Photonic crystals in biology - NanoTR-VI

PPPPPPoster Session, Thursday, June 17Theme F686 - N1123Fabrication of Aligned Silk Fibroin Nanofibers by Electrospinning1234Gamze DoanP P, UGüldemet BaalUP P*, Ali Bora BaltaP P, Ouz BayraktarP1 Department of Textile Engineering, Uak University, Uak 64100, Turkey2PDepartment of Textile Engineering, Ege University, zmir 35100, TurkeyPDepartment of Biotechnology and Bioengineering, zmir Istitute of Technology, zmir 35430, Turkey4PDepartment of Chemical Engineering, zmir Istitute of Technology, zmir 35430, Turkey3Abstract- Aligned nanofibers provide some advantages in fabrication of scaffolds for tissue engineering. In this study, silk fibroin nanofiberswere fabricated by an electrospinning unit with a rotating drum as a collector at three different drum speeds (surface velocity), and the influenceof drum speed on fiber size and alignment were investigated.Tissue engineering is a field of regenerative medicine,which deals with the development of tissue substitutes(scaffolds) to repair, maintain, or improve the function ofdiseased or damaged tissues. Mimicking of cellmicroenviroment as close as possible when designingscaffolds is the key issue in tissue engineering [1].Electrospun biopolymer nanofibers have potential uses asscaffolds, due to their resemblance to natural extra cellularmatrix (ECM), high surface area to volume ratio and highporosities [2]. The ECM is a nano fibrous network whichholds cells and tissues together and provides a controlledenvironment inside which migratory cells can move andinteract with each other [3].Several natural or synthetic biodegrable polymers have beenturned into scaffolds for tissue engineering. Silk fibroin (SF)is a great candidate for this purpose. It has a slow degradationrate, good mechanical properties, high oxygen permeabilityand it is non-toxic [4, 5].One of the most widely used method for the fabrication ofnanofibrous scaffolds is electrospinning. This method involvesthe ejection and stretching of a polymer solution or melt froma capillary tube by electrostatic forces. In electrospinningmethod, stationary collectors are used for the production ofrandom nanofiber bundles. Rotating targets such as disks anddrums are used for the fabrication of aligned nanofibers [6, 7].Alignment of nanofibers plays an important role in repairingtissues that have structural orientation in one direction such asmuscle and nerve tissues. According to contact guidancetheory aligned nanofiber scaffolds can exhibit more ECMproduction than random nanofiber scaffolds [8]. These alignednanofiber scaffolds also have a more dense structure and highstrength value compared to random nanofiber scaffolds [9].In this study, aligned nanofibers were fabricated from silkfibroin (SF) by utilizing an electrospinning set up with arotating drum and the effects of the surface velocity of therotating drum on fiber size and alignment of fibers wereinvestigated.Silk fibroin solution was prepared using 98% formic acid.The concentration of SF in the solution was 6 wt%. Appliedvoltage was 20 kV. Flow rate was set to 7 μL/min. Distancebetween the collector and the needle tip was adjusted to 11.2cm. All of these parameters were kept constant, except thesurface velocity of the rotating drum. Electrospinning wasperformed at three different surface velocities: 50, 100 and150m/min. Results revealed that the influence of drum speedon fber alignment and fber size was significant. Figure 1shows the SEM image of silk fibroin nanofibers collected at asurface velocity of 150 m/min. Average fiber diameterdecreased when surface velocity of the drum increased.Average fiber diameters were 80, 69, and 65 nm for thesurface velocities of 50, 100 and 150, respectively.Figure 1. SEM image of silk fibroin nanofibers collected onto a drumwith a surface velocity of 150 m/min.*Corresponding author: guldemet.basal@ege.edu.tr[1] Venugopal J., Prbhakaran M.P., Low S., Choon AT, Zhang Y.Z.,Deepika G., Ramakrishna S., 2008. Current Pharmaceutical Design,14, 2184-2200.[2] Subbiah T., Bhat G.S., Tock R.W., Parameswaran S., RamkumarS.S., 2005. Journal of App. Polymer Science, Vol. 96, 557–569.[3] http://themedicalbiochemistrypage.org/extracellularmatrix.html[4] Lia C., Veparia C., Jina H.J., Kima H.J., Kaplan D.L., 2006.Biomaterials, 27, 3115–3124.[5] Wang S., Zhang Y., Wang H., Yin G., Dong Z., 2009.Biomacromolecules, 10, 2240–2244[6] Fennessey S.F., Farris R.J., 2004. Polymer, 45, 4217-4225.[7] Bazbouz M.B., Stylios G.K., 2008. European Polymer Journal,44, 1–12[8] Venugopal J., Low S., Choon A.T., Ramakrishna S., 2008.Journal of Biomed. Mat. Res. Part B, App. Biomaterials, 84 (1), 34-48.[9] Kumbar, S.G., James, R., Nukavarapu, S.P., and Laurencin, C.T.,2008. Biomed. Mat., 3, 15pp.6th Nanoscience and Nanotechnology Conference, zmir, 2010 787