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Radiotherapy is a pivotal means of cancer treatment, but it often leads to radiation dermatitis, a skin injury caused by radiation-induced excess reactive oxygen species (ROS). Scavenging free radicals in the course of radiation therapy will be an effective means to prevent radiation dermatitis. This study demonstrates a novel double network hydrogel doped with MoS2 nanosheets for the prevention of radiation-induced dermatitis. The resultant SPM hydrogel constructed from polyacrylamide (PAM) and sodium alginate (SA) nanofiber presented favorable mechanical and adhesion properties. It could conform well to the human body's irregular contours without secondary dressing fixation, making it suitable for skin protection applications. The in vitro and in vivo experiments showed that the antioxidant properties conferred by MoS2 nanosheets enable SPM to effectively mitigate excessive ROS and reduce oxidative stress, thereby preventing radiation dermatitis caused by oxidative damage. Biosafety assessments indicated good biocompatibility of the composite hydrogel, suggesting SPM's practicality and potential as an external dressing for skin radiation protection. [ABSTRACT FROM AUTHOR]

Chopped fiber (CF)- and nano-hydroxyapatite (n-HA)-enhanced silk fibroin (SF) porous hybrid scaffolds (SHCF) were prepared by freeze-drying for bone augmentation. Compared with pristine SF scaffolds, the incorporation of CF and n-HA can significantly enhance the mechanical properties of the composite scaffold. The results of cell experiments and mouse subcutaneous implantation indicated that the SHCF could alleviate foreign body reactions (FBR) led by macrophages and neutrophils, promote the polarization of RAW264.7 cells to anti-inflammatory M2 macrophages, and inhibit the secretion of pro-inflammatory cytokine TNF-α. A rat femoral defect repair model and bulk-RNA-seq analysis indicated that the CF- and n-HA-enhanced SHCF promoted the proliferation and osteogenic differentiation of bone mesenchymal stem cells (BMSCs) by the upregulation of Capns1 expression and regulated the calcium signaling pathway to mediate osteogenesis-related cell behavior, subsequently promoting bone regeneration. [ABSTRACT FROM AUTHOR]

The promotion of vascular network formation in the early stages of implantation is considered a prerequisite for successful functional bone regeneration. In this study, we successfully constructed 3D printed scaffolds with strong mechanical strength and a controllable pore structure that can sustainably release strontium (Sr) ions and simvastatin (SIM) for up to 28 days by incorporation of Sr2+ and SIM-loaded hydroxyapatite microspheres (MHA) into a poly(ε-caprolactone) (PCL) matrix. In vitro cell experiments showed that Sr-doped scaffolds were beneficial to the proliferation and osteogenic differentiation of bone mesenchymal stem cells (BMSCs), an appropriate dose of SIM was beneficial to cell proliferation and angiogenesis, and a high dose of SIM was cytotoxic. The Sr- and SIM-dual-loaded scaffolds with an appropriate dose significantly induced osteogenic differentiation of BMSCs and tube formation of human umbilical vein endothelial cells (HUVECs) in vitro and promoted vascular network and functional bone formation in vivo. Ribose nucleic acid (RNA) sequencing analysis suggested that the mechanism of promotion of vascularized bone regeneration by fabricated scaffolds is that dual-loaded Sr2+ and SIM can upregulate osteogenic and vasculogenic-related genes and downregulate osteoclast-related genes, which is beneficial for vascular and new bone regeneration. The 3D printed composite scaffolds loaded with high-stability and low-cost inorganic Sr2+ ions and SIM small-molecule drugs hold great promise in the field of promoting vascularized bone regeneration. [ABSTRACT FROM AUTHOR]

The deformation shrinkage of a poly(lactide-co-glycolide) (PLGA) fibrous material seriously affects its biomedical application. To demonstrate the underlying shrinking mechanism and to find a method to prevent the shrinkage of an electrospun PLGA membrane, we investigated the shrinking behavior of PLGA electrospun membranes under various test conditions and discussed the underlying shrinking mechanism. The results indicated that the shrinkage of the electrospun PLGA membrane was mainly regulated by the glass transition of its polymer fiber; the temperature and liquid environment were found to be the two main factors leading to the shrinkage of the electrospun PLGA membrane through affecting its glass transition. Then a heat stretching (HS) technique was proposed by us to stabilize the electrospun PLGA membrane. After HS treatment, the glass transition temperature (Tg) of the electrospun PLGA membrane could increase from 48.38 °C to 54.55 °C. Our results indicated that the HS-treated membranes could maintain a high area percentage of 90.89 ± 2.27% and 84.78 ± 3.36% after immersion respectively in PBS and blood at 37 °C for 2 hours. Further experiments confirmed that the HS technique could also stabilize the dimensional structure of the electrospun PDLLA membrane in PBS and blood at 37 °C. This study provides an effective strategy for preventing the shrinkage of electrospun polyester biomaterials in a physiological environment that may benefit both the material structural stability and the in vivo biological performance. [ABSTRACT FROM AUTHOR]

The ideal scaffold for bone repair should have a hierarchical pore structure and gradient degradation performance to satisfy the uniform adhesion and proliferation of cells in the scaffold at the early stage of implantation, as well as providing space for the subsequent regeneration of bone tissue. To this end, we developed a hierarchical polylactic acid glycolic acid copolymer (PLGA)/nano-hydroxyapatite (n-HA)/gelatin (Gel) (PHG) scaffold with a printed PLGA/n-HA (PH) framework and a Gel network filler for bone regeneration by the combination of 3D printing and freeze-drying technologies. The fabricated PHG scaffold features large front hole size (>1100 μm × 1100 μm) and side hole size (>500 μm) to provide sufficient open space and reliable integrated support for cell and tissue ingrowth. The gelatin network filled in the PH framework played the role of a cell holder just like an extracellular matrix (ECM) in the early stage. In vitro degradation experiments revealed that the gelatin network completely degraded within 5 weeks while the structural integrity of the framework still remained at the 32nd week. The results of cell culture confirmed that the PHG scaffold was more conducive to cell attachment. In vivo assessments in a rat femoral defect model showed that PHG scaffolds were more favored for new bone formation and achieving a tighter bond between the scaffold and the original tissues. The hierarchical PHG scaffold has great application potential in bone tissue engineering and will provide a reference for the model design of bone scaffolds. [ABSTRACT FROM AUTHOR]

To solve the high instances of failure caused by endodontic reinfection, herein, an improved root filling material was produced to meet the multi-functional demand of sealers for root canal therapy. In this study, polyurethane (PU)-based nanocomposites were prepared by loading bismuth oxide, hydroxyapatite and antibacterial agents, namely Ag3PO4 and ZnO nanoparticles, which were named CP-Ag and CP-Zn sealers, respectively. A parallel biological evaluation at bacterial and cellular levels was performed to determine the fate of the different components of the PU-based sealers. Furthermore, the composition of sealers was quantified by screening their antibacterial activity and apoptotic factors, considering the potential toxicity of the nanoparticles and high dosage of metals. The in vitro optimization investigation was conducted systematically against Streptococcus mutans and Staphylococcus aureus, including bacteriostatic and dynamic tests, and the expression of the B-cell lymphoma-2 gene family and caspase proteases in the mitochondria-mediated apoptotic pathway was evaluated using the commercial AH Plus® and Apexit® Plus sealers for comparison. Additionally, the physical properties and sealing ability of sealers were assessed. The results showed that all PU-based sealers could meet the requirements of ISO 6876:2012 for root canal sealing materials. Based on the evaluation system, CP-Zn sealers expressed longer lasting antibacterial activity and lower toxic effect on cells compared to CP-Ag sealers. Especially, the CP-Zn5 sealer exhibited selective antimicrobial efficacy and hypo-toxicity, which were better than that of the two commercial sealers. According to the two-dimensional and three-dimensional methods, the good sealing ability of the CP-Zn5 sealer is the same as the excellent filling characters of AH Plus, which adapts to irregular root canals. [ABSTRACT FROM AUTHOR]

Attributed to their structure and composition manipulated to mimic natural bone tissue, porous scaffolds composed of inorganic nano-hydroxyapatite (n-HA) and organic polymers with different degrees of degradability have been proven to be a promising bone regeneration strategy. However, long-term and in-depth comparative research on the effects of scaffolds with different matrices and degrees of degradability on bone reconstruction is still lacking. In this study, the ultralong-term osteogenic performance of three polymeric composite scaffolds based on non-degradable polyamide 66 (PA66), slowly degradable polycaprolactone (PCL) and fast degradable poly (lactic-co-glycolic acid) (PLGA) were investigated comparatively after implanting the scaffolds into rabbit femoral defects for 12, 15, 18 and 21 months. The results demonstrated that the structural integrity of the scaffolds played a positive role in long-term bone reconstruction. Thus the n-HA/PA66 and n-HA/PCL scaffolds have a higher relative bone volume and bone density than the n-HA/PLGA scaffolds from 12 to 21 months. In addition, the favorable surface wettability and collagen-like molecular structure should endow the n-HA/PA66 scaffold with the best long-term osteogenic property among the three scaffolds. The ultralong-term comparative study reveals that a relatively stable scaffold integrity, together with favorable matrix molecular characteristics and hydrophilicity, may be more important for long-term osteogenesis besides the effect of scaffold pore structure, rather than the pursuit of fast scaffold degradation. The results also show that the space left by scaffold degradation is not easily occupied by new bone tissue, especially after bone tissue has formed a stable structure or the bone interface has become inert. [ABSTRACT FROM AUTHOR]

Scaffolds composed of polymers and nano-hydroxyapatite (n-HA) have received extensive attention in bone reconstructive repair; however there is a lack of in-depth and long-term comparative study on the effect of scaffold degradability on bone reconstruction. In this study, the osteogenic behaviors of three polymeric composite scaffolds based on fast degradable poly(lactic-co-glycolic acid) (PLGA), slowly degradable polycaprolactone (PCL) and non-degradable polyamide 66 (PA66) were investigated and compared via implanting the scaffolds into rabbit femoral defects for 1, 3, 6 and 12 months. The in vivo results demonstrated that although the n-HA/PLGA scaffold could obtain higher new bone volume at 3 months, its fast degradation caused the loss of scaffold structural integrity and led to reduction of bone volume after 3 months. The n-HA/PCL scaffold displayed slow degradation mainly after 6 months (∼20% degradation) and the n-HA/PA66 scaffold showed no degradation during the entire 12 months; these two scaffolds could maintain their structural integrity and exhibited a constant increase in bone volume with the implantation time, and even achieved higher bone volume than the n-HA/PLGA scaffold at 12 months. The year-long in vivo research revealed the following important aspects: (1) bone reconstruction is strongly related to scaffold degradability, and the scaffold structural integrity should be maintained at least for one year before complete degradation in vivo; (2) the in vivo experiment of a bone scaffold must take more time than the conventional 3 or 6 months, which is normally neglected. The study suggests a principle for future design and application of bone scaffolds that must have a relatively stable osteogenic space and scaffold interface, or have a scaffold degradation speed slower than the time of bone reconstruction completion. [ABSTRACT FROM AUTHOR]

in order to build fibrous bone tissue scaffolds for guided bone regeneration and to mimic the trilayer structure and the multifunctional properties of the natural periosteum, we fabricated two fibrous trilayer membranes by conjugate electrospinning technology, in which poly(ε-caprolactone) (PCL) fiber was designed as an outer layer, the mixed fibers of PCL and polyurethane (co-PUPCL) as the interlayer, and degradable polyurethane fibers with or without nano-hydroxyapatite (n-HA) as the inner layer (PUHA or PU). The microstructure and characteristics of the trilayer membranes were evaluated and different monolayer fibers were fabricated as the contrast samples. The tensile strength values of each layer increased from the inner layer to the outer layer in the designed structure, while the step-by-step electrospinning method produced good adhesion of different layers. Furthermore, the degradable properties and hydrophilicity of the layers changed with dissymmetric fibrous structures. Cell proliferation assay and cell morphology observation indicated that the PUHA inner fibrous layer exhibited better cell attachment and proliferation than PU. In addition, the osteogenicity of the PUHA fibrous layer has been attested through protein expression by the differentiation of rat mesenchymal stem cells (rMSCs) into the osteogenic lineage. Cell infiltration testing on the two sides of the trilayer membranes in vitro and in vivo showed that the inner layer had good cellular penetration deep into the scaffolds, whereas the cells were barred by the outer layer. We have developed a trilayer structured membrane with different polymer fibers to replicate the natural periosteum by improving functional outcomes, which is a promising fibrous scaffold for clinical use in the repair of destroyed bone. [ABSTRACT FROM AUTHOR]

ZnCo2O4 nanowire cluster arrays (NWCAs) were directly grown on Ni foam via a facile hydrothermal method. The resulting products were analyzed by using X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The ZnCo2O4 NWCAs on Ni foam were directly used as integrated electrodes for supercapacitors and exhibited a high specific capacitance of 4.05 F cm-2 at 20 mA cm-2 (1620 F g-1 at 8 A g-1) in 3 M KOH aqueous solution, and an excellent cycling ability at various current densities up to 100 mA cm-2 (40 A g-1); 90% of the initial capacitance remained after 6000 cycles. Moreover, the asymmetric supercapacitor had a high energy density of 41.00 W h kg-1 at a power density of 384 W kg-1 and 16.63 W h kg-1 at a high power density of 2561 W kg-1. Such excellent rate properties and superior cycling life suggest that ZnCo2O4 NWCAs can not only be applied in high energy density fields, but also used in high power density applications. [ABSTRACT FROM AUTHOR]

In this study, we investigated the nanocomposites composed of graphene, SnOx and carbon fibers (CFs) for humidity sensing applications. The composites were obtained by an electrospinning method followed by addition of graphene. SnOx/CFs uniformly dispersed into graphene nanosheets. SnOx and graphene were proved to be promising sensing materials. The amorphous carbon fibers could supply more channels for transportation of protons or electrons. Therefore, the composites exhibited high humidity sensing performance. The resistance of the sensor increases two times with decreasing relative humidity from 55% to 30%. The sensitivity to humidity increased by almost 100% after adding graphene to SnOx/CF nanocomposites. The response and recovery times were 8 s and 6 s at 30% RH, respectively. The results demonstrated that rational design of nanocomposites with graphene could be a favorable strategy to improve humidity sensing properties. [ABSTRACT FROM AUTHOR]

In order to repair the soft magnetic properties of wasted silicon steel, a theoretical process of co-depositing Co-Fe soft magnetic alloy on the surface of wasted silicon steel is proposed. The results show that the co-deposited Co-Fe alloy coatings can serve to repair the soft magnetic properties of wasted silicon as detected by the vibrating sample magnetometer, and the alloy coatings with Co 7 Fe 3 as the main phase structure can provide surface protection for silicon steel. Subsequently, the mechanism of co-deposited Co-Fe alloys was investigated, and it was concluded that Co 2+ and Fe 2+ undergo a one-step two-electron co-deposition reaction, as studied using cyclic voltammetry. The chronoamperometric analysis and its fitting results indicated that the deposition of Co 2+ and Fe 2+ was a diffusion-controlled transient nucleation process, and the AC impedance indicated that higher voltages were favorable for the deposition of Co-Fe alloys but were accompanied by hydrogen precipitation reactions., Competing Interests: All authors disclose no relevant relationships., (This journal is © The Royal Society of Chemistry.)