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Bone is the second most common connective tissue worldwide and more than four million bone grafts or substitutes are used annually to treat bone defects. Due to the restrictions of using these therapies, today the development of bioactive 3D scaffolds has become a major field in bone tissue engineering. The main aim of this study was to fabricate polylactic acid/ polycaprolactone bone scaffolds by freeze extraction method. In order to improve the rheological, mechanical and biological properties of these scaffolds, hydroxyapatite, silica and their mixture were used as the filler loaded into scaffolds (35 wt%). All scaffolds were fabricated in three different concentrations of 5, 6.5 and 8% w/w based on polymer to investigate the effect of polymer concentration on their properties. In this regard, to evaluate the surface morphology of scaffolds and the size of pores, SEM analysis and porosity test were used. FTIR analysis was performed to identify functional groups and possible molecular interactions in the scaffold. The degree of degradation of scaffolds was conducted when incubated in PBS and also to better investigate the mechanical properties, a compression test was performed on cylindrical specimens. SEM images indicated that the pores were interconnected in the composite scaffolds and their size varied from 23 to 114 μm. The amount of porosity of the scaffolds made in this project ranged from 62.2 to 84.1%. These values demonstrated that the scaffolds prepared by the freeze extraction method had suitable pore sizes for use in tissue engineering. Considering the morphology and porosity as well as the appropriate pore size distribution in the 6.5% hybrid sample, this scaffold was selected as the optimal scaffold. The results indicated that the hydrophilicity of the scaffold surface was improved by the addition of silica nanoparticles and hydroxyapatite. The use of HA alone improved the mechanical properties of the porous structure, but the addition of SiO2 to HA more effectively strengthened the scaffolds. Furthermore, in samples containing silica, an increase in degradation was observed. According to the results of MTT test, the constructed scaffolds not only did not show cytotoxicity but also increased the rate of cell growth and proliferation. Pathological images showed that ECM deposition and collagen deposition were significantly higher in the hybrid groups from the third week onwards than in the other groups. [ABSTRACT FROM AUTHOR]

Along with providing an environment for cell attachment and proliferation, a tissue engineering scaffolds should possess physical and mechanical properties that would fit the target tissue. The present study aimed to manipulate physico-mechanical properties of polyacrylamide/gelatin hydrogels using response surface method-central composite design (RSM-CCD) to reach a scaffold with defined properties. On this demand, mixtures of gelatin and acrylamide (AAm) monomer were used to prepare semi-interpenetrating hydrogels by free radical polymerization of AAm. Selected variables for statistical modeling were chosen to be weight ratios of monomer/crosslinker, monomer/gelatin, and monomer/initiator. The desired responses were compressive modulus, compressive strength, and swelling. Results showed that desired responses could be tailored by varying these parameters with the highest impact for monomer/crosslinker ratio. The swelling ratio of hydrogels was in the range of 947–1654%, while the modulus varied between 5 and 35 kPa. The cyclic compressive test showed the durability of hydrogels under cyclic loadings. Finally, the results of cell attachment and cytocompatibility analyses indicated that the hydrogels were completely biocompatible and enhanced cell attachment. Thus, these hydrogels could potentially be used as tissue engineering scaffolds for load-bearing organs, including muscle and cartilage, or could be used for in vitro differentiation of stem cells using mechanical clues. [ABSTRACT FROM AUTHOR]

Gel treatment using preformed particle gels is a technique applied in mature reservoirs to control excess water production. In this study, a novel nanocomposite gel was proposed and optimized for better performance in high-salinity and high-temperature conditions of oilfields. Gels were prepared by grafting copolymerization of crosslinked polyacrylamide onto starch (starch-g-CPAM) and loaded with silica nanoparticles. Different tests were performed on nanocomposite prepared particle gels (NCPPGs) to investigate the effect of silica content (2–10 wt%), temperature, and brine concentration on network structure, swelling, and mechanical behavior of the gels. The NCPPG with 5 wt% showed a superior swelling ratio. Rheological studies depicted that nanosilica could increase the mechanical strength of the NCPPGS in high temperature and high salinity brines (90 °C and 225,000 ppm) up to 900 Pa. Finally, loading nanosilica up to 5 wt. % into the NCPPG resulted in capable mechanical stability and water uptake under harsh conditions. [ABSTRACT FROM AUTHOR]

• Nanocomposites were synthesized by copolymerization of AM/AMPS in modified NPs dispersions in-situ. • NPs were modified with TMS to incorporate vinyl functional groups on their surfaces. • The behavior of nanocomposite solutions was investigated for oil recovery application. • Adding NPs results in a polymer crosslinking network and a stable solid hybrid system. • Nano-silica makes polymer solutions possess better heat and shear resistance than nano-alumina. Many nanoparticles such as silicon dioxide (SiO 2) and aluminum oxide (Al 2 O 3) have been recently proposed to increase the performance of water-soluble polymers for use in oil recovery (EOR). However, nanoparticles in nanocomposites tend to precipitate, agglomerate, or even precipitate under harsh conditions such as high-temperature and high-salinity (HT-HS), which reduces their potential for field applications. In this work, silica and alumina nanoparticles were modified with 3-methoxysilyl-propyl-methacrylate (TMS) coupling agent containing a vinyl group to enhance better dispersibility in reaction media and much stronger adhesion with the polymer. Then, acrylamide (AM) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) monomers were copolymerized in the presence of modified NPs via radical polymerization and were covalently bound to the NPs. In this study, the effect of AM/AMPS ratio and alumina as well silica loading amount on thermal stability, rheological properties and aging of composite solution was investigated and compared with commercial HPAM used for EOR. Results depicted that used method of synthesis could improve the rheological properties and better dispersion of nanoparticles in the polymer. It was found that the modified nanoparticles reduced the thermal degradation of the polymer and protect its original structure when compared to the neat copolymer. After 30 days of aging, the loss of viscosity in PAMS and HPAM was approximately 46% and 75% while PAMS10-Silica2% and PAMS10-Alumina2% exhibited a viscosity loss of 27%. [ABSTRACT FROM AUTHOR]

• In situ modification of sawdust was done and magnetized sawdust is obtained. • The effect of magnetorheological properties on absorption capacity was studied. • Highly hydrophobic and oleophilic properties was revealed due to surface modification with polymer. • Magnetorheological behavior of the fluid (oil + modified sawdust) was modeled with Bingham plastic model. • The effect of magnetic field on the formation of parallel web of magnetic particles was studied. Protecting the environment is important for its impact on the life of humans and organisms. Oil pollution is one of the most important factors affecting the life of creatures. Here we are looking for the way to magnetize oil contamination by modified sawdust. The iron oxide nanoparticles were coated in situ on the sawdust using co-precipitation method, which magnetized the sawdust. Subsequently, the magnetic sawdust was successfully functionalized with a saline coupling agent to form a highly hydrophobic and oleophilic surface. FE-SEM, FTIR, EDXA, VSM, WCA and optical microscopy were performed to complete characterization of the products. In addition, a new magnetorheological (MR) fluid based on the crude oil and magnetized sawdust was developed and its rheological properties studied by a rheometer furnished with a magnetic field generator. The results were completely fitted using Bingham model. The strong MR response induced in the crude oil by adding the modified sawdust could exhibit a high crude oil removal capacity of about 47 times the modified sawdust weight. [ABSTRACT FROM AUTHOR]

• Maleic terminated PEG (PEG-MA) was synthesized without use of any catalyst. • Chitosan/PEG-MA hydrogels were fabricated using facile thermal crosslinking method. • In vitro and in vivo results showed complete biocompatibility and accelerated wound closure for hydrogels. The aim of this study was to fabricate a hydrogel based therapy to accelerate full-thickness wound healing process. Hydrogel matrix was composed from of chitosan as backbone and maleic terminated polyethylene glycol (PEG-MA) as crosslinking agent. PEG-MA was synthesized through a reaction of PEG with maleic anhydride. For hydrogel preparation, various PEG-MA/chitosan ratios were assessed to find the optimum ratio. Further improvement on hydrogel properties was achieved by adding TiO 2 nanoparticles to the matrix. PEG-MA synthesis was confirmed using 1H NMR and FTIR. Several characteristics of hydrogels, including swelling ratio, mechanical properties, water contact angle, and in vitro biocompatibility were appraised for both TiO 2 -free hydrogels and TiO 2 loaded hydrogels. Optimum hydrogels were then selected for in vivo analysis. Results indicate that hydrogels have a porous structure with swelling ratio in the range of 240–280%. In vitro estimations also revealed that hydrogels are completely biocompatible, while they could support human fibroblast cell proliferation during tested time (7 days). In vivo biocompatibility and full-thickness wound closure tests proved the biocompatibility of hydrogels in vivo and accelerated wound closure, respectively, in rat models. Overall, our findings indicate that the fabricated hydrogels are good nominates for wound healing applications as they enhance the wound contraction process with improved vascularization. [ABSTRACT FROM AUTHOR]

• Polymer/fiber composite membrane was presented for gas separation. • Capillary condensation mechanism occurred for CO 2 transport in polymer/fiber interface. • Composite membranes showed simultaneous enhancements in CO 2 permeability and CO 2 /CH 4 ideal selectivity. One of the most important shortcomings of the polymeric membranes in comparison with inorganic membranes is the trade-off between permeability and selectivity. Gas permeability in inorganic membranes follows different mechanisms including capillary condensation mechanism. The aim of present study was improving the polymeric membranes performance by introducing capillary condensation mechanism for the gas transport similar to that observed in the inorganic membranes. Capillary condensation of gases needs a continuous diffusion pathway, therefore in the present study short glass wool fibers (with a micro size in diameter and millimeter size in length) were chosen as a proper alternative instead of nanoparticles. Short glass wool fibers present proper dispersion in the Pebax matrix as a result of its good compatibility with polymer segments. Gas permeability behavior in such composite membranes was assisted using pure CO 2 , CH 4 and N 2 gases. Obtained results demonstrated that gas permeability behavior in the short fiber reinforced composite membranes is depends on the fiber content. At lower content of the fiber, such reinforcement causes simultaneous increment in gas permeabilities in a way that 62.37%, 32.12% and 50.71% increase in permeability was observed for CO 2 , CH 4 , and N 2 respectively. But at higher content due to formation of more continuous interface, capillary condensation was appeared for more condensable gas (CO 2) which results in 17.65% reduction in its permeability. Based on the results the using of short fiber instead of nanoparticles in polymeric membranes can be more beneficial in performance and economic point of view. [ABSTRACT FROM AUTHOR]

Polymers are used in various industries and, particularly in the medical industry, the use of skin-friendly, biocompatible materials is essential. In this field, using natural and biocompatible carbonaceous materials to replace petroleum-derived materials is the most efficient solution. In this study, which was performed in two phases, polyurethane foam made from natural polyol obtained from rapeseed oil (RPO) and containing silver (Ag) nanoparticles for use in wound dressings was prepared and examined. In the first phase, bio-based polyurethane was prepared via a specific method and characterized using Fourier-transform infrared and nuclear magnetic resonance analysis. Polyol foams were prepared using different ratios of natural polyol to a petroleum based polyol. The results of the water absorption test showed that PF-NPO-35 (containing 35% natural polyol) has a 145% absorption rate. The water vapor transfer rate test was also conducted on this sample, giving results in the range of 8–9 mg cm−2 h−1, which is a suitable range for a wound dressing application. After selecting PF-NPO-35 as the optimal sample, different amounts of Ag nanoparticles were added to this sample and the final foams with different percentages of Ag nanoparticles were prepared. The antibacterial properties of the samples showed that PF-NPO-35-Ag-7 (7% Ag nanoparticles) was more sensitive to Escherichia coli than to Staphylococcus aureus. Increasing the amount of Ag nanoparticles improved the antibacterial properties. Cytotoxicity tests also showed that all samples containing Ag nanoparticles survived for 48 h. High levels of cell viability were observed in the presence of the synthetic foams. In the animal tests, the healing process of the wounds treated with a sample containing silver nanoparticles showed improved progress after 14 days. [ABSTRACT FROM AUTHOR]

In this study, we have demonstrated a facile method to convert corncob, an abundant and low-cost bio-waste, into a superhydrophobic magnetic bio-sorbent with potential application in oil spill remediation. We immobilized CoFe 2 O 4 nanoparticles on the surface of corncob using the co-precipitation method to magnetize the surface of the bio-waste. Additionally, we applied silica and octadecylamine (ODA) coatings to create a rough and low surface energy sorbent material, respectively, which significantly improved its oil sorption capacity. The fabricated magnetic composite exhibited excellent magnetic responsivity (saturation magnetization: 32 emu/g), superhydrophobicity (water contact angle: 165˚), and superoleophilicity (oil contact angle: 0˚). The modified corncob (MCC) powder was easily separated using a magnetic field and showed oil sorption capacity 22.13, 13.33, 57.65, and 44.17 times its original weight for crude oils with API 23.5° and 29.7°, fresh and used motor oil, respectively. The fabricated bio-sorbent could be recovered and reused in oil-water separation at least 10 times, with a water contact angle and sorption capacity of 158.5˚ and 42 g/g, respectively, after 10 cycles. Furthermore, it displayed remarkable durability in corrosive media. We compared the performance of MCC powder with three different bio-wastes, including coconut husk, acorn, and rice husk, and found that MCC powder and coconut husk showed preferable performance over the others. Overall, our study provides a facile and efficient method for converting corncob and other bio-wastes into a superhydrophobic magnetic bio-sorbent for oil spill cleanup. [Display omitted] • Different bio-wastes including corncob, acorn shell, coconut and rice husk were used to produce recyclable magnetic sorbents. • The modified magnetic bio-sorbents exhibited excellent hydrophobicity and oleophilicity. • Fast and selective removal of oils from water surface was maintained with modified bio-wastes. • Modified corncob sorbent showed super oil remediation even after ten cycles and under corrosive environment. [ABSTRACT FROM AUTHOR]

A high-gradient magnetic separator that utilizes two kinds of plate including flat and lattice plates to provide a high-gradient magnetic field and separate magnetic particles from suspension was investigated in this paper. The separation of magnetic particles by in-situ observation has been carried out, and the results indicated that the magnetic particles formed shapes like a spike at the entrance of the separation system where magnetic particles were influenced by the magnetic field. Although long spike shapes were also observed at lower flow rates and lower magnetic field, the spikes appeared to be denser under the conditions of high magnetic field and high flow rates. The results achieved from in-situ observations can provide valuable information for the simulation of such a system. The two most important experimental variables, flow rate and distance between magnets, have been optimized for the separation of magnetic particles from suspension. The most efficient backwash system was also offered to reuse magnetic particles. The suggested system can be used to separate magnetic particles larger than 50 μm where using filter matrix is limited due to fast clogging. [ABSTRACT FROM AUTHOR]

In this research, short fiber/polymer composite membranes is introduced for gas separation. Our attempt is to increase the membranes performance by using wide interface between fiber and polymer. Short glass wool fiber (SGWF) was used as a polar micro size reinforcement and was mechanically dispersed in polyurethane matrix. Scanning electron microscope (SEM) images showed that fibers have a good dispersion and adhesion to polymer matrix. In order to survey the phase separation and crystallization behavior of polyurethane segments, differential scanning calorimetery (DSC) and dynamic mechanical thermal analysis (DMTA) were used. The results indicated that polar surface of glass wool is a suitable site for attraction of hard segments. Thermal transition of soft segments were assisted using DMTA. Obtained results were showed that the presence of glass wool fiber remarkably reduced the soft segments glass transition temperature (T g ). Gas permeation properties of membranes were assisted using pure CO 2 , CH 4 and N 2 gases. Presence of SGWF caused a simultaneous increase in permeability and ideal selectivity (permselectivity) in a way that composite membranes showed high performance. Thus, using of fiber instead of nanoparticles in polymeric membranes can be more beneficial in view of economic and performance for industrial applications. [ABSTRACT FROM AUTHOR]

Amino-functionalized magnetic mesoporous microsphere has been successfully synthesized through a two-step coating process of silica on a magnetic core (FeO). In the synthesis process, cetyltrimethyl ammoniumbromide (CTAB) was used as a structure-directing agent and it was removed by combination of solvent extraction and calcination modified processes. In this method, mesoporous silica shell with higher surface area was formed which could facilitate the loading of much more amino groups and the capacity to adsorb more heavy metal ions such as Zn was provided. Different amounts of 3-aminopropyl triethoxysilane (APTES) were examined in order to obtain an optimum amount of amino groups which can be grafted on FeO/SiO/ meso-SiO microsphere. The resultant multifunctional microsphere was characterized by field emission scanning electron microscope, transmission electron microscope, FTIR spectrophotometer, X-ray diffraction, vibration sample magnetometer, thermogravimetric analysis, nitrogen adsorption-desorption and particle size analyzer. Comparing to functionalized amino group on traditional magnetic mesoporous silica, the as-prepared microsphere not only exhibited higher specific surface area (617.31 m g) but also demonstrated higher adsorption capacity for Zn(II) (270.2703 mg g at 25 °C). Important of all, the adsorbent was simply removed from sample solution by magnetic field and it was regenerated by acid treatment. Graphical Abstract: Synthetic route of FeO/SiO/ meso-SiO-NH and its use for Zn(II) ions removal. [ABSTRACT FROM AUTHOR]

Integrally skinned asymmetric membranes based on nanocomposite polyethersulfone were prepared by the phase separation process using the supercritical CO 2 as a nonsolvent for the polymer solution. All the membranes have been prepared from originally dense nanocomposite films inducing asymmetry by the formation of the porous layer adding N,N-dimethylacetamide as solvent and supercritical CO 2 (SC-CO 2 ) to one side of the dense films, and then allowing the supercritical CO 2 expansion to occur. The effect of pressure, temperature and nanoparticles on the permeability of CH 4 and CO 2 and also selectivity performance of membranes has been investigated. The results showed that the membranes formation pressures which varied from 100 to 120 bar have significant effect on the pore sizes and thickness of obtained dense and porous layers. Also, the effect of the temperature which varied from 45 to 55 °C has been evaluated and it was concluded that by changing the temperature, it is possible to induce a very-controlled asymmetry in a dense film and pore sizes and thus increasing in CO 2 permeability and selectivity performance of membranes. Finally, the permeability of CH 4 and CO 2 measured at the constant temperatures of 30, 40 and 50 °C and at the pressures of 8, 10 and 12 bar and the effects of temperature and nanoparticle on selectivity performance and permeability of gases has been investigated. [ABSTRACT FROM AUTHOR]

Abstract: The transport performances of carbon dioxide (CO2) and methane (CH4) gases were investigated in polyesterurethane mixed matrix membranes (MMMs), in separate tests, containing different fumed silica nanoparticles. Non-modified and commercially-modified silica (with octylsilane and polydimethylsiloxane) were used as fillers. The structural characteristics of the membranes were studied by scanning electron microscopy, infrared spectroscopy, X-ray diffraction and differential scanning calorimetry to confirm some interactions between the PU and nanoparticles and the changes induced in PU microphase in the presence of silica. Surface treatment of silica filler with long hydrophobic chains reduced the aggregation of nanoparticles and improved dispersion in MMMs. Addition of silica nanoparticles into PU matrix increased both separation factor and CO2 permeation in the membranes. The fumed silica disrupted chain packing and increased dynamic free volume to improve CO2 permeation regardless of silica type. The results revealed that among silica nanoparticles, the unmodified particles with OH groups on their surface showed better performance for CO2/CH4 separation. In our current research, a new model for prediction of gas permeation through PU/silica membranes was proposed considering the presence of filler aggregation in the matrix as well as free volume at the interface layer. [Copyright &y& Elsevier]

Highlights: [•] MMMs based on polyetherurethane and polyesterurethane, comprising silica prepared. [•] The gas transport properties of CH4 and CO2 in the membranes were investigated. [•] The selectivity of CO2 over CH4 through membranes increased with silica content. [•] ESPU/silica membranes showed higher gas permeability compared to ETPU/silica ones. [•] ESPU/silica had a greater CO2/CH4 selectivity than ETPU/silica membranes. [Copyright &y& Elsevier]

This study was focused on the optimization of synthesis conditions of iron oxide nanoparticles coated by silica and 3- (trimethoxysilyl) propyl methacrylate, Fe 3 O 4 @SiO 2 @MPS, as an oil absorbent with magnetic properties. The change in the structure and its effect on the oil absorption capacity of these core-shell magnetic nanoparticles (MNP) were investigated upon pH and reactant concentration variations. An excellent oil sorption capacity of about 48.5 times of MNPs weight was reached and this work clearly demonstrated the relationship between the absorption capacity and hydrodynamic diameter of magnetic clusters formed in two different crude oils. The particles were fully characterized by field emission electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), vibrating sample magnetometer (VSM), energy dispersive X-ray spectroscopy(EDS), Brunauer Emmett Teller (BET) analysis and water contact angle in order to compare the morphology, magnetic, structural properties and specific surface area of the nanoparticles. • Magnetic nanoparticles were optimized to have the highest sorption capacity. • Effect of medium polarity on absorption capacity was investigated. • There was an optimal point for sorption capacity based on hydrodynamic radius. • Both adsorption and absorption had role in such a high sorption capacity. • The lower the pH, the higher the coagulation of MNPs [ABSTRACT FROM AUTHOR]

3D printing-based technologies can fabricate scaffolds offer great precision to control internal architecture and print complicated structures based upon the defect site. However, the materials used in the direct printing are restricted depending on the printing technology used and the indirect one can overcome this limitation. In the present study, indirect 3D printing approach was used to develop bone scaffolds from polylactic acid/ polycaprolactone/ hydroxyapatite (PLA/PCL/HA) composites. Casting of the composite suspensions was done into a dissolvable 3D printed negative mold, in order to achieve simultaneous macro- and micro-porous composites, using freeze drying/particle leaching method. To evaluate morphology, functional groups, and elemental analysis of the scaffolds, scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and energy dispersive spectroscopy (EDS) were respectively used. Scaffolds' porosity was measured with the aid of liquid replacement technique. Also, the mechanical strength of scaffolds was examined by compression test and measuring the compressive modulus Considering the microstructure, porosity and pore size as well as mechanical property, the scaffold composed of PLA/PCL 70/30 w /w and 35% HA was more favorable. The PLA/PCL/HA 70/30–35% scaffold presented a porosity of 77%, an average pore size of 160 μm, and Young's modulus of 1.35 MPa. Cell adhesion, viability and mineral deposits formation for PLA/PCL/HA scaffolds at PLA/PCL ratios of 70/30, 50/50 and 30/70 and the fixed amount of HA (35%) were also studied in vitro by the means of MG63 cells. The cytotoxicity assessment showed that the cells could be viable and proliferate on the scaffolds. The results indicated that composite scaffold with the PLA/PCL weight ratio of70/30 accomplished more favorable properties in terms of biocompatibility, viability, and osteoinduction property. Unlabelled Image • PLA/PCL/HA scaffolds were fabricated by indirect 3D printing method. • Macro- and micro-porous structure was obtained with an appropriate porosity. • Increasing HA resulted in decreased porosity and increased compressive modulus. • PLA rich scaffolds showed higher compressive modulus than PCL rich samples. • The prepared scaffolds were capable of proliferating MG63 cells on their surfaces. [ABSTRACT FROM AUTHOR]

Osteoconductive biomaterials were used to find the most reliable materials in bone healing. Our focus was on the bone healing capacity of the stem cell–loaded and unloaded PLA/PCL/HA scaffolds. The 3D scaffold of PLA/PCL/HA was characterized by scanning electron microscopy (SEM), rheology, X-ray diffraction (XRD), and Fourier transform-infrared (FT-IR) spectroscopy. Bone marrow stem cells (BMSCs) have multipotential differentiation into osteoblasts. Forty Wistar male rats were used to organize four experimental groups: control, autograft, scaffold, and BMSCs-loaded scaffold groups. qRT-PCR showed that the BMSCs-loaded scaffold had a higher expression level of CD31 and osteogenic markers compared with the control group (P < 0.05). Radiology and computed tomography (CT) scan evaluations showed significant improvement in the BMSCs-loaded scaffold compared with the control group (P < 0.001). Biomechanical estimation demonstrated significantly higher stress (P < 0.01), stiffness (P < 0.001), and ultimate load (P < 0.01) in the autograft and BMSCs-loaded scaffold groups compared with the untreated group and higher strain was seen in the control group than the other groups (P < 0.01). Histomorphometric and immunohistochemical (IHC) investigations showed significantly improved regeneration scores in the autograft and BMSCs-loaded scaffold groups compared with the control group (P < 0.05). Also, there was a significant difference between the scaffold and control groups in all tests (P < 0.05). The results depicted that our novel approach will allow to develop PLA/PCL/HA 3D scaffold in bone healing via BMSC loading. [ABSTRACT FROM AUTHOR]

• Bilayered nanofibers of PCL/Gel loaded with n-ZnO and amoxicillin were fabricated. • Scaffolds showed prolonged steady release profile for the drug. • Presence of drug could give antibacterial activity to scaffolds while did not adversely affected their biocompatibility. • Scaffolds accelerated mesenchymal stromal cell proliferation. • Scaffolds promoted angiogenesis and full-thickness wound healing. Treatment of diabetic, chronic, and full-thickness wounds is a challenge as these injuries usually lead to infections that cause delayed and inappropriate healing. Therefore, fabrication of skin scaffolds with prolonged antibacterial properties are of great interest. Due to this demand, bilayered nanofibrous scaffolds were fabricated based on polycaprolactone and gelatin. The top layer of these scaffolds contained amoxicillin as a model drug and the bottom layer was loaded with zinc oxide nanoparticles to accelerate wound healing. Several characterization techniques including FTIR, SEM, swelling, tensile test, in vitro degradation, drug release, antibacterial activity, and MTT assay were used to assess physical, mechanical, and biological properties of produced nanofibers. SEM results demonstrated that bilayered scaffolds have smooth bead-free microstructures while in vitro release test showed that samples have a sustained release for amoxicillin up to 144 h (tested time). Disk diffusion assessment confirmed the potency of scaffolds for hindering bacterial growth while results of cytotoxicity evaluation revealed that scaffolds could effectively accelerate cell proliferation. Finally, in vivo tests on full-thickness rat models revealed that fabricated nanofibers accelerate wound contraction, increase collagen deposition and angiogenesis, and prevent scar formation. Altogether, results showed that fabricated scaffolds are promising candidates for treatment of full-thickness wounds. [ABSTRACT FROM AUTHOR]