A Biomimetic Fibrous Composite Scaffold with Nanotopography-Regulated Mineralization for Bone Defect Repair.

The effective regeneration of large bone defects via bone tissue engineering is challenging due to the difficulty in creating an osteogenic microenvironment. Inspired by the fibrillar architecture of the natural extracellular matrix, we developed a nanoscale bioengineering strategy to produce bone fibril-like composite scaffolds with enhanced osteogenic capability. To activate the surface for biofunctionalization, self-adaptive ridge-like nanolamellae were constructed on poly(ε-caprolactone) (PCL) electrospinning scaffolds via surface-directed epitaxial crystallization. This unique nanotopography with a markedly increased specific surface area offered abundant nucleation sites for Ca2+ recruitment, leading to a 5-fold greater deposition weight of hydroxyapatite than that of the pristine PCL scaffold under stimulated physiological conditions. Bone marrow mesenchymal stem cells (BMSCs) cultured on bone fibril-like scaffolds exhibited enhanced adhesion, proliferation, and osteogenic differentiation in vitro. In a rat calvarial defect model, the bone fibril-like scaffold significantly accelerated bone regeneration, as evidenced by micro-CT, histological histological and immunofluorescence staining. This work provides the way for recapitulating the osteogenic microenvironment in tissue-engineered scaffolds for bone repair.

Abundance, characteristics, and removal of microplastics in the Cihu Lake-wetland microcosm system.

Sewage treatment plants (STPs) are significant routes through which microplastics (MPs) are released into the aquatic environment. Constructed wetland is an effective facility for deep treatment of tailwater. At present, research on the removal of MPs in the tailwater of STPs by multi-stage constructed wetlands is limited. This work investigated and analyzed the removal characteristics of MPs in the tailwater treatment system of Cihu wetland park in Huangshi, Hubei Province of China. The abundance/removal of MPs in the Cihu Lake-wetland microcosm system was investigated. The results showed that the multi-stage constructed wetlands achieved a total removal rate of 94.7% for MPs with 2.2 particles/L MPs in the effluent. The removal rates of MPs reached 89 and 37.5%, respectively, in the (horizontal/vertical) subsurface flow constructed wetland and surface flow constructed wetland. The abundance of MPs in receiving water of Cihu Lake substantially decreased due to the dilution of wetland effluents. This study partially bridged the knowledge gap hypothesis on the treatment of MPs in tailwater by multi-stage constructed wetlands.

Optimizing the Biocompatibility of PLLA Stent Materials: Strategy with Biomimetic Coating.

Background: Poly-L-lactic acid (PLLA) stents have broad application prospects in the treatment of cardiovascular diseases due to their excellent mechanical properties and biodegradability. However, foreign body reactions caused by stent implantation remain a bottleneck that limits the clinical application of PLLA stents. To solve this problem, the biocompatibility of PLLA stents must be urgently improved. Albumin, the most abundant inert protein in the blood, possesses the ability to modify the surface of biomaterials, mitigating foreign body reactions-a phenomenon described as the "stealth effect". In recent years, a strategy based on albumin camouflage has become a focal point in nanomedicine delivery and tissue engineering research. Therefore, albumin surface modification is anticipated to enhance the surface biological characteristics required for vascular stents. However, the therapeutic applicability of this modification has not been fully explored. Methods: Herein, a bionic albumin (PDA-BSA) coating was constructed on the surface of PLLA by a mussel-inspired surface modification technique using polydopamine (PDA) to enhance the immobilization of bovine serum albumin (BSA). Results: Surface characterization revealed that the PDA-BSA coating was successfully constructed on the surface of PLLA materials, significantly improving their hydrophilicity. Furthermore, in vivo and in vitro studies demonstrated that this PDA-BSA coating enhanced the anticoagulant properties and pro-endothelialization effects of the PLLA material surface while inhibiting the inflammatory response and neointimal hyperplasia at the implantation site. Conclusion: These findings suggest that the PDA-BSA coating provides a multifunctional biointerface for PLLA stent materials, markedly improving their biocompatibility. Further research into the diverse applications of this coating in vascular implants is warranted.

Highly selective electrochemical impedance spectroscopy-based graphene electrode for rapid detection of microplastics.

The widespread occurrence of microplastics (MPs) in aquatic ecosystems that caused environmental pollution has attracted worldwide attention. Herein, graphene electrode was initially derived from petroleum waste. Then the electrochemical responses of the electrode were evaluated using electrochemical impedance spectroscopy (EIS) toward polystyrene (PS) under various optimum conditions. For the quantitative measurement of PS concentration, principal component analysis (PCA) score images displayed that the data points offered the best discrimination of the classes, and singular value decomposition (SVD) showed that a good linearity was achieved between Z"u(1) and lgCps in the concentration range of 0.01-25 mg L-1. Especially for PS with particle size of 1 µm, the highest correlation coefficient (R2 = 0.9914) was obtained. The sensor ability to determine the polystyrene concentration in real samples was evaluated with the recovery of 98.4-113.3 % and reliable reproducibility (RSD < 9.72 %). For the quantitative measurement of the particle size of PS, SVD images exhibited that a linearity was obtained between Z'u(1)and lgDps in the particle size range of 0.08-20 µm. A good linearity with R2 = 0.9877 was obtained when the concentration was 1 mg L-1. The recovery was in the range of 100.8-118.0 % with the RSD < 6.38 %. Therefore, a novel method is established for the rapid detection of PS MPs.

Environmental risks of polymer materials from disposable face masks linked to the COVID-19 pandemic.

The indispensable role of plastic products in our daily life is highlighted by the COVID-19 pandemic again. Disposable face masks, made of polymer materials, as effective and cheap personal protective equipment (PPE), have been extensively used by the public to slow down the viral transmission. The repercussions of this have generated million tons of plastic waste being littered into the environment because of the improper disposal and mismanagement amid. And plastic waste can release microplastics (MPs) with the help of physical, chemical and biological processes, which is placing a huge MPs contamination burden on the ecosystem. In this work, the knowledge regarding to the combined effects of MPs and pollutants from the release of face masks and the impacts of wasted face masks and MPs on the environment (terrestrial and aquatic ecosystem) was systematically discussed. In view of these, some green technologies were put forward to reduce the amounts of discarded face masks in the environment, therefore minimizing MPs pollution at its source. Moreover, some recommendations for future research directions were proposed based on the remaining knowledge gaps. In a word, MPs pollution linked to face masks should be a focus worldwide.

Comprehensive understanding the impacts of dietary exposure to polyethylene microplastics on genetically improved farmed tilapia (Oreochromis niloticus): tracking from growth, microbiota, metabolism to gene expressions.

Microplastics (MPs) pollution has been recognized as a threat to sustainable fisheries due to the risks of MPs contamination in the process of feed production and susceptibility of fish to ingest MPs from the aquatic environment. In this study, we applied comprehensive approaches to investigate the impacts of polyethylene microplastics (PE-MPs) on juvenile genetically improved farmed tilapia (GIFT, Oreochromis niloticus) through 9-week dietary exposure based on growth performance, gut microbiota, liver metabolism, and gene expressions in brain and liver tissues. Dietary exposure to two kinds of PE-MPs with different median size (27 µm and 63 µm, respectively) concentration-dependently decreased weight gain (WG), while increased feed conversion ratio (FCR) and hepatosomatic index (HSI) of the tilapia. Dietary administration of PE-MPs also significantly reduced the activities of intestinal protease and amylase. PE-MPs particles of the larger size groups (63 µm) were mainly detected in feces, but those of the smaller ones (27 µm) tended to be accumulated in intestine. PE-MPs ingestion resulted in the alteration of gut microbiota composition, with Fusobacteria, Verrucomicrobia and Firmicutes as the overrepresented bacterial taxa. Metabolomic assays of liver samples in fish fed the diets containing 8 % of PE-MPs revealed the particle size-specific variations in composition of differential metabolites and metabolism pathways such as amino acid and glycerophospholipid metabolism. Gene expressions of brain and liver samples were analyzed by RNA-seq. Photoperiodism and circadian rhythm were the representative biological processes enriched for the differentially expressed genes (DEGs) identified from the brain. Citrate cycle (TCA cycle) was the most enriched pathway revealed by a joint transcriptomic and metabolic pathway analysis for the liver, followed by propanoate and pyruvate metabolism. Furthermore, an integration analysis of the gut microbiome and liver transcriptome data identified significant associations between several pathogenic bacteria taxa and immune pathways. Our findings demonstrated that the sizes and concentrations of PE-MPs are critically related to their toxic impacts on microbiota community, metabolism, gene expressions and thus fish growth.

Microplastic degradation methods and corresponding degradation mechanism: Research status and future perspectives.

Microplastics (MPs) pollution has become a global environmental concern because of their severe threat to biota. However, limited studies on the elimination of MPs pollution were reported. The conventional treatment methods were not suitable for MPs owing to their smaller size than plastic items. Hence many methods for MPs treatment have been examined. This review summarized the recently reported MPs degradation methods including AOPs (direct photodegradation, photocatalytic oxidation, and electrochemical oxidation) and biodegradation, corresponding degradation mechanism as well as current development state. The characteristics and limitations of each technique were discussed in detail. We found that all of them achieved almost satisfying degradation performance of MPs, but most of them exhibited that MPs can only be degraded partially into useful products or even CO2 and H2O under lab conditions. Given these, some recommendations for future research directions were proposed based on the knowledge gaps in these reported literatures. The aim of this review is to give a comprehensive introduction of several MPs degradation methods and acquaint the readers with the current research status of MPs degradation.

[Effect of renal artery embolization using 2-poly-hydroxyethyl-methacrylate as a liquid embolic agent: a study in rabbits].

OBJECTIVE: To assess the effect of a liquid embolic agent 2-poly-hydroxyethyl -methacrylate (2-P-HEMA) for renal artery embolization in rabbits. METHODS: The precipitation time of different concentrations (2%, 3.5%, 5%, 6.5%, 8% and 9.5%) of 2-P-HEMA dissolved in different solutions (ethanol, ethanol/iobitridol, and ethanol/Bi2O3) were determined in flowing water. The mixtures of 2-P-HEMA (2%, 5%, and 8%) with ethanol/ Bi2O3 were injected into the renal arteries of the rabbits, and the artery-embolizing effects were assessed using angiography at 2 and 12 weeks after the injection, with also macroscopic and microscopic examination of the embolized kidneys. RESULTS: The mixtures of 2-P-HEMA and ethanol formed flocculent precipitation a few seconds after injection into flowing water, and the precipitation time showed no significant variations with the concentration of 2-P-HEMA in the mixture. Low and moderate concentrations of 2-P-HEMA could pass through the microcatheter smoothly with little injection resistance, and resulted in complete occlusion of the renal arteries without adhesion to the microcatheter. Angiography at 2 and 12 weeks detected no recanalization of the occluded renal arteries. Macroscopically, the lumen of the renal arteries was found to be occluded by the embolic agents, and deep penetration of the embolic agents into the glomerular arteries was observed microscopically. The mixture containing high-concentration 2-P-HEMA was difficult to deliver through the microcatheter due to high injection resistance. CONCLUSION: 2-P-HEMA can be rapidly precipitated after injection into flowing water, and allows complete embolization of the renal arteries of rabbits at proper concentrations, suggesting its great potential as an endovascular liquid embolic agent.

[Biocompatibility of polyurethane-BaFe(12)O(19 ) composite microsphere as a new endovascular embolization material].

OBJECTIVE: To investigate the biocompatibility of polyurethane-BaFe(12)O(19) magnetic composite microsphere as a new endovascular embolization material. METHODS: The biocompatibility of BaFe(12)O(19) particle was evaluated in vitro using Ames test, cell toxicity test, acute and subacute systemic toxicity test, hemolysis test, bleeding time and clotting time test and blood clotting function assay. RESULTS: Ames test showed that the MR values of this particle leaching solution were all less than 2 without mutagenicity. Cell toxicity test showed that leaching solution at different concentrations had grade I toxicity on L929 cells. Acute and subacute systemic toxicity test showed that the experimental animals had good general condition without obvious pathological abnormality. The hemolysis rate of experimental group was 2.43%, which met the ISO standard (no more than 5%). The bleeding time and clotting time in mice were comparable between the experimental group and control group (P>0.05). There were no significant differences in blood clotting function between experimental group and control group (P>0.05). CONCLUSION: The material has no obvious toxicity or mutagenicity, and does not cause hemolysis or hemopexis or affect the bleeding time and clotting time. Polyurethane-BaFe(12)O( 19) particle possesses satisfactory biocompatibility.