Browsing by Subject "Polymerization."

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Open Access
Electrospinning of biocompatible polymeric nanofibers functionalized with cyclodextrin inclusion complex
(2012) Aytaç, Zeynep
Electrospinning is a simple, versatile and cost-effective method to produce nanofibers. Electrospun nanofibers have high surface area to volume ratio and nanoporous structure. Moreover, electrospun nanofibers could be functionalized with additives to extend their application areas. Cyclodextrins (CDs) are cyclic oligosaccharides and have truncated-cone shape structure. Due to their hydrophobic cavity, CDs have ability to form inclusion complex (IC) with a variety of molecule. In our study, we functionalized electrospun nanofibers with CDs and CD-ICs. In the first part, we successfully produced hydroxypropyl cellulose- (HPC), carboxymethyl cellulose- (CMC) and alginate-based nanofibers via electrospinning. Then we functionalized these nanofibers with CDs. The morphological characterizations of nanofibers were performed through scanning electron microscopy (SEM). Here, we have combined the properties of both electrospun nanofibers and CDs, and these nanofibers could be used in drug delivery, wound healing and tissue engineering applications. In the second part, we prepared IC of sulfisoxazole (SFS) (hydrophobic drug) with hydroxypropyl-beta-cyclodextrin (HPβCD) (SFS/HPβCD-IC). Then electrospinning of SFS/HPβCD-IC incorporating hydroxypropyl cellulose (HPC) nanofibers were performed (SFS/HPβCD-IC-HPC-NFs). In the third part of our study, we produced IC of α-tocopherol (α-TC) (antioxidant molecule) with beta-cyclodextrin (β-CD) (α-TC/β-CD-IC); and polycaprolactone (PCL) nanofibers incorporating α-TC/β-CD-IC was obtained via electrospinning (α- TC/β-CD-PCL-NFs). In the fourth part, IC of allyl isothiocyanate (AITC) (antibacterial compound) with β-CD (AITC/β-CD-IC) was produced. The electrospinning of AITC/β-CD-IC incorporating polyvinyl alcohol (PVA) nanofibers was carried out (AITC/β-CD-IC-PVA-NFs). In the fifth part, IC of quercetin (QU) (antioxidant molecule) with β-CD (QU/β-CD-IC) was prepared; and polyacrylic acid (PAA) nanofibers incorporating QU/β-CD-IC was obtained via electrospinning (QU/β-CD-IC-PAA-NFs). The structural and thermal characterizations of SFS/HPβCD-IC-HPC-NFs, α-TC/β-CD-PCL-NFs, AITC/β- CD-IC-PVA-NFs and QU/β-CD-IC-PAA-NFs were carried out by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The amount of released molecules were determined via liquid chromatography-mass spectroscopy (LC-MS) for SFS/HPβCD-IC-HPC-NFs; high performance liquid chromatography (HPLC) for α-TC/β-CD-PCL-NFs and QU/β-CD-IC-PAA-NFs and gas chromatography-mass spectrometry (GC-MS) for AITC/β-CD-IC-PVANFs. The antioxidant activity of α-TC/β-CD-PCL-NFs and QU/β-CD-IC-PAANFs was investigated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Moreover, α-TC/β-CD-PCL-NFs released great proportion of α-TC after exposing UV light. Thus, α-TC/β-CD-PCL-NFs exhibited quite high photostability. The antibacterial activity of AITC/β-CD-IC-PVA-NFs was evaluated by colony counting method against Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus). In brief, we concluded that SFS/HPβCD-ICHPC-NFs, α-TC/β-CD-PCL-NFs, AITC/β-CD-IC-PVA-NFs and QU/β-CD-ICPAA-NFs are promising materials for drug delivery and wound healing applications.
Open Access
Nanofibrous nanocomposites via electrospinning
(2011) Deniz, Ali Ekrem
In recent years, numerous studies have been reported for fabrication of composite nanofibers from polymeric and inorganic materials by using electrospinning method. In the first part of this study, TiO2 and ZnO inorganic nanofibers were produced by electrospinning from their precursors by using polymeric carrier matrix and their photocatalytic activity of these metal oxide nanofibers were studied. Moreover, electrospun TiO2 nanofibers were crushed into short nanofibers (TiO2-SNF) and embedded in electrospun polymeric nanofiber matrixes such as poly(methyl methacrylate) (PMMA), polyacrylonitrile (PAN), polyethylene terephthalate (PET), polycarbonate (PC) and polyvinylidene fluoride (PVDF). Different weight loading of TiO2-SNF ranging from 2% to 8% (w/w, respect to polymer) incorporated into PVDF nanofibrous matrix was applied and the structural and morphological changes along with their photocatalytic activities were also examined. In the second part, metallic nanoparticles produced by laser ablation method were incorporated into nanofibrous polymeric matrix by using electrospinning technique. For example, gold (Au) and silver (Ag) nanoparticles (NPs) were produced from their metallic sources by laser ablation method directly in the polymer solutions. The NPs/polymer mixtures were electrospun and surface plasmon resonance effect of Au-NPs and Ag-NPs on optical properties of the nanofibers was studied. In addition, germanium nanocrystals produced by means of laser ablation were mixed with PVDF polymer solution and consequently electrospun into composite polymeric nanofiber matrix.