Porous Nanofibrous Structure Research Articles

Enhanced differentiation of mesenchymal stem cells in coral-incorporated PCL/elastin scaffold enables 3D defect healing in osteoporosis rat model

In osteoporosis, bone quality adversely affects the tissue structural competence which increases the risk of a complicated fracture healing. In the present study highly potent scaffold containing natural coral particles was designed and considered for the healing of critical size bone defect in osteoporosis rat model. Scaffold morphological evaluation confirmed the porous nanofibrous structure. Water uptake of about 900 % was obtained for the fabricated scaffold as the result of its composition and three-dimensional structure. Mechanical analysis revealed the compressive modulus of about 50 kPa for the fabricated coral-incorporated nanofibrous structure. In vitro cellular assessments revealed that the designed scaffold induces no toxicity and provides the proper substrate for cell attachment together with increased and prolonged cell proliferation. In vivo experiments demonstrated that implantation of the fabricated scaffold in the femoral defects of osteoporotic rats significantly increased the number of osteocytes and osteoblasts, and enhanced the BTV, and BMP-2 expression compared with the control group. Furthermore, it was observed that seeding the scaffolds with MSCs prior to implantation, resulted in substantial improvements in mRNA expression of the BMP-2 and VEGF genes and considerable enhancement in stereological findings such as significantly higher number of osteoblasts, osteocytes, TVB, and BTV.

Preparation of NO-Releasing electrospun chitosan nanofibrous scaffolds for osteoconduction

ABSTRACT This study focuses on fabricating sodium nitroprusside-releasing chitosan-based (CS/SNP) nanofibers through electrospinning. Based on SEM images and FTIR spectroscopy, the application of one-step photocrosslinking significantly improved the stability of the nanofibers in aqueous environments. SEM images showed that the porous nanofibrous structure was maintained for up to 24 h. Incorporating SNP into the nanofibrous scaffolds demonstrated an enhanced biocompatibility with osteogenic cells. The cell viability increased with rising SNP content. Enhanced cell attachment, spreading, and proliferation were also observed through fluorescence microscope images of CS/SNP nanofibers, followed by the positive regulation of Smad and Runx2 pathway. The crosstalk between CS and NO reduced the possible toxicity and enhanced the osteoinductivity of NO. Furthermore, the nanofibers contributed to escalated osteogenic differentiation and mineralization, as evidenced by heightened expression of osteogenic markers such as alkaline phosphatase (ALP) expression and calcium deposition. Overall, the photo-crosslinked electrospun CS/SNP nanofibers demonstrate substantial potential as scaffolds in the field of bone tissue engineering.

Fabrication and Development of Binder-Free Mn-Fe-S Mixed Metal Sulfide Loaded Ni-Foam as Electrode for the Asymmetric Coin Cell Supercapacitor Device.

Currently, the fast growth and advancement in technologies demands promising supercapacitors, which urgently require a distinctive electrode material with unique structures and excellent electrochemical properties. Herein, binder-free manganese iron sulfide (Mn–Fe–S) nanostructures were deposited directly onto Ni-foam through a facile one-step electrodeposition route in potentiodynamic mode. The deposition cycles were varied to investigate the effect of surface morphologies on Mn–Fe–S. The optimized deposition cycles result in a fragmented porous nanofibrous structure, which was confirmed using Field Emission Scanning Electron Microscopy (FE−SEM). X-ray photoelectron spectroscopy (XPS) confirmed the presence of Mn, Fe, and S elements. The energy dispersive X-ray spectroscopy and elemental mapping revealed a good distribution of Mn, Fe, and S elements across the Ni-foam. The electrochemical performance confirms a high areal capacitance of 795.7 mF cm−2 with a 24 μWh cm−2 energy density calculated at a 2 mA cm−2 current density for porous fragmented nanofiber Mn–Fe–S electrodes. The enhancement in capacitance is due to diffusive-controlled behavior dominating the capacitator, as shown by the charge–storage kinetics. Moreover, the assembled asymmetric coin cell device exhibited superior electrochemical performance with an acceptable cyclic performance of 78.7% for up to 95,000 consecutive cycles.

Composite Superelastic Aerogel Scaffolds Containing Flexible SiO2 Nanofibers Promote Bone Regeneration (Adv. Healthcare Mater. 15/2022)

Hybrid Aerogel Scaffolds In article number 2200499 by Xiumei Mo and co-workers, inorganic-organic hybrid aerogel scaffolds are prepared by hybrid thermal crosslinking of organic poly lactic acid (PLA)/gel electrospun short nanofibers and flexible SiO2 electrospun short nanofibers. The electrospun nanofibrous aerogel scaffolds have excellent elasticity and porous structure, which enables them to have good shape memory for intimately filled articular bone defects. The silicon ions released from the PLA/gel/SiO2 aerogel scaffold with porous nanofibrous structure can promote the formation of blood vessels and the expression of bone-related genes, thereby promoting the regeneration of rat calvaria.

Investigation of co‐electrospun gelatin:TiO2/polycaprolactone:silk fibroin scaffolds for wound healing applications

AbstractElectrospinning is a facile technique to create porous nanofiber scaffolds with a high capability of natural environment mimicking. Here, co‐electrospinning of gelatin:TiO2, polycaprolactone:silk fibroin (G:T/P:F) was investigated with the aim of wound healing. Polycaprolactone improved the mechanical properties and gelatin:TiO2enhanced cellular interactions. Silk fibroin was extracted from theBombyx morisilkworm and increased the cellular and mechanical properties of the designed scaffolds. The morphology of the scaffolds was observed with field emission scanning electron microscopy (FESEM) and confirmed bead free porous nanofibrous structure. The fiber diameter rose after silk fibroin and TiO2addition but it was in the favorable fiber range. The contact angle, swelling, and mechanical properties of the G:T/P:F scaffolds supplied the requirements for skin tissue engineering. The designed scaffold showed over 80% cell viability with filopodia formation after 48 h according to cell adhesion observations and MTT assay results. The DAPI and LIVE/DEAD staining results confirmed high cell viability and the scratch assay observations proved the high wound healing potential of the G:T/P:F scaffolds. Furthermore, antibacterial properties were shown. It seems the designed scaffold can be useful in skin tissue regeneration. Further research may address the suggested skin scaffold.

Biocompatible Composite Microspheres of Chitin/Ordered Mesoporous Carbon CMK3 for Bilirubin Adsorption and Cell Microcarrier Culture.

Extra bilirubin in the blood can provoke serious illness in patients with severe liver disease. Hemoperfusion is an effective method to remove the extra bilirubin, but its application is limited by the low adsorption efficiency and poor biocompatibility of available adsorbent materials. In this study, chitin/ordered mesoporous carbon CMK3 (Ch/CMK3) microspheres are successfully prepared. Results of characterization experiments indicated that these composite microspheres possess a multilayered porous nanofibrous structure with an extremely large specific surface area (300.19 m2 g-1 ) and large pore size. Notably, the Ch/CMK3 microspheres demonstrated a high bilirubin adsorption capacity (228.19mg g-1 ) in phosphate buffer solution (PBS), and an outstanding bilirubin removal ratio (76.78% ± 4.40%) in the plasma of rabbits with hyperbilirubinemia without affecting the protein components. More importantly, the Ch/CMK3 microspheres showed no effect on other blood components, no cytotoxicity, and no systemic toxicity to mice. Cell co-culture experiments revealed that the microspheres can provide a 3-dimensional (3D) space to promote cell adhesion, proliferation, and nutrient exchange. These Ch/CMK3 microspheres featuring a strong ability for bilirubin adsorption and good biocompatibility can be a promising candidate in biomedical applications such as hemoperfusion, cell microcarrier, and 3D tissue engineering.

Preparation and sustained-release properties of poly(lactic acid)/graphene oxide porous biomimetic composite scaffolds loaded with salvianolic acid B.

Biomimetic scaffolds loaded with drugs can improve the osteogenesis and neovascularisation of scaffolds. A series of PLA/GO/Sal-B drug-loaded scaffolds was prepared by thermally induced phase separation. The addition of Sal-B increased the diameter of the fibres, but the scaffold showed a porous nanofibrous structure after drug release. X-ray diffraction results showed that the addition of Sal-B did not affect the formation of the nanofibre biomimetic structure of the scaffold. FTIR results indicated a certain interaction between Sal-B and PLA/GO. Water absorption and porosity test results revealed that the scaffolds had good hydrophilicity and appropriate porosity. The addition of Sal-B was also conducive to the formation of sediments possibly due to the good water solubility of Sal-B itself. The prepared scaffolds had good blood compatibility and cytocompatibility, and a small additional amount of Sal-B could significantly promote cell proliferation and alkaline phosphatase activity. Their sustained release performance indicated that the biomimetic scaffolds had controlled the release of Sal-B. The kinetic model showed that the PLA/GO/Sal-B drug-loaded biomimetic scaffolds followed the diffusion mechanism.

A Review on Electrospun Nanofibers Based Advanced Applications: From Health Care to Energy Devices.

Electrospun nanofibers have been exploited in multidisciplinary fields with numerous applications for decades. Owing to their interconnected ultrafine fibrous structure, high surface-to-volume ratio, tortuosity, permeability, and miniaturization ability along with the benefits of their lightweight, porous nanofibrous structure, they have been extensively utilized in various research fields for decades. Electrospun nanofiber technologies have paved unprecedented advancements with new innovations and discoveries in several fields of application including energy devices and biomedical and environmental appliances. This review article focused on providing a comprehensive overview related to the recent advancements in health care and energy devices while emphasizing on the importance and uniqueness of utilizing nanofibers. A brief description regarding the effect of electrospinning techniques, setup modifications, and parameters optimization on the nanofiber morphology was also provided. The article is concluded with a short discussion on current research challenges and future perspectives.

Thermal and Spectroscopic Analyses of Human Adipose Tissue-Derived Extracellular Matrix.

In this study, nanofibrous extracellular matrix (ECM) was prepared from human adipose tissue, and the stepwise products were analyzed using differential thermal analysis (DTA)/thermogravimetric analysis (TGA) and Fourier-transform infrared (FTIR)/Raman spectroscopy. Human adipose tissue was liposuctioned (sample 1), centrifuged (sample 2), pulverized, centrifuged again (sample 3), and finally freeze-dried (sample 4). Each sample was subjected to DTA/TGA and FTIR/Raman analyses. In the DTA curve of sample 1, the major peak was observed at approximately 60 °C. However, relatively flat DTA curves were detected in samples 2 and 4. In the TGA results, sample 1 showed a more rapid weight loss pattern than the other samples. Samples 1, 2, and 3 showed similar FTIR spectra with a strong, broad absorption feature at ~3400 cm-1. Amide I, II, and III bands were clearly observed in the FTIR spectrum of sample 4. Samples 1 and 2 showed typical adipose tissue Raman spectra. However, in samples 3 and 4, the Raman signal was low. Scanning electron microscopic analysis of the freeze-dried ECM (sample 4) confimed its three-dimensional porous nanofibrous structure. These findings suggest that human adipose tissue, intermediate products, and human adipose tissue-derived ECM can be easily and effectively characterized with thermal and spectroscopic analyses. These efficient analyses can aid in the preparation of ECM and in clinical applications for regenerative medicine.

Fabrication of polydopamine-based NIR-light responsive imprinted nanofibrous membrane for effective lysozyme extraction and controlled release from chicken egg white

The development of highly efficient performance matrix for protein adsorption and scalable throughput adsorbent is highly desired, especially in pharmaceuticals and food industries. In this work, we present a simple methodology to prepare a nanofibrous membrane based surface molecular imprinted matrix (MIP) for selective separation of lysozyme. The MIP was developed by coating carboxylated poly (vinyl alcohol-co-ethylene) nanofibrous mat (EVOH-CCA NFM) with a near infrared (NIR)-light responsive polydopamine (PDA) layer. The open porous nanofibrous structure and a thin PDA layer endowed the MIPs with adsorption capacity (500 mg.g−1) within 150 min. The developed surface MIPs not only showed imprinting factor (IF = 4) with reusability upon 5 cycles, but also capability of extracting lysozyme from egg-white directly. The MIPs showed controlled release of extracted lysozyme triggered by the NIR-light responsive property of the PDA layer. Moreover, the released lysozyme possesses good bioactivity, evidenced by efficient decomposition of micrococcus bacterial cell wall.

Electrospun PVP/PVA Nanofiber Mat as a Novel Potential Transdermal Drug-Delivery System for Buprenorphine: A Solution Needed for Pain Management

Over the past several decades, the formulation of novel nanofiber-based drug-delivery systems has been a frequent focus of scientists around the world. Aiming to introduce a novel nanofibrous transdermal drug-delivery system to treat pain, the nanofiber mats of buprenorphine-loaded poly (vinyl pyrrolidone) (Bup/PVP) and buprenorphine-loaded poly(vinyl alcohol)/poly(vinyl pyrrolidone) (Bup/PVP/PVA) were successfully fabricated by the electrospinning process for transdermal drug delivery. Similarly, PVP and PVP/PVA nanofibers were fabricated in the same conditions for comparison. The viscosity and electrical conductivity of all electrospinning solutions were measured, and nanofiber mats were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy and contact angle analysis. The conductivity of PVP and PVP/PVA solutions showed a considerable increase by the addition of buprenorphine due to the polarity of buprenorphine. SEM images showed a smooth, fine and porous nanofibrous structure without any adhesion or knot for all of the samples. The contact angle analysis showed the increased hydrophilicity and wettability of PVP/PVA and Bup/PVP/PVA nanofibers compared to PVP and Bup/PVP nanofibers which can be attributed to the addition of PVA. Attenuated total reflectance (ATR) FT-IR results confirmed that the electrospinning process did not affect the chemical integrity of the drug. For the modification of the drug release rate, the cross-linking of nanofiber mats was carried out using glutaraldehyde. Drug release measurements using high-performance liquid chromatography (HPLC) analysis demonstrated that Bup/PVP/PVA nanofibers exhibited better physical and chemical properties compared to Bup/PVP. Furthermore, the cross-linking of nanofibers led to an increase in drug release time. Thus, the novel buprenorphine-loaded nanofibers can be efficient biomaterial patches for transdermal delivery against pain improving carrier retention and providing a controlled release of the drug.

Parametric Finite Element Model and Mechanical Characterisation of Electrospun Materials for Biomedical Applications.

Electrospun materials, due to their unique properties, have found many applications in the biomedical field. Exploiting their porous nanofibrous structure, they are often used as scaffolds in tissue engineering which closely resemble a native cellular environment. The structural and mechanical properties of the substrates need to be carefully optimised to mimic cues used by the extracellular matrix to guide cells’ behaviour and improve existing scaffolds. Optimisation of these parameters is enabled by using the finite element model of electrospun structures proposed in this study. First, a fully parametric three-dimensional microscopic model of electrospun material with a random fibrous network was developed. Experimental results were obtained by testing electrospun poly(ethylene) oxide materials. Parameters of single fibres were determined by atomic force microscopy nanoindentations and used as input data for the model. The validation was performed by comparing model output data with tensile test results obtained for electrospun mats. We performed extensive analysis of model parameters correlations to understand the crucial factors and enable extrapolation of a simplified model. We found good agreement between the simulation and the experimental data. The proposed model is a potent tool in the optimisation of electrospun structures and scaffolds for enhanced regenerative therapies.

Nailed-bat like halloysite nanotube filled polyamide 6,6 nanofibers by electrospinning

ABSTRACT The present study focuses on fabrication and characterization of halloysite nanotube (HNT) filled polyamide 6,6 nanocomposite fibers. HNTs were incorporated into the spinning solution at various concentration levels changing from 5 to 30 wt%. To understand the changes in the fiber morphology, viscosity, and conductivity of the electrospining solutions were also investigated. Depending on the filler ratio, increase in the solution viscosity was around 5–19%. However the change in solution conductivity was not significant and around 0.22–2.5 %. In addition to solution properties, morphology, structure, thermal and mechanical properties of the electrospun nanocomposite fibers were characterized. Morphological analysis showed the highly porous nanofibrous mat structure for all samples. HNT filled samples showed higher average fiber diameter than PA 6,6 fibers with the values around 105–162 nm. One significant outcome of the study was to obtain nano nailed-bat like morphology. During the electrospinning some of the halloysite nanotubes protruded from the fiber axis and formed nano nailed-bat like morphology. HNT/PA 6,6 nanofibers showed better thermal stability. T10% values moved around 5–30 °C and char yield increased to 9–27% based on the filler ratio. On the other hand, the tensile strength of the HNT/PA 6,6 nanofibers decreased around 32–42%.

Urethra-inspired biomimetic scaffold: A therapeutic strategy to promote angiogenesis for urethral regeneration in a rabbit model

Limited angiogenesis and epithelialization make urethral regeneration using conventional tissue-engineered grafts a great challenge. Consequently, inspired from the native urethra, bacterial cellulose (BC) and bladder acellular matrix (BAM) were combined to design a three dimensional (3D) biomimetic scaffold. The developed BC/BAM scaffold was engineered for accelerating urethral regeneration by enhancing angiogenesis and epithelialization. The BC/BAM scaffold reveals the closest mimic of native urethra in terms of the 3D porous nanofibrous structure and component including collagen, glycosaminoglycans, and intrinsic vascular endothelial growth factor (VEGF). In vitro studies showed that the bioinspired BC/BAM scaffold promoted in vitro angiogenesis by facilitating human umbilical vein endothelial cells (HUVECs) growth, expression of endothelial function related proteins and capillary-like tube formation. Effect of the BC/BAM scaffold on angiogenesis and epithelialization was studied by its implantation in a rabbit urethral defect model for 1 and 3 months. Results demonstrated that the improved blood vessels formation in the urethra-inspired BC/BAM scaffold significantly promoted epithelialization and accelerated urethral regeneration. The urethra-inspired BC/BAM scaffold provides us a new design approach to construct grafts for urethral regeneration. Statement of significanceFindings in urethral regeneration demonstrate that an ideal tissue-engineered urethra should have adequate angiogenesis to support epithelialization for urethral regeneration in vivo. In this study, inspired from the native urethra, a bioinspired bacterial cellulose/bladder acellular matrix (BC/BAM) scaffold was developed to promote angiogenesis and epithelialization. The designed scaffold showed the closest physical structure and component to natural urethra, which is beneficial to angiogenesis and regeneration of urethral epithelium. This is the first time to utilize BC and dissolved BAM to develop biomimetic scaffold in urethral tissue engineering. Our biomimetic strategy on urethra graft design provided enhanced angiogenesis and epithelialization to achieve an accelerated and successful rabbit urethral repair. We believe that our urethra-inspired biomimetic scaffold would provide new insights into the design of urethral tissue engineering grafts.

P8. Electrospun synthetic bone grafts promote mesenchymal stem cell function and spinal fusion

BACKGROUND CONTEXT Synthetic bone grafts are being developed to lessen the need for autograft and allograft. Electrospun bone grafts (ESBG) have a highly porous nanofibrous structure with a large surface area-to-volume ratio, potentially improving its osteoconductive and osteoinductive properties. PURPOSE We investigate the potential of ESBG to stimulate mesenchymal stem cell (MSC) function in vitro, and to facilitate BMP-2 mediated spinal fusion in a rat model. STUDY DESIGN/SETTING In vitro analysis of MSC adhesion, proliferation, and differentiation seeded in ESBG. In vitro analysis of ESBG-facilitated posterolateral spine fusion in a rat model. PATIENT SAMPLE For the in vitro study: MSCs seeded with and without ESBG. For the in vivo study: 36 Lewis rats underwent posterolateral spine fusions. OUTCOME MEASURES In vitro: adhesion, proliferation, and osteogenic differentiation of MSCs. In vivo: rat fusion rate, fusion stiffness, fusion bone volume, fusion connectivity density and histological evaluation. METHODS Adhesion, proliferation, and osteogenic differentiation of MSCs seeded with and without ESBG for 7 days was analyzed. In vivo, 36 rats underwent posterolateral spine fusions in the following groups: (I) ESBG+bone marrow aspirate (BMA), (II) ESBG+BMA+BMP-2 (low-dose), and (III) BMA. Rats were followed for 3 months and the fusion masses were characterized with manual palpation, biomechanical tests, micro-CT and histological evaluation. RESULTS Ninety percent of cultured MSCs adhered to ESBG. When seeded in ESBG, there was a significant increase in MSC proliferation (0.18 to 0.43, p CONCLUSIONS This is the first reported characterization of ESBG for spinal applications. ESBGs provide a novel scaffold that supports MSC binding, proliferation and osteogenic differentiation. In a rat spine fusion model, ESBG impregnated with BMA and low-dose BMP-2 allowed for 100% fusion with strong biomechanical properties. ESBGs represent a promising synthetic graft and should be further investigated for clinical feasibility. FDA DEVICE/DRUG STATUS Unavailable from authors at time of publication.

Structure and mechanical properties of nanofibrous ZrO2 derived from alternating field electrospun precursors

Abstract Nanofibrous zirconia (ZrO2) meshes were prepared from precursor fibers which were synthesized using the method of free-surface, high-yield alternating field electrospinning (AFES). The weight ratio of zirconyl chloride salt to polyvinylpyrrolidone (PVP) polymer in liquid precursors was investigated for its effect on the spinnability and formation of precursor fibers as well as on the resulting fibrous ZrO2. The precursor fiber generation measured at a rate up to 5.6 g/h was achieved with a single flat 25-mm diameter alternating current (AC) electrode, which corresponded to production of up to 1.5 g/h of fibrous ZrO2. The calcination process involved annealing the fibers at temperatures which ranged from 600 °C to 1000 °C and produced 0.1–0.2 mm thick fibrous ZrO2 meshes. Individual nanofibers were found to have diameters between 50 and 350 nm and either a tetragonal (t-ZrO2) or monoclinic (t-ZrO2) structure depending on the calcination temperature. The annealed meshes with total porosity between 98.0 ± 0.2% and 94.6 ± 0.2% showed little deformation or cracking. Tensile strength and modulus of fibrous t-ZrO2 meshes strongly depended on porosity and varied from 0.07 ± 0.03 MPa to 1.05 ± 0.3 MPa and from 90 ± 40 MPa to 388 ± 20 MPa, respectively. The m-ZrO2 meshes resulted similar moduli, but much lower strengths due to their brittleness. A power-law relationship between the elastic modulus and porosity of AFES-derived nanofibrous t-ZrO2 meshes, in comparison with other porous zirconia materials, was also investigated. The results of this study have demonstrated the feasibility of free-surface AFES in sizeable production of zirconia nanofibers and highly porous nanofibrous ceramic structures.

Electrospun Polycaprolactone Nanofibers as a Reaction Membrane for Lateral Flow Assay.

Electrospun polycaprolactone (PCL) nanofibers have emerged as a promising material in diverse biomedical applications due to their various favorable features. However, their application in the field of biosensors such as point-of-care lateral flow assays (LFA) has not been investigated. The present study demonstrates the use of electrospun PCL nanofibers as a reaction membrane for LFA. Electrospun PCL nanofibers were treated with NaOH solution for different concentrations and durations to achieve a desirable flow rate and optimum detection sensitivity in nucleic acid-based LFA. It was observed that the concentration of NaOH does not affect the physical properties of nanofibers, including average fiber diameter, average pore size and porosity. However, interestingly, a significant reduction of the water contact angle was observed due to the generation of hydroxyl and carboxyl groups on the nanofibers, which increased their hydrophilicity. The optimally treated nanofibers were able to detect synthetic Zika viral DNA (as a model analyte) sensitively with a detection limit of 0.5 nM. Collectively, the benefits such as low-cost of fabrication, ease of modification, porous nanofibrous structures and tunability of flow rate make PCL nanofibers a versatile alternative to nitrocellulose membrane in LFA applications. This material offers tremendous potential for a broad range of point-of-care applications.

Facile synthesis of mesoporous NiCo2O4 fibers with enhanced photocatalytic performance for the degradation of methyl red under visible light irradiation

Mesoporous NiCo2O4 fibers were synthesized by the coordination co-precipitation-decomposition method using ammonia as morphology-controller. The as-prepared NiCo2O4 powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis absorption spectra and photoluminescence (PL) analysis. The as-prepared NiCo2O4 materials showed typical intertwined porous nanofibrous structures with specific surface area of 74.6 m2/g and average pore size of 11.79 nm. The mesoporous NiCo2O4 fibers showed remarkably enhanced photocatalytic performance towards methyl red (MR) degradation under visible-light irradiation compared to the Co3O4 and NiO. The degradation efficiency of MR over the NiCo2O4 reached up to 95.1% after irradiation for 120 min. Superior photocatalytic activity of 1D NiCo2O4 fibers can be attributed to the higher light harvesting capacity resulted from large surface area and unique mesoporous structure. Finally, a possible mechanism for the photodegradation of MR over the NiCo2O4 was proposed.

An aligned porous electrospun fibrous membrane with controlled drug delivery – An efficient strategy to accelerate diabetic wound healing with improved angiogenesis

A chronic wound in diabetic patients is usually characterized by poor angiogenesis and delayed wound closure. The exploration of efficient strategy to significantly improve angiogenesis in the diabetic wound bed and thereby accelerate wound healing is still a significant challenge. Herein, we reported a kind of aligned porous poly (l-lactic acid) (PlLA) electrospun fibrous membranes containing dimethyloxalylglycine (DMOG)-loaded mesoporous silica nanoparticles (DS) for diabetic wound healing. The PlLA electrospun fibers aligned in a single direction and there were ellipse-shaped nano-pores in situ generated onto the surface of fibers, while the DS were well distributed in the fibers and the DMOG as well as Si ion could be controlled released from the nanopores on the fibers. The in vitro results revealed that the aligned porous composite membranes (DS-PL) could stimulate the proliferation, migration and angiogenesis-related gene expression of human umbilical vein endothelial cells (HUVECs) compared with the pure PlLA membranes. The in vivo study further demonstrated that the prepared DS-PL membranes significantly improved neo-vascularization, re-epithelialization and collagen formation as well as inhibited inflammatory reaction in the diabetic wound bed, which eventually stimulated the healing of the diabetic wound. Collectively, these results suggest that the combination of hierarchical structures (nanopores on the aligned fibers) with the controllable released DMOG drugs as well as Si ions from the membranes, which could create a synergetic effect on the rapid stimulation of angiogenesis in the diabetic wound bed, is a potential novel therapeutic strategy for highly efficient diabetic wound healing. Statement of SignificanceA chronic wound in diabetic patients is usually characterized by the poor angiogenesis and the delayed wound closure. The main innovation of this study is to design a new kind of skin tissue engineered scaffold, aligned porous poly (l-lactic acid) (PlLA) electrospun membranes containing dimethyloxalylglycine (DMOG)-loaded mesoporous silica nanoparticles (DS), which could significantly improve angiogenesis in the diabetic wound bed and thereby accelerate diabetic wound healing. The results revealed that the electrospun fibers with ellipse-shaped nano-pores on the surface were aligned in a single direction, while there were DS particles distributed in the fibers and the DMOG as well as Si ions could be controllably released from the nanopores on the fibers. The in vitro studies demonstrated that the hierarchical nanostructures (nanopores on the aligned fibers) and the controllable released chemical active agents (DMOG drugs and Si ions) from the DS-PL membranes could exert a synergistic effect on inducing the endothelial cell proliferation, migration and differentiation. Above all, the scaffolds distinctly induced the angiogenesis, collagen deposition and re-epithelialization as well as inhibited inflammation reaction in the wound sites, which eventually stimulated the healing of diabetic wounds in vivo. The significance of the current study is that the combination of the hierarchical aligned porous nanofibrous structure with DMOG-loaded MSNs incorporated in electrospun fibers may suggest a high-efficiency strategy for chronic wound healing.

Constructing three-dimensional nanofibrous bioglass/gelatin nanocomposite scaffold for enhanced mechanical and biological performance

The unique properties of bioactive glasses (BGs) make them promising for bone regeneration. Unfortunately, their brittleness greatly limits their clinical application. Combining BGs with polymers is an ideal solution such that their advantages (toughness of the polymers and bioactivity of BGs) can be combined. In this work, a novel nanocomposite biomaterial consisting of BG nanofibers with a diameter of only 31nm and gelatin coating has been developed for bone regeneration. The BG nanofibrous scaffold was synthesized via a template-assisted sol-gel method by using natural three-dimensional (3D) bacterial cellulose as the template. The BG nanofibers were subsequently coated with gelatin followed by crosslinking with proanthocyanidin (PA) to yield the BG/gelatin nanocomposite scaffolds. Characterizations with scanning electron microscope (SEM), transmission electron microscope (TEM), atomic force microscope (AFM), mercury intrusion porosimetry, nitrogen adsorption–desorption, and mechanical testing reveal that the as-obtained BG/gelatin scaffolds maintain the 3D interconnected porous nanofibrous structure of pristine BC, show tri-modal pore structure (20–60μm, 1–2μm, 3–32nm), and exhibit improved mechanical strength over bare BG scaffold. Cell studies using primary osteoblasts demonstrate more favorable cell growth, higher alkaline phosphatase (ALP) activity, and more calcium deposition on the BG/gelatin scaffold than other nanocomposite scaffolds as well as bare BG scaffold, strongly indicating a coating thickness-dependent synergistic effect between BGs and gelatin. This novel type of BG/gelatin scaffold has great potential in applications of bone regeneration.