Electrospun Biocompatible Polyurethanes with The Addition of Multi-Walled Carbon Nanotubes

Three different Polyurethanes (PUs) Lycra®, HydroThaneTM, and BioSpan®, were electrospun and characterized using Scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform-infrared spectroscopy (FTIR), & Raman spectroscopy. Nanofiber composites were made by incorporating MWCNTs at three different concentration 0.1wt% 0.5wt% and 1.0wt% to the three PUs. These samples were characterized and mechanical and thermal test were done. The TEM images showed MWCNT bundling in the polymer matrix at the highest concentration, the FTIR showed shifts in characteristic urethane bands indicating an interaction with the polymer and MWCNTs. Mechanical test showed a decrease in the Young’s modulus (E’) in most of the composites with the exception of Bio-MWCNTs 0.1wt%. The thermal gravimetric analysis (TGA) did not show an enhancement in the thermal properties of the polymer when the MWCNTs were added. Indicating that the MWCNTs are weakling the stiffness and the thermal stability of the PUs

Microscopic and Spectroscopic Studies of Thermally Enhanced Electrospun PMMA Micro- and Nanofibers

Carbon nanofibers (CNFs) have been incorporated into poly(methyl methacrylate) (PMMA) through electrospinning. The resulting micro- and nanofibers have been characterized by Scanning Electron Microscopy (SEM), which confirmed fiber formation and demonstrated a core-sheath structure of the PMMA fibers. Thermogravimetric Analysis (TGA) was used to obtain the thermal properties of the materials, indicating an enhancement in the thermal properties of the composite fibers. In addition, Fourier Transform Infrared Spectroscopy (FTIR) was utilized to investigate the interactions of PMMA micro- and nanofibers with CNFs, demonstrating the preferred sites of intermolecular interactions between the polymer matrix and the filler

Imaging, Spectroscopy, Mechanical, Alignment and Biocompatibility Studies of Electrospun Medical Grade Polyurethane (Carbothane™ 3575A) Nanofibers and Composite Nanofibers Containing Multiwalled Carbon Nanotubes

In the present study, we discuss the electrospinning of medical grade polyurethane (Carbothane™ 3575A) nanofibers containing multi-walled-carbon-nanotubes (MWCNTs). A simple method that does not depend on additional foreign chemicals has been employed to disperse MWCNTs through high intensity sonication. Typically, a polymer solution consisting of polymer/MWCNTs has been electrospun to form nanofibers. Physiochemical aspects of prepared nanofibers were evaluated by SEM, TEM, FT-IR and Raman spectroscopy, confirming nanofibers containing MWCNTs. The biocompatibility and cell attachment of the produced nanofiber mats were investigated while culturing them in the presence of NIH 3T3 fibroblasts. The results from these tests indicated non-toxic behavior of the prepared nanofiber mats and had a significant attachment of cells towards nanofibers. The incorporation of MWCNTs into polymeric nanofibers led to an improvement in tensile stress from 11.40 ± 0.9 to 51.25 ± 5.5 MPa. Furthermore, complete alignment of the nanofibers resulted in an enhancement on tensile stress to 72.78 ± 5.5 MPa. Displaying these attributes of high mechanical properties and non-toxic nature of nanofibers are recommended for an ideal candidate for future tendon and ligament grafts

Imaging, Spectroscopic, Mechanical and Biocompatibility Studies of Electrospun Tecoflex® EG 80A Nanofibers and Composites Thereof Containing Multiwalled Carbon Nanotubes

The present study discusses the design, development and characterization of electrospun Tecoflex® EG 80A class of polyurethane nanofibers and the incorporation of multiwalled carbon nanotubes (MWCNTs) to these materials. Scanning electron microscopy results confirmed the presence of polymer nanofibers, which showed a decrease in fiber diameter at 0.5% wt. and 1% wt. MWCNTs loadings, while transmission electron microscopy showed evidence of the MWCNTs embedded within the polymer matrix. The fourier transform infrared spectroscopy and Raman spectroscopy were used to elucidate the polymer-MWCNTs intermolecular interactions, indicating that the C-N and N-H bonds in polyurethanes are responsible for the interactions with MWCNTs. Furthermore, tensile testing indicated an increase in the Young’s modulus of the nanofibers as the MWCNTs concentration was increased. Finally, NIH 3T3 fibroblasts were seeded on the obtained nanofibers, demonstrating cell biocompatibility and proliferation. Therefore, the results indicate the successful formation of polyurethane nanofibers with enhanced mechanical properties, and demonstrate their biocompatibility, suggesting their potential application in biomedical area

Fabrication of Poly(vinylidene fluoride) (PVDF) Nanofibers Containing Nickel Nanoparticles as Future Energy Server Materials

In the present study, we introduce Poly(vinylidene fluoride) (PVDF) nanofibers containing nickel (Ni) nanoparticles (NPs) as a result of an electrospinning. Typically, a colloidal solution consisting of PVDF/Ni NPs was prepared to produce nanofibers embedded with solid NPs by electrospinning process. The resultant nanostructures were studied by SEM analyses, which confirmed well oriented nanofibers and good dispersion of Ni NPs over them. The XRD results demonstrated well crystalline feature of PVDF and Ni in the obtained nanostructures. Physiochemical aspects of prepared nano-structures were characterized for TEM which confirmed nanofibers were welloriented and had good dispersion of Ni NPs. Furthermore, the prepared nano-structures were studied for hydrogen production applications. Due to high surface to volume ratio of nanofibers form than the thin film ones, there was tremendous increase in the rate of hydrogen production. Overall, results satisfactorily confirmed the use of these materials in hydrogen production

Electrospun Polystyrene-Multiwalled Carbon Nanotubes: Imaging, Thermal and Spectroscopic Characterization

Polystyrene (PS) nano- and micro-fibers presenting a fiber-bead structure were obtained by electrospinning. Incorporation of multiwalled carbon nanotubes (MWCNTs) into polymer solutions followed by electrospinning was also performed, thus affording composite electrospun fibers. Scanning electron microscopy (SEM) studies showed that the fiber-bead morphology for PS and the composite fibers changed gradually as the MWCNTs concentration increased, resulting in smooth defect-free fibers. Furthermore, thermogravimetric analysis did not show a significant enhancement in the thermal properties with the addition of the carbon nanotubes. However, the intermolecular interactions between the polymer nano- and micro-fibers and the MWCNTs were investigated through Fourier transform infrared spectroscopy (FT-IR), which revealed that the aromatic ring in the polystyrene matrix was deformed when interacting with the MWCNTs

Biodegradable DNA-enabled poly(ethylene glycol) hydrogels prepared by copper-free click chemistry

<div><p></p><p>Significant research has focused on investigating the potential of hydrogels in various applications and, in particular, in medicine. Specifically, hydrogels that are biodegradable lend promise to many therapeutic and biosensing applications. Endonucleases are critical for mechanisms of DNA repair. However, they are also known to be overexpressed in cancer and to be present in wounds with bacterial contamination. In this work, we set out to demonstrate the preparation of DNA-enabled hydrogels that could be degraded by nucleases. Specifically, hydrogels were prepared through the reaction of dibenzocyclooctyne-functionalized multi-arm poly(ethylene glycol) with azide-functionalized single-stranded DNA in aqueous solutions via copper-free click chemistry. Through the use of this method, biodegradable hydrogels were formed at room temperature in buffered saline solutions that mimic physiological conditions, avoiding possible harmful effects associated with other polymerization techniques that can be detrimental to cells or other bioactive molecules. The degradation of these DNA-cross-linked hydrogels upon exposure to the model endonucleases Benzonase^® and DNase I was studied. In addition, the ability of the hydrogels to act as depots for encapsulation and nuclease-controlled release of a model protein was demonstrated. This model has the potential to be tailored and expanded upon for use in a variety of applications where mild hydrogel preparation techniques and controlled material degradation are necessary including in drug delivery and wound healing systems.</p></div

Fabrication of Mineralized Collagen from Bovine Waste Materials by Hydrothermal Method as Promised Biomaterials

In the present study, we aimed to produce mineralized-collagen by hydrothermal process. A simple method not depending on additional foreign chemicals has been employed to isolate the mineralized-collagen fibers from bovine waste. The process of extraction involves the use of hydrothermal method from available bovine bones. The structural and morphological properties of the collagen fibers were characterized by using scanning electron microscopy and transmission electron microscopy. These results indicated well received collagen fibers, having a diameter less than 1 μm and with established mineral content in the individual fibers. The X-ray diffraction showed the crystalline feature of the obtained nano-compounds. The thermo gravimetric analysis was used to differentiate between the collagen and mineral parts of obtained product. Overall, the results generously indicated production of well received collagen fibers from bovine bones