Lab-on-a-disk extraction of PBMC and metered plasma from whole blood: An advanced event-triggered valving strategy

Abstract

In this paper we present a centrifugal microfluidic concept employing event-triggered valving for automated extraction of metered plasma and peripheral blood mononuclear cells (PBMC). This "Lab-on-a-Disc" system has been developed for retrieving different density layers from a liquid column by 'overflowing' the layers sequentially using the pressure exerted by density-gradient liquid. Defined volumes of plasma and PBMCs were efficiently forwarded into designated microfluidic chambers as a sample preparation step prior to further downstream processing. Furthermore, the extracted PBMCs were counted directly on-disc using an automated optical unit by object-based image analysis, thus eliminating the requirement for the post-processing of the extracted PBMCs. This study is a direct continuation of our previous work 1 where we demonstrated combined on-disc detection of C-reactive protein (CRP) and quantification of PBMCs following on-disc extraction of plasma and PBMCs from a single blood sample using centrifugo-pneumatic valving mechanism.However, the former valving technique featured limited PBMC extraction efficiency. Here, integrating the novel concept along with event-triggered valving mechanism, we eliminated the occurrence of a specific microfluidic effect which led us to increase PBMC extraction efficiency to 88%. This extraction method has the potential to be utilized for efficiently separating multiple density layers from a liquid sample in relevant biomedical applications.

Low–High–Low Rotationally Pulse-Actuated Serial Dissolvable Film Valves Applied to Solid Phase Extraction and LAMP Isothermal Amplification for Plant Pathogen Detection on a Lab-on-a-Disc

“…Modeling this using Boyle’s Law is facile, , and through careful design, automation of 8 LUOs has been demonstrated using these valves . Both rotationally actuated “burst” DF valves and “event-triggered” dissolvable film valves have been applied to a wide range of applications ,,− with good success. However, a limitation of DF valves remains that the actuation of these valves is dependent on either tuning the valve opening spin-speed, which necessitates limiting the number of LUOs on the disc, or determining the dissolve time of the DF (usually ∼40 s), limiting the ability to perform sometimes assay critical incubations on the LoaD.…”

Automated Centrifugal Microfluidic Chip Integrating Pretreatment and Molecular Diagnosis for Hepatitis B Virus Genotyping from Whole Blood

“…Due to its advantageous characteristics, centrifugal microfluidic chip has been used in many fields including microbiological detection, antibiotic evaluation, single-cell whole-genome amplification, and so on. In particular, for clinical diagnosis from whole blood samples, the centrifugal microfluidic chip has obvious advantages to combine the separation of whole blood with follow-up detection, and there are more and more studies that have used its advantages to carry out many kinds of assays for whole blood such as serum metabolite analysis, single-vesicle analysis, blood plasma separation, extraction and count of peripheral blood mononuclear cells, and so on. Although some researchers have designed centrifugal chips to extract nucleic acids from whole blood, they have not integrated all pretreatments and subsequent multiplex molecular diagnosis in one chip, which limits the application of the centrifugal microfluidic chip in deeper clinical diagnosis.…”