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Lab-on-a-chip (LOC) technology offers new possibilities for portable and point-of-care diagnostics and prognosis of various human diseases including cancer. Microfluidic-based medical assay and biochemical assay provide high-throughput, multiplexed, and comprehensive detection of target biomarkers from the complex biological samples, greatly simplifying the detection processes using minimal sample volume. For example, microfluidic-based LOC devices for liquid biopsies have shown tremendous potential for the early-stage diagnosis and monitoring. However, clinical samples for liquid biopsy such as whole blood is complex blend of blood cells, extracellular vesicles, and proteins and thus, they need to be pretreated on the microfluidic devices in order to increase sensitivity and specificity. The separation of blood cells from whole blood and extraction of cell-free serum or plasma in which the most disease biomarkers including circulating miRNA, cfDNA, and exosomes present are critical steps in many LOC-based liquid biopsy applications.
Lab-on-a-chip (LOC) technology offers new possibilities for portable and point-of-care diagnostics and prognosis of various human diseases including cancer. Microfluidic-based medical assay and biochemical assay provide high-throughput, multiplexed, and comprehensive detection of target biomarkers from the complex biological samples, greatly simplifying the detection processes using minimal sample volume. For example, microfluidic-based LOC devices for liquid biopsies have shown tremendous potential for the early-stage diagnosis and monitoring. However, clinical samples for liquid biopsy such as whole blood is complex blend of blood cells, extracellular vesicles, and proteins and thus, they need to be pretreated on the microfluidic devices in order to increase sensitivity and specificity. The separation of blood cells from whole blood and extraction of cell-free serum or plasma in which the most disease biomarkers including circulating miRNA, cfDNA, and exosomes present are critical steps in many LOC-based liquid biopsy applications.
We have presented the self-powered poly(dimethylsiloxane) (PDMS) microfluidic devices and a molecular diffusion analysis model of dynamic blood flow and plasma separation of the pressure-driven devices. We integrated PDMS pump, broadly used to fabricate microfluidic devices because it is cheap and easy to fabricate, into simple, sedimentation microfluidic devices to eliminate external power and complex fabrication of microchannel structures to drive blood flow and separate plasma. The porous property of PDMS allows the diffusion of air molecules through the bulk PDMS and makes it possible that void structures in the devices play as an innate vacuum pumping system, which ultimately pulls fluid through microchannels.
We have presented the self-powered poly(dimethylsiloxane) (PDMS) microfluidic devices and a molecular diffusion analysis model of dynamic blood flow and plasma separation of the pressure-driven devices. We integrated PDMS pump, broadly used to fabricate microfluidic devices because it is cheap and easy to fabricate, into simple, sedimentation microfluidic devices to eliminate external power and complex fabrication of microchannel structures to drive blood flow and separate plasma. The porous property of PDMS allows the diffusion of air molecules through the bulk PDMS and makes it possible that void structures in the devices play as an innate vacuum pumping system, which ultimately pulls fluid through microchannels.
Plasma separation by the self-powered PDMS device. (a) An example image of the device shows the flow of whole blood through the microchannel by the pressure difference between the microchannel and the vacuum pocket and the separation of plasma by sedimentation (blue arrow). Inset shows clean plasma collected in the plasma collection reservoir. (b) Microscopy images of (b) whole blood and (c) plasma collected in the reservoir of the device on the hemocytometer grid showing no blood cells in the plasma.
Plasma separation by the self-powered PDMS device. (a) An example image of the device shows the flow of whole blood through the microchannel by the pressure difference between the microchannel and the vacuum pocket and the separation of plasma by sedimentation (blue arrow). Inset shows clean plasma collected in the plasma collection reservoir. (b) Microscopy images of (b) whole blood and (c) plasma collected in the reservoir of the device on the hemocytometer grid showing no blood cells in the plasma.
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