Editorial Open Access
Zein and Abdullah, J Nanomed Nanotechol 2012, 3:4
DOI: 10.4172/2157-7439.1000e108
Volume 3 • Issue 4 • 1000e108
J Nanomed Nanotechol
ISSN:2157-7439 JNMNT an open access journal
For centuries, metals and alloys have been used in substitution
for anatomical structures owing to their extraordinary mechanical
properties [1]. Type 316L Stainless Steel (SS) is known to be widely used
for implantation purposes in orthopedic surgery due to its corrosion
resistance, efective cost and superior mechanical properties [1,2].
However, several incidences of failures involving type 316L SS have
been occurred which released the metal ions into tissues [1] and blood
stream surrounding the implants, thus causing histological changes of
the local tissue by direct toxic efects or local hypersensitivity reaction
[3]. It is highly probable that electrophoretically deposited Multiwall
Carbon Nanotubes (MWCNTs) and Hydroxyapatite (HA) on type
316L SS could minimize this limitation, and further investigation of its
corrosion behavior using in vitro electrochemical techniques [1,4] may
confrm the acceptability of modifed SS as an efective biomaterial to
be used as orthopedic implants.
An ideal orthopedic implant should possess biocompatible,
osteoconductivity [5], superior mechanical properties [6-8] and
excellent corrosion resistance to physiological environments of
the human body [1,9]. Diferent electrochemical techniques for
evaluation of corrosion behavior have been studied extensively
included Electrochemical Impedance Spectroscopy (EIS), cyclic
potentiodynamics polarization and Open Circuit Potential (OCP)
studies [2]. EIS is a useful approach to monitor in situ electrochemical
changes [10] and to develop understanding of the physical process
occurring at the electrode-electrolyte interface [11-13]. EIS study was
carried out based on an appropriate circuit model in order to ft the
experimental data to equivalent circuit model parameters, whereas
each parameter would represents macroscopic physical quantity which
contributing to interface impedance [11]. An equivalent circuit was
selected to represent the electrochemical behavior of metals implants
that have been coated with an unsealed porous flm [14]. Te equivalent
circuit consists of solution resistance of the electrolyte (experimental
human body fuid solution), R
e
, capacitance of non-defective coating
layer, C
p
, charge transfer resistance of electrolyte’s penetration through
pinholes, R
p
, polarization resistance of substrate, R
b
and electrical
double-layer capacitance at substrate/electrolyte interface, C
b
[4]. Tis
physical model of the electrochemical reactions that occurred at the
electrodes is important to interpret the electrochemical behavior of the
metal implants from EIS spectra [15].
Certain amount of current density is necessary to generate activity
in stimulation process which resulted in interface impedance of the
metal implants [4]. Te equivalent model comprises an interface
capacitance, shunted by charge transfer resistance and in series with
solution resistance [16]. Ten, a theoretical equation has been used to
determine the interface capacitance impedance and solution resistance
in order to confrm the results that correspond well with the ftted
parameter values, hence validating the model equations [4]. Impedance
behaviors of the metals implants could be expressed either in a Bode
plot of logarithm of impedance modulus (|Z|) and phase angle (Φ)
as a function of logarithm of frequency or in a Nyquist plot of Z”
(ω) as a function of Z’(ω) [14,17]. Te Bode plots of logarithm total
impedance |Z| vs. frequency for uncoated SS and coated samples of
SS/MWCNT-OH are shown in Figure 1(a) and for uncoated SS and
*Corresponding author: Sharif Hussein Sharif Zein, School of Chemical Engineering,
Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal,
Seberang Perai Selatan, Pulau Pinang, Malaysia, E-mail: chhussein@eng.usm.my
Received April 27, 2012; Accepted April 27, 2012; Published May 02, 2012
Citation: Zein SHS, Abdullah MF (2012) Electrochemical Impedance Spectroscopy
(EIS) Study of Modifed Type-316L Stainless Steel (SS) as an Effective
Biomaterial for Orthopedic Implant Applications. J Nanomed Nanotechol 3:e108.
doi:10.4172/2157-7439.1000e108
Copyright: © 2012 Zein SHS, et al. This is an open-access article distributed under
the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original author and
source are credited.
Electrochemical Impedance Spectroscopy (EIS) Study of Modified Type-
316L Stainless Steel (SS) as an Effective Biomaterial for Orthopedic
Implant Applications
Sharif Hussein Sharif Zein* and Muhammad Faiq Abdullah
School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang, Malaysia
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0 1 10 100 1.000 10.000
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0 1 10 100 1,000 10,000
(a)
Frequency, f (Hz)
Uncoated SS
SS/MWCNT
SS/MWCNT
SS/MWCNT
SS/MWCNT
SS/MWCNT
-OH 70 V
-OH 80 V
-OH 90 V
-OH 100 V
-OH 60 V
Uncoated SS
SS/MWCNT-
SS/MWCNT-
SS/MWCNT-
OH/HA 70 V
OH/HA 80 V
OH/HA 90 V
Frequency, f (Hz)
loglzl, (Ω)
b
loglzl, (Ω)
Figure 1: Bode plots of logarithm total impedence z vs. frequency of (a)
uncoated SS and coated samples of SS/MWCNT-OH and (b) uncoated SS
and coated samples of SS/MWCNT-OH/HA.
Journal of
Nanomedicine & Nanotechnology
J
o
u
r
n
a
l
o
f
N
a
n
o
m
e
d
i
c
i
n
e
&
N
a
n
o
t
e
c
h
n
o
l
o
g
y
ISSN: 2157-7439