Three-Dimensional Cross-Linking Network Coating for the Flame Retardant of Bio-Based Polyamide 56 Fabric by Weak Bonds.

Weak bonds usually make macromolecules stronger; therefore, they are often used to enhance the mechanical strength of polymers. Not enough studies have been reported on the use of weak bonds in flame retardants. A water-soluble polyelectrolyte complex composed of polyethyleneimine (PEI), sodium tripolyphosphate (STPP) and melamine (MEL) was designed and utilized to treat bio-based polyamide 56 (PA56) by a simple three-step process. It was found that weak bonds cross-linked the three compounds to a 3D network structure with MEL on the surface of the coating under mild conditions. The thermal stability and flame retardancy of PA56 fabrics were improved by the controlled coating without losing their mechanical properties. After washing 50 times, PA56 still kept good flame retardancy. The cross-linking network structure of the flame retardant enhanced both the thermal stability and durability of the fabric. STPP acted as a catalyst for the breakage of the PA56 molecular chain, PEI facilitated the char formation and MEL released non-combustible gases. The synergistic effect of all compounds was exploited by using weak bonds. This simple method of developing structures with 3D cross-linking using weak bonds provides a new strategy for the preparation of low-cost and environmentally friendly flame retardants.

Modified Stabilization Test to Diagnose Chronic Syndesmotic Injuries Based on Posture Control.

BACKGROUND: To propose and validate a modified noninvasive method for the diagnosis of chronic syndesmotic injuries. METHODS: This study included 16 patients with chronic ankle instability. Herein, we propose the Modified Stabilization Test, a new measurement for use in the diagnosis of chronic syndesmotic injury, as determined by wearing a 60-kPa pneumatic brace. The test combines the center of pressure and sensory organization test to measure postural control. For comparison, we also measured the tibiofibular clear space, tibiofibular overlap, and medial clear space using anteroposterior radiograph; a line marked horizontally above the tibial plaque using computed tomography (CT) to measure the syndesmotic gap and fibular rotation angle; and magnetic resonance imaging (MRI) scans to determine the presence of the λ sign. The distance of syndesmosis was confirmed in 16 individuals through arthroscopy, and the results of the examination were used to determine the diagnostic efficacy of each index. RESULTS: Receiver operating characteristic curve analysis revealed that the optimal cut-off value, sensitivity, and specificity of the Modified Stabilization Test for the diagnosis of chronic syndesmotic injuries were 0.80, 100%, and 87.5%, respectively. The area under the curve (AUC) of the Modified Stabilization Test was 0.906 (95% CI 0.656, 0.993; P < .001), which was superior to imaging indices such as radiography, CT, and MRI (AUC = 0.516-0.891). CONCLUSION: We developed the Modified Stabilization Test-a noninvasive diagnostic tool for the screening of chronic syndesmotic injuries. The test showed high sensitivity and specificity for the identification of chronic syndesmotic injuries and is helpful in the identification of chronic syndesmotic injuries. LEVEL OF EVIDENCE: Level II, diagnostic-investigating a diagnostic test.

Enhanced visible light photocatalytic performance of a novel FeIn2S4 microsphere/BiOBr nanoplate heterojunction with a Z-scheme configuration.

The rational design of heterojunction photocatalysts is an effective way to improve semiconductor photocatalytic activity. The simple solvothermal method was used to successfully prepare visible light-driven FeIn2S4 microsphere/BiOBr nanoplate binary heterojunction photocatalysts with varying FeIn2S4 contents. The crystal structure, morphology, surface composition, specific surface area, charge separation, and optical properties of the as-prepared photocatalysts were investigated using a variety of analytical methods. In the photocatalytic degradation of rhodamine B, the FeIn2S4/BiOBr photocatalysts obtained a degradation efficiency of 96% within 60 min, which was approximately 5.33 and 2.59 times higher than pure FeIn2S4 and BiOBr, respectively. Radical trapping experiments and ESR measurements revealed the main active species (·OH, ·O2-, and h+) produced during photocatalytic degradation. The increased photocatalytic activity was due to the formation of Z-scheme heterojunctions between FeIn2S4 and BiOBr, which contributed to the improved effective charge separation of photogenerated charge carriers, augmented specific surface area, and enhanced redox capacity. It is expected that our current study will provide a hopeful way for future environmental remediation research.

Magnetic porphyrin-based metal organic gel for rapid RhB removal and enhanced antibacterial activity by heterogeneous Photo-Fenton reaction under visible light.

Nanomaterials with visible light-driven catalytic ability are beneficial in controlling environmental pollutants. Porphyrin-based metal organic gel (MOG) was herein synthesized in one step and magnetic metal organic gel (MMOG) was successfully prepared via in-situ reaction of MOG and Fe3O4. This MMOG was developed as a novel visible light assisted Fenton-like catalyst. The catalytic experiments showed the high photo-Fenton activity of MMOG in the degradation of Rhodamine B (RhB) in the presence of visible light and H2O2 with a RhB degradation efficiency of 94.2% within 40 min. Notably, the obtained MMOG can kill E. coli and S. aureus with high killing rate (>99.999%) under visible light. Importantly, the MMOG can be recovered simply by an external magnetic field due to the unique magnetic property. This easily synthesized MMOG with photo-Fenton activity under visible light and magnetic property makes MOG based on the photo-Fenton reaction a prospective material for the environmental and biomedical applications.

Shaping Magnetite by Hydroxyl Group Numbers of Small Molecules.

Despite numerous reports on magnetite formation with the assistance of various additives, the role of hydroxyl group (-OH) numbers in small polyol molecules has not yet been understood well. We selected small molecules containing different -OH numbers, such as ethanol, ethylene glycol, propanetriol, butanetetrol, pentitol, hexanehexol, and cyclohexanehexol, as additives in coprecipitation. By increasing the -OH number in these small polyol molecules, the formation of crystallization was slowed, and the size and shape of magnetite were regulated as well possibly due to the changed complexation strength and the stability of the precursor. The increase in temperature and the Fe2+/Fe3+ ratio can reduce the complexation strength. The nucleation and growth of magnetite proceed possibly through the aggregation of polyol-stabilized amorphous complexes and two-line ferrihydrite with low crystallinity based on the -OH numbers, suggesting a nonclassical pathway. The as-prepared magnetite showed a r2/r1 ratio after in vitro MRI measurement as follows: Fe3O4@He-6OH rod < Fe3O4@Pr-3OH sheet < Fe3O4@Pe-5OH cube. The Fe3O4@He-6OH rod and Fe3O4@Pr-3OH sheet displayed T1-T2 dual modal contrast ability, while the Fe3O4@Pe-5OH cube can be T2-dominated. This research provides a simple but an essential approach for designing MRI contrast agents.

Physiochemical properties and paclitaxel release behaviors of dual-stimuli responsive copolymer-magnetite superparamagnetic nanocomposites.

Magnetically driven drug delivery systems of superparamagnetic iron oxide nanoparticles have a considerable potential as candidates to overcome the present obstacles of drug delivery in anti-tumor therapy owing to its remote controllability by external magnetic fields and other unique properties. In this work, a biodegradable anionic copolymer with side carboxylic groups named methoxy-poly (ethylene glycol)-block-poly(α-carboxyl-ε-caprolactone) was synthesized to complex iron oxide magnetic nanoparticles and load paclitaxel (PTX) to form dual-stimuli responsive copolymer-magnetite superparamagnetic nanocomposites with an elastic core and carboxylic groups on the surface in a very easy way. The physiochemical properties of these nanocomposites were measured. High PTX loading content and high saturation magnetization were obtained. Being proved to be stable at a wide pH range and low cytotoxic in vitro, these nanocomposites presented faster PTX release in vitro at pH 6.5 than at pH 7.4 and obviously reduced burst release.

Carboxylic Terminated Thermo-Responsive Copolymer Hydrogel and Improvement in Peptide Release Profile.

To improve the release profile of peptide drugs, thermos-responsive triblock copolymer poly (ε-caprolactone-co-p-dioxanone)-b-poly (ethylene glycol)-b-poly (ε-caprolactone-co-p-dioxanone) (PECP) was prepared and end capped by succinic anhydride to give its carboxylic terminated derivative. Both PCEP block copolymer and its end group modified derivative showed temperature-dependent reversible sol-gel transition in water. The carboxylic end group could significantly decrease the sol-gel transition temperature by nearly 10 °C and strengthen the gel due to enhanced intermolecular force among triblock copolymer chains. Furthermore, compared with the original PECP triblock copolymer, HOOC-PECP-COOH copolymer displayed a retarded and sustained release profile for leuprorelin acetate over one month while effectively avoiding the initial burst. The controlled release was believed to be related to the formation of conjugated copolymer-peptide pair by ionic interaction and enhanced solubility of drug molecules into the hydrophobic domains of the hydrogel. Therefore, carboxyl terminated HOOC-PECP-COOH hydrogel was a promising and well-exhibited sustained release carrier for peptide drugs with the advantage of being able to develop injectable formulation by simple mixing.

Polymer-coated nanoparticles: Carrier platforms for hydrophobic water- and air-sensitive metallo-organic compounds.

Many of the relevant compounds for anticancer therapy are metal-based compounds (metallodrugs), being platinum-based drugs such as cisplatin, carboplatin (Paraplatin®), and oxaliplatin (Eloxatin®) the most widely used. Despite this, their application is limited by issues such as cell-acquired platinum resistance and manifold side effects following systemic delivery. Thus, the development of new metal-based compounds is highly needed. The catalytic properties of a variety of metal-based compounds are nowadays very well known, which opens new opportunities to take advantage of them inside living cells or organisms. However, many of these compounds are hydrophobic and thus not soluble in aqueous solution, as they lack stability against water or oxygen presence. Thus, versatile platforms capable of enhancing the features of these compounds in aqueous solutions are of importance in the development of new drugs. Surface engineered nanoparticles may render metallodrugs with good colloidal stability in water and in complex media containing high salt concentration and/or proteins. Herein, polymer coated nanoparticles are proposed as a platform to link insoluble and water/oxygen sensitive drugs. The linkage of insoluble and oxygen sensitive tin clusters to nanoparticles is presented, aiming to enhance both, the solubility and the stability of these compounds in water, which may be an alternative approach in the development of metal-based drugs. The formation of the cluster-nanoparticle system was confirmed via inductively coupled plasma mass spectrometry experiments. The catalytic activity and the stability of the cluster in water were studied through the reduction of methylene blue. Results demonstrate that in fact the tin clusters could be transferred into aqueous solution and retained their catalytic activity.

Regulation of the osteoblastic and chondrocytic differentiation of stem cells by the extracellular matrix and subsequent bone formation modes.

While various factors have been reported to direct stem cell differentiation lineage, little is known about how nature orchestrates the mesenchymal stem cell (MSC) differentiation and bone morphogenesis during skeleton development and bone regeneration. The present study reports that the matrix has a critical regulating effect on MSC differentiation and the subsequent bone formation modes. A simply combined hydroxyapatite (HA)-collagen matrix stimulates the MSC differentiation into the osteoblastic lineage and leads to a straightforward intramembranous bone formation mode, in contrast to the chondrocytic differentiation and endochondral mode observed on HA-synthetic hydrogel matrix. The accelerated MSC condensation and robust MSC-matrix and MSC-MSC interactions on collagen-based matrix might be the critical factors contributing to such events, likely through the orchestrated signal cascades and cellular events modulated by the extracellular matrix. The results demonstrate that matrix plays critical role in modulating the stem cell differentiation lineage and bone formation mode, which has been largely overlooked.