Nanoplastic Exposure at Environmental Concentrations Disrupts Hepatic Lipid Metabolism through Oxidative Stress Induction and Endoplasmic Reticulum Homeostasis Perturbation.

In this study, we investigated the mechanism underlying the perturbation of hepatic lipid metabolism in response to micro/nanoplastic (MP/NP) exposure at environmentally relevant concentrations. Polystyrene (PS) MPs/NPs with different sizes (0.1, 0.5, and 5.0 µm) were studied for their effects on the homeostasis and function of Nile tilapia (Oreochromis niloticus) liver. Results showed that PS MPs/NPs were readily internalized and accumulated in various internal organs/tissues, especially in fish liver and muscle. Smaller-sized NPs caused more severe toxicity than larger MPs, including hepatic steatosis, inflammatory response, and disturbed liver function. Mechanistically, PS NPs with a particle size of 100 nm perturbed protein homeostasis in the endoplasmic reticulum (ER) by inhibiting the expression of chaperone proteins and genes involved in ER-associated degradation. This led to the activation of the PERK-eIF2α pathway, which caused dysfunction of hepatic lipid metabolism. Induction of oxidative stress and activation of the Nrf2/Keap1 pathway were also involved in the PS NP-induced hepatic lipid accumulation. These findings highlight the potential adverse effects of environmental MPs/NPs on aquatic organisms, raising concerns about their ecotoxicity and food safety.

Immobilization of type-I collagen and basic fibroblast growth factor (bFGF) onto poly (HEMA-co-MMA) hydrogel surface and its cytotoxicity study.

Type-I collagen and bFGF were immobilized onto the surface of poly (HEMA-co-MMA) hydrogel by grafting and coating methods to improve its cytotoxicity. The multi-layered structure of the biocompatible layer was confirmed by FTIR, AFM and static water contact angles. The layers were stable in body-like environment (pH 7.4). Human skin fibroblast cells (HSFC) were seeded onto Col/bFGF-poly (HEMA-co-MMA), Col-poly (HEMA-co-MMA) and poly (HEMA-co-MMA) films for 1, 3 and 5 day. MTT assay was performed to evaluate the extraction toxicity of the materials. Results showed that the cell attachment, proliferation and differentiation on Col/bFGF-poly (HEMA-co-MMA) film were higher than those of the control group, which indicated the improvement of cell-material interaction. The extraction toxicity of the modified materials was also lower than that of the unmodified group. The protein and bFGF immobilized poly (HEMA-co-MMA) hydrogel might hold great promise to be a biocompatible material.

[Effect of extraction on condylar process position and upper airway in 12-14 years old females with skeletal Class â ¡ high angle].

PURPOSE: To investigate the effect of extraction on condylar process position and upper airway in 12-14 years old females with skeletal ClassⅡhigh angle. METHODS: Twenty seven 12-14 years old females with skeletal ClassⅡhigh angle (experimental group) and 30 physical examinees without malocclusion (control group) in Stomatology Hospital Affiliated to Southwest Medical University from January 2016 and June 2017 were enrolled. All patients received cone-beam CT (CBCT) examinations. Mimics 20.0 was used to process the data. The changes of the condylar process position and upper airway were recorded. The data were analyzed using SPSS 20.0 software package. RESULTS: Before treatment, patients in the experimental group had higher Sa as well as lower Sp than those of the control group (P<0.05), but with no difference in Su between 2 groups before treatment (P>0.05). After treatment, Sa was decreased in the experimental group (P<0.05), but no change was observed in Sp and Su(P>0.05). After treatment, the joint space indexes were increased in the experimental group (P<0.05). Before treatment, the V total, V tongue, V mouth, and SMIN in the experimental group were significantly lower than those of the control group (P<0.05). Before treatment, V nose, V palate, V larynx, APTE, APHP and APSP in the experimental group showed no difference with those of the control group (P>0.05). V nose, V larynx, APHP and APTE showed no difference before and after treatment within the experimental group (P>0.05). After treatment, the V total, V tongue, V palate, V mouth, SMIN and APSP in the experimental group were significantly increased (P<0.05). CONCLUSIONS: Extraction treatment can widen the airway, suggesting that there may be a certain correlation between the changes of condyle position and upper airway volume.

Dual responsive zein hydrogel membrane with selective protein adsorption and sustained release property.

Drug-loaded hydrogels have been paid increasing attentions in biomedical fields. As a sort of natural plant protein, zein generally cannot form hydrogel with high water retention because of its predominant hydrophobicity, which will limit its application as biomaterial. In this paper, zein electrospun fibrous membranes (ZEFM) are fabricated through a chemical modification of zein using citric acid and acetic anhydride. The resulting ZEFM can be totally soluble in neutral phosphate buffer solution. After being crosslinked by sodium hexametaphosphate, the ZEFM can form a hydrogel membrane and displays stimuli-responsive behavior towards pH and ionic strength. The hydrogel membrane exhibits better protein adsorption, selectivity and sustained release profile for positively-charged proteins such as cytochrome C, compared with those unmodified ones, and also shows fast biodegradation behavior and qualified cytotoxicity, which all make it favourable for biomedical use.

Coaxial electrospun zein nanofibrous membrane for sustained release.

Zein nanofibrous membranes for sustained release have been prepared by coaxial electrospinning. Core-sheath structure has been successfully fabricated using zein as both the core and sheath component. Impact of solvent and solution concentration on the morphology of the resulting fibers was investigated. Allyltriphenylphosphonium bromide was used as a model drug to test the sustained release effect. The sustained release profile and the antimicrobial activity of the resulting membranes were investigated and compared with that of the single fluid electrospinning of zein/drug blended membrane. The ratio of the inner and outer feeding rates was found to influence the encapsulation of drugs, and in turn affect the sustained release effect of the resulting membranes. The coaxial electrospinning membrane can remarkably suppress the initial burst release of drugs by giving a releasing amount of 15% in the first 1 h when the inner/outer ratio was larger than 1:2. This drug-loaded zein membrane with preferable sustained release effect can be applied in many fields such as wound healing and packaging sector.

Recent progress in protein imprinting technology.

Protein-imprinted materials have drawn great attention nowadays for their promising application in biotechnology and biomedical engineering. Despite the success of molecular imprinting technique of small molecules in chemical and biomedical industry, imprinting of large molecules especially biomacromolecules remains a challenge. In recent years, however, a number of significant protein imprints have been reported, some of which may have great potential in applications for chromatography and biosensors. In this article, we review current development and patents on various protein imprinting approaches and materials developed recently. The advantages and disadvantages of the methods are discussed, and the trends are also highlighted.

Protein recognition via molecularly imprinted agarose gel membrane.

Agarose gel membranes (AGMs), which could selectively recognize bovine serum albumin (BSA) and bovine hemoglobin (Hb), were prepared by molecular imprinting technique under moderate preparation conditions. Four imprinting processes, including gelation without any treatment, second gel-melting, and two glutaraldehyde crosslinking processes of fumigation or direct addition of the crosslinking agent, were developed to investigate the protein-recognition behavior of the AGMs. Results showed that the preparation processes affected the adsorption capacity and selectivity of the imprinted AGMs. Both BSA- and Hb-imprinted AGMs exhibited higher adsorption abilities for the targeted proteins (3.77-5.72 times for BSA, 1.31-2.18 times for Hb) than the nonimprinted ones. And the selectivity of BSA-imprinted AGMs for BSA molecules (the selective factor K = 3.29-4.90) was higher than that of Hb-imprinted AGMs for Hb (K = 0.32-1.17). The optimal adsorption capacity of BSA- and Hb-imprinted AGMs was 25.90 and 117.45 mg/g, respectively, when the membrane was crosslinked by glutaraldehyde with a fumigation process; the optimal selectivity of BSA- and Hb-imprinted AGMs was 4.91 when the membrane was prepared by second gel-melting process, and 0.76 when the membrane was prepared without any treatment. These findings demonstrate that the molecularly imprinted AGMs are hopeful to be used in specific protein analysis.

Agar/collagen membrane as skin dressing for wounds.

Agar, a highly hydrophilic polymer, has a special gel property and favorable biocompatibility, but moderate intension strength in an aqueous condition and a low degradation rate. In order to tailor both properties of mechanical intension and degradation, type I collagen was composited with agar in a certain ratio by drying at 50 degrees C or by a freeze-dry process. Glutaraldehyde was chosen as a crosslinking agent, and the most favorable condition for crosslinking was that the weight ratio of agar to glutaraldehyde was 66.7 and the pH value about 5. Dynamic mechanical analysis results showed that the single agar membrane had a modulus value between 640 MPa and 1064 MPa, but it was between 340 MPa and 819 MPa after being composited with type I collagen. It was discovered under an optical microscope that the pores were interconnected in the composite scaffolds instead of the honeycomb-like pores in a single type I collagen scaffold or the laminated gaps in a single agar scaffold. The results of an acute toxicity test disclosed that the composites were not toxic to mice although the composites were crosslinked with a certain concentration of glutaraldehyde. The results of gross examinations showed that when the composite membranes or scaffolds were applied to a repair rabbit skin lesion, the composites had a good repair effect without infection, liquid exudation or visible scar in the lesion covered with them. But in the control group, the autologous skin showed necrosis and there were a lot of scar tissues in the lesion site. H&E staining results showed that the repair tissue was similar to the normal one and very few scaffolds or membranes were left without degradation after 2 or 3 weeks. In conclusion, it is proved that type I collagen increases the toughness of the agar membrane, and the agar/type I collagen composites are promising biomaterials as wound dressings for healing burns or ulcers.

Agarose/collagen composite scaffold as an anti-adhesive sheet.

The objective of this work was to find a new material or new technology to achieve satisfactory post-surgery anti-adhesion. An agarose/collagen composite sheet was developed to prevent mesenchymal cells and extracellular matrix from adhering on the lesion site, in which agarose formed uniaxial channels that hindered penetration and intercommunication of cells among pores in a 3D sheet. The tensile strength of the composite sheet in the designed ratio of agarose and collagen was over 17 MPa in dry and 2 MPa in wet, which was suitable and convenient to be sewed or operated on in other general surgery. In vitro and in vivo experimental results showed that fibroblasts, adult-derived adipose stem cells, could not penetrate into the sheet and formed a 3D tissue, and agarose did not degrade in three weeks. The demonstration that this sheet can prevent mesenchymal cells from penetrating in 3D and forming a tissue warrants the agarose-based composite for an anti-adhesive membrane.