Electrospun Nanofibrous Meshes Research Articles

Peptide direct growth on poly(acrylic acid)/poly(vinyl alcohol) electrospun fibers coated with branched poly(ethylenimine): A solid-phase approach for scaffolds biofunctionalization

Due to their resemblance to the fibrillar structure of the extracellular matrix, electrospun nanofibrous meshes are currently used as porous and mechanically stable scaffolds for cell culture. In this study, we propose an innovative methodology for growing peptide sequences directly onto the surface of electrospun nanofibers. To achieve this, electrospun fibers were produced from a poly(acrylic acid)/poly(vinyl alcohol) blend that was thermally crosslinked and subjected to a covalent coating of branched poly(ethylenimine). The exposed amino functionalities on the fiber surface were then used for the direct solid-phase synthesis of the RGD peptide sequence. In contrast to established strategies, mainly involving the grafting of pre-synthesized peptides onto the polymer chains before electrospinning or onto the nanofibers surface, this method allows for the concurrent synthesis and anchoring of peptides to the substrate, with potential applications in combinatorial chemistry. The incorporation of this integrin-binding motive significantly enhanced the nanofibers' ability to capture human cervical carcinoma (HeLa) cells, selected as a proof of concept to assess the functionalities of the developed material.

Immunobiology of foreign body response to composite PLACL/gelatin electrospun nanofiber meshes with mesenchymal stem/stromal cells in a mouse model: Implications in pelvic floor tissue engineering and regeneration

Pelvic Organ Prolapse (POP) is a common gynaecological disorder where pelvic organs protrude into the vagina. While transvaginal mesh surgery using non-degradable polymers was a commonly accepted treatment for POP, it has been associated with high rates of adverse events such as mesh erosion, exposure and inflammation due to serious foreign body response and therefore banned from clinical use after regulatory mandates. This study proposes a tissue engineering strategy using uterine endometrium-derived mesenchymal stem/stromal cells (eMSC) delivered with degradable poly L-lactic acid-co-poly ε-caprolactone (PLACL) and gelatin (G) in form of a composite electrospun nanofibrous mesh (P + G nanomesh) and evaluates the immunomodulatory mechanism at the material interfaces. The study highlights the critical acute and chronic inflammatory markers along with remodelling factors that determine the mesh surgery outcome. We hypothesise that such a bioengineered construct enhances mesh integration and mitigates the Foreign Body Response (FBR) at the host interface associated with mesh complications. Our results show that eMSC-based nanomesh significantly increased 7 genes associated with ECM synthesis and cell adhesion including, Itgb1, Itgb2, Vcam1, Cd44, Cdh2, Tgfb1, Tgfbr1, 6 genes related to angiogenesis including Ang1, Ang2, Vegfa, Pdgfa, Serpin1, Cxcl12, and 5 genes associated with collagen remodelling Col1a1, Col3a1, Col6a1, Col6a2, Col4a5 at six weeks post-implantation. Our findings suggest that cell-based tissue-engineered constructs potentially mitigate the FBR response elicited by biomaterial implants. From a clinical perspective, this construct provides an alternative to current inadequacies in surgical outcomes by modulating the immune response, inducing angiogenesis and ECM synthesis during the acute and chronic phases of the FBR.

Electrospun Nanofibrous Mesh Based on PVA, Chitosan, and Usnic Acid for Applications in Wound Healing.

Injuries and diseases of the skin require accurate treatment using nontoxic and noninvasive biomaterials, which aim to mimic the natural structures of the body. There is a strong need to develop biodevices capable of accommodating nutrients and bioactive molecules and generating the process of vascularization. Electrospinning is a robust technique, as it can form fibrous structures for tissue engineering and wound dressings. The best way of forming such meshes for wound healing is to choose two polymers that complement each other regarding their properties. On the one hand, PVA is a water-soluble synthetic polymer widely used for the preparation of hydrogels in the field of biomedicine owing to its biocompatibility, water solubility, nontoxicity, and considerable mechanical properties. PVA is easy to subject to electrospinning and can offer strong mechanical stability of the mesh, but it is necessary to improve its biological properties. On the other hand, CS has good biological properties, including biodegradability, nontoxicity, biocompatibility, and antimicrobial properties. Still, it is harder to electrospin and does not possess as good mechanical properties as PVA. As these structures also allow the incorporation of bioactive agents due to their high surface-area-to-volume ratio, the interesting point was to incorporate usnic acid into the structure as it is a natural and suitable alternative agent for burn wounds treatment which avoids an improper or overuse of antibiotics and other invasive biomolecules. Thus, we report the fabrication of an electrospun nanofibrous mesh based on PVA, chitosan, and usnic acid with applications in wound healing. The obtained nanofibers mesh was physicochemically characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). In vitro biological assays were performed to evaluate the antimicrobial properties of the samples using the MIC (minimum inhibitory concentration) assay and evaluating the influence of fabricated meshes on the Staphylococcus aureus biofilm development, as well as their biocompatibility (demonstrated by fluorescence microscopy results, an XTT assay, and a glutathione (GSH) assay).

Chondrogenic differentiation induced by extracellular vesicles bound to a nanofibrous substrate

Extracellular vesicles (EVs) are being increasingly studied owing to its regenerative potential, namely EVs derived from human bone marrow mesenchymal stem cells (hBM-MSCs). Those can be used for controlling inflammation, repairing injury, and enhancing tissue regeneration. Differently, the potential of EVs derived from human articular chondrocytes (hACs) to promote cartilage regeneration has not been thoroughly investigated. This work aims to develop an EVs immobilization system capable of selectively bind EVs present in conditioned medium obtained from cultures of hACs or hBM-MSC. For that, an anti-CD63 antibody was immobilized at the surface of an activated and functionalized electrospun nanofibrous mesh. The chondrogenic potential of bound EVs was further assessed by culturing hBM-MSCs during 28 days under basal conditions. EVs derived from hACs cultured under differentiation medium or from chondrogenically committed hBM-MSCs induced a chondrogenic phenotype characterized by marked induction of SOX9, COMP, Aggrecan and Collagen type II, and matrix glycosaminoglycans synthesis. Indeed, both EVs immobilization systems outperformed the currently used chondroinductive strategies. These data show that naturally secreted EVs can guide the chondrogenic commitment of hBM-MSCs in the absence of any other chemical or genetic chondrogenic inductors based in medium supplementation.

Prevention of excessive scar formation using nanofibrous meshes made of biodegradable elastomer poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

To reduce excessive scarring in wound healing, electrospun nanofibrous meshes, composed of haloarchaea-produced biodegradable elastomer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), are fabricated for use as a wound dressing. Three PHBV polymers with different 3HV content are used to prepare either solution-cast films or electrospun nanofibrous meshes. As 3HV content increases, the crystallinity decreases and the scaffolds become more elastic. The nanofibrous meshes exhibit greater elasticity and elongation at break than films. When used to culture human dermal fibroblasts in vitro, PHBV meshes give better cell attachment and proliferation, less differentiation to myofibroblasts, and less substrate contraction. In a full-thickness mouse wound model, treatment with films or meshes enables regeneration of pale thin tissues without scabs, dehydration, or tubercular scar formation. The epidermis of wounds treated with meshes develop small invaginations in the dermis within 2 weeks, indicating hair follicle and sweat gland regeneration. Consistent with the in vitro results, meshes reduce myofibroblast differentiation in vivo through downregulation of α-SMA and TGF-β1, and upregulation of TGF-β3. The regenerated wounds treated with meshes are softer and more elastic than those treated with films. These results demonstrate that electrospun nanofibrous PHBV meshes mitigate excessive scar formation by regulating myofibroblast formation, showing their promise for use as wound dressings.

Measurement of Adhesion of In Situ Electrospun Nanofibers on Different Substrates by a Direct Pulling Method

In some cases, we hope to remove the electrospun nanofibrous mesh from the collector easily. But in some cases such as wound dressing, we observe that the in situ electrospun nanofibers can stick to the collector (e.g., skin). Therefore, the adhesion between the in situ electrospun web and the substrate becomes important in the performance and practical application of the electrospun material. In this paper, we reported a direct pulling method to measure the adhesion and understand the adhesion mechanism. In this method, we used gravity to pull the fiber directly from the substrate and then measured the gravity to calculate the adhesion. This new test method is more convenient and practical than the previously reported methods. In addition, the adhesion of the in situ electrospun web on different substrates (e.g., aluminium foil, wood pulp paper, and silicon paper) was also studied by this method. The adhesion was influenced by spinning voltage, electrical conductivity, and surface roughness of the substrates.

PVA/CA based electrospun nanofibers: Influence of processing parameters in the fiber diameter

Recently, the electrospinning technique has been explored as a natural and synthetic polymer processing tool due to its versatility and potential to generate complex structures at a nanoscale. In this work, non-woven nanofibrous mats were electrospun, with a structure resembling the extracellular matrix, for prospective biomedical uses. Poly (vinyl alcohol) (PVA) and cellulose acetate (CA) based electrospun nanofibrous meshes were prepared at different ratios 100/0, 90/10, 80/20 and 70/30 and characterized in terms of fiber diameter. The process was kept as green as possible by resorting to a combination of acetic acid and distilled water as solvents. Optimal conditions for PVA/CA processing were established at 29 kV, feeding rate of 0.8 mL/h and distance between needle and collector of 17 cm. These allowed for the most uniform fibers with the smallest diameters to be produced.

Electrospun nanohybrid hydrogels for enhanced differentiation of myoblasts

Enhancement of myogenic differentiation was accomplished with nanohybrid hydrogels composed of fragmented electrospun nanofibrils (NFs) and gelatin/alginate hydrogels. Electrospun nanofibrous meshes were fragmented and hydrolyzed to short fragments of NFs and subsequently embedded in gelatin/alginate hydrogels and further crosslinked with C2C12 cells. Cell-incorporated NF-embedded hydrogels exhibited a lower swelling ratio and higher mechanical properties as compared to hydrogels without NF due to the rigidity of NF and increased matrix-to-cell interaction. Viability of C2C12 cells in the hydrogels gradually increased in proportion to the amount of NF in the hydrogels. Both confocal microscopy and myogenic gene expression analysis indicated that the formation and maturation of myotubes and the expression of muscle motor proteins were significantly accelerated when NF-embedded hydrogels were employed. Contraction behavior of matured myotubes under electrical stimulation revealed that myotubes in NF-embedded hydrogels exhibited a longer contraction length than that of myotubes in hydrogels without NF. Thus, the nanohybrid matrix demonstrates the potential of nanofiber-embedded hydrogels for engineering myotube formation with topographical cues.

Chondrogenesis-inductive nanofibrous substrate using both biological fluids and mesenchymal stem cells from an autologous source

During the last decade, many cartilage tissue engineering strategies have been developed, being the stem cell-based approach one of the most promising. Transforming Growth Factor-β3 (TGF-β3) and Insulin-like Growth Factor-I (IGF-I) are key proteins involved in the regulation of chondrogenic differentiation. Therefore, these two growth factors (GFs) were immobilized at the surface of a single electrospun nanofibrous mesh (NFM) aiming to differentiate human Bone Marrow-derived Mesenchymal Stem Cells (hBM-MSCs). The immobilization of defined antibodies (i.e. anti-TGF-β3 and anti-IGF-I) allows the selective retrieval of the abovementioned GFs from human platelet lysates (PL). Biochemical assays, involving hBM-MSCs cultured on biofunctional nanofibrous substrates under basal culture medium during 28 days, confirm the biological activity of bound TGF-β3 and IGF-I. Specifically, the typical spherical morphology of chondrocytes and the immunolocalization of collagen type II confirmed the formation of a cartilaginous ECM. Therefore, the proposed biofunctional nanofibrous substrate is able to promote chondrogenesis.

Blood compatibility investigation of nanofibrous PU–copper nanoparticles–avocado membrane

Wound healing is a complicated phenomenon, and it needs to be assisted properly to avoid life-threatening complications. In this present work, an electrospun nanofibrous mesh composed of polyurethane (PU), avocado extract (AC) and copper nanoparticles (CUPs) is developed and assessed for its wound healing potential. Green synthesis of CUPs was performed using aloe vera extract, and the formation of CUPs was evident in the ultraviolet/visible absorption spectrum. The developed mesh was characterized for its physicochemical and hemocompatible properties. Scanning electron micrographs showed the continuous, smooth, interconnected nanofibrous morphology of the PU–AC–CUP mesh. Also, energy-dispersive X-ray spectroscopy analysis confirmed the presence of CUPs in the mesh. Fourier transform infrared spectra indicated the addition of AC-based hydrophilic chemical groups, which enhanced the wettability of the composites. Protein adsorption studies revealed the selective adsorption of albumin rather than fibrinogen. The composite scaffold also offers a highly hemocompatible surface by delaying coagulation of blood through contact activation pathways and by limiting damage to red blood cells. Therefore, the excellent physicochemical properties, selective protein adsorption and blood compatibility of the fabricated mesh will be conducive for wound healing applications.

Electrohydrodynamic Printing of Microscale PEDOT:PSS-PEO Features with Tunable Conductive/Thermal Properties.

Electrohydrodynamic (EHD) printing has been recently investigated as an effective technique to produce high-resolution conductive features. Most of the existing EHD printing studies for conductive features were based on metallic nanoparticle inks in a microdripping mode, which exhibited relatively low efficiency and commonly required high-temperature annealing process to achieve high conductivity. The EHD printing of high-resolution conductive features at a relatively low temperature and in a continuous cone-jetting mode is still challenging because the conductive inks might connect the charged nozzle, and the grounded conductive or semiconductive substrates to cause discharge and terminate the printing process. In this study, the EHD printing process of conductive polymers in a low-temperature cone-jetting mode was explored to fabricate conductive microstructures. The smallest width of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) lines was 27.25 ± 3.76 μm with a nozzle diameter of 100 μm. It was interesting to find that the electrohydrodynamically printed PEDOT:PSS-PEO features exhibited unique thermal properties when a dc voltage was applied. The conductive and thermal properties of the resultant features were highly dependent on the printing layer number. Microscale PEDOT:PSS features were further encapsulated into electrospun nanofibrous mesh to form a flexible sandwich structure. The EHD printing of PEDOT:PSS features with tunable conductive and thermal properties might be useful for the applications of flexible and wearable microdevices.

Electrospun Poly(ε-caprolactone) Nanofibrous Mesh for Imiquimod Delivery in Melanoma Therapy.

Drug delivery systems (DDS) are commonly employed to administer drug-loaded composites to their therapeutic targets both in vitro and in vivo. Thus, we herein report the study of imiquimod-poly(ε-caprolactone) (IMQ-PCL) nanofibrous meshes for application in melanoma therapy. The preparation route employed was based on the electrospinning technique, with the melanoma cells being cultured on electrospun nanofibrous meshes to study their biocompatibility. All parameters employed, including the flow rate and polymer solution concentration, were examined to gain an improved understanding of the factors influencing the diameter and morphology of the electrospun fibre. The optimised parameters were employed to produce 12 IMQ-PCL nanofibrous meshes with diameters ranging from 100 to 900 nm to the melanoma cell viability. The relationship between the fibrous diameter and the imiquimod release profile was also determined using UV-Vis spectroscopy. In addition, similar results were obtained for the simulated imiquimod release profile obtained by COMSOL Multiphysics®. The IMQ-PCL nanofibrous meshes were found to decrease cell viability by ≥50%, with the number of cells dropping by ~10% over 48 h. As the cell viability was affected by the release of imiquimod, we believe that IMQ-PCL nanofibrous meshes are a promising drug delivery system for application in melanoma therapy.

In situ crosslinked electrospun gelatin nanofibers for skin regeneration

Due to its intrinsic similarity to the extracellular matrix, gelatin electrospun nanofibrous meshes are promising scaffold structures for wound dressings and tissue engineering applications. However, gelatin is water soluble and presents poor mechanical properties, which generally constitute relevant limitations to its applicability. In this work, gelatin was in situ crosslinked with 1,4-butanediol diglycidyl ether (BDDGE) at different concentrations (2, 4 and 6wt%) and incubation time-points (24, 48 and 72h) at 37°C. The physico-chemical and biological properties of BDDGE-crosslinked electrospun gelatin meshes were investigated. Results show that by changing the BDDGE concentration it is possible to produce nanofibers crosslinked in situ with well-defined morphology and modulate fiber size and mechanical properties. Crosslinked gelatin meshes show no toxicity towards fibroblasts, stimulating their adhesion, proliferation and synthesis of new extracellular matrix, thereby indicating the potential of this strategy for skin tissue engineering.

Repairing a bone defect with a three-dimensional cellular construct composed of a multi-layered cell sheet on electrospun mesh

In addition to providing maneuverability, electrospun nanofibrous meshes can make excellent supports for constructing flexible cell sheets to regulate cell behavior by nanofiber features. With the target of bone regeneration, herein composite nanofibers with two different fiber arrangements (nestlike, random) were electrospun from a blend solution containing poly(l-lactide) (PLLA) and gelatin (1:1 in weight ratio). Unlike the non-woven morphology in a random nanofibrous mesh, PLLA/gelatin composite nanofibers in the nestlike nanofibrous mesh displayed both non-woven and parallel morphologies. Both kinds of nanofibrous mesh were ∼50 μm thick as-prepared, and shrank to ∼30 μm after seeding with bone mesenchymal stromal cells (BMSCs). After 7 days of in vitro culture, cell sheets could form on both meshes (CSM) and on the culture plate. It was found that application of nanofibrous mesh promoted the osteogenic differentiation of BMSC sheets compared with the control. The nestlike mesh displayed slight superiority over the random mesh in enhancing osteogenic differentiation, but their different fiber arrangements did not cause much difference in cell proliferation. Three-dimensional multi-layered CSM constructs were built by stacking four mono-layered CSMs together. The CSM constructs (based on a nestlike or random nanofibrous mesh) were incubated in vitro for 3 days before being implanted into rat cranial defects. In comparison with the control group, there was significant formation of new calcified bone in both CSM construct-filled groups at 12 weeks’ post-operation. The nestlike group showed slightly better bone healing (based on both qualitative and quantitative analysis) than the random group, while showing insignificant differences. We showed that the concept of using a three-dimensional multi-layered CSM construct in enhancing bone regeneration was feasible. Future studies should take more nanofiber features (e.g. bioactive components) into account to further enhance osteogenesis.

Electrospun Nanofibrous Sheets for Selective Cell Capturing in Continuous Flow in Microchannels.

Electrospun nanofibrous meshes were surface-modified for selective capturing of specific cells from a continuous flow in PDMS microchannels. We electrospun nanofibrous mats composed of poly(ε-carprolactone) (PCL) and amine-functionalized block copolymers composed of PCL and poly(ethylenimine) (PEI). A mixture of biotinylated PEG and blunt PEG was chemically tethered to the nanofibrous mats via the surface-exposed amines on the mat. The degree of biotinylation was fluorescently and quantitatively assayed for confirming the surface-biotinylation levels for avidin-specific binding. The incorporation level of avidin gradually increased when the blend ratio of biotinylated PEG on the mat increased, confirming the manipulated surfaces with various degree of biotinylation. Biotinylated cells were incubated with avidin-coated biotinylated mats and the specific binding of biotinylated cells was monitored in a microfluidic channel with a continuous flow of culture medium, which suggests efficient and selective capturing of the biotinylated cells on the nanofibrous mat.

Layer-by-layer surface decoration of electrospun nanofibrous meshes for air–liquid interface cultivation of epidermal cells

PEG multilayered nanofibrous mat for air–liquid interface cell cultivation.

Nucleic acid-scavenging electrospun nanofibrous meshes for suppressing inflammatory responses.

Fragmented nucleic acids are potent stimulators for inflammatory responses provoking pathological outcomes by activating adaptive immunity. In this study, highly cationic surfaces were prepared on electrospun nanofibrous meshes to scavenge nucleic acids to the surfaces. Poly(ε-caprolactone) [PCL]-poly(ethylenimine) [PEI] block copolymers were synthesized by coupling the carboxyl-terminated PCL to the primary amines of branched PEI. Polymeric solutions composed of PCL-PEI and PCL were electrospun to nanofibrous mats, and the surfaces were further methylated to prepare highly cationic surfaces on the mats. Raman spectroscopy revealed that the presence of increased methylated amines on the surfaces of the mats compared to unmodified mats. The methylated surfaces showed significant increases of wettability after methylation, suggesting highly charged surfaces caused by methylation of the primary amines. When the blend ratio of PCL-PEI was increased, the scavenged DNA was also increased, and the methylation further strengthened the scavenging ability of the mats. Fluorescently labeled oligodeoxynucleic acids were significantly adsorbed on the surface of the mats depending on the amounts of PCL-PEI and the degree of methylation. In the presence of the methylated nanofibrous mats, inflammatory responses induced by CpG oligonucleotides in murine macrophages were significantly reduced, which was confirmed by measuring inflammatory cytokine levels including TNF-α and IFN-γ.

Foreign body reaction associated with PET and PET/chitosan electrospun nanofibrous abdominal meshes.

Electrospun materials have been widely explored for biomedical applications because of their advantageous characteristics, i.e., tridimensional nanofibrous structure with high surface-to-volume ratio, high porosity, and pore interconnectivity. Furthermore, considering the similarities between the nanofiber networks and the extracellular matrix (ECM), as well as the accepted role of changes in ECM for hernia repair, electrospun polymer fiber assemblies have emerged as potential materials for incisional hernia repair. In this work, we describe the application of electrospun non-absorbable mats based on poly(ethylene terephthalate) (PET) in the repair of abdominal defects, comparing the performance of these meshes with that of a commercial polypropylene mesh and a multifilament PET mesh. PET and PET/chitosan electrospun meshes revealed good performance during incisional hernia surgery, post-operative period, and no evidence of intestinal adhesion was found. The electrospun meshes were flexible with high suture retention, showing tensile strengths of 3 MPa and breaking strains of 8–33%. Nevertheless, a significant foreign body reaction (FBR) was observed in animals treated with the nanofibrous materials. Animals implanted with PET and PET/chitosan electrospun meshes (fiber diameter of 0.71±0.28 µm and 3.01±0.72 µm, respectively) showed, respectively, foreign body granuloma formation, averaging 4.2-fold and 7.4-fold greater than the control commercial mesh group (Marlex). Many foreign body giant cells (FBGC) involving nanofiber pieces were also found in the PET and PET/chitosan groups (11.9 and 19.3 times more FBGC than control, respectively). In contrast, no important FBR was observed for PET microfibers (fiber diameter = 18.9±0.21 µm). Therefore, we suggest that the reduced dimension and the high surface-to-volume ratio of the electrospun fibers caused the FBR reaction, pointing out the need for further studies to elucidate the mechanisms underlying interactions between cells/tissues and nanofibrous materials in order to gain a better understanding of the implantation risks associated with nanostructured biomaterials.

Biological Characteristics of Mesenchymal Stem Cells Grown on Different Topographical Nanofibrous Poly-L-Lactide Meshes

The nanotopographical features of artificial scaffolds have complex effects on the biological characteristics of stem cells. They influence cell adhesion, spreading, proliferation, and differentiation; however we have limited knowledge on how these processes occur under nanotopographical cues. In this study, two kinds of electrospun nanofibrous meshes with different fiber arrangements (totally non-woven and lattice-like) were fabricated and used for in vitro culture of mesenchymal stem cells (MSCs). By comparing the characteristic marks related to osteogenic differentiation, we found that with prolonged culture time, osteopontin (OPN), osteocalcin (OCN) and alkaline phosphatase (ALP), as well as related genes (Runx2 and Colla genes), were all expressed at higher levels on lattice-like nanofibrous meshes than on non-woven ones. These results indicated that the lattice-like nanofibrous mesh activated the osteogenic differentiation of MSCs owing to changes in cell morphology directed by nanofiber orientations. Compared with pure non-woven nanofibrous meshes, lattice-like ones possessed a combined structure of parallel, magnetic-line-like, and non-woven regions. MSCs adhering onto them had upregulated expression levels of integrin subunits a5 and b1, and activated downstream signaling pathways of Ras homolog gene family member A (RhoA) and extracellular signal-regulated kinase (ERK). When the specific inhibitors PD98059 and Y27632 were used to inhibit phosphorylated ERK and p160 ROCKII activity, respectively, F-actin became disordered and the expression level of Runx2 was downregulated. Thus, we concluded that the scaffold nanotopography may modulate the microenvironment of MSCs and promote their osteogenic differentiation through the RhoA and ERK signaling pathways. These findings provided valuable information on the selection of artificial matrices suitable for MSCs application in bone tissue engineering.

A sulfated nanofibrous mesh supporting the osteogenic differentiation of periosteum-derived cells.

The periosteum is a thin fibrous membrane covering the surface of long bone and is known to play a critical role in bone development and adult bone fracture healing. Loss or damage of the periosteum tissue during traumatic long bone injuries can lead to retarded healing of bone graft-mediated repair. The regenerative potential of periosteum-derived progenitor cells (PDCs) has inspired their use as an alternative to bone marrow-derived mesenchymal stromal cells (MSCs) to augment scaffold-assisted bone repair. In this study, we first demonstrated that PDCs isolated from adult rat long bone exhibited innate advantages over bone marrow-derived MSCs in terms of faster proliferation and more potent osteogenic differentiation upon induction in plastic-adherent culture. Further, we examined the potential of two electrospun nanofibrous meshes, an uncharged regenerated cellulose mesh and a sulfated mesh, to support the attachment and osteogenic differentiation of PDCs. We showed that both nanofibrous meshes were able to support the attachment and proliferation of PDCs and MSCs alike, with the sulfated mesh enabling significantly higher seeding efficiency than the cellulose mesh. Both meshes were also able to support the osteogenic differentiation of adherent PDCs upon induction by osteogenic media, with the sulfated mesh facilitating more potent mineral deposition by adherent PDCs. Our study supports the sulfated nanofibrous mesh as a promising synthetic periosteal membrane for the delivery of exogenous PDCs to augment bone healing.