Regulating Tumor N6 -Methyladenosine Methylation Landscape using Hypoxia-Modulating OsSx Nanoparticles.

The epigenetic dysregulation and hypoxia are two important factors that drive tumor malignancy, and N6 -methyladenosine (m6 A) in mRNA is involved in the regulation of gene expression. Herein, a nanocatalyst OsSx -PEG (PEG = poly(ethylene glycol)) nanoparticles (NPs) as O2 modulator is developed to improve tumor hypoxia. OsSx -PEG NPs can significantly downregulate genes involved in hypoxia pathway. Interestingly, OsSx -PEG NPs elevate RNA m6 A methylation levels to cause the m6 A-dependent mRNA degradation of the hypoxia-related genes. Moreover, OsSx -PEG NPs can regulate the expression of RNA m6 A methyltransferases and demethylases. Finally, DOX@OsSx -PEG (DOX = doxorubicin; utilized as a model drug) NPs modulate tumor hypoxia and regulate mRNA m6 A methylation of hypoxia-related genes in vivo. As the first report about relationship between catalytic nanomaterials and RNA modifications, the research opens a new avenue for unveiling the underlying action mechanisms of hypoxia-modulating nanomaterials and shows potential of regulating RNA modification to overcome chemoresistance.

Mouse IgM Fc receptor, FCMR, promotes B cell development and modulates antigen-driven immune responses.

FcR specific for pentameric IgM (FCMR) is expressed at high levels by B cells. Although circulating IgM has profound effects on responses to pathogens, autoimmunity, and B cell homeostasis, the biologic consequences of its binding to FCMR are poorly understood. We interrogated FCMR contributions to B cell function by studying mice that lack FCMR. FCMR transcripts are expressed at different levels by various B cell subsets. FCMR-deficient mice have reduced numbers of developing B cells, splenic follicular and peritoneal B-2 cells, but increased levels of peritoneal B-1a cells and autoantibodies. After immunization, germinal center B cell and plasma cell numbers are increased. FCMR-deficient B cells are sensitive to apoptosis induced by BCR ligation. Our studies demonstrate that FCMR is required for B cell differentiation and homeostasis, the prevention of autoreactive B cells, and responsiveness to antigenic challenge.

Effect of Common Consumer Washing Methods on Bisphenol A Release in Tritan Drinking Bottles.

Bisphenol A (BPA)-free plastic products are widely available. Transient BPA release has been reported in Tritan drinking bottles. This study assessed the effectiveness of common consumer washing methods in removing BPA contamination in Tritan bottles using both ELISA and HPLC-MS/MS assays. BPA release was detected in 2 out of 10 kinds of Tritan drinking bottles tested. Average BPA level was 0.493 µg/L in water samples from a type of Tritan kid drinking bottle following 24-hour incubation at room temperature, corresponding to a release rate of 0.015 ng/cm2/h. Of the common consumer cleaning methods identified in an informal survey, dishwashing was the most effective method that significantly reduced, even eliminated BPA release from the tested BPA-positive Tritan bottles, while rinsing with water and handwashing with soap and water were ineffective. The bioactivity of the leached BPA was confirmed using a rodent cardiac myocyte acute exposure model and an invertebrate 7-day exposure model. The BPA release is possibly the result of surface contamination in the manufacturing process. As a case study, our result may be informative for general consumer practice and for better quality control by the manufactures.

Diethyldithiocarbamate/silk fibroin/polyethylene oxide nanofibrous for cancer therapy: Fabrication, characterization and in vitro evaluation.

Cancer has become a serious disease threatening human health. To tackle this issue, developing the existing potent anticancer drugs is critical to reducing the time and cost associated with creating a new drug from scratch. Diethyldithiocarbamate (DDC) - an anticancer drug- has received considerable attention due to its selectivity and reactivity. In this study, we prepared a nanofibrous matrix from silk fibroin/polyethylene oxide loaded with diethyldithiocarbamate (DDC@SF/PEO) from an aqueous solution via an electrospinning process. Upon DDC incorporation, the nanofiber's diameter has increased from 450 nm (SF/PEO) to 1202 nm (DDC@SF/PEO) confirming the successful incorporation of DDC. Furthermore, the hydrophobicity of DDC@SF/PEO nanofibrous matrix was improved by turning SF structure from random coil (silk I) to ß-sheet (silk II) through ethanol vapor treatment. Biocompatibility of DDC@SF/PEO nanofibrous matrix on human normal cells (Wi-38) showed it was safe and the apoptosis-mediated anticancer activity of DDC was enhanced. Thus, loading DDC on SF/PEO nanofibrous matrix is the key descriptor for enhanced anticancer efficacy of DDC. Considering the all-aqueous and simplistic process, the DDC@SF/PEO nanofibrous matrix could be a promising candidate for cancer treatment applications.

Nanofiber configuration affects biological performance of decellularized meniscus extracellular matrix incorporated electrospun scaffolds.

Electrospinning represents the simplest approach to fabricate nanofiber scaffolds that approximate the heterogeneous fibrous structure of the meniscus. More effort is needed to understand the relationship between scaffold properties and cell responses to determine the appropriate scaffolds supporting meniscus tissue repair and regeneration. In this study, we investigate the influence of nanofiber configuration of electrospun scaffolds on phenotype and matrix production of meniscus cells, as well as on scaffold degradation behaviors and biocompatibility. Twisting electrospun nanofibers into yarns not only recapitulates the major collagen bundles of the meniscus but also increases the pore size and porosity of resultant scaffolds. The yarn scaffold significantly regulated expression levels of meniscus-associated genes and promoted extracellular matrix production compared with conventional electrospun scaffolds with random or aligned nanofiber orientation. Additionally, the yarn scaffold allowed considerable cell infiltration and experienced faster degradation and tissue remodeling upon subcutaneous implantation in a rat model. These results suggest that nanofiber configuration dictates cell interactions, scaffold degradation and integration with host tissue, providing design parameters of porosity and pore size of electrospun scaffolds toward meniscus repair.

Magnesium oxide-incorporated electrospun membranes inhibit bacterial infections and promote the healing process of infected wounds.

Bacterial infections cause severe secondary damage to wounds and hinder wound healing processes. We prepared magnesium oxide (MgO) nanoparticle-incorporated nanofibrous membranes by electrospinning and investigated their potential for wound dressing and fighting bacterial infection. MgO-Incorporated membranes possessed good elasticity and flexibility similar to native skin tissue and were hydrophilic, ensuring comfortable contact with wound beds. The cytocompatibility of membranes was dependent on the amounts of incorporated MgO nanoparticles: lower amounts promoted while higher amounts suppressed the proliferation of fibroblasts, endothelial cells, and macrophages. The antibacterial capacity of membranes was proportional to the amounts of incorporated MgO nanoparticles and they inhibited more than 98% E. coli, 90% S. aureus, and 94% S. epidermidis. MgO nanoparticle-incorporated membranes effectively suppressed bacterial infection and significantly promoted the healing processes of infected full-thickness wounds in a rat model. Subcutaneous implantation demonstrated that the incorporation of MgO nanoparticles into electrospun membranes elevated their bioactivity as evidenced by considerable cell infiltration into their dense nanofiber configuration and enhanced the remodeling of implanted membranes. This study highlights the potential of MgO-incorporated electrospun membranes in preventing bacterial infections of wounds.

Fabrication of chitosan/silk fibroin composite nanofibers for wound-dressing applications.

Chitosan, a naturally occurring polysaccharide with abundant resources, has been extensively exploited for various biomedical applications, typically as wound dressings owing to its unique biocompatibility, good biodegradability and excellent antibacterial properties. In this work, composite nanofibrous membranes of chitosan (CS) and silk fibroin (SF) were successfully fabricated by electrospinning. The morphology of electrospun blend nanofibers was observed by scanning electron microscopy (SEM) and the fiber diameters decreased with the increasing percentage of chitosan. Further, the mechanical test illustrated that the addition of silk fibroin enhanced the mechanical properties of CS/SF nanofibers. The antibacterial activities against Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) were evaluated by the turbidity measurement method; and results suggest that the antibacterial effect of composite nanofibers varied on the type of bacteria. Furthermore, the biocompatibility of murine fibroblast on as-prepared nanofibrous membranes was investigated by hematoxylin and eosin (H&E) staining and MTT assays in vitro, and the membranes were found to promote the cell attachment and proliferation. These results suggest that as-prepared chitosan/silk fibroin (CS/SF) composite nanofibrous membranes could be a promising candidate for wound healing applications.

Polyvinyl Alcohol/Hydroxyethylcellulose Containing Ethosomes as a Scaffold for Transdermal Drug Delivery Applications.

This study aims to develop scaffold for transdermal drug delivery method (TDDM) using electrospinning technique from polyvinyl alcohol (PVA) and hydroxyethylcellulose (HEC). The fluorescein isothiocyanate (FITC) loaded on ethosomes (FITC@Eth) was used as a drug model. The prepared PVA/HEC/FITC@Eth scaffold was characterized via scanning electron microscope (SEM) that show morphology change by adding FITC@Eth. Also, Fourier transform infrared spectroscopy (FTIR), mechanical properties, X-ray diffraction (XRD), thermal gravimetric (TGA) analysis show that the addition of FITC@Eth to PVA/HEC does not change the scaffold properties. Franz diffusion cells were used for in vitro skin permeation experiments using rat dorsal skins. The FITC@Eth penetration was better than that of free FITC due to the presence of ethosome which enhance the potential skin targeting. In conclusion, the prepared PVA/HEC/FITC@Eth scaffold can serve as a promising transdermal scaffold for sustained FITC release.

A biodegradable multifunctional nanofibrous membrane for periodontal tissue regeneration.

Biomaterial-based membranes represent a promising therapeutic option for periodontal diseases. Although conventional periodontal membranes function greatly in preventing the ingrowth of both fibroblasts and epithelial cells as well as connective tissues, they are not capable of promoting periodontal tissue regeneration. Here, we report a multifunctional periodontal membrane prepared by electrospinning biodegradable polymers with magnesium oxide nanoparticles (nMgO). nMgO is a light metal-based nanoparticle with high antibacterial capacity and can be fully resorbed in the body. Our results showed that incorporating nMgO into poly(L-lactic acid) (PLA)/gelatin significantly improved the overall properties of membranes, including elevated tensile strength to maintain structural stability and adjusted degradation rate to fit the time window of periodontal regeneration. Acidic degradation products of PLA were neutralized by alkaline ions from nMgO hydrolysis, ameliorating pH microenvironment beneficial for cell proliferation. In vitro studies demonstrated considerable antibacterial and osteogenic properties of nMgO-incorporated membranes that are highly valuable for periodontal regeneration. Further investigations in a rat periodontal defect model revealed that nMgO-incorporated membranes effectively guided periodontal tissue regeneration. Taken together, our data indicate that nMgO-incorporated membranes might be a promising therapeutic option for periodontal regeneration. STATEMENT OF SIGNIFICANCE: Traditional clinical treatments of periodontal diseases largely focus on the management of the pathologic processes, which cannot effectively regenerate the lost periodontal tissue. GTR, a classic method for periodontal regeneration, has shown promise in clinical practice. However, the current membranes might not fully fulfill the criteria of ideal membranes. Here, we report bioabsorbable nMgO-incorporated nanofibrous membranes prepared by electrospinning to provide an alternative for the clinical practice of GTR. The membranes not only function greatly as physical barriers but also exhibit high antibacterial and osteoinductive properties. We therefore believe that this study will inspire more practice work on the development of effective GTR membranes for periodontal regeneration.

Fabrication and characterization of biodegradable nanofibrous mats by mix and coaxial electrospinning.

The aim of this study is to investigate an innovative tissue engineering scaffold with a controllable drug-releasing capability. The hypothesis is that the nanofibers fabricated by coaxial electrospinning could encapsulate and release sustainedly Tetracycline Hydrochloride (TCH). To testify the hypothesis, nanofibers were prepared by coaxial electrospinning from Poly(L-lactid-co-epsilon-caprolactone) [PLLACL]/2,2,2-Frifluoroethanol (TFE) solutions (as the shell solutions) and TCH/TFE solutions (as the core solutions). In addition, nanofibers of PLLACL-blend-TCH were also prepared as the control by mix electrospinning. The relationship between fibers morphologies and processed conditions in electrospinning were investigated. TCH release behaviors from the nanofibrous mats were studied. The antibacterial properties of aforementioned nanofibers were detected by the Escherichia coli growth-inhibiting tests. The results indicated that the nanofibers prepared by coaxial-electrospinning had the desired and controllable TCH encapsulation/release profile; thus, it could be utilized as both a drug encapsulation/release vehicle and a tissue engineering scaffold.

Polyethylenimine and sodium cholate-modified ethosomes complex as multidrug carriers for the treatment of melanoma through transdermal delivery.

Aim: Multidrug resistance is the main reason for the failure of chemotherapy during the treatment of the tumor. To overcome multidrug resistance, this study attempts to develop a novel transdermal drug-delivery system (TDDS) loading cytotoxic drug and chemosensitizer. Materials & methods: The polyethylenimine-modified ethosomes (Eth-PEI) and sodium cholate-modified ethosomes (Eth-SC) were firstly fabricated, and then a novel TDDS based on the carriers complex of Eth-PEI/Eth-SC was prepared by electrostatic interaction and evaluated both in vitro and in vivo. Results: The Eth-PEI/Eth-SC showed the excellent antitumor effect on treating melanoma, using doxorubicin and curcumin as the cytotoxic drug and chemosensitizer, respectively. Conclusion: The as-prepared TDDS composed of Eth-PEI/Eth-SC loading multidrug is an effective means for treating melanoma.

Synthesis and characterization of incorporating mussel mimetic moieties into photoactive hydrogel adhesive.

Surgical adhesive is the optimal candidate for the replacement of traditional mechanical wound closure. In our paper, mussel adhesive proteins inspired hydrogel adhesive was prepared with 3, 4-dihydroxyphyenylanine acrylamide (DOPA-AA), poly (ethylene glycol) diacrylate (PEGDAA) and thiolated chitosan (CSS) by UV irradiation. DOPA-AA, containing catechol group and vinyl group, was successful synthesized and characterized by FTIR and 1HNMR. The gelation time, equilibrium water content, degradation, materials properties and adhesive strength of the hydrogels were studied. We found that the gelation time was retarded and the materials mechanical strength was decreased because of the inhibitory effect of catechol group. Equilibrium water content was slightly affect by the increasing concentration of DOPA-AA (1-5%). Nevertheless, catechol group can remarkably improve the adhesive properties because of the complex and durable interactions of the hydrogel, especially, the interaction between the thiol group of CSS and catechol group of DOPA-AA, which also greatly slowed down the degradation of the adhesive hydrogels. CSS and DOPA-AA was introduced to ensure the adhesive properties, DOPA-AA lend the adhesive nature to hydrogel and CSS can protect the catechol group from oxidation and enhance durable adhesion. Moreover, cytotoxicity of the resulting hydrogels showed that the L929 cell viability was weaken, it mostly probably induced by the catechol oxidation.

Macroporous nanofibrous vascular scaffold with improved biodegradability and smooth muscle cells infiltration prepared by dual phase separation technique.

INTRODUCTION: The fast degradation of vascular graft and the infiltration of smooth muscle cells (SMCs) into the vascular graft are considered to be critical for the regeneration of functional neo-vessels. In our previous study, a novel dual phase separation technique was developed to one-pot prepare macroporous nanofibrous poly(L-lactic acid) (PLLA)/poly(ε-caprolactone) (PCL) vascular scaffold by phase separating the immiscible polymer blend. However, the slow degradation of PLLA/PCL limited cell infiltration. Herein, we hypothesized that poly(lactic-co-glycolic acid) (PLGA) would be miscible with PLLA but immiscible with PCL. Then, PLGA can be introduced into the PLLA/PCL blend to fabricate macroporous nanofibrous scaffold with improved biodegradability by using dual phase separation technique. MATERIALS AND METHODS: The miscibility of PLGA with PLLA and PCL was evaluated. Then, the PLLA/PLGA/PCL scaffold was prepared by dual phase separation technique. The prepared scaffolds were characterized in terms of the morphology, in vitro degradation, mechanical properties, and cells' infiltration and viability for human vascular SMCs (HVSMCs). Finally, platelet-derived growth factor-BB (PDGF-BB) was immobilized on the scaffold and its effect on the bioactivity of HVSMCs was studied. RESULTS: PLGA is miscible with PLLA but immiscible with PCL as hypothesized. The addition of PLGA enlarged the pore size and improved the biodegradability of composite scaffold. Notably, PLLA/PLGA/PCL scaffold with the blend ratio of 30:40:30 possessed improved pore interconnectivity for cells' infiltration and enough mechanical properties. Moreover, HVSMCs could grow and infiltrate into this scaffold, and surface modification with PDGF-BB on the nanofibrous scaffold enhanced HVSMCs migration and proliferation. CONCLUSION: This study provides a strategy to expand dual phase separation technique into utilizing ternary even multinary polymer blend to fabricate macroporous nanofibrous scaffold with improved physicochemical properties. The prepared PLLA/PLGA/PCL scaffold would be promising for the regeneration of functional tunica media in vascular tissue engineering.

Sarcoma-Targeting Peptide-Decorated Polypeptide Nanogel Intracellularly Delivers Shikonin for Upregulated Osteosarcoma Necroptosis and Diminished Pulmonary Metastasis.

PURPOSE: Osteosarcoma is the most common primary bone cancer and is notorious for pulmonary metastasis, representing a major threat to pediatric patients. An effective drug targeting osteosarcoma and its lung metastasis is urgently needed. DESIGN: In this study, a sarcoma-targeting peptide-decorated disulfide-crosslinked polypeptide nanogel (STP-NG) was exploited for enhanced intracellular delivery of shikonin (SHK), an extract of a medicinal herb, to inhibit osteosarcoma progression with minimal systemic toxicity. RESULTS: The targeted, loaded nanogel, STP-NG/SHK, killed osteosarcoma cells by inducing RIP1- and RIP3-dependent necroptosis in vitro. Necroptosis is a novel cell death form that could be well adapted as an efficient antitumor strategy, the main obstacle of which is its high toxicity. After intravenous injection, STP-NG/SHK efficiently suppressed tumor growth and reduced pulmonary metastasis, offering greater tumor necrosis and higher RIP1 and RIP3 upregulation compared to free SHK or untargeted NG/SHK in vivo. Additionally, the treatment with NG/SHK or STP-NG/SHK showed minimal toxicity to normal organs, suggesting low systemic toxicity compared to free SHK. CONCLUSION: The STP-guided intracellular drug delivery system using the necroptosis mechanism showed profound anti-osteosarcoma activity, especially eliminated lung metastasis in vivo. This drug formulation may have great potential for treatment of osteosarcoma.

Green electrospun grape seed extract-loaded silk fibroin nanofibrous mats with excellent cytocompatibility and antioxidant effect.

Silk fibroin (SF) from Bombyx mori has an excellent biocompatibility and thus be widely applied in the biomedical field. Recently, various SF-based composite nanofibers have been developed for more demanding applications. Additionally, grape seed extract (GSE) has been demonstrated to be powerful on antioxidation. In the present study, we dedicate to fabricate a GSE-loaded SF/polyethylene oxide (PEO) composite nanofiber by green electrospinning. Our results indicated the successful loading of GSE into the SF/PEO composite nanofibers. The introduction of GSE did not affect the morphology of the SF/PEO nanofibers and GSE can be released from the nanofibers with a sustained manner. Furthermore, comparing with the raw SF/PEO nanofibrous mats, the GSE-loaded SF/PEO nanofibrous mats significantly enhanced the proliferation of the skin fibroblasts and also protected them against the damage from tert-butyl hydroperoxide-induced oxidative stress. All these findings suggest a promising potential of this novel GSE-loaded SF/PEO composite nanofibrous mats applied in skin care, tissue regeneration and wound healing.

Synthesis of hollow mesoporous silica nanoparticles with tunable shell thickness and pore size using amphiphilic block copolymers as core templates.

This paper presents a facile method for the fabrication of uniform hollow mesoporous silica nanoparticles (HMSNs) with tunable shell thickness and pore size. In this method, a series of amphiphilic block copolymers of polystyrene-b-poly (acrylic acid) (PS-b-PAA) with different hydrophobic block (PS) lengths were first synthesized via atom transfer radical polymerization (ATRP). The as-synthesized PS-b-PAA and cetyltrimethylammonium bromide (CTAB) were subsequently used as co-templates to fabricate HMSNs. This approach allows the control of shell thickness and pore size distribution of the synthesized HMSNs simply by changing the amounts of PS-b-PAA and CTAB, respectively. In vitro cytotoxicity and hemolysis assays demonstrated that the synthesized HMSNs had a low and shell thickness-dependent cytotoxicity and hemolytic activity. Therefore, these HMSNs have great potential for biomedical applications due to their good biocompatibility and ease of synthesis.

Vitamin E-loaded silk fibroin nanofibrous mats fabricated by green process for skin care application.

In the present study, we reported fabrication and skin benefit of a novel vitamin E (VE)-loaded silk fibroin (SF) nanofibrous mats. RRR-α-Tocopherol polyethylene glycol 1000 succinate (VE TPGS), a water-soluble derivative of VE, was incorporated into SF nanofiber successfully by aqua solution electrospinning for the first time. Morphology of the composite nanofibers changed with the different amount of VE TPGS: a ribbon-like shape for lower loading dose of VE TPGS, while a round shape for higher loading dose (more than 4% (wt/wt) based on the weight of SF). After treated with 75% (v/v) ethanol vapor, the composite nanofibrous mats showed an excellent water-resistant ability. In vitro study disclosed a sustained release behavior of VE TPGS disassociated from the nanofibrous mats. The mouse skin fibroblasts (L929 cells) cultured on the VE-loaded SF nanofibrous mats spread and proliferated much better than on cover slips. Moreover, the incorporation of VE TPGS was found strengthening the ability of SF nanofibrous mats on protecting the cells against oxidation stress induced by tert-butyl hydroperoxide. Our data presented impressive skin benefits of this VE-loaded SF nanofibrous mats, suggesting a promising applicative potential of this novel product on personal skin care, tissue regeneration and other related area.

Fabrication of fibrinogen/P(LLA-CL) hybrid nanofibrous scaffold for potential soft tissue engineering applications.

Coelectrospinning of native proteins and elastic synthetic polymers is an attractive technique to fabricate hybrid fibrous scaffolds that combine the bioactivity and mechanical features of each material component. In this study, hybrid fibrous scaffolds composed of synthetic P(LLA-CL) elastomeric and naturally derived fibrinogen protein were fabricated and characterized for their bioactive and physiochemical properties. Fiber diameters of hybrid scaffolds increased with increasing P(LLA-CL) content, and the shape of fibers changed from cylindrical shape on pure polymer scaffolds to flat structure on hybrid scaffolds. Characterizations of ATR-FTIR, XRD, and thermal properties indicated that the hybrid scaffolds contain two different phases, one composed of pure fibrinogen and the other corresponding to a mixture of fibrinogen and P(LLA-CL), and no obvious chemical reaction takes place between two components. The hybrid fibrous scaffolds showed tailorable degradation rates than pure P(LLA-CL) and higher mechanical properties than pure fibrinogen, and both tensile strength and breaking strain increased with increasing P(LLA-CL) content. In Vitro studies revealed that L929 cells on hybrid scaffolds achieved relatively higher level of cell attachment after 12 h of culture and significant increased cell proliferation rate after 7 days of culture, when compared with pure fibrinogen and P(LLA-CL) scaffolds, and the cells exhibited a spreading polygonal shape on the hybrid fibrous surfaces compared to a round shape on surfaces of pure polymer scaffolds. Therefore, the fibrinogen/P(LLA-CL) hybrid fibrous scaffolds possess the combined benefits of each individual component, which make it capable as scaffolds for soft tissue reconstruction.

Fabrication of gelatin-hyaluronic acid hybrid scaffolds with tunable porous structures for soft tissue engineering.

The development of three-dimensional (3-D) scaffolds with highly open porous structure is one of the most important issues in tissue engineering. In this study, 3-D macroporous gelatin/hyaluronic acid (GE/HA) hybrid scaffolds with varying porous morphology were prepared by freeze-drying their blending solutions and subsequent chemical crosslinking by using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). The resulting scaffolds were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Their swelling, in vitro degradation properties and compressive strength were also investigated. To evaluate in vitro cytocompatibility of scaffolds, mouse L929 fibroblasts were seeded onto the scaffolds for cell morphology and cell viability studies. It was found that the porous structure of scaffolds can be tailored by varying the ratios of gelatin to HA, both the swelling ratios and degradation rate increased with the increase of HA content in hybrid scaffolds, and crosslinking the scaffolds with EDC improved the degradation resistance of the scaffold in culture media and increased the mechanical strength of scaffolds. The in vitro results revealed that the prepared scaffolds do not induce cytotoxic effects and suitable for cell growth, especially in the case of scaffolds with higher gelatin content. The combined results of the physicochemical and biological studies suggested that the developed GE/HA hybrid scaffolds exhibit good potential and biocompatibility for soft tissue engineering applications.

Preparation and characterization of coaxial electrospun thermoplastic polyurethane/collagen compound nanofibers for tissue engineering applications.

Collagen functionalized thermoplastic polyurethane nanofibers (TPU/collagen) were successfully produced by coaxial electrospinning technique with a goal to develop biomedical scaffold. A series of tests were conducted to characterize the compound nanofiber and its membrane in this study. Surface morphology and interior structure of the ultrafine fibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM), whereas the fiber diameter distribution was also measured. The crosslinked membranes were also characterized by SEM. Porosities of different kinds of electrospun mats were determined. The surface chemistry and chemical composition of collagen/TPU coaxial nanofibrous membranes were verified by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrometry (FTIR). Mechanical measurements were carried out by applying tensile test loads to samples which were prepared from electrospun ultra fine non-woven fiber mats. The coaxial electrospun nanofibers were further investigated as a promising scaffold for PIECs culture. The results demonstrated that coaxial electrospun composite nanofibers had the characters of native extracellular matrix and may be used effectively as an alternative material for tissue engineering and functional biomaterials.