RÉSUMÉ
Inflammation caused by a bacterial infection and the subsequent dysregulation of the host immune-inflammatory response are detrimental to periodontal regeneration. Herein, we present an infection-sensitive scaffold prepared by layer-by-layer assembly of Feraheme-like superparamagnetic iron oxide nanoparticles (SPIONs) on the surface of a three-dimensional-printed polylactic-co-glycolic acid (PLGA) scaffold. The SPION/PLGA scaffold is magnetic, hydrophilic, and bacterial-adhesion resistant. As indicated by gene expression profiling and confirmed by quantitative real-time reverse transcription polymerase chain reaction and flow cytometry analysis, the SPION/PLGA scaffold facilitates macrophage polarization toward the regenerative M2 phenotype by upregulating IL-10, which is the molecular target of repair promotion, and inhibits macrophage polarization toward the proinflammatory M1 phenotype by downregulating NLRP3, which is the molecular target of anti-inflammation. As a result, macrophages modulated by the SPS promote osteogenic differentiation of bone marrow mesenchymal stromal cells (BMSCs) in vitro. In a rat periodontal defect model, the SPION/PLGA scaffold increased IL-10 secretion and decreased NLRP3 and IL-1ß secretion with Porphyromonas gingivalis infection, achieving superior periodontal regeneration than the PLGA scaffold alone. Therefore, this antibacterial SPION/PLGA scaffold has anti-inflammatory and bacterial antiadhesion properties to fight infection and promote periodontal regeneration by immunomodulation. These findings provide an important strategy for developing engineered scaffolds to treat periodontal defects.
Sujet(s)
Antibactériens , Macrophages , Copolymère d'acide poly(lactique-co-glycolique) , Porphyromonas gingivalis , Structures d'échafaudage tissulaires , Animaux , Copolymère d'acide poly(lactique-co-glycolique)/composition chimique , Copolymère d'acide poly(lactique-co-glycolique)/pharmacologie , Macrophages/effets des médicaments et des substances chimiques , Macrophages/métabolisme , Antibactériens/composition chimique , Antibactériens/pharmacologie , Rats , Porphyromonas gingivalis/effets des médicaments et des substances chimiques , Structures d'échafaudage tissulaires/composition chimique , Rat Sprague-Dawley , Nanoparticules magnétiques d'oxyde de fer/composition chimique , Mâle , Régénération/effets des médicaments et des substances chimiques , Phénotype , Cellules souches mésenchymateuses/effets des médicaments et des substances chimiques , Cellules souches mésenchymateuses/cytologie , SourisRÉSUMÉ
Catheter-associated urinary tract infection (CAUTI) is a common clinical problem, especially during long-term catheterization, causing additional pain to patients. The development of novel antimicrobial coatings is needed to prolong the service life of catheters and reduce the incidence of CAUTIs. Herein, we designed an antimicrobial catheter coated with a piezoelectric zinc oxide nanoparticles (ZnO NPs)-incorporated polyvinylidene difluoride-hexafluoropropylene (ZnO-PVDF-HFP) membrane. ZnO-PVDF-HFP could be stably coated onto silicone catheters simply by a one-step solution film-forming method, very convenient for industrial production. In vitro, it was demonstrated that ZnO-PVDF-HFP coating could significantly inhibit bacterial growth and the formation of bacterial biofilm under ultrasound-mediated mechanical stimulation even after 4 weeks. Importantly, the on and off of antimicrobial activity as well as the strenth of antibacterial property could be controlled in an adaptive manner via ultrasound. In a rabbit model, the ZnO-PVDF-HFP-coated catheter significantly reduced the incidence CAUTIs compared with clinically-commonly used catheters under assistance of ultrasonication, and no side effect was detected. Collectively, the study provided a novel antibacterial catheter to prevent the occurrence of CAUTIs, whose antibacterial activity could be controlled in on-demand manner, adaptive to infection situation and promising in clinical application.
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Guided bone regeneration (GBR) membranes that reside at the interface between the bone and soft tissues for bone repair attract increasing attention, but currently developed GBR membranes suffer from relatively poor osteogenic and antibacterial effects as well as limited mechanical property and biodegradability. We present here the design and fabrication of a bifunctional Janus GBR membrane based on a shear flow-driven layer by a layer self-assembly approach. The Janus GBR membrane comprises a calcium phosphate-collagen/polyethylene glycol (CaP@COL/PEG) layer and a chitosan/poly(acrylic acid) (CHI/PAA) layer on different sides of a collagen membrane to form a sandwich structure. The membrane exhibits good mechanical stability and tailored biodegradability. It is found that the CaP@COL/PEG layer and CHI/PAA layer contribute to the osteogenic differentiation and antibacterial function, respectively. In comparison with the control group, the Janus GBR membrane displays a 2.52-time and 1.84-time enhancement in respective volume and density of newly generated bone. The greatly improved bone repair ability of the Janus GBR membrane is further confirmed through histological analysis, and it has great potential for practical applications in bone tissue engineering.
Sujet(s)
Antibactériens , Régénération osseuse , Ostéogenèse , Régénération osseuse/effets des médicaments et des substances chimiques , Antibactériens/pharmacologie , Antibactériens/composition chimique , Ostéogenèse/effets des médicaments et des substances chimiques , Animaux , Chitosane/composition chimique , Chitosane/pharmacologie , Phosphates de calcium/composition chimique , Phosphates de calcium/pharmacologie , Membrane artificielle , Collagène/composition chimique , Collagène/pharmacologie , Polyéthylène glycols/composition chimique , Polyéthylène glycols/pharmacologie , Régénération tissulaire guidée/méthodes , Ingénierie tissulaire/méthodes , Différenciation cellulaire/effets des médicaments et des substances chimiquesRÉSUMÉ
In recent years, the demand for clinical bone grafting has increased. As a new solution for orthopedic implants, polyether ether ketone (PEEK, crystalline PAEK) has excellent comprehensive performance and is practically applied in the clinic. In this research, a noteworthy elevated scheme to enhance the performance of PEEK scaffolds is presented. The amorphous aggregated poly (aryl ether ketone) (PAEK) resin is prepared as the matrix material, which maintains high mechanical strength and can be processed through the solution. So, the tissue engineering scaffolds with multilevel pores can be printed by low-temperature deposited manufacturing (LDM) to improve biologically inert scaffolds with smooth surfaces. Also, the feature of PAEK's solution processing is profitable to uniformly add the functional components for bone repair. Ultimately, A system of orthopedic implantable PAEK material based on intermolecular interactions, surface topology, and surface modification is established. The specific steps include synthesizing PAEK that contain polar carboxyl structures, preparing bioinks and fabricating scaffolds by LDM, preparation of scaffolds with strontium-doped mineralized coatings, evaluation of their osteogenic properties in vitro and in vivo, and investigation on the effect and mechanism of scaffolds in promoting osteogenic differentiation. This work provides an upgraded system of PAEK implantable materials for clinical application.
RÉSUMÉ
Osteoporosis (OP) is a highly prevalent disorder characterized by low bone mass that severely reduces patient quality of life. Although numerous treatments for OP have been introduced in clinic, many have side effects and high costs. Therefore, there is still an unmet need for optimal solutions. Here, raw signal analysis was used to identify potential high-risk factors for OP, and the biological functions and possible mechanisms of action (MOAs) of these factors were explored via gene set enrichment analysis (GSEA). Subsequently, molecular biological experiments were performed to verify and analyze the discovered risk factors in vitro and in vivo. PMAIP1 was identified as a potential risk factor for OP and significantly suppressed autophagy in osteoblasts via the AMPK/mTOR pathway, thereby inhibiting the proliferation and differentiation of osteoblasts. Furthermore, we constructed an ovariectomy (OVX) model of OP in rats and simultaneously applied si-PMAIP1 for in vivo interference. si-PMAIP1 upregulated the expression of LC3B and p-AMPK and downregulated the expression of p-mTOR, and these effects were reversed by the autophagy inhibitor. Micro-CT revealed that, si-PMAIP1 significantly inhibited the development of osteoporosis in OVX model rats, and this therapeutic effect was attenuated by treatment with an autophagy inhibitor. This study explored the role and mechanism of PMAIP1 in OP and demonstrated that PMAIP1 may serve as a novel target for OP treatment.
Sujet(s)
AMP-Activated Protein Kinases , Autophagie , Modèles animaux de maladie humaine , Ostéoblastes , Ostéoporose , Transduction du signal , Sérine-thréonine kinases TOR , Animaux , Femelle , Humains , Rats , AMP-Activated Protein Kinases/métabolisme , AMP-Activated Protein Kinases/physiologie , Autophagie/génétique , Différenciation cellulaire/génétique , Prolifération cellulaire/génétique , Cellules cultivées , Expression des gènes/génétique , Ostéoblastes/métabolisme , Ostéoporose/métabolisme , Ostéoporose/génétique , Ostéoporose/étiologie , Ovariectomie , Rat Sprague-Dawley , Transduction du signal/génétique , Sérine-thréonine kinases TOR/métabolisme , Sérine-thréonine kinases TOR/physiologieRÉSUMÉ
Pulsed electromagnetic field (PEMF) stimulation is a prospective non-invasive and safe physical therapy strategy for accelerating bone repair. PEMFs can activate signalling pathways, modulate ion channels, and regulate the expression of bone-related genes to enhance osteoblast activity and promote the regeneration of neural and vascular tissues, thereby accelerating bone formation during bone repair. Although their mechanisms of action remain unclear, recent studies provide ample evidence of the effects of PEMF on bone repair. In this review, we present the progress of research exploring the effects of PEMF on bone repair and systematically elucidate the mechanisms involved in PEMF-induced bone repair. Additionally, the potential clinical significance of PEMF therapy in fracture healing is underscored. Thus, this review seeks to provide a sufficient theoretical basis for the application of PEMFs in bone repair.
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The removal of a failed implant with high torque causes significant damage to the surrounding tissue, compromising bone regeneration and subsequent osseointegration in the defect area. Here, we report a case of carrier screw fracture followed by immediate implant removal, bone grafting and delayed reimplantation. A dental implant with a fractured central carrier screw was removed using the bur-forceps technique. The resulting three-wall bone defect was filled with granular surface demineralized freeze-dried bone allograft (SD-FDBA). Cone-beam computerized tomography was performed at 1 week, 6 months and 15 months postoperatively and standardized for quantitative evaluation. The alveolar bone width and height at 15 months post-surgery were about 91% of the original values, with a slightly lower bone density, calculated using the gray value ratio. The graft site was reopened and was found to be completely healed with dense and vascularized bone along with some residual bone graft. Reimplantation followed by restoration was performed 8 months later. The quality of regenerated bone following SD-FDBA grafting was adequate for osseointegration and long-term implant success. The excellent osteogenic properties of SD-FDBA are attributed to its human origin, cortical bone-like structure, partly demineralized surfaces and bone morphogenetic protein-2-containing nature. Further investigation with more cases and longer follow-up was required to confirm the final clinical effect.
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Evidence presented that osteoporosis is closely related to the dysfunction of bone mesenchymal stem cells (BMSCs). But most studies are insufficient to reveal what actually happens to the osteoporotic BMSCs. In this study, BMSCs were harvested from ovariectomized and sham-operated rats. After checking the characteristics of rat models and stem cells, the BMSCs were carried out for RNA sequencing. Part of the findings were verified that seven mRNAs (Abi3bp, Aifm3, Ccl11, Cdkn1c, Chst10, Id2, Vcam1) were significantly up-regulated in osteoporotic BMSCs while seven mRNAs (Cep63, Fgfr3, Myc, Omd, Pou2f1, Smarcal1, Timm10b) were down-regulated. In addition, potential miRNA-mRNA and lncRNA-mRNA regulatory networks were illustrated. The changes in osteoporotic BMSCs covered a large set of biological processes, including cell viability, differentiation, immunoreaction, bone repairment and estrogen defect. This study enriched the pathophysiological mechanisms of BMSCs and osteporosis, as well as provided dozens of attractive RNA targets for further treatment.
Sujet(s)
Cellules souches mésenchymateuses , Ostéoporose , Rats , Animaux , Ostéoporose/génétique , Ostéoporose/thérapie , Différenciation cellulaire/génétique , Analyse de séquence d'ARN , ARN messager , Ostéogenèse/génétique , Cellules cultivéesRÉSUMÉ
Additively manufactured biodegradable zinc (Zn) scaffolds have great potential to repair infected bone defects due to their osteogenic and antibacterial properties. However, the enhancement of antibacterial properties depends on a high concentration of dissolved Zn2+, which in return deteriorates osteogenic activity. In this study, a vancomycin (Van)-loaded polydopamine (PDA) coating was prepared on pure Zn porous scaffolds to solve the above dilemma. Compared with pure Zn scaffolds according to comprehensive in vitro tests, the PDA coating resulted in a slow degradation and inhibited the excessive release of Zn2+ at the early stage, thus improving cytocompatibility and osteogenic activity. Meanwhile, the addition of Van drug substantially suppressed the attachment and proliferation of S. aureus and E. coli bacterial. Furthermore, in vivo implantation confirmed the simultaneously improved osteogenic and antibacterial functions by using the pure Zn scaffolds with Van-loaded PDA coating. Therefore, it is promising to employ biodegradable Zn porous scaffolds with the proposed drug-loaded coating for the treatment of infected bone defects.
RÉSUMÉ
The combination of bioactive Zn-2Mg alloy and additively manufactured porous scaffold is expected to achieve customizable biodegradable performance and enhanced bone regeneration. Herein, Zn-2Mg alloy scaffolds with different porosities, including 40% (G-40-2), 60% (G-60-2), and 80% (G-80-2), and different unit sizes, including 1.5 mm (G-60-1.5), 2 mm (G-60-2), and 2.5 mm (G-60-2.5), are manufactured by a triply periodic minimal surface design and a reliable laser powder bed fusion process. With the same unit size, compressive strength (CS) and elastic modulus (EM) of scaffolds substantially decrease with increasing porosities. With the same porosity, CS and EM just slightly decrease with increasing unit sizes. The weight loss after degradation increases with increasing porosities and decreasing unit sizes. In vivo tests indicate that Zn-2Mg alloy scaffolds exhibit satisfactory biocompatibility and osteogenic ability. The osteogenic ability of scaffolds is mainly determined by their physical and chemical characteristics. Scaffolds with lower porosities and smaller unit sizes show better osteogenesis due to their suitable pore size and larger surface area. The results indicate that the biodegradable performance of scaffolds can be accurately regulated on a large scale by structure design and the additively manufactured Zn-2Mg alloy scaffolds have improved osteogenic ability for treating bone defects.
Sujet(s)
Ostéogenèse , Structures d'échafaudage tissulaires , Structures d'échafaudage tissulaires/composition chimique , Porosité , Alliages , ZincRÉSUMÉ
How to ensure dental stability in new positions and reduce the likelihood of relapse is a major clinical concern in the orthodontic field. Occlusal contacts between arches may affect the transmission of masticatory forces, thereby influencing the biological response of the periodontal and the oromandibular system. Occlusion factors that may influence the stability after orthodontic tooth movement (OTM) remain largely unknown. Hence, this research was conducted in order to investigate the influence of different occlusal contact patterns on tooth stability and oromandibular system including the masseter muscle and the temporomandibular joint following OTM. By modifying the occlusal surfaces, in vivo animal study models with distinct occlusal patterns corresponding to clinical circumstances were established. The relapse distance of teeth and the level of inflammatory factors in the gingival cervical fluid were analyzed. We also closely observed the histological remodeling of periodontal tissue, masseter tissue, and joint tissue after one week of relapse. Moreover, genes expression in the alveolar bone was analyzed to illustrate the potential biological mechanisms of relapse under the influence of different occlusal contact patterns following OTM. Different occlusal contact patterns after OTM in rats were established. The intercuspation contact between cusp and fossa group exhibited the lowest level of relapse movement, inflammatory factors and osteoclast activity (P < 0.05). On the other hand, groups with interferences or inadequate contacts exhibited more relapse movement, and tend to promote inflammation of periodontal tissue and activate bone resorption (P < 0.05). Adequate occlusal contacts without interference may enhance tooth stability and reduce the likelihood of relapse. After active orthodontic treatment, necessary occlusal adjustment should be made to achieve the desired intercuspation contact relationship and ensure adequate contact between the arches. The elimination of occlusal interferences is crucial to achieving optimal stability and promoting overall healthy condition of the oromandibular system.
Sujet(s)
Résorption osseuse , Mouvement dentaire , Rats , Animaux , Ostéoclastes , RécidiveRÉSUMÉ
BACKGROUND: Ferroptosis has been implicated in the pathological process of type 2 diabetic osteoporosis (T2DOP), although the specific underlying mechanisms remain largely unknown. This study aimed to clarify the role and possible mechanism of acid sphingomyelinase (ASM)-mediated osteoblast ferroptosis in T2DOP. METHODS: We treated hFob1.19 cells with normal glucose (NG) and different concentrations of high glucose (HG, 26.25 mM, 35 mM, or 43.75 mM) for 48 h. We then measured cell viability and osteogenic function, quantified ferroptosis and autophagy levels, and measured the levels of ASM and ceramide in the cells. To further investigate the specific mechanism, we examined these indicators by knocking down ASM expression, hydroxychloroquine (HCQ) treatment, or N-acetylcysteine (NAC) treatment. Moreover, a T2DOP rat model was induced and microcomputed tomography was used to observe the bone microstructure. We also evaluated the serum levels of iron metabolism-associated factors, ceramide and lipid peroxidation (LPO) and measured the expression of ASM, LC3 and GPX4 in bone tissues. RESULTS: HG inhibited the viability and osteogenic function of osteoblasts by inducing ferroptosis in a concentration-dependent manner. Furthermore, the expression of ASM and ceramide and autophagy levels were increased by HG treatment, and these factors were required for the HG-induced reactive oxygen species (ROS) generation and LPO. Similarly, inhibiting intracellular ROS also reduced HG-induced ASM activation and autophagy. ASM-mediated activation of autophagy was crucial for HG-induced degradation of GPX4, and inhibiting ASM improved osteogenic function by decreasing HG-induced autophagy, GPX4 degradation, LPO and subsequent ferroptosis. We also found that inhibiting ASM could alleviated ferroptosis and autophagy and improved osteogenic function in a T2DOP rat model. CONCLUSION: ASM-mediated autophagy activation induces osteoblast ferroptosis under HG conditions through the degradation of GPX4, providing a novel mechanistic insight into the treatment and prevention of T2DOP.
Sujet(s)
Diabète de type 2 , Ferroptose , Ostéoporose , Animaux , Rats , Autophagie , Céramides , Glucose , Ostéoporose/traitement médicamenteux , Ostéoporose/étiologie , Espèces réactives de l'oxygène , Sphingomyeline phosphodiesterase/génétique , Microtomographie aux rayons XRÉSUMÉ
Bioactive materials that communicate with bio-tissues via simultaneous chemical and electrical information promise an advanced medical treatment strategy. Rational design of simultaneous chemically and electrically active materials is still challenging. In this study, we develop a bioactive wound healing patch that enables functional recovery of scald skin wounds by integrating electrically and chemically active units at the molecular level. The patch should be used with massages for 10 min daily during the recovery process. This healing patch consists of a closely intertwined piezoelectric poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF) film and a self-adhesive poly(N,N-dimethylacrylamide) (PDMAA) hydrogel layer, which permits itself to adhere on skin wounds reversibly. Frequency-dependent electrical and chemical dose delivery is achieved in response to mechanical stimuli via the electrical-chemical crosstalk within the healing patch. Animal scald experiments show that the patch can effectively guide the functional recovery of grade I and shallow grade II scald wounds, promoting proper collagen deposition and hair follicle, blood vessel, and gland regeneration. Integrating electrically and chemically active units at the molecular level in treatment devices provides a new design concept for tissue engineering and medical treatment materials.
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Brûlures , Traumatismes des tissus mous , Animaux , Céments résine , Cicatrisation de plaie , Brûlures/traitement médicamenteux , Collagène/pharmacologie , Hydrogels/pharmacologieRÉSUMÉ
Zinc (Zn) alloy porous scaffolds produced by additive manufacturing own customizable structures and biodegradable functions, having a great application potential for repairing bone defect. In this work, a hydroxyapatite (HA)/polydopamine (PDA) composite coating was constructed on the surface of Zn-1Mg porous scaffolds fabricated by laser powder bed fusion, and was loaded with a bioactive factor BMP2 and an antibacterial drug vancomycin. The microstructure, degradation behavior, biocompatibility, antibacterial performance and osteogenic activities were systematically investigated. Compared with as-built Zn-1Mg scaffolds, the rapid increase of Zn2+, which resulted to the deteriorated cell viability and osteogenic differentiation, was inhibited due to the physical barrier of the composite coating. In vitro cellular and bacterial assay indicated that the loaded BMP2 and vancomycin considerably enhanced the cytocompatibility and antibacterial performance. Significantly improved osteogenic and antibacterial functions were also observed according to in vivo implantation in the lateral femoral condyle of rats. The design, influence and mechanism of the composite coating were discussed accordingly. It was concluded that the additively manufactured Zn-1Mg porous scaffolds together with the composite coating could modulate biodegradable performance and contribute to effective promotion of bone recovery and antibacterial function.
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Background: This study attempts to detect the potential effects of local bone morphogenetic protein -2 (BMP-2) on orthodontic tooth movement and periodontal tissue remodeling. Methods: Forty adult SD rats were randomly divided into four groups: blank control group, unilateral injection of BMP-2 on the pressure side or tension side of orthodontic teeth and bilateral injection of BMP-2. Their maxillary first molar was moved by a 30 g constant force closed coil spring. 60 µL of BMP-2 with a concentration of 0.5 µg/mL was injected into each part at a time. In addition, three rats were selected as healthy control rats without any intervention. Fluorescent labeled BMP-2 was used to observe the distribution of exogenous BMP-2 in tissues. Micro-CT was used to measure the microscopic parameters of tooth displacement, trabecular bone and root absorption volume. Three different histological methods were used to observe the changes of tissue remodeling, and then the number of osteoclasts and the content of collagen fibers were calculated. Results: Compared with the blank control group, BMP-2 injection reduced the movement distance and increased the collagen fiber content and bone mass (p < 0.01). There was no significant difference in tooth movement distance, BV/TV ratio and BMD between injection sites in unilateral injection group (p > 0.05). In the case of bilateral injection of BMP-2, the osteogenesis is enhanced. Unilateral injection of BMP-2 did not promote root resorption, but double injection showed root resorption (p < 0.01). Conclusion: Our study does show that the osteogenesis of BMP-2 is dose-dependent rather than site-dependent when a certain amount of BMP-2 is applied around orthodontic teeth. Local application of BMP-2 around orthodontic teeth in an appropriate way can enhance bone mass and tooth anchorage without increasing the risk of root absorption volume. However, high levels of BMP-2 may cause aggressive root resorption. These findings are of great significance, that is, BMP-2 is an effective target for regulating orthodontic tooth movement.
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High-capacity metal oxides based on non-toxic earth-abundant elements offer unique opportunities as advanced anodes for lithium-ion batteries (LIBs). But they often suffer from large volumetric expansion, particle pulverization, extensive side reactions, and fast degradations during cycling. Here, an easy synthesis method is reported to construct amorphous borate coating network, which stabilizes conversion-type iron oxide anode for the high-energy-density semi-solid-state bipolar LIBs. The nano-borate coated iron oxide anode has high tap density (1.6 g cm-3 ), high capacity (710 mAh g-1 between 0.5 - 3.0 V, vs Li/Li+ ), good rate performance (200 mAh g-1 at 50 C), and excellent cycling stability (≈100% capacity resention over 1,000 cycles at 5 A g-1 ). When paired with high-voltage cathode LiCoO2 , it enables Cu current collector-free pouch-type classic and bipolar full cells with high voltage (7.6 V with two stack layers), achieving high energy density (≈350 Wh kg-1 ), outstanding power density (≈6,700 W kg-1 ), and extended cycle life (75% capacity retention after 2,000 cycles at 2 C), superior to the state-of-the-art high-power LIBs using Li4 Ti5 O12 anode. The design and methodology of the nanoscale polyanion-like coating can be applied to other metal oxides electrode materials, as well as other electrochemical materials and devices.
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Piezocatalysis has received great attention in recent years. However, despite the great promise therein, high-performance piezocatalysts are still rare and the principles in designing high-performance piezocatalysts remain lacking. We demonstrate here a novel piezocatalyst design by integrating the oxidizing and reducing reaction sites heterojunction on a piezoelectric and conductive matrix. The catalytic composite generates reactive oxidizing species with unprecedented high capabilities. The â¢O2- yield is over 400% that of previously reported catalysts and for the first time realized effective piezocatalytic bactericidal effects over 99%. A range of structural features, including proper energy band alignments, high capacitance, patterned high conductivity, voltage-regulated wettability, and effective piezoelectrical capability, are believed to synergize for their high piezocatalytic performance. This study has extended the piezocatalysts with new design principles, effective descriptors of merits, new applications, and effective performance capabilities.
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The presence of periosteum can greatly affect the repair of a bone fracture. An artificial periosteum imitates the biological function of natural periosteum, which is capable of protecting and maintaining bone tissue structure and promoting bone repair. In our artificial periosteum, biocompatible methacrylate gelatin was used to provide the mechanical support of the membrane, E7 peptide added bioactivity, and Wharton's jelly provided the biological activity support of the membrane, resulting in a hydrogel membrane (G-E-W) for the chemotactic recruitment of bone marrow mesenchymal stem cells (BMSCs) and promoting cell proliferation and osteogenic differentiation. In an in vitro experiment, the G-E-W membrane recruited BMSCs and promoted cell proliferation and osteogenic differentiation. After 4 weeks and 8 weeks of implantation in a rat skull defect, the group implanted with a G-E-W membrane was superior to the blank control group and single-component membrane group in both quantity and quality of new bone. The artificial G-E-W membrane recruits BMSC chemotaxis and promotes cell proliferation and osteogenic differentiation, thereby effectively improving the repair efficiency of fractures and bone defects.
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There is an endogenous electric field in living organisms, which plays a vital role in the development and regeneration of bone tissue. Therefore, self-powered piezoelectric material for bone repair has become hot research in recent years. However, the current piezoelectric materials for tissue regeneration still have the shortcomings of lack of biological activity and three-dimensional structure. Here, we proposed a three-dimensional polyurethane foam (PUF) scaffold coated with piezoelectric poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and modified by a calcium phosphate (CaP) mineralized coating. The preferred scaffold has an open circuit voltage and short circuit current output of 5â V and 200â nA. Combining the physical and chemical properties of the CaP coating, the piezoelectric signal of PVDF-HFP and the three-dimensional structure of PUF, the scaffold exhibits superior promotion of cell osteogenic differentiation and ectopic bone formation inâ vivo. The mechanism is attributed to an increase in intracellular Ca2+ levels in response to chemical and piezoelectric stimulation with the material. This research not only paves the way for the application of piezoelectric scaffolds to stimulate osteoblasts differentiation inâ situ, but also lays the foundation for the clinical treatment of long-term osteoporosis.
Sujet(s)
Ostéogenèse , Structures d'échafaudage tissulaires , Polyvinyles/composition chimique , Différenciation cellulaireRÉSUMÉ
The specific surface area is one of the important indicators for measuring the quality of cement products. Realizing accurate prediction for specific surface area is very important for the production scheduling of the cement industry, energy conservation and consumption reduction and improvement of cement performance. However, due to the non-linearity, uncertainty, multiple interference, dynamic time-varying delay and multi scales in cement grinding process, it is difficult to establish an accurate soft-sensing model for cement quality prediction. Aiming at the above problems, we proposed a spatio-temporal decoupling convolution neural network model (STG-DCNN) to predict specific surface area by extracting and fusing data features in temporal and spatial dimension. To complete the prediction of specific surface area, we established the temporal series map and spatial series map by the production variables data according to the mechanism of cement grinding process. Then, sliding window technique was utilized to match the time scale in temporal series map and construct variable coupling relationship in spatial series map. The prediction accuracy, robustness and superiority of the proposed method were demonstrated by experiments results implemented on the actual cement grinding quality management database in a cement production enterprise.