Layer-by-Layer Assembly of Multifunctional NR/MXene/CNTs Composite Films with Exceptional Electromagnetic Interference Shielding Performances and Excellent Mechanical Properties.

With the rapid advance of electronics, the light, flexible, and multifunctional composite films with high electromagnetic interference (EMI) shielding effectiveness and excellent thermal management are highly desirable for next-generation portable and wearable electronic devices. Herein, a series of flexible and ultrathin natural rubber/MXene/carbon nanotubes (NR/MXene/CNTs) composite films with sandwich structure are constructed layer by layer through a facile vacuum-assisted filtration method for EMI shielding and Joule heating application. The fabricated NR/MXene/CNTs-50 composite film, with NR/MXene as inner layer and NR/CNTs as out layers, not only has high EMI shielding efficiency, but also has excellent comprehensive mechanical properties at the thickness of only 200 µm. In addition, the superior environmental durability, high electrothermal conversion efficiency, hydrophobicity, and fine performance stability after periodic cyclic bending make the film possess more value in practical application.

Chemical stability and osteogenic activity of plasma-sprayed boron-modified calcium silicate-based coatings.

In recent years, CaSiO3 bio-ceramic coatings have attracted great attention because of their good bioactivity. However, their high degradation rates in physiological environment restrict their practical applications. In this work, boron-modified CaSiO3 ceramic (Ca11Si4B2O22, B-CS) coating was developed on Ti substrates by plasma-spraying technique attempting to obtain enhanced chemical stability and osteogenic activity. The B-CS coating possessed significantly increased chemical stability due to the introduction of boron and consequently the modified crystal structure, while maintaining good bioactivity. Scanning electron microscope and immunofluorescence studies showed that better cellular adhesion and extinctive filopodia-like processes were observed on the B-CS coating. Compared with the pure CaSiO3 (CS) coating, the B-CS coating promoted MC3T3-E1 cells attachment and proliferation. In addition, enhanced collagen I (COL-I) secretion, alkaline phosphatase activity, and extracellular matrix mineralization levels were detected from the B-CS coating. According to RT-PCR results, notable up-regulation expressions of mineralized tissue-related genes, such as runt-related transcription factor 2 (Runx2), bone sialoprotein and osteocalcin, and bone morphogenetic protein 7 (BMP-7) were observed on the B-CS coating compared with the CS coating. The above results suggested that Ca11Si4B2O22 coatings possess excellent osteogenic activity and might be a promising candidate for orthopedic applications.

Promoting tissue repair using deferoxamine nanoparticles loaded biomimetic gelatin/HA composite hydrogel.

To effectively address underlying issues and enhance the healing process of hard-to-treat soft tissue defects, innovative therapeutic approaches are required. One promising strategy involves the incorporation of bioactive substances into biodegradable scaffolds to facilitate synergistic tissue regeneration, particularly in vascular regeneration. In this study, we introduce a composite hydrogel design that mimics the extracellular matrix by covalently combining gelatin and hyaluronic acid (HA), with the encapsulation of deferoxamine nanoparticles (DFO NPs) for potential tissue regeneration applications. Crosslinked hydrogels were fabricated by controlling the ratio of HA in the gelatin-based hydrogels, resulting in improved mechanical properties, enhanced degradation ability, and optimised porosity, compared with hydrogel formed by gelatin alone. The DFO NPs, synthesized using a double emulsion method with poly (D,L-lactide-co-glycolide acid), exhibited a sustained release of DFO over 12 d. Encapsulating the DFO NPs in the hydrogel enabled controlled release over 15 d. The DFO NPs, composite hydrogel, and the DFO NPs loaded hydrogel exhibited excellent cytocompatibility and promoted cell proliferationin vitro. Subcutaneous implantation of the composite hydrogel and the DFO NPs loaded hydrogel demonstrated biodegradability, tissue integration, and no obvious adverse effects, evidenced by histological analysis. Furthermore, the DFO NPs loaded composite hydrogel exhibited accelerated wound closure and promoted neovascularisation and granular formation when tested in an excisional skin wound model in mice. These findings highlight the potential of our composite hydrogel system for promoting the faster healing of diabetes-induced skin wounds and oral lesions through its ability to modulate tissue regeneration processes.

High transparency, degradable and UV-protective poly(lactic acid) composites based on elongational rheology and chain extender assisted melt blending.

Conventional polylactic acid (PLA) melt plasticization and toughening processes are typically achieved at the expense of PLA strength and transparency, which is clearly detrimental to its application in areas such as smart home and food packaging. Herein, an ultraviolet (UV)-protective PLA-based composite (PP6) that simultaneously achieves high strength (63.3 MPa), high plasticity (125.3 %), and enhanced toughness (4.3 kJ/m2) by adding only 6 wt% poly(3-hydroxybutyrate-4-hydroxybutyrate) (P34HB) under the assist of 1 wt% chain extender was prepared using melt blending technique. Benefiting from the cross-linking effect of the chain extender and the elongational flow during processing, the compatibility between P34HB and PLA, as well as the thermomechanical properties, heat resistance, and biodegradable properties of the composite, have been enhanced significantly. The extremely low melt enthalpy (1.9 J/g) and the low crystallinity PLA phase contribute to an appropriate transparency (78.3 % of glass in 400-1100 nm). The prepared composites display mid- and long-wave UV-protective performance, which is superior to conventional industrial glasses. Through the superior elongational rheology technology, PP6 maintains favorable overall properties even after six thermomechanical cycles. Collectively, the composite fabricated in this work is an attractive candidate for future applications such as smart windows, food packaging, agricultural films, and biomedical applications.

Excellent removal performance of 4,4'-biphenyldicarboxaldehyde m-phenylenediamine Schiff base magnetic polymer towards phenanthrene and 9-phenanthrol: Experimental, modeling and DFT calculations studies.

Phenanthrene (PTH) and 9-phenanthrol (9-PTH) exhibited severe health threats and ecological hazards, for this reason, exploring a high-efficient removing strategy for PTH and 9-PTH could be considered of great urgency. Herein the 4,4'-biphenyldicarboxaldehyde m-phenylenediamine Schiff base magnetic polymer (magnetic BIPH-PHEN) was successfully fabricated via Schiff base polycondensation reaction and the subsequently one-pot embedded method. The mutual aromatic nucleus of BIPH-PHEN polymer and PTH/9-PTH could form π-π interaction, thus improving the capture ability, the embedded Fe3O4 nanoparticles provided the possibility for rapid separation. The physical and chemical properties of the magnetic BIPH-PHEN were systematically characterized. The removal rate of magnetic BIPH-PHEN towards PTH and 9-PTH was 85.65 % and 98.52 %, respectively (PTH or 9-PTH: 8 mg/L; Adsorbent: 0.2 g/L). The DFT calculations including energy calculations and electrostatic potential distribution analyzed the different bonding modes and proposed the most possible bonding modes in the adsorbent/adsorbate system. Moreover, the LUMO and HOMO orbits combined with energy gaps analysis proved the existence and specific types of the π-π interaction. The monolayer adsorption occurred on the homogeneous magnetic BIPH-PHEN surface, simultaneously the chemisorption was dominant. This work not only proposed new sights on assembling magnetic Schiff base polymer for removing polycyclic aromatic hydrocarbons, but also provided a deeper understanding of intramolecular interactions.

Electrostatic Adsorption and Cytotoxity of Cellulose Nanocrystals with Loading Trace Metal Elements.

Cellulose nanocrystal (CNC) is the rod-like nano-object derived from natural cellulose with the features of low toxicity and good biocompatibility, widely used as the functional additive and nanomaterial in the biomedicine. Two negatively charged cellulose nanocrystals, CNC and TO-CNC (surface oxidized CNC), are prepared by the sulfuric acid hydrolysis and further surface oxidization. Based on electrostatic adsorption, five trace metal elements (TMEs) including cobalt (Co), nickel (Ni), manganese (Mn), lead (Pb), and cadmium (Cd) are loaded on the surface of two nanocrystals as the biocompatible nanocarriers. The adsorbed contents of TMEs on two nanocrystals are affected by their surface charge densities and the complexes can keep stability under three varied pH conditions. Two cell lines, viz. human nasopharyngeal cancer cell and normal human bronchial epithelial cell, are selected for the investigation of cytotoxity of these TME-loaded nanocrystals at the concentration range of 0.1-500 µg mL-1 . The high concentrations of TME-loaded nanocrystals will induce the inhibition of cells activity and proliferation, particularly for Pb2+ - and Cd2+ -loaded nanocrystals. The cancer cell generally exhibits more sensitivity of cytotoxity to these metal elements than the normal cell, which may be potentially used as the activity inhibitor for specific cells in the future study.

Development and mechanical properties of straw-polyethylene imitation rattan material with wheat straw fibre.

A new type of imitation rattan was developed via a two-step method that used modified wheat straw as the raw materials and low-density polyethylene to make up wood plastic composite. Post-modification, a graft condensation reaction was carried out between silane as a coupling agent and wheat straw powder, which improved the thermal stability of the composite. A high level of contact and interaction at the fibre-matrix interface was observed. The optimum formula for the first step was 80% wheat straw powder, 4% silane coupling agent, and 16% calcium carbonate, with a modification temperature of 120 °C sustained for 10 min. For the second step, the mechanical properties had been greatly improved with the addition of modified wheat straw fibre and maleic anhydride grafted polypropylene (MA-g-PP). The use of 10% modified straw fibre and 5% MA-g-PP exhibited the highest tensile strength (8.75 MPa) and highest melt index (2.86 g/10 min). In particular, the MA-g-PP had an extremely advantage to the elastic modulus of wheat straw imitation rattan. The elastic modulus reached the maximum value of 2761.70 MPa at the amount of MA-g-PP added reached 5%. Our present study indicated the innovation of a new type of imitation rattan, which provides a new choice for utilizing wheat straw as industrial raw material, and other agricultural by-products containing liginocellulose could be used in a similar way.

Effects of a helium cold atmospheric plasma on bonding to artificial caries-affected dentin.

This study investigated the effects of a helium cold atmospheric plasma (CAP) on the bonding performance and surface modification of the caries-affected dentin (CAD). Artificial CAD was created by pH-cycling. The microtensile bond of CAD were examined before and after CAP treatments at 24 h and after 2-year aging. The effects of surface modification were studied with contact-angle measurement, scanning electron microscopy and X-ray photoemission spectroscopy. Thirty-second CAP treatment increased the immediate bond strength of CAD to a level that was statistically the same as sound dentin, and slowed the aging process of the bonding as well. The CAP treatment induced modified CAD surface with increased wettability, cleaner appearance, and increased percentage of the mineral-associated elements and oxygen. This research demonstrated that the helium CAP jet treatments of 30 s and 45 s improved the bond strength of the artificial CAD, and was considerably effective in its surface modification.

Cellulosic nanofibers filled poly(ß-hydroxybutyrate): Relations between viscoelasticity of composites and aspect ratios of nanofibers.

Dispersion states are vital for fibrous nanocelluloses to be used as reinforcements for polymers, which is highly dependent on geometry of nanocelluloses. Three types of nanocelluloses with various fiber aspect ratios were used to prepare target composite samples with poly(ß-hydroxybutyrate) in this work. Viscoelasticity/elastoplasticity were used as probes to detect the flexibility-morphology relations of nanocelluloses in polymer. Cellulose nanocrystals (aspect ratio = 8) were rigid in polymer, retaining their rod-like shape, whereas bacterial celluloses (aspect ratio = 600) fully flexible, forming closely networked structure, and cellulose nanofibers (aspect ratio = 70) semi-flexible, dispersing as loosely flocculated clusters. Owing to these differences, the viscoelastic flow and elastoplastic deformation of three kinds of composites differed from one another. The strain-scaling and hysteresis work-scaling behaviors were then used to establish relaxation scale-structure correlations of target samples. This work provides interesting information around regulating the dispersion of nanocelluloses in polymer composites by tailoring aspect ratios of nanocelluloses.

Boron-incorporated micro/nano-topographical calcium silicate coating dictates osteo/angio-genesis and inflammatory response toward enhanced osseointegration.

Orthopedic implant coatings with optimal surface features to achieve favorable osteo/angio-genesis and inflammatory response would be of great importance. However, to date, few coatings are capable of fully satisfying these requirements. In this work, to take advantage of the structural complexity of micro/nano-topography and benefits of biological trace elements, two types of boron-containing nanostructures (nanoflakes and nanolamellars) were introduced onto plasma-sprayed calcium silicate (F-BCS and L-BCS) coatings via hydrothermal treatment. The C-CS coating using deionized water as hydrothermal medium served as control. Boron-incorporated CS coating stimulated osteoblastic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Specifically, the combination of ß1 integrin-vinculin-mediated cell spreading and activation of bone morphogenetic protein signaling pathway acted synergistically to cause significant upregulation of runt-related transcription factor 2 (RUNX2) protein and Runx2 gene expression in BMSCs on the F-BCS coating surface, which induced the transcription of downstream osteogenic differentiation marker genes. F-BCS coating allowed specific boron ion release, which favored angiogenesis as evidenced by the enhanced migration and tube formation of human umbilical vein endothelial cells in the coating extract. Boron-incorporated coatings significantly suppressed the expression of toll-like receptor adaptor genes in RAW264.7 macrophages and subsequently the degradation of nuclear factor-κB inhibitor α, accompanied by the inactivation of the downstream pro-inflammatory genes. In vivo experiments confirmed that F-BCS-coated Ti implant possessed enhanced osseointegration compared with L-BCS- and C-CS-coated implants. These data highlighted the synergistic effect of specific nanotopography and boron release from orthopedic implant coating on improvement of osseointegration.

A soft anti-virulence liposome realizing the explosive release of antibiotics at an infectious site to improve antimicrobial therapy.

Pore-forming toxins (PFTs), the most common virulence proteins, are promising therapeutic keys in bacterial infections. CAL02, consisting of sphingomyelin (Sm) and containing a maximum ratio of cholesterol (Ch), has been applied to sequester PFTs. However, Sm, a saturated phospholipid, leads to structural rigidity of the liposome, which does not benefit PFT combination. Therefore, in order to decrease the membrane rigidity and improve the fluidity of liposomes, we have introduced an unsaturated phospholipid, phosphatidylcholine (Pc), to the saturated Sm. In this report, a soft nanoliposome (called CSPL), composed of Ch, Sm and Pc, was artificially prepared. In order to further improve its antibacterial effect, vancomycin (Van) was loaded into the hydrophilic core of CSPL, where Van can be released radically at the infectious site through transmembrane pores formed by the PFTs in CSPL. This soft Van@CSPL nanoliposome with detoxification/drug release was able to inhibit the possibility of antibiotic resistance and could play a better role in treating severe invasive infections in mice.

Designing a nanoparticle-containing polymeric substrate for detecting cancer cells by computer simulations.

Efficient and accurate detection of cancer cells (from normal cells) is of great importance in cancer diagnosis and prognosis. In this work, we design a new type of polymeric substrate containing nanoparticles for detecting cancers by the dissipative particle dynamics (DPD) simulation. It is found that the cancer cells and the normal cells can be indeed distinguished since the uptake number of nanoparticles from the substrate is different. The competition between the nanoparticle-cell specific interaction and nanoparticle-polymer non-specific interaction is the main factor for different uptake behaviors. Moreover, the dynamics of the nanoparticle diffusion in the polymer layer also plays an important role in the detection. To improve the detection accuracy, we further investigate the effect of the polymer type and density as well as the ligand type on the detection, and find that there may exist an optimal parameter to maximize the difference between cancer cells and normal cells. The present study may provide useful insights into the design of functionalized substrate-based nanodevices in biomedicine.

The enhanced angiogenic responses to ionic dissolution products from a boron-incorporated calcium silicate coating.

Early vascularization is crucial for osteogenic repair of bone defects and plays an essential role in the fate of implanted biomaterials. Thus, there is a growing interest in the use of biomaterials to release inorganic ions that are capable of stimulating angiogenesis. Since it has been established that boron (B) may play roles in angiogenesis, the aim of our study was to investigate the in vitro angiogenic effects of the ionic dissolution products from the B-incorporated calcium silicate (Ca11Si4B2O22, B-CS) coating. The results showed that ionic products of B-CS coating extract obviously stimulated the proliferation and migration of human umbilical vein endothelial cells (HUVECs) as well as the in vitro tubule formation when compared with those of CS coating extract. In addition, the gene expression levels of pro-angiogenic growth factors (VEGF, bFGF, ANG1) and receptors (VEGFR-2, bFGFR) were significantly upregulated when stimulated with the B-CS coating extract. Moreover, VEGF and VEGFR-2 protein synthesis, eNOS, and Akt phosphorylation, as well as NO synthesized by HUVECs were increased by the B-CS coating extract. Hence, the B-CS coating offers a potential solution to enhance bone vascularization essential for successful osseointegration of orthopedic implants.

Improved osteogenesis of boron incorporated calcium silicate coatings via immunomodulatory effects.

Osteoimmunology has revealed the importance of a favorable immune response for successful biomaterial-mediated osteogenesis. Boron-incorporated calcium silicate (Ca11 Si4 B2 O22 , B-CS) coating has been reported as a potential candidate for improving osteogenesis in orthopedic applications in vitro. However, relatively little is known about its effects on the immune response and subsequent osteogenesis. In this work, the immunomodulatory properties of the B-CS coating and its specific mechanism of action were explored. We found that the B-CS coating decreased M1 polarization and converted macrophages to the M2 phenotype via restraining the toll-like receptor signaling pathway, thus inducing a significant reduction in pro-inflammatory cytokines and an increase in anti-inflammatory cytokines. Moreover, the B-CS coating inhibited osteoclastogenesis and osteoclastic activities by downregulating osteoclastogenic genes and inhibiting the RANKL/RANK system. BMP2 and VEGF were also significantly upregulated by macrophages and bone mesenchymal stem cells, leading to activation of the BMP2 signaling pathway and subsequent upregulation of osteogenesis-associated genes, finally promoting osteogenic differentiation. These findings show that the B-CS coating could be a promising coating material for hip and knee implants. Furthermore, incorporation of the element boron into bioceramic coatings could be a good strategy in the design of bone biomaterials with beneficial immune responses. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 12-24, 2019.

[Study on the effect of hydraulic delivery vertebroplasty on vertebral morphology and bone cement diffusion].

OBJECTIVE: To evaluate the effect of different bone cement injection methods during percutaneous vertebroplasty(PVP) on vertebral morphology and cement diffusion. METHODS: The clinical data of 52 patients with single-segment osteoporotic vertebral compression fracture treated from January 2016 to December 2017 were retrospectively analyzed. The patients were divided into hydraumatic group (28 cases) and pusher group (24 cases) according to bone cement injection method during PVP. By comparing visual analogue scale(VAS), height of anterior vertebral body, compression ratio, kyphosis angle before and after operation and analyzing filling ratio of bone cement in the first 1/3, median line and back 1/3 of the vertebral body in lateral X-rays and the conditions of bone cement diffusion in AP X-rays were to evaluate the effect of different bone cement injection methods on vertebral morphology and cement diffusion. RESULTS: Postoperative VAS was obviously improved in all patients and hydraumatic group was better than pusher group(P<0.05). Postoperative height of anterior vertebral body, compression ratio and kyphosis angle obviously restored in all patients while there was no significant difference between two groups(P>0.05). There was no significant difference in filling ratio of bone cement in the first 1/3 and median line of the vertebral body by lateral X-ray films between two groups(P>0.05), but in the back 1/3 of the vertebral body filling ratio of bone cement in hydraumatic group was better than in pusher group(P<0.05). The distribution of bone cement from AP X-ray films were more significant in hydraumatic group(P<0.05). CONCLUSIONS: Hydraulic delivery vertebroplasty (HDVP) has better clinical efficacy and it can guarantee sufficient distribution of bone cement into the fractured vertebra and preferably restore the morphology of vertebral body, which is worthy of clinical application.

Effect of ultrasound on adsorption of Geniposide on polymeric resin.

The effects of pulse ultrasound with different pulse parameter on the adsorption isotherm and kinetics of Geniposide on Resin 1300 were studied. And the mass transfer model describing the adsorption process was constructed. Amount of Geniposide adsorbed on Resin 1300 in the presence of ultrasound is lower than that in the absence of ultrasound. At our experimental conditions, the adsorption equilibrium constant decreases with increasing ultrasonic intensity and pulse duty ratio, and with decreasing pulse period. In addition, pulse ultrasound can enhance both liquid film diffusion and intraparticle diffusion, and the intensification of liquid film diffusion with pulse ultrasound is stronger than that of intraparticle diffusion. The intraparticle diffusion coefficient D(e)/R2 increases with increasing ultrasonic intensity and pulse duty ratio, and with decreasing pulse period.

Effect of elevated total cholesterol level and hypertension on the risk of fatal cardiovascular disease: a cohort study of Chinese steelworkers.

BACKGROUND: Increased blood pressure and elevated total cholesterol (TC) level are the two most important modifiable risk factors of cardiovascular disease (CVD) in the world. Hypertension and hypercholesterolemia co-exist more often than would be expected and whether there is a synergistic impact on fatal CVD between elevated TC and hypertension need to be further examined in Chinese population. METHODS: We conducted a cohort study which recruited 5092 Chinese male steelworkers aged 18 - 74 years in 1974 - 1980 and followed up for an average of 20.84 years. Totally 302 fatal CVD events were documented by the year of 2001. Cox proportional hazards regression models were undertaken to adjust for baseline variables with fatal CVD events as the outcome variable. Additive interaction model was used to evaluate the interaction between elevated TC and hypertension. RESULTS: Hypercholesterolemia and hypertension were significantly associated with an increased hazard ratio (HR) of fatal CVD (1.67 (95%CI 1.18 - 2.38) and 2.91 (95%CI 2.23 - 3.80) respectively. Compared to participants with normotension and TC < 240 mg/dl, the HRs were 1.11 (95%CI 0.56 - 2.21), 2.74 (95%CI 2.07 - 3.64) for hypercholesterolemia and hypertension respectively, and 5.51 (95%CI 3.58 - 8.46) for participants with both risk factors. There was an additive interaction with a 2.65 (95%CI 0.45 - 4.85) relative excess risk (RERI) between hypercholesterolemia and hypertension on CVD. CONCLUSION: We found that the risk of fatal CVD was significantly associated with an additive interaction due to hypercholesterolemia and hypertension besides a conventional main effect derived from either of them, which highlights that the prevention and treatment of both risk factors might improve the individual risk profile thus reduce the CVD mortality.