This document summarizes research on developing a point-of-care microfluidics device for detecting high-risk human papillomavirus (hr-HPV) through impedance spectroscopy. The device uses a microfluidic chip made of cyclo-olefin polymer with gold interdigitated electrodes to take impedance measurements of cervical cell samples. Analysis of variance and Tukey tests showed significant differences in phase characteristics between control groups at certain frequencies, providing evidence to distinguish hr-HPV positive and negative samples. Further experiments are needed to validate the results before developing a graphical user interface to analyze impedance data and diagnose hr-HPV status. The low-cost, portable device could improve hr-HPV screening in resource-

1. “Point Of Care” Microfluidics Device for hr-HPV Detection
Lena Liu, Randal So, Rahul Veetekat, William Zhen, Catherine Klapperich
Department of Biomedical Engineering, Boston University, Boston MA
High-risk human papillomavirus (hr-HPV) is a DNA
virus known to be transmitted through genital contact
and a necessary precursor in 70% cases of cervical
cancer. Current practices in screening such as a Pap
test detects for cancerous or precancerous regions in
the cervix. In resource-limited areas, the feasibility of
detection of HPV is limited by lack of developed
infrastructure. To this end, we present a low cost
microfluidics diagnostic chip that identifies hr-HPV
positive patient samples through impedance
spectroscopy. This diagnostic tool offers future
possibilities of point-of-care diagnostics for HPV and
more accessible options for low resource regions.
• Fixed cells obtained through a joint IRB between
BIDMC and BMC are suspended in Detachin for
approximately 8 minutes
• Once cells have sufficiently disassociated, the
sample is then pipetted onto a microfluidic chip,
made from cyclo-olefin polymer (COP), that
contains a gold film inter-digitated (IDT)
electrodes
• A static impedance measurement is then taken
with the 4294A Impedance Analyzer (Agilent
Technologies) once the flow has stopped within
the channel
• This will allow for impedance measurements (of
both magnitude and phase) to be taken over a
continuous range of frequencies (40 Hz – 2
MHz using a 500 mV source signal)
Detachin was utilized to dissociate the cervical cell samples provided by Dr.
Rajan Dewar from BIDMC. Figures 3A and 3B show the variance when
Detachin is absent vs. when Detachin is present.
Analysis of Variance (ANOVA) was used to test for significance between the
three groups. Once noted that the low frequencies have F-ratio results that
pass the critical value, Tukey tests were performed to ascertain which of the
three groups are different. The two plots below show the two-step data
analysis results. We obtained evidence for the low frequencies having
significant differences between the three groups.
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Klapperich Laboratory
Catherine Klapperich, Ph.D, Andy Fan, Ph.D, Jacqueline Linnes, Ph.D,
Sharon Wong, Ph.D
Beth Israel Deaconess Medical Center
Rajan Dewar, Ph.D, M.D.
Boston University College of Engineering
David Freedman, Ph.D, James Galagan, Ph.D
Introduction
Materials and Methods
Results
Figure 4A: Performing ANOVA provides the F-
ratios for all frequencies. The F-ratio critical
value is determined by our experimental
parameters. Above this value we obtain data
that has significant differences. However, it does
not determine which group is significantly
different from the others. Note the low
frequencies have the values passing the
significance threshold.
Figure 4B: The high F-ratio frequencies are
plotted above with Tukey test results on the
line of the F-ratio critical value. Green is the
result that all three groups are different. Blue
and black represent no significant differences
between two of the three groups.
Using ANOVA and the Tukey Test, we have evidence
for a range of frequencies where the three different
control groups used have distinguishable phase
characteristics.
More experiments are required to further support our
claim. Alternative material choices such as
Polydimethylsiloxane (PDMS) will be utilized for its
higher fabrication tolerances, which could lead to
more consistent results.
With more conclusive results, we plan to develop
and calibrate a graphical user interface that will be
able to analyze raw data outputted by the
Impedance Analyzer, and diagnose a patient on hr-
HPV status.
Conclusion
Figure 3A: Patient cervical cells provided by
BIDMC were pipetted into the 1.2 mm channel
of the microfluidic chip and imaged under the
Axioplan 2 imaging system at a 10x objective.
Figure 3B: The addition of Detachin
(Genlantis) and a digestion time of 8 minutes
or more, the patient cervical cells observed
under the Axioplan 2 imaging system become
dissociated
Acknowledgements
References
Figure 1: Final COP chip
design, consisting of IDT
electrodes made from a
gold film
Figure 2: General Setup of Impedance Experiment; Cells are
pipetted into microfluidic channel where an impedance analyzer will
measure the impedance of the channel