Impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena
The article has investigated the removal of water borne pathogens using dielectrophoresis (DEP) filter which is energized by varying the frequency of the applied potential from 10 kHz to 2 MHz with different voltage levels of 5; 10; 15 and 20 V. Separate experiments are conducted in artificially co...
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| Zitieren: | Impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena / A. Sankaranarayanan, K.M. Prabu Sankarlal, D. Raja // Химия и технология воды. — 2016. — Т. 38, № 2. — С. 210-219. — Бібліогр.: 16 назв. — англ. |
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Sankaranarayanan, A. Prabu Sankarlal, K.M. Raja, D. 2019-11-19T15:43:07Z 2019-11-19T15:43:07Z 2016 Impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena / A. Sankaranarayanan, K.M. Prabu Sankarlal, D. Raja // Химия и технология воды. — 2016. — Т. 38, № 2. — С. 210-219. — Бібліогр.: 16 назв. — англ. 0204-3556 https://nasplib.isofts.kiev.ua/handle/123456789/160777 The article has investigated the removal of water borne pathogens using dielectrophoresis (DEP) filter which is energized by varying the frequency of the applied potential from 10 kHz to 2 MHz with different voltage levels of 5; 10; 15 and 20 V. Separate experiments are conducted in artificially contaminated water samples with Escherichia coli, Staphylococcus aureus and Vibrio cholera up to 2 h. The impact of signal frequency and voltages on DEP based water treatment system has been analyzed statistically. Results have demonstrated that an ac signal of 20 V with frequency range of 500 kHz to 2 MHZ is suitable to remove the tested bacterial population and the rate of removal of E. coli is the highest with a dielectrophoretic filtration efficiency of 77,1%. en Інститут колоїдної хімії та хімії води ім. А.В. Думанського НАН України Химия и технология воды Биологические методы очистки воды Impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena Article published earlier |
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| title |
Impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena |
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Impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena Sankaranarayanan, A. Prabu Sankarlal, K.M. Raja, D. Биологические методы очистки воды |
| title_short |
Impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena |
| title_full |
Impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena |
| title_fullStr |
Impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena |
| title_full_unstemmed |
Impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena |
| title_sort |
impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena |
| author |
Sankaranarayanan, A. Prabu Sankarlal, K.M. Raja, D. |
| author_facet |
Sankaranarayanan, A. Prabu Sankarlal, K.M. Raja, D. |
| topic |
Биологические методы очистки воды |
| topic_facet |
Биологические методы очистки воды |
| publishDate |
2016 |
| language |
English |
| container_title |
Химия и технология воды |
| publisher |
Інститут колоїдної хімії та хімії води ім. А.В. Думанського НАН України |
| format |
Article |
| description |
The article has investigated the removal of water borne pathogens using dielectrophoresis (DEP) filter which is energized by varying the frequency of the applied potential from 10 kHz to 2 MHz with different voltage levels of 5; 10; 15 and 20 V. Separate experiments are conducted in artificially contaminated water samples with Escherichia coli, Staphylococcus aureus and Vibrio cholera up to 2 h. The impact of signal frequency and voltages on DEP based water treatment system has been analyzed statistically. Results have demonstrated that an ac signal of 20 V with frequency range of 500 kHz to 2 MHZ is suitable to remove the tested bacterial population and the rate of removal of E. coli is the highest with a dielectrophoretic filtration efficiency of 77,1%.
|
| issn |
0204-3556 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/160777 |
| citation_txt |
Impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena / A. Sankaranarayanan, K.M. Prabu Sankarlal, D. Raja // Химия и технология воды. — 2016. — Т. 38, № 2. — С. 210-219. — Бібліогр.: 16 назв. — англ. |
| work_keys_str_mv |
AT sankaranarayanana impactofdifferentfrequenciesintheentrapmentofbacterialpathogensfromdrinkingwaterusingdielectrophoreticphenomena AT prabusankarlalkm impactofdifferentfrequenciesintheentrapmentofbacterialpathogensfromdrinkingwaterusingdielectrophoreticphenomena AT rajad impactofdifferentfrequenciesintheentrapmentofbacterialpathogensfromdrinkingwaterusingdielectrophoreticphenomena |
| first_indexed |
2025-11-26T06:44:10Z |
| last_indexed |
2025-11-26T06:44:10Z |
| _version_ |
1850615867456356352 |
| fulltext |
ISSN 0204–3556. Химия и технология воды, 2016, т.38, №2210
© A. Sankaranarayanan, K.M. Prabu Sankarlal, D. Raja, 2016
Биологические методы очистки воды
A. Sankaranarayanan1, K.M. Prabu Sankarlal2, D. Raja1
IMPAct of DIffeRent fRequencIeS
In the entRAPMent of bActeRIAl PAthogenS
fRoM DRInKIng wAteR uSIng DIelectRoPhoRetIc
PhenoMenA
1Department of Microbiology K.S. Rangasamy College of Arts and Science
(Autonomous), Tamil Nadu state, India;
2Department of Electronics and Communication
K.S. Rangasamy College of Arts and Science (Autonomous),
Tamil Nadu state, India
drsankarkamal@gmail.com
The article has investigated the removal of water borne pathogens using
dielectrophoresis (DEP) filter which is energized by varying the frequency of the
applied potential from 10 kHz to 2 MHz with different voltage levels of 5; 10; 15
and 20 V. Separate experiments are conducted in artificially contaminated water
samples with Escherichia coli, Staphylococcus aureus and Vibrio cholera up to 2 h.
The impact of signal frequency and voltages on DEP based water treatment system
has been analyzed statistically. Results have demonstrated that an ac signal of 20 V
with frequency range of 500 kHz to 2 MH
Z
is suitable to remove the tested bacterial
population and the rate of removal of E. coli is the highest with a dielectrophoretic
filtration efficiency of 77,1%.
Keywords: water borne pathogens, drinking water, frequency, dielectrophoretic
phenomena.
IntRoDuctIon
Water-borne pathogens have been the primary causative factor for
high mortality. The World Health Organization report revealed that more
than 2,5 million peoples die in a year throughout the world due to water-
borne maladies.Almost 80% of diseases and over one third of mortality
in developing countries are caused by the consumption of contaminated
water which invoked an increased level of public and professional concern
ISSN 0204–3556. Химия и технология воды, 2016, т.38, №2 211
about water safety in the light of reported outbreaks of water borne
diseases and recognition of new causative agents of diseases [1]. Although
inadequate drinking water and sanitation are the major causes of morbidity
and mortality but appropriate treatment of water using a suitable method
paves the way for obtaining pure and safe drinking water. Among many
water borne pathogens, Escherichia coli, Staphylococcus aureus and Vibrio
cholera were found to be more harmful for human health [1]. The existing
water treatment filter systems which utilize pores to trap the contaminant
particles have the drawback of clogging and choking of particles which
require frequent maintenance and leads to increased cost of operation
[2]. The systems demand a very long time to obtain the expected
microbiological results [3] and not suitable for providing a fast, real time
diagnosis in the event of emergency [4]. The traditional microorganism
separation methods, such as electrophoresis, have their own inherent
limitation that the microbes are separated based on their characteristic
charge-to mass ratio and is not selective and prone to variations in various
chemical environments [5]. The movement of the particles in the electrode
determined by the dielectric properties (conductivity and permittivity) [6].
Dielectrophoresis (DEP) provides an alternation to conventional methods
because of its ability to concentrate and separate microorganisms in a
selective, rapid and reversible manner [3, 5]. The motion of a particle due
to the unbalanced force present in a non-uniform electric field pulls the
particle electrostatically along slope of electric field [4] which produces
an unbalanced electrostatic force on the charge in a particle referred as
DEP. This mechanism has non-linear dependence on electric field and
is able to perform microorganism concentration as well as separation in
water monitoring systems. Dielectrophoretic phenomena for removing food
borne pathogens using a DEP chip with a fixed ac voltage and frequency of
20 V and 1 MHz. The signal frequencies are varied and the performance of
DEP based traps for bacterial detection was analyzed in [7]. However the
impact of voltage and frequency dependant properties of DEP phenomena
for drinking water treatment has not been exploited yet.
In our present investigation, we have made an effort for removal of
selected water borne pathogens from artificially contaminated water using
Dielectrophoretic system. Moreover, quantitative analysis has been made
regarding the changing properties of DEP phenomena with respect to changing
frequency and voltages in trapping the pathogens from contaminated water.
ISSN 0204–3556. Химия и технология воды, 2016, т.38, №2212
experimental
Three different bacteria Esherechia coli, Staphylococcus aureus and Vibrio
cholera were isolated from drinking water to prepare artificially contaminated
water samples separately [8] and known volumes of colums were added in sterile
deionised water.
To check the efficiency of DEP 100; 50 and 10 μl, of 16 – 18 h aged inoculum
was added in 99 ml of deionised water and prepared the dilution of 102; 103; 104,;
105. From this 0,1 ml of inoculum was transferred into nutrient agar and triptic
Soy agar ("Himedia", India) plates and incubated at 37°C for 24 h to obtain
viable cell count with triplicates. The CFU in every dilution was quantified
using colony counter. To get the load of bacterial cell, spectrophotometer
observation was performed at 530 nm [2].
The dielectrophoretic chip design [2,5] consists of two conducting electrodes
with thickness of 0,54 mm and a length of 15 mm copper sheets are placed in
parallel with a gap of 2 mm. A transparent glass chamber with thickness of
5 mm, length of 15 mm and width of 10 mm covers them and tiny glass beads of
borosilicate with 2 mm diameter are placed between the copper electrodes such
that the resulting gap is filled with glass beads in single file and to find the strong
electric field areas on the surfaces to trap cells. The glass chamber is provided
with an entrance and exit ports for application and collection of contaminated
sample. The copper electrodes are electrically energized with an AC sinusoidal
waveform from function generator with adjustable frequency control and an
instrumental amplifier [9] provides variable output voltage levels.
In the designed DEP filter system, 1 ml of bacterial inoculum added in
deionized water (Average no of CFU/mL) was circulated for 2h (flow rate of
1 mL/min) at room temperature (34°C). Absorbance (530 nm) and viable cell
counts of the bacterial suspension were measured before and after circulation.
An AC signal applied in the voltage range of 5; 10; 15 and 20 V with
different frequencies ranging from 10 kHz to 2 MHz for 2 h with artificially
contaminated water. The processed sample was plated again to obtain the
viable cells and spectrophotometer reading was also taken in all samples.
Dielectrophoretic filtration efficiency (DFE, %) is calculated by [2]:
DFE = [( 0
v v
iN N− ) –(N
i
–N
0
)]/ i
iN ⋅ 100.
The total filtration efficiency (TFE,%), also known as cell elimination
efficiency, is calculated as,
ISSN 0204–3556. Химия и технология воды, 2016, т.38, №2 213
TFE = [( 0
v v
iN N− )] / i
iN ⋅ 100 ,
where v
iN and 0
vN are the cell count before and after circulation with voltage
application. N
i
, N
0
the counts without voltage application i
iN is the initial cell
numbers.
The acquired data was analyzed using statistical tool SPSS 17. To describe
the degree of relationship between two variables; the signal frequency and
the spectrophotometer reading, we find the correlation using Karl Pearson’s
coefficient. To find the area of convergence we have classified the frequency
range into three groups and standard deviation is applied for the groups of
signal frequencies 10 to 50 kHz (Low_ Group), 100 to 300 kHz (Mid_ Group)
and 500 kHz to 2MHz (High_ Group).
Results and discussion
In the present study, the ability of DEP filtration (DF) system to capture
E. coli, S. aureus and V. cholera was examined in artificially contaminated
water sample. Filtration is the most important method to remove the bacteria
from liquid form of any sample. The earlier works [2, 10, 11] insisted upon the
need of an alternative method to the existing ones due to the drawbacks such
as cost, clogging of filter, time and periodical monitoring filtration system.
The scarcity of the water and prevalence of water borne diseases and pollutants
thereby increases the health hazards through water borne pathogens.
The initial bacterial count was estimated at 0 hour in colony counter and
spectrophotometer (at 530 nm) (data not shown). Without the application
of voltage, the microbial cells were not captured in the DF system [9]. The
relationship between the migrations of charged unicellular bacteria when
placed in an electric field was observed [11]. When the electrode voltage was
increased, more cells were collected around the glass beads and also results
increased rate of entrapment [3, 4, 12]. The initial value of E. coli at 0 V was
0,865 and it is reduced to 0,003 with a DFE of 77,1% and TFE of 82,08%. For
S. aureus, the initial value of 0,094 is reduced to 0,003 with a DFE of 75,53% and
TFE of 91,49 % and the amount of V. cholera is also diminished from the initial
value of 0,912 to 0,009 with a DFE of 73,8% and TFE of 77,41%. The results
are presented in Table 1 and the curves shown in Fig 1 – 3 graphically depict
the comparison of decreasing bacterial population by the impact of changing
applied frequency and voltages. The graphical illustration suggests that 20 V is
ISSN 0204–3556. Химия и технология воды, 2016, т.38, №2214
the most suitable voltage for curbing bacterial population effectively in all the
three cases and also it is observed that beyond 1 MHz there is no noticeable
reduction of bacterial count.
10 100 1000
0
0,2
0,4
0,6
0,8
P
op
u
la
ti
on
Frequency (kHz)
20V
15V
10V
5V
Fig. 1. Comparison of E. coli population.
10 100 1000
0
0,2
0,4
0,6
0,8
P
op
u
la
ti
on
Frequency (kHz)
20V
15V
10V
5V
Fig. 2. Comparison of S. aurues population.
ISSN 0204–3556. Химия и технология воды, 2016, т.38, №2 215
10 100 1000
0
0,2
0,4
0,6
0,8
P
op
u
la
ti
on
Frequency (kHz)
20V
15V
10V
5V
Fig. 3. Comparison of V. cholera population.
Further, we have found that the application of ac voltage has a negative
correlation with the bacterial count in all the three samples. The correlation
is more negative in S. aureus (–0,877) with 5 V and it is less negative in E. coli
(–0,528) with 20 V applied. The result (negative correlation of –0,5 to –0,8)
demonstrates the effective elimination of bacterial population (Table 2).
The negative correlation between the applied voltage and bacterial count
is graphically shown in Fig. 4. Moreover, the obtained values of filtration
efficiency are also dissimilar for different tested bacteria and the bacterial
size, morphology and the movement of the cell under electric field may
probably be the reasons behind the differentiation of entrapment of tested
bacterial cells. Since high Joule heating take place due to the immersion
of electrode at high electric field, the behavior of biological cell is not only
influenced by DEP but also by the thermal convection of f low of liquid in
the system [4, 13, 14] which altogether leads to high entrapment of biological
cells at high voltage. The applied signal voltage is increased from 5 V and
up to 20 V in order to enhance the generated DEP force to overwhelm the
drag force exerted by liquid f low in the DF, thus the particles which are
suspended could be trapped [4, 15, 16] and eliminated from the f lowing
liquid.
ISSN 0204–3556. Химия и технология воды, 2016, т.38, №2216
Ta
bl
e
1.
E
ff
ic
ie
nc
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of
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in
r
em
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ri
a
at
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30
n
m
O
rg
an
is
m
V
ol
ta
ge
(V
)
F
re
qu
en
cy
(
kH
z/
M
H
z)
10
20
30
50
10
0
20
0
30
0
50
0
1
2
E
. c
ol
i
20
0,
71
3
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44
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31
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ISSN 0204–3556. Химия и технология воды, 2016, т.38, №2 217
Table 2. Correlation between spectrometer reading (530 nm) Vs signal frequencies
Bacteria Voltage (V) Correlation (r)
E. coli
5 -0,668
10 -0,694
15 -0,626
20 -0,528
S. aureus
5 -0,877
10 -0,855
15 -0,777
20 -0,723
V. cholerae
5 -0,798
10 -0,786
15 -0,745
20 -0,719
E.Coli S.Aureus V.Cholerae
�0,8
�0,6
�0,4
�0,2
0,0
C
or
re
la
ti
on
(
r)
Bacterial Population
5V 10V 15V 20V
Fig. 4. Correlation among bacterial population.
ISSN 0204–3556. Химия и технология воды, 2016, т.38, №2218
The area of convergence of maximal elimination of bacterial population
over the entire frequency range is estimated by assorting the frequency into
three regions; namely, Low_ Group, Mid_ Group and High_ Group. The
Mean and Standard deviation of spectrometer reading for the three groups of
frequencies are listed in Table 3. The minimum deviation is present in the High
Group of frequencies (500 kHz to 2 MHz) with a deviation of ±0,0065 and a
mean of 0,0169 with 0,024 and 0,011 as maximum and minimum readings for
S. aureus which indicates the area of convergence.
Table 3. Mean and Standard deviation of spectrometer reading of different groups
of signal frequency
Bacteria
Frequency
classification
Mean ± Std Dev(Max, Min)
E. coli
Low_ Group 0,5495±0,1855 (0,785; 0,349)
Mid_ Group 0,1965±0.0751 (0,278; 0.13)
High_ Group 0,0492±0,0125 (0,062; 0,037)
S. aureus
Low_ Group 0,0826±0,0078 (0,091; 0,074)
Mid_ Group 0,0518±0,0127 (0,065; 0,039)
High_ Group 0,0169±0,0065 (0,024; 0,011)
V. cholera
Low_ Group 0,6763±0,1197 (0,797; 0,536)
Mid_ Group 0,3408±0,1043 (0,452; 0,246)
High_ Group 0,0677±0,048 (0,119; 0.023)
concluSIonS
We have investigated an innovative approach for water treatment using
Dielectrophoretic phenomena. Exceptional properties of electric signals such
as frequency and voltage were utilized in our study in order to ameliorate the
performance of DEP system in removing water-borne pathogens and ensure
safe drinking water. We have tested the performance of our DEP system using
artificially contaminated water samples with E. coli, S. aureus and V. cholera.
Statistical analysis indicated that changing the signal properties contribute
to the improved performance of the DF in removing bacteria. The highest
ISSN 0204–3556. Химия и технология воды, 2016, т.38, №2 219
efficiency of DF for trapping tested organisms has been observed at 20 V and
around 500 kHz to 2 MHz frequency.
AcKnowleDgeMent
The authors are grateful to the Management and Principal of K.S.
Rangasamy college of Arts and Science for providing lab facility to carry out
the experiments.
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Received 20.12.2013
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