Photonic crystals in biology - NanoTR-VI

PPPPPoster Session, Thursday, June 17Theme F686 - N1123Electrospinnability of Hyaluronic Acid123UGamze DoanUP P*, Güldemet BaalP P, Ali Bora BaltaP P, Ouz BayraktarP1PDepartment 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- Natural biopolymer nanofibers have advantages in tissue engineering applications due to their good biocompatibility,biodegradability, and resemblance to native extracellular matrix which enhances the tissue regeneration. Hyaluronic acid, a naturalbiopolymer existing in human body, is commonly used in scaffold fabrication. One recent fabrication technique for the creation of scaffoldsis electrospinning. However, electrospinability of hyaluronic acid is very poor due its high viscosity. This study reveals the problems faced inelectrospinning of hyaluronic acid and focuses on determining proper solvent systems and blends which allow the successful production ofhyaluronic acid nanofibers.4Hyaluronic acid attracts much attention in tissueengineering applications since it is a basic component ofextra cellular matrix [1]. Hyaluronic acid is an anionicpolysaccharide composed of alternating units of glucuronicacid and N-asetyl-glucosamine (Fig.1). It is hydrophilic,non-immunogenic and possesses high viscosity [2]. Highsurface tension and viscosity of hyaluronic acid makes itvery difficult to electrospin.Viscosity is one of the most important parameters thataffects nanofiber formation in electrospinning process.Intrinsic viscosity is a function of molecular weight.Viscosity of hyaluronic acid with molecular weights of 40,1000, 3000 and 7000 kDa at zero shear rate are 2.1, 36,3000, and 20000 mPas, respectively [3]. Besides molecularweight, concentration, temperature, and solvent type arethe other parameters that affect solution viscosity. As theconcentration of hyaluronic acid solution is raised from1%wt to 4%wt the viscosity of the solution increases 15times[4].Figure 1. Chemical Structure of Hyaluronic AcidIn order to overcome the high surface tension andviscosity problems of hyaluronic acid, several researcherstried to electrospin HA by dissolving it in different solventsystems, blending it with synthetic polymers likepolyethylene oxide [2, 4, 6] and making somemodifications on the electrospinning equipment [7].In this study hyaluronic acid with a molecular weight of1600 kDa was dissolved in different solvent systems.Water, ethanol, dimethyl formamide, and sodiumhydroxide were chosen as solvents. Different combinationsof these solvents were used to prepare HA solutions forelectrospinning. In addition, HA was blended with PEGand PVA in different weight ratios. All of the solventsystems resulted in electrosprayed droplets. Neitheruniform nor beaded nanofiber formation was obtained.Electrospinning of HA was achieved by blending it withPVA at high PVA weight ratios. As seen in Figure 2, evenat high PVA ratios only beaded nanofibers were formed.Figure 2. SEM image of 1% wt PVA:HA (97:3) nanofibers*Corresponding author: gamze.dogan@usak.edu.tr[1] Wang T.W., Spector M., 2009. Development of hyaluronicacid-based scaffolds for brain tissue engineering, ActaBiomaterialia, 5, 2371–2384.[2] Schiffman J.D., 2009. Determination of the electrospinningparameters for biopolyelectrolytes and their modifcations, DrexelUniversity, Doctor of Philosophy Thesis, 300 p.[3] Bergmann G., Kölbel R., Rohlmann A., 1987. Biomechanics:Basic and Applied Research, Martinus Nijhoff Publishers,Dortrecht, The Netherlands, 275-276.[4] Brenner E.K., 2009. Investigation into the Electrospinning ofHyaluronic Acid, Drexel University, Master of Science Thesis,93 p.[6] Young, D.S., 2006. Hyaluronic Acid Based Nanofibers viaElectrospinning, North Carolina State University, Master ofScience Thesis, 97 p.[7] Um, I.C., Fang, D., Hsiao, B.S., Okamoto, A., and Chu, B.,2004. Electro-Spinning and Electro-Blowing of Hyaluronic Acid,Biomacromolecules, 5, 1428-1436.6th Nanoscience and Nanotechnology Conference, zmir, 2010 788