Simple filter microchip for rapid separation of plasma and viruses from whole blood

Abstract

Sample preparation is a significant challenge for detection and sensing technologies, since the presence of blood cells can interfere with the accuracy and reliability of virus detection at the nanoscale for point-of-care testing. To the best of our knowledge, there is not an existing on-chip virus isolation technology that does not use complex fluidic pumps. Here, we presented a lab-on-a-chip filter device to isolate plasma and viruses from unprocessed whole blood based on size exclusion without using a micropump. We demonstrated that viruses (eg, HIV) can be separated on a filter-based chip (2-µm pore size) from HIV-spiked whole blood at high recovery efficiencies of 89.9% ± 5.0%, 80.5% ± 4.3%, and 78.2% ± 3.8%, for viral loads of 1000, 10,000 and 100,000 copies/mL, respectively. Meanwhile, 81.7% ± 6.7% of red blood cells and 89.5% ± 2.4% of white blood cells were retained on 2 µm pore-sized filter microchips. We also tested these filter microchips with seven HIV-infected patient samples and observed recovery efficiencies ranging from 73.1% ± 8.3% to 82.5% ± 4.1%. These results are first steps towards developing disposable point-of-care diagnostics and monitoring devices for resource-constrained settings, as well as hospital and primary care settings.

Membrane-Based, Sedimentation-Assisted Plasma Separator for Point-of-Care Applications

“…The device used an external vacuum pump to provide negative pressure for plasma extraction. Wang et al 30 reported on a similar microfluidic-based plasma separation chip with an embedded 2-μm pore size membrane filter for plasma and HIV virus separation. To avoid the use of a pump, Wang et al 30 extracted plasma containing HIV virus from 40 μL of whole blood by washing it with 300 μLPBS buffer.…”

“…Wang et al 30 reported on a similar microfluidic-based plasma separation chip with an embedded 2-μm pore size membrane filter for plasma and HIV virus separation. To avoid the use of a pump, Wang et al 30 extracted plasma containing HIV virus from 40 μL of whole blood by washing it with 300 μLPBS buffer. Such extensive dilution may, however, adversely affect the limit-of-detection, which is critical in viral load detection.…”

Miniaturized devices for point of care molecular detection of HIV

“…Wang et al [36] developed a microfluidic-based plasma separation device with a 2-μm pore size membrane filter, which separated plasma and HIV virus from pre-diluted whole blood with virus recovery efficiencies ranging from 73.1% to 82.5%. However, the pre-dilution of blood reduces the ultimate limit of detection, which is critical in HIV viral load quantification.…”

Recent advances in micro/nanotechnologies for global control of hepatitis B infection

“…Advances in nanotechnology and microfluidic platforms rapidly enable significant developments of biosensing technologies and medical diagnostics (Wang et al, 2012a; Wang et al, 2012b). Particularly, advances in micro-nanofabrication technologies allow for developing rapid, user-friendly, accurate and specific diagnostic tools/methods, which achieve low detection limits of the target analytes/cells.…”

“…Another SPR-based HBV detection technology was reported to detect recombinant HBV surface antigens (HBsAg) by immobilizing anti-HBsAg polyclonal antibodies to a dextran layer of N-hydroxysuccinimide activated CM5 sensor chips (Hwang et al, 2005). HBsAg is reported as the most important biomarker for diagnosis HBV, and its serum levels exhibit an acute and chronic HBV infection and probable infectivity (El-Ghitany and Farghaly, 2013; Wang et al, 2010b). This microfluidic-integrated SPR platform is focused to examine the binding characteristics between recombinant HBsAg and polyclonal antibody, and this binding analysis demonstrated that approximately six antibody molecules captured one HBsAg molecule at saturation level.…”