Integrated MOF-74 Coatings on Magnesium for Corrosion Control, Cytocompatibility, and Antibacterial Properties.

Biodegradable Mg and its alloys can degrade safely in vivo without toxicity. The major bottleneck inhibiting their clinical use is the high corrosion rate, which leads to the loss of mechanical integrity prematurely and bad biocompatibility. One ideal strategy is the modification with anticorrosive and bioactive coatings. Numerous metal-organic framework (MOF) membranes show satisfactory anticorrosion performance and biocompatibility. In this study, MOF-74 membranes are prepared on an NH4TiOF3 (NTiF) layer-modified Mg matrix, fabricating integrated bilayer coatings (MOF-74/NTiF) for corrosion control, cytocompatibility, and antibacterial properties. The inner NTiF layer serves as the primary protection for the Mg matrix and a stable surface for the growth of MOF-74 membranes. The outer MOF-74 membranes further enhance corrosion protection, whose crystals and thicknesses can be adjusted for different protective effects. Owing to superhydrophilic, micro-nanostructural, and nontoxic decomposition products, MOF-74 membranes significantly promote cell adhesion and proliferation, showing excellent cytocompatibility. Utilizing the decomposition of MOF-74 to generate the products of Zn2+ and 2,5-dihydroxyterephthalic acid can effectively inhibit Escherichia coli and Staphylococcus aureus, displaying highly efficient antibacterial properties. The research may shed valuable strategies for MOF-based functional coatings in the applications of biomedicine fields.

Mycobacteriaceae Mineralizes Micropolyethylene in Riverine Ecosystems.

Microplastic (MP) contamination is a serious global environmental problem. Plastic contamination has attracted extensive attention during the past decades. While physiochemical weathering may influence the properties of MPs, biodegradation by microorganisms could ultimately mineralize plastics into CO2. Compared to the well-studied marine ecosystems, the MP biodegradation process in riverine ecosystems, however, is less understood. The current study focuses on the MP biodegradation in one of the world's most plastic contaminated rivers, Pearl River, using micropolyethylene (mPE) as a model substrate. Mineralization of 13C-labeled mPE into 13CO2 provided direct evidence of mPE biodegradation by indigenous microorganisms. Several Actinobacteriota genera were identified as putative mPE degraders. Furthermore, two Mycobacteriaceae isolates related to the putative mPE degraders, Mycobacterium sp. mPE3 and Nocardia sp. mPE12, were retrieved, and their ability to mineralize 13C-mPE into 13CO2 was confirmed. Pangenomic analysis reveals that the genes related to the proposed mPE biodegradation pathway are shared by members of Mycobacteriaceae. While both Mycobacterium and Nocardia are known for their pathogenicity, these populations on the plastisphere in this study were likely nonpathogenic as they lacked virulence factors. The current study provided direct evidence for MP mineralization by indigenous biodegraders and predicted their biodegradation pathway, which may be harnessed to improve bioremediation of MPs in urban rivers.

[Protective effect of oleanolic acid liposomes on cisplatin-induced oligoasthenospermia in mice].

OBJECTIVE: To study the protective effect of oleanolic acid liposomes (OA-Lips) on cisplatin-induced oligoasthenospermia (COAS) in mice. METHODS: Sixty ICR mice were randomly divided into a normal control, a COAS model control, a positive control and a low-, a medium- and a high-dose OA-Lips group. The animals in the low-, medium- and high-dose OA-Lips and positive control groups were given intragastrically OA-Lips solution at 25, 50, and 100 mg/kg/d and vitamin E at 50 mg/kg/d, respectively. On the 28th day, the mice in the COAS model control, positive control and OA-Lips groups were injected intraperitoneally with cisplatin solution at 10 mg/kg, while those in the normal control group with the same dose of normal saline. Three days after administration, all the mice were sacrificed and their testis tissues collected for detection of the semen parameters and observation of the testicular morphology. RESULTS: Both the percentage of motile sperm and sperm concentration were significantly increased in the high-dose OA-Lips group (P < 0.05). HE staining showed that OA-Lips remarkably improved the damaged testis tissue (P < 0.05) and protected the seminiferous tubules and interstitial cells. The percentage of progressively motile sperm (PMS) and the curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), linearity (LIN), straightness (STR), wobble (WOB), amplitude of lateral head displacement (ALH) and beat-cross frequency (BCF) of sperm were gradually increased in a dose-dependent manner in the OA-Lips groups. The serum T level was significantly higher (P < 0.05) in the OA-Lips-treated mice than in the COAS model controls while the percentage of morphologically abnormal sperm (MAS) markedly lower in the high-dose OA-Lips group than in the model control, positive control and low-dose OA-Lips groups (P < 0.05). CONCLUSION: OA-Lips can relieve oligoaspermia and improve the productive ability of mice.

Sodium alginate/collagen hydrogel loaded with human umbilical cord mesenchymal stem cells promotes wound healing and skin remodeling.

Stem cell transplantation is a promising therapy for wound healing, but the low retention and survival of transplanted stem cells limit their application. Injectable hydrogels exert beneficial effects in skin tissue engineering. In this study, an injectable hydrogel composed of sodium alginate (SA) and collagen type I (Col) was synthesized as a tissue scaffold to improve the efficacy of stem cells in a full-thickness excision wound model. Our results showed that SA/Col hydrogel was injectable, biodegradable, and exhibited low immunogenicity, which could promote the retention and survival of hUC-MSCs in vivo. SA/Col loaded with hUC-MSCs showed reduced wound size (p < 0.05). Histological and immunofluorescence results confirmed that SA/Col loaded with hUC-MSCs significantly promoted the formation of granulation, enhanced collagen deposition and angiogenesis, increased VEGF and TGF-ß1 expression (p < 0.05), and mitigated inflammation evidenced by lower production of TNF-α and IL-1ß and higher release of IL-4 and IL-10 (p < 0.05). Furthermore, SA/Col loaded with hUC-MSCs significantly lowered the expression of NLRP3 inflammasome-related proteins (p < 0.05). Taken together, our results suggest that SA/Col loaded with hUC-MSCs promotes skin wound healing via partly inhibiting NLRP3 pathway, which has potential to the treatment of skin wounds.

Preparation of Silk Fibroin/Carboxymethyl Chitosan Hydrogel under Low Voltage as a Wound Dressing.

At present, silk fibroin (SF) hydrogel can be prepared by means of electrodeposition at 25 V in direct current (DC) mode. Reducing the applied voltage would provide benefits, including lower fabrication costs, less risk of high voltage shocks, and better stability of devices. Here, a simple but uncommon strategy for SF-based hydrogel preparation using 4 V in DC mode is discussed. SF was mixed and cross-linked with carboxymethyl chitosan (CMCS) through hydrogen bonding, then co-deposited on the graphite electrode. The thickness, mass, and shape of the SF/CMCS hydrogel were easily controlled by adjusting the electrodeposition parameters. Morphological characterization of the prepared hydrogel via SEM revealed a porous network within the fabricated hydrogel. This structure was due to intermolecular hydrogen bonding between SF and CMCS, according to the results of thermogravimetric analysis and rheological measurements. As a potential wound dressing, SF/CMCS hydrogel maintained a suitable moisture environment for wound healing and demonstrated distinct properties in terms of promoting the proliferation of HEK-293 cells and antibacterial activity against Escherichia coli and Staphylococcus aureus. Furthermore, histological studies were conducted on a full-thickness skin wound in rats covered with the SF/CMCS hydrogel, with results indicating that this hydrogel can promote wound re-epithelization and enhance granulation tissue formation. These results illustrate the feasibility of using the developed strategy for SF-based hydrogel fabrication in practice for wound dressing.

Farnesal-loaded pH-sensitive polymeric micelles provided effective prevention and treatment on dental caries.

BACKGROUND: Farnesol is a sesquiterpene from propolis and citrus fruit that shows promising anti-bacterial activity for caries treatment and prevention, but its hydrophobicity limits the clinical application. We aimed to develop the novel polymeric micelles (PMs) containing a kind of derivative of farnesol and a ligand of pyrophosphate (PPi) that mediated PMs to adhere tightly with the tooth enamel. RESULTS: Farnesal (Far) was derived from farnesol and successfully linked to PEG via an acid-labile hydrazone bond to form PEG-hyd-Far, which was then conjugated to PPi and loaded into PMs to form the aimed novel drug delivery system, PPi-Far-PMs. The in vitro test about the binding of PPi-Far-PMs to hydroxyapatite showed that PPi-Far-PMs could bind rapidly to hydroxyapatite and quickly release Far under the acidic conditions. Results from the mechanical testing and the micro-computed tomography indicated that PPi-Far-PMs could restore the microarchitecture of teeth with caries. Moreover, PPi-Far-PMs diminished the incidence and severity of smooth and sulcal surface caries in rats that were infected with Streptococcus mutans while being fed with a high-sucrose diet. The anti-caries efficacy of free Far can be improved significantly by PPi-Far-PMs through the effective binding of it with tooth enamel via PPi. CONCLUSIONS: This novel drug-delivery system may be useful for the treatment and prevention of dental caries as well as the targeting therapy of anti-bacterial drugs in the oral disease.

14.7% Efficiency Organic Photovoltaic Cells Enabled by Active Materials with a Large Electrostatic Potential Difference.

Although significant improvements have been achieved for organic photovoltaic cells (OPVs), the top-performing devices still show power conversion efficiencies far behind those of commercialized solar cells. One of the main reasons is the large driving force required for separating electron-hole pairs. Here, we demonstrate an efficiency of 14.7% in the single-junction OPV by using a new polymer donor PTO2 and a nonfullerene acceptor IT-4F. The device possesses an efficient charge generation at a low driving force. Ultrafast transient absorption measurements probe the formation of loosely bound charge pairs with extended lifetime that impedes the recombination of charge carriers in the blend. The theoretical studies reveal that the molecular electrostatic potential (ESP) between PTO2 and IT-4F is large, and the induced intermolecular electric field may assist the charge generation. The results suggest OPVs have the potential for further improvement by judicious modulation of ESP.

Selective Degradation of Organic Pollutants Using an Efficient Metal-Free Catalyst Derived from Carbonized Polypyrrole via Peroxymonosulfate Activation.

Metal-free carbonaceous materials, including nitrogen-doped graphene and carbon nanotubes, are emerging as alternative catalysts for peroxymonosulfate (PMS) activation to avoid drawbacks of conventional transition metal-containing catalysts, such as the leaching of toxic metal ions. However, these novel carbocatalysts face relatively high cost and complex syntheses, and their activation mechanisms have not been well-understood. Herein, we developed a novel nitrogen-doped carbonaceous nanosphere catalyst by carbonization of polypyrrole, which was prepared through a scalable chemical oxidative polymerization. The defective degree of carbon substrate and amount of nitrogen dopants (i.e., graphitic nitrogen) were modulated by the calcination temperature. The product carbonized at 800 °C (CPPy-F-8) exhibited the best catalytic performance for PMS activation, with 97% phenol degradation efficiency in 120 min. The catalytic system was efficient over a wide pH range (2-9), and the reaction of phenol degradation had a relatively low activation energy (18.4 ± 2.7 kJ mol-1). The nitrogen-doped carbocatalyst activated PMS through a nonradical pathway. A two-step catalytic mechanism was extrapolated: the catalyst transfers electrons to PMS through active nitrogen species and becomes a metastable state of the catalyst (State I); next, organic substrates are oxidized and degraded by serving as electron donors to reduce State I. The catalytic process was selective toward degradation of various aromatic compounds with different substituents, probably depending on the oxidation state of State I and the ionization potential (IP) of the organics; that is, only those organics with an IP value lower than ca. 9.0 eV can be oxidized in the CPPy-F-8/PMS system.

Adsorption behavior of aniline pollutant on polystyrene microplastics.

Microplastic contamination is ubiquitous in aquatic environments. As global plastic production increases, the abundance of microplastic contaminants released into the environment has also continued to soar. The hydrophobic surfaces of plastic particles can adsorb a variety of chemical pollutants, and could therefore facilitate toxin accumulation through the food chain. In this study, the adsorption behavior of aniline, a priority environmental pollutant from industrial production, on the surface of polystyrene microplastics (mPS) was investigated. The results showed that the maximum adsorption capacity of mPS was 0.060 mg/g. Adsorption equilibrium was reached after 24 h, and the pseudo-second-order model was employed to explain the adsorption kinetics of aniline on the mPS particles. The Freundlich models could describe the adsorption isotherms. The potential adsorption mechanisms may include π-π interactions and hydrophobic interactions. pH, ionic strength, and ambient temperature of the solution played important roles in the adsorption process.

MFN2 Deficiency Impairs Mitochondrial Transport and Downregulates Motor Protein Expression in Human Spinal Motor Neurons.

Charcot-Marie-Tooth (CMT) disease is one of the most common genetically inherited neurological disorders and CMT type 2A (CMT 2A) is caused by dominant mutations in the mitofusin-2 (MFN2) gene. MFN2 is located in the outer mitochondrial membrane and is a mediator of mitochondrial fusion, with an essential role in maintaining normal neuronal functions. Although loss of MFN2 induces axonal neuropathy, the detailed mechanism by which MFN2 deficiency results in axonal degeneration of human spinal motor neurons remains largely unknown. In this study, we generated MFN2-knockdown human embryonic stem cell (hESC) lines using lentivirus expressing MFN2 short hairpin RNA (shRNA). Using these hESC lines, we found that MFN2 loss did not affect spinal motor neuron differentiation from hESCs but resulted in mitochondrial fragmentation and dysfunction as determined by live-cell imaging. Notably, MFN2-knockodwn spinal motor neurons exhibited CMT2A disease-related phenotypes, including extensive perikaryal inclusions of phosphorylated neurofilament heavy chain (pNfH), frequent axonal swellings, and increased pNfH levels in long-term cultures. Importantly, MFN2 deficit impaired anterograde and retrograde mitochondrial transport within axons, and reduced the mRNA and protein levels of kinesin and dynein, indicating the interfered motor protein expression induced by MFN2 deficiency. Our results reveal that MFN2 knockdown induced axonal degeneration of spinal motor neurons and defects in mitochondrial morphology and function. The impaired mitochondrial transport in MFN2-knockdown spinal motor neurons is mediated, at least partially, by the altered motor proteins, providing potential therapeutic targets for rescuing axonal degeneration of spinal motor neurons in CMT2A disease.

Targeted Delivery of Dual Anticancer Drugs Based on Self-Assembled iRGD-Modified Soluble Drug-Polymer Pattern Conjugate Nanoparticles.

A tumor-penetrating peptide, iRGD (a tumor-homing peptide, CRGDKGPDC), could enhance the penetration of drugs via the specific receptor-binding affinity to αvß3 and NRP-1 that overexpressed on tumor vasculature and tumor cells. Considering the side effects of traditional chemotherapy, here, poly(ethylene glycol) (PEG, Mw = 7500)-based and iRGD-modified poly(ethylene glycol)-based nanoparticles were successfully prepared. iRGD, as a tumor-targeting and tumor-penetrating agent, was combined with PEG after the esterification reaction between PEG and diosgenin (DGN). After the efficient loading of 10-hydroxycamptothecin (HCPT), the iRGD-PEG-DGN/HCPT NPs of chemotherapy were established. The characteristics of iRGD-PEG-DGN/HCPT NPs were evaluated. This nano-delivery system possessed high drug loading efficiency (∼17.34 wt % HCPT), controlled release rate, good pH response, and iRGD active targeting and passive targeting with an appropriate size (∼140 nm). All these features forcefully indicated that the iRGD-modified drug delivery system could markedly ameliorate the tumor therapy efficacy compared to the nontargeted nanoparticles through enhancing the tumor accumulation and penetration.

Soft tissue release combined with joint-sparing osteotomy for treatment of cavovarus foot deformity in older children: Analysis of 21 cases.

BACKGROUND: Cavovarus foot is a common form of foot deformity in children, which is clinically characterized by an abnormal increase of the longitudinal arch of the foot, and it can be simultaneously complicated with forefoot pronation and varus, rearfoot varus, Achilles tendon contracture, or cock-up toe deformity. Muscle force imbalance is the primary cause of such deformity. Many diseases can lead to muscle force imbalance, such as tethered cord syndrome, cerebral palsy, Charcot-Marie-Tooth disease, and trauma. At present, many surgical treatments are available for cavovarus foot. For older children, priority should be given to midfoot osteotomy and fusion. Since complications such as abnormal foot length, foot stiffness, and abnormal gait tend to develop postoperatively, it is important to preserve the joints and correct the deformity as much as possible. Adequate soft tissue release and muscle balance are the keys to correcting the deformity and avoiding its postoperative recurrence. AIM: To assess the efficacy of soft tissue release combined with joint-sparing osteotomy in the treatment of cavovarus foot deformity in older children. METHODS: The clinical data of 21 older children with cavovarus foot deformity (28 feet) who were treated surgically at the Ninth Department of Orthopedics of Jizhong Energy Xingtai Mining Group General Hospital from November 2014 to July 2017 were retrospectively analyzed. The patients ranged in age from 10 to 14 years old, with an average age of 12.46 ± 1.20 years. Their main clinical manifestations were deformity, pain, and gait abnormality. The patients underwent magnetic resonance imaging of the lumbar spine, electromyographic examination, weight-bearing anteroposterior and lateral X-rays of the feet, and the Coleman block test. Surgical procedures including metatarsal fascia release, Achilles tendon or medial gastrocnemius lengthening, "V"-shaped osteotomy on the dorsal side of the metatarsal base, opening medial cuneiform wedge osteotomy, closing cuboid osteotomy, anterior transfer of the posterior tibial tendon, peroneus longus-to-brevis transfer, and calcaneal sliding osteotomy to correct hindfoot varus deformity were performed. After surgery, long leg plaster casts were applied, the plaster casts were removed 6 wk later, Kirschner wires were removed, and functional exercise was initiated. The patients began weight-bearing walk 3 mo after surgery. Therapeutic effects were evaluated using the Wicart grading system, and Meary's angles and Hibbs' angles were measured based on X-ray images obtained preoperatively and at last follow-up to assess their changes. RESULTS: The patients were followed for 6 to 32 mo, with an average follow-up period of 17.68 ± 6.290 mo. Bone healing at the osteotomy site was achieved at 3 mo in all cases. According to the Wicart grading system, very good results were achieved in 18 feet, good in 7, and fair in 3, with a very good/good rate of 89.3%. At last follow-up, mean Meary's angle was 6.36° ± 1.810°, and mean Hibbs' angle was 160.21° ± 4.167°, both of which were significantly improved compared with preoperative values (24.11° ± 2.948° and 135.86° ± 5.345°, respectively; P < 0.001 for both). No complications such as infection, skin necrosis, or bone nonunion occurred. CONCLUSION: Soft tissue release combined with joint-sparing osteotomy has appreciated efficacy in the treatment of cavovarus foot deformity in older children.

Photothermal and biodegradable polyaniline/porous silicon hybrid nanocomposites as drug carriers for combined chemo-photothermal therapy of cancer.

To develop photothermal and biodegradable nanocarriers for combined chemo-photothermal therapy of cancer, polyaniline/porous silicon hybrid nanocomposites had been successfully fabricated via surface initiated polymerization of aniline onto porous silicon nanoparticles in our experiments. As-prepared polyaniline/porous silicon nanocomposites could be well dispersed in aqueous solution without any extra hydrophilic surface coatings, and showed a robust photothermal effect under near-infrared (NIR) laser irradiation. Especially, after an intravenous injection into mice, these biodegradable porous silicon-based nanocomposites as non-toxic agents could be completely cleared in body. Moreover, these polyaniline/porous silicon nanocomposites as drug carriers also exhibited an efficient loading and dual pH/NIR light-triggered release of doxorubicin hydrochloride (DOX, a model anticancer drug). Most importantly, assisted with NIR laser irradiation, polyaniline/PSiNPs nanocomposites with loading DOX showed a remarkable synergistic anticancer effect combining chemotherapy with photothermal therapy, whether in vitro or in vivo. Therefore, based on biodegradable PSiNPs-based nanocomposites, this combination approach of chemo-photothermal therapy would have enormous potential on clinical cancer treatments in the future. STATEMENT OF SIGNIFICANCE: Considering the non-biodegradable nature and potential long-term toxicity concerns of photothermal nanoagents, it is of great interest and importance to develop biodegradable and photothermal nanoparticles with an excellent biocompatibility for their future clinical applications. In our experiments, we fabricated porous silicon-based hybrid nanocomposites via surface initiated polymerization of aniline, which showed an excellent photothermal effect, aqueous dispersibility, biodegradability and biocompatibility. Furthermore, after an efficient loading of DOX molecules, polyaniline/porous silicon nanocomposites exhibited the remarkable synergistic anticancer effect, whether in vitro and in vivo.

Fabrication of Sustained-release CA-PU Coaxial Electrospun Fiber Membranes for Plant Grafting Application.

Plant grafting is a well-known activity in orchards, greenhouses and vineyards gardens. However, low survival rate still limits the promotion of grafting and breeding of improved varieties. We report on polymeric fibers, obtained through coaxial electrospun, as carriers for the sustained release of drugs to heal wounds in plants. The CA-PU co-electrospun fibers show a rather uniform diameter, a smooth and hydrophilic surface. As long as 10days of sustained drugs release meets with the physiological requirement of plant grafting. The callus toxicity test shows that the CA-PU fibers are not toxic for plant cells. We show that loading the core of CA-PU fibers with 6-Benzylaminopurine (6-BA), a first-generation synthetic cytokinin that elicits plant growth and development, results in fibers that can efficiently promote the healing of plant wounds, thereby significantly improving the grafting survival rate.

A comparison of three-dimensional marginal adaptation among three all-ceramic crown systems.

PURPOSE: This study was to compare the marginal adaptation of single crown made of 3 different all-ceramic systems (IPS e.max, In-Ceram alumina, Kavo Everest) in vitro using a light-body silicone supported by a heavy-body silicone material. METHODS: The crowns were made for 1 extracted maxillary premolar prepared with a 0.8-mm chamfer margin and 6-degree tapered walls by milling. Ten crowns per system were fabricated. The horizontal marginal discrepancies, vertical marginal discrepancies and absolute marginal discrepancies were measured under an optical microscope at 39.2 magnification. The data were analyzed with one-way analysis of variance (ANOVA) using SPSS 13.0 software package. RESULTS: The results showed the mean values for horizontal marginal discrepancies were between 41.1µm and 44.9µm, for vertical marginal discrepancies were between 51.4µm and 71.7µm, and for absolute marginal discrepancies were between 66.2µm and 85.1µm. CONCLUSIONS: The horizontal marginal discrepancies, vertical marginal discrepancies and absolute marginal discrepancies of the three all-ceramic crown systems were within the clinically acceptable standard. However, the IPS e.max system and the Kavo Everest System showed a better marginal fit compared with the In-Ceram alumina system.