Photonic crystals in biology

Poster Session, Tuesday, June 15
Theme A1 - B702
Preparat ion of Ag doped HAP/PHBV Nanocompos ite Fibers via Electrospinning Technique
Aslihan Suslu 1 *, Aylin Ziylan Albayrak 1 and Umit Cocen 1
1 Department of Metallurgical and Materials Engineering, Dokuz Eylul University, 35160, Izmir, Turkey
Abstract- Silver doped hydroxyapatites were produced by coprecipitation method and Ag doped HAP-PHBV nanocomposite suspensions
were prepared with the aid of the surfactant, 12-hydroxysteric acid (HSA). Nanocomposite fibers prepared from Ag doped HAP-PHBV
suspensions were produced via electrospinning. Surface morphology of the fibers analyzed by SEM and HAP dispersion on the fiber surface
was investigated by EDS analysis via Ca, P and Ag quantity determination. XRD was used in order to see whether the crystal structure of
HAP is maintained or not.
An ideal tissue scaffold should be mechanically stable,
bio-compatible and capable of functioning biologically in
the implant site. Biologic functioning is regulated by
biologic signals from growth factors, extracellular matrix
(ECM), and the surrounding cells. ECM molecules
surround cells to provide mechanical support and regulate
cell activities [1].To mimic natural ECM, many research
groups have tried to produce nanofibrous tissue scaffolds
using electro-spinning method [2]. Electrospinning is an
actively investigated technique recently, as well as the
simplicity of the process; it offers ultrafine polymer fibers,
high specific surface area, highly porous structure and the
possibility of various modifications [3-5]. In tissue
engineering applications in particular, ultrafine nanofibers
have been fabricated from biodegradable and
biocompatible natural or synthetic polymers such as
collagen, fibrinogen, poly(glycolic acid) (PGA), poly(L-
Lactic acid) (PLA), poly(lactic acid-co-glycolic acid)
(PLGA), poly(3-hydroxybutyrate-co-3-hydroxyvalerate)
(PHBV) [6].
The target of our study is to produce polymer based
tissue scaffold that can be used in the field of tissue
engineering. As the main matrix, PHBV as a
biodegradable and a biocompatible polymer was chosen.
Together with the cheapness, PHBV has longer
degradation time than PLA and PLGA polymers, which
means that the scaffold can maintain its mechanical
integrity until there is sufficient tissue formation [6]. To
increase the mechanical strength of the main matrix and
also to improve cell adhesion hydroxyapatite (HAP) is
used. In addition, as the cation exchange rate of HAP is
very high, HAP is doped with minor amount of Ag ions in
this way tissue scaffold will gain antibacterial function as
well as the osteoconductive function. [7-9]. Due to its
nontoxic and cell-friendly nature HSA is a safely used
chemical in biomedical applications as a surfactant [10]. In
this study, HSA was used to disperse Ag doped HAP in
the PHBV matrix in a homogenous manner. Also,
organosoluble salt benzyl triethylammonium chloride
(BTEAC) was used to increase the conductivity of solution
and to obtain uniform fibers.
Ag doped (2 wt %) hydroxyapatite powder was
produced by coprecipitation method using AgNO 3 , H 3 PO 4
and Ca(OH) 2 as starting materials. Ag doped HAP
powders were characterized by XRD and SEM/EDS. As
the Ag content of the powders was very low, no difference
between the XRD patterns of HAP and Ag dopped HAP
was observed. Nanocomposite fibers were successfully
fabricated by using the Ag doped HAP-PHBV suspensions
via electrospinning. Optimum parameters were defined as
follows: Voltage supply, 20 kV; distance between the
needle and the collector, 15 cm; flow rate, 0,3 ml/h. SEM
and EDS analyses showed Ag doped HAP was
successfully incorporated and homogenously dispersed on
the PHBV fibers. In order to reduce the fiber diameter and
get better spinability BTEA C salt (2-5 wt %) was used.
In conclusion Ag doped HAP powder was synthesized
successfully by coprecipitation method. Ag doped HAP-
PHBV nanocomposite suspensions prepared. The innate
dispersion and agglomerate problems associated within
hydrophilic bioceramic powder within hydrophobic
biopolymers were solved by using a surfactant.
Nanocomposite fibers successfully produced from the
prepared Ag doped HAP-PHBV suspensions via
electrospinning technique. Author A.S acknowledges the
support from TUBITAK, in the framework of the National
Scholarship Programmes for PhD Students.
* Corresponding author: 0Taslihan.suslu@deu.edu.tr
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6th Nanoscience and Nanotechnology Conference, zmir, 2010 375