasal administration of PEG-g-chitosan nanoparticles in rabbits enhanced the absorption of insulin by the nasal mucosa to a greater extent than a suspension of insulin-PEG-g-chitosan and control insulin solution. PEG-g-chitosan nanoparticles are promising vehicles for insulin transport through the nasal mucosa.

pH-responsive charge-reversal polymer-functionalized boron nitride nanospheres for intracellular doxorubicin delivery.

BACKGROUND: Anticancer drug-delivery systems (DDSs) capable of responding to the physiological stimuli and efficiently releasing drugs inside tumor cells are highly desirable for effective cancer therapy. Herein, pH-responsive, charge-reversal poly(allylamine hydrochlorid)-citraconic anhydride (PAH-cit) functionalized boron nitride nanospheres (BNNS) were fabricated and used as a carrier for the delivery and controlled release of doxorubicin (DOX) into cancer cells. METHODS: BNNS was synthesized through a chemical vapor deposition method and then functionalized with synthesized charge-reversal PAH-cit polymer. DOX@PAH-cit-BNNS complexes were prepared via step-by-step electrostatic interactions and were fully characterized. The cellular uptake of DOX@PAH-cit-BNNS complexes and DOX release inside cancer cells were visualized by confocal laser scanning microscopy. The in vitro anticancer activity of DOX@ PAH-cit-BNNS was examined using CCK-8 and live/dead viability/cytotoxicity assay. RESULTS: The PAH-cit-BNNS complexes were nontoxic to normal and cancer cells up to a concentration of 100 µg/mL. DOX was loaded on PAH-cit-BNNS complexes with high efficiency. In a neutral environment, the DOX@PAH-cit-BNNS was stable, whereas the loaded DOX was effectively released from these complexes at low pH condition due to amide hydrolysis of PAH-cit. Enhanced cellular uptake of DOX@PAH-cit-BNNS complexes and DOX release in the nucleus of cancer cells were revealed by confocal microscopy. Additionally, the effective delivery and release of DOX into the nucleus of cancer cells led to high therapeutic efficiency. CONCLUSION: Our findings indicated that the newly developed PAH-cit-BNNS complexes are promising as an efficient pH-responsive DDS for cancer therapy.

Light-induced formation of partially reduced oxygen species limits the lifetime of photosystem 1-based biocathodes.

Interfacing photosynthetic proteins specifically photosystem 1 (PS1) with electrodes enables light-induced charge separation processes for powering semiartificial photobiodevices with, however, limited long-term stability. Here, we present the in-depth evaluation of a PS1/Os-complex-modified redox polymer-based biocathode by means of scanning photoelectrochemical microscopy. Focalized local illumination of the bioelectrode and concomitant collection of H2O2 at the closely positioned microelectrode provide evidence for the formation of partially reduced oxygen species under light conditions. Long-term evaluation of the photocathode at different O2 concentrations as well as after incorporating catalase and superoxide dismutase reveals the particularly challenging issue of avoiding the generation of reactive species. Moreover, the evaluation of films prepared with inactivated PS1 and free chlorophyll points out additional possible pathways for the generation of oxygen radicals. To avoid degradation of PS1 during illumination and hence to enhance the long-term stability, the operation of biophotocathodes under anaerobic conditions is indispensable.

Polyethyleneimine-functionalized boron nitride nanospheres as efficient carriers for enhancing the immunostimulatory effect of CpG oligodeoxynucleotides.

CpG oligodeoxynucleotides (ODNs) stimulate innate and adaptive immune responses. Thus, these molecules are promising therapeutic agents and vaccine adjuvants against various diseases. In this study, we developed a novel CpG ODNs delivery system based on polyethyleneimine (PEI)-functionalized boron nitride nanospheres (BNNS). PEI was coated on the surface of BNNS via electrostatic interactions. The prepared BNNS-PEI complexes had positive zeta potential and exhibited enhanced dispersity and stability in aqueous solution. In vitro cytotoxicity assays revealed that the BNNS-PEI complexes with concentrations up to 100 µg/mL exhibited no obvious cytotoxicity. Furthermore, the positively charged surface of the BNNS-PEI complexes greatly improved the loading capacity and cellular uptake efficiency of CpG ODNs. Class B CpG ODNs loaded on the BNNS-PEI complexes enhanced the production of interleukin-6 and tumor necrosis factor-α from peripheral blood mononuclear cells compared with CpG ODNs directly loaded on BNNS. Contrary to the free CpG ODNs or CpG ODNs directly loaded on BNNS, class B CpG ODNs loaded on the BNNS-PEI complexes induced interferon-α simultaneously. PEI coating may have changed the physical form of class B CpG ODNs on BNNS, which further affected their interaction with Toll-like receptor 9 and induced interferon-α. Therefore, BNNS-PEI complexes can be used to enhance the immunostimulatory effect and therapeutic activity of CpG ODNs and the treatment of diseases requiring interleukin-6, tumor necrosis factor-α, and interferon-α.

Preparation, characterization, and properties of PMMA-doped polymer film materials: a study on the effect of terbium ions on luminescence and lifetime enhancement.

Poly(methylmethacrylate) (PMMA) doped with Tb-based imidazole derivative coordination polymer {[Tb(3)(L)(µ(3)-OH)(7)]·H(2)O}(n) (1) (L = N,N'-bis(acetoxy)biimidazole) was synthesized and its photophysical properties were studied. The L'(L' = N,N'-bis(ethylacetate)biimidazole) ligand was synthesized by an N-alkylation reaction process followed by ester hydrolysis to produce ligand L. Polymer 1 and ligand L' have been characterized by (1)H NMR and IR spectroscopy, elemental analysis, PXRD and X-ray single-crystal diffraction. Coordination polymer 1 is the first observation of a CdCl(2) structure constructed with hydroxy groups and decorated by ligand L in lanthanide N-heterocyclic coordination polymers. In the 2D layered structure of 1, each Tb3 metal center is connected with three Tb1 and three Tb2 metal centers by seven hydroxyl groups in different directions, resulting in a six-membered ring. After doping, not only the luminescence intensity and lifetime enhanced, but also their thermal stability was increased in comparison with 1. When 1 was doped into poly(methylmethacrylate) (1@PMMA), polymer film materials were formed with the PMMA polymer matrix (w/w = 2.5%-12.5%) acting as a co-sensitizer for Tb(3+) ions. The luminescence intensity of the Tb(3+) emission at 544 nm increases when the content of Tb(3+) was 10%. The lifetime of 1@PMMA (914.88 µs) is more than four times longer than that of 1 (196.24 µs). All τ values for the doped polymer systems are higher than coordination polymer 1, indicating that radiative processes are operative in all the doped polymer films. This is because PMMA coupling with the O-H oscillators from {[Tb(3)(L)(µ(3)-OH)(7)]·H(2)O}(n) can suppress multiphonon relaxation. According to the variable-temperature luminescence (VT-luminescence) investigation, 1@PMMA was confirmed to be a stable green luminescent polymer film material.

Microfluidic generation of chitosan/CpG oligodeoxynucleotide nanoparticles with enhanced cellular uptake and immunostimulatory properties.

Chitosan/cytosine-phosphodiester-guanine oligodeoxynucleotide (CpG ODN) nanoparticles as potential immunostimulatory adjuvants were synthesized by the conventional bulk mixing (BM) method and a novel microfluidic (MF) method. Their size and size distribution, CpG ODN loading efficiency, surface charge, biocompatibility, cellular uptake, and immunostimulatory response were investigated. In the BM method, nanoparticles were synthesized by vortexing a mixture of chitosan solution and CpG ODN2006x3-PD solution. In the MF method, the nanoparticles were synthesized by rapidly mixing a chitosan solution and CpG ODN solution in a poly(dimethylsiloxane) microfluidic device. Our results indicated that particle size and size distribution, CpG ODN loading efficiency, and surface charge could be easily adjusted by using the tuning preparation method and controlling the flow ratio of fluid rates in the different microfluidic channels. Compared with the BM method, the MF method yielded a decrease in particle size and size range, an increase in CpG ODN loading efficiency, and a decrease in surface charge. After the particles were exposed to 293XL-hTLR9 cells, a water-soluble tetrazolium salt assay indicated that the BM and MF-processed nanoparticles had no significant toxicity and were biocompatible. An immunochemical assay indicated that both types of nanoparticles entered 293XL-hTLR9 cells and were located in the endolysosomes. The MF-processed nanoparticles showed much higher cellular uptake efficiency. After the particles were exposed to peripheral blood mononuclear cells, an enzyme-linked immunosorbent assay quantitatively indicated that both types of nanoparticles stimulated the production of interleukin-6 and the MF-processed nanoparticles showed a much stronger immunostimulatory response. These results indicate that the MF method can be used to synthesize nanoparticles with a controllable size and size range for enhancing the biological activity of DNA and other biomolecules.

Dynamic competitive adsorption of bone-related proteins on calcium phosphate ceramic particles with different phase composition and microstructure.

The biocompatibility and bioactivity of biomaterials used for hard tissue repair are closely related to their adsorption capacities for bone-related proteins. In the present study, three types of calcium phosphate (CaP) ceramic particles with different phase composition or microstructure were fabricated, and their protein adsorption abilities were investigated by a self-made device under the simulated dynamic physiological circumstance. The results of X-ray diffraction, field emission scanning electron microscopy, mercury penetration test, and nitrogen sorption test showed that the irregular hydroxyapatite (HA) ceramic particles obtained by conventional drying and sintering (named as HA-C) had fewer micropores and lower specific surface area (SSA) than did the spherical HA or biphasic calcium phosphate (BCP) ceramic particles made by spray drying and sintering (named as HA-S and BCP-S, respectively). The dynamic protein adsorption study proved that both the phase composition and microstructure of CaP ceramic particles affected their adsorption capacities for those bone-related proteins. The spherical HA-S and BCP-S particles with abundant micropores and high SSA showed higher adsorption of serum proteins, including fibronectin and vitronectin, than the irregular HA-C did. On the other hand, in spite of the relatively high concentration of bovine serum albumin (BSA) in the binary bone morphogenetic protein 2 (BMP-2)/BSA solution, BMP-2 adsorption on the three CaP ceramic particles increased with the increase in its initial concentration. Similarly, HA-S and BCP-S particles had a larger amount of the adsorbed BMP-2 per gram solid than HA-C did. Therefore, it could be believed that the difference of various CaP ceramics in the phase composition and microporous structure would affect their binding capacity for those bone-related proteins and thus lead to their difference in osteoinduction.