An All-in-One Microfluidic Device for Blood Plasma Separation and Fluorescence Detection of Cocaine in Whole Blood

Blood
drug testing can provide real-time data to assess
the recent
consumption of illicit drugs. Microfluidic devices have great promise
in rapid finger-prick blood tests at point-of-care settings. However,
the fabrication of an integrated microfluidic device for whole blood
testing remains a challenge because the separation performance is
sensitive to modification in downstream product microchambers. In
this work, a hydrodynamic force-based blood plasma separation unit
has been developed to regulate the blood plasma separation efficiency
and yield after it is integrated with the waste outlet, the connection,
and detection zones in a microfluidic device. After the plasma is
separated from blood by this microfluidic separation unit, it is driven
to an aptamer-based detection zone downstream. As a result, this integrated
fluorescence microfluidic device can directly detect the cocaine metabolite,
benzoylecgonine (BEC), in a drop of whole blood sample with readout
by a hand-held fluorescence reader, achieving a limit of detection
(LOD) of 0.62 μg/mL. This integrated all-in-one microfluidic
device can serve as a general detection platform for the measurement
of various analytes in finger-prick whole blood samples.