Browsing by Subject "cyclodextrin"

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Open Access
Antibacterial electrospun poly(lactic acid) (PLA) nanofibrous webs incorporating triclosan/cyclodextrin inclusion complexes
(2013) Kayaci F.; Umu O.C.O.; Tekinay, T.; Uyar, T.
Solid triclosan/cyclodextrin inclusion complexes (TR/CD-IC) were obtained and then incorporated in poly(lactic acid) (PLA) nanofibers via electrospinning. α-CD, β-CD, and γ-CD were tested for the formation of TR/CD-IC by a coprecipitation method; however, the findings indicated that α-CD could not form an inclusion complex with TR, whereas β-CD and γ-CD successfully formed TR/CD-IC crystals, and the molar ratio of TR to CD was found to be 1:1. The structural and thermal characteristics of TR/CD-IC were investigated by 1H NMR, FTIR, XRD, DSC, and TGA studies. Then, the encapsulation of TR/β-CD-IC and TR/γ-CD-IC in PLA nanofibers was achieved. Electrospun PLA and PLA/TR nanofibers obtained for comparison were uniform, whereas the aggregates of TR/CD-IC crystals were present and distributed within the PLA fiber matrix as confirmed by SEM and XRD analyses. The antibacterial activity of these nanofibrous webs was investigated. The results indicated that PLA nanofibers incorporating TR/CD-IC showed better antibacterial activity against Staphylococcus aureus and Escherichia coli bacteria compared to PLA nanofibers containing only TR without CD-IC. Electrospun nanofibrous webs incorporating TR/CD-IC may be applicable in active food packaging due to their very high surface area and nanoporous structure as well as efficient antibacterial property. © 2013 American Chemical Society.
Open Access
Cyclodextrin functionalized poly(methyl methacrylate) (PMMA) electrospun nanofibers for organic vapors waste treatment
(Elsevier BV, 2010) Uyar, Tamer; Havelund, R.; Nur, Y.; Balan, A.; Hacaloglu, J.; Toppare, L.; Besenbacher, F.; Kingshott, P.
Poly(methyl methacrylate) (PMMA) nanofibers containing the inclusion complex forming betacyclodextrin (_-CD) were successfully produced by means of electrospinning in order to develop functional nanofibrous webs for organic vapor waste treatment. Electrospinning of uniform PMMA nanofibers containing different loadings of _-CD (10%, 25% and 50% (w/w)) was achieved. The surface sensitive spectroscopic techniques; X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) showed that some of the _-CD molecules are present on the surface of the PMMA nanofibers, which is essential for the trapping of organic vapors by inclusion complexation. Direct pyrolysis mass spectrometry (DP-MS) studies showed that PMMA nanowebs containing _-CD can entrap organic vapors such as aniline, styrene and toluene from the surroundings due to inclusion complexation with _-CD that is present on the fiber surface. Our study showed that electrospun nanowebs functionalized with cyclodextrinsmayhave the potential to be used as molecular filters and/or nanofilters for the treatment of organic vapor waste and air filtration purposes.
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
Electrospinning of functional poly(methyl methacrylate) nanofibers containing cyclodextrin-menthol inclusion complexes
(Institute of Physics Publishing, 2009) Uyar, Tamer; Nur, Y.; Hacaloglu, J.; Besenbacher, F.
Electrospinning of nanofibers with cyclodextrin inclusion complexes (CD-ICs) is particularly attractive since distinct properties can be obtained by combining the nanofibers with specific functions of the CD-ICs. Here we report on the electrospinning of poly(methyl methacrylate) (PMMA) nanofibers containing cyclodextrin-menthol inclusion complexes (CD-menthol-ICs). These CD-menthol-IC functionalized nanofibers were developed with the purpose of producing functional nanofibers that contain fragrances/flavors with high temperature stability, and menthol was used as a model fragrance/flavor material. The PMMA nanofibers were electrospun with CD-menthol-ICs using three type of CD: α-CD, β-CD, and γ-CD. Direct pyrolysis mass spectrometry (DP-MS) studies showed that the thermal evaporation of menthol occurred over a very high and a broad temperature range (100-355 °C) for PMMA/CDmenthol-IC nanowebs, demonstrating the complexation of menthol with the CD cavity and its high temperature stability. Furthermore, as the size of CD cavity increased in the order α-CD<β-CD<γ-CD, the thermal evolution of menthol shifted to higher temperatures, suggesting that the strength of interaction between menthol and the CD cavity is in the order γ-CD>β-CD>α-CD. © 2009 IOP Publishing Ltd.
Open Access
The formation and characterization of cyclodextrin functionalized polystyrene nanofibers produced by electrospinning
(2009) Uyar, Tamer; Havelund, R.; Hacaloglu J.; Zhou X.; Besenbacher F.; Kingshott P.
Polystyrene (PS) nanofibers containing the inclusion complex forming beta-cyclodextrin (β-CD) were successfully produced by electrospinning aimed at developing functional fibrous nanowebs. By optimization of the electrospinning parameters, which included varying the relative concentration of PS and β-CD in the solutions, bead-free fibers were produced. Homogeneous solutions of β-CD and PS in dimethylformamide (DMF) were used with concentrations of PS varying from 10% to 25% (w/v, with respect to DMF), and β-CD concentrations of 1% to 50% (w/w, with respect to PS). The presence of β-CD facilitated the production of bead-free PS fibers even from lower polymer concentrations as a result of the higher conductivity of the PS/CD solutions. The morphology and the production of bead-free PS/CD fibers were highly dependent on the β-CD contents. Transmission electron microscope (TEM) and atomic force microscope (AFM) images showed that incorporation of β-CD yielded PS fibers with rougher surfaces. Thermogravimetric analysis (TGA) and direct insertion probe pyrolysis mass spectroscopy (DP-MS) results confirmed the presence of β-CD in the PS fibers. X-ray diffraction (XRD) spectra of the fibers indicated that the β-CD molecules are distributed within the PS matrix without any phase separated crystalline aggregates up to 40% (w/w) β-CD loading. Furthermore, chemical analyses by Fourier transform infrared (FTIR) spectroscopy studies confirm that β-CD molecules are located within the PS fiber matrix. Finally, preliminary investigations using x-ray photoelectron spectroscopy (XPS) and time-of-flight static secondary ion mass spectrometry (ToF-static-SIMS) show the presence of the cyclodextrin molecules in the outer molecular layers of the fiber surfaces. The XPS and ToF-SIMS findings indicate that cyclodextrin functionalized PS webs would have the potential to be used as molecular filters and/or nanofilters for the purposes of filtration/purification/separation owing to surface associated β-CD molecules which have inclusion complexation capability. © 2009 IOP Publishing Ltd.