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TRACK 3 TRACK 3 Technical Program

thelium compared to healthy donors. In contrast, conventional aggregometry Hopkins Hospital in Baltimore, USA. Volunteers for the study were recruited
analysis was very time consuming and tedious. Also, on a collagen-coated from a set of patients visiting for pelvic examination in the emergency room.
flow chamber we found no significant difference in platelet coverage be- On-site staff using the instrument for the first time was trained using the
tween normal controls and samples from subjects on antiplatelet agents. tutorial resource accessed via the smartphone application. Samples from
each patient were tested in parallel by the platform and the gold standard
Taken together, this study using clinical blood samples demonstrates that NAAT assay for verification. We correctly identified 2 positives among 30 pa-
our microfluidic device containing fixed endothelium could potentially be- tients, demonstrating comparable performance to the gold standard for the
come an accurate, rapid and reliable point-of-care platelet function assay. samples tested. Evaluation by the on-site staff using a subset of the samples
Because human endothelial cells are chemically preserved by fixation, it also yielded results in agreement with the standard.
can also be stored, shipped and used when required, either in a laboratory
setting or in the clinic. Comparative effectiveness studies attest to the importance of cost and sen-
sitivity as decisive parameters for patients to seek POC over standard NAAT.
10:40am Design and evaluation of a mobile nucleic acid amplifi- In particular, POC tests offer important strategies to address the Chlamydia
cation testing system in a hospital emergency setting epidemic, since diagnosis and immediate treatment can prevent transmis-
sion to sexual partners. By reducing turnaround for NAAT from days to an
hour, our work demonstrates a paradigm-changing approach for making
Technical Presentation. NEMB2016-6089 affordable and sensitive diagnostic tests more readily accessible outside
centralized diagnostic workflow.
Dong Jin Shin, Tza-huei Wang, Pornpat Athamanolap, Liben
Chen, Johns Hopkins University, Baltimore, MD, United States

Integration of sample processing and detection is an essential feature in
the delivery of molecular assays under POC settings. However, an often
overlooked pitfall of integration is that it increases the complexity of the
instrument and disposable components, which gives rise to sophisticated
but expensive devices or instruments whose portability and affordability are
compromised. Here we present a fully mobile platform for nucleic acid am-
plification test (NAAT) utilizing a droplet magnetofluidic cartridge. We eval-
uated our platform for testing urogenital chlamydia infection from patients
in the hospital emergency department, with results in agreement with the
clinical laboratory-based NAAT.

Our system consists of three components: a droplet microfluidic cartridge,
a rechargeable lithium polymer battery-powered mobile instrument for car-
tridge processing, and a smartphone app for user interface, data acquisition
and user training. The microfluidic cartridge design is based on the principle
of open-surface magnetofluidic manipulation, which enables bioassays
requiring multiple buffer exchanges using magnetic particle-based analyte
transport and obviates the need for precise microfabrication or pneumatic
controls such as pumps and valves. We developed a novel design and
fabrication process for a sealed magnetofluidic cartridge using poly-meth-
ylmethacrylate (PMMA) as the base material and polytetrafluoroethylene
(PTFE) film for hydrophobic surface generation. The cartridge utilizes the
adhesive force of aqueous buffers on hydrophilic surfaces in order to form
discrete buffer reservoirs that are required for DNA extraction and amplifi-
cation, which is traversed by magnetic particles on the smooth PTFE surface
at each buffer exchange step of the assay. Each cartridge is less than $2
in material cost using off-the-shelf reagents and materials, which compares
favorably with the current cost of NAAT (US$33.48). The mobile instrument
is an integrated electromechanical device that performs magnetic bead ma-
nipulation, thermal incubation, optical signal processing and wireless com-
munication to the smartphone interface. Microcontroller-mediated control of
an RC servomotor along a pre-programmed routine facilitates bead washing
and transport. Alternating the top and bottom magnet on the same position
of the cartridge causes the magnetic particles to traverse the two surfaces,
facilitating efficient particle mixing. Thermal incubation is facilitated by a
PID-controlled thermoelectric element driven using microcontroller-mediat-
ed output from an H-bridge amplifier. Passive optical components facilitate
routing of fluorescence signal from amplification reaction to a smartphone
CMOS sensor for detection. Bluetooth-based communication facilitates inte-
gration of the peripheral sensor-actuator modules into the smartphone user
interface. The entire workflow takes approximately 1 hour to complete.

Urogenital chlamydia was selected as the focus of this study based on a
needs assessment for POC tests among clinicians and opinion leaders.
Fluorescent LAMP assay incorporating bead-based DNA extraction was ini-
tially developed and characterized, yielding analytical sensitivity of 102-103
genomic copies per test and no cross-reactivity with normal vaginal flora.
Afterwards, platform validation was performed using an archived set of 20 47
vaginal swabs with results in agreement with the standard NAAT. The plat-
form was subsequently evaluated in the Emergency Department at Johns