The shortcomings of standard plasma-separation methods limit the point-of-care application of microfluidics in clinical facilities and at the patient’s bedside. To overcome the limitations of this inconvenient, laborious, and costly technique, a new plasma-separation technique and device were developed. This new separation method relies on immunological capture and filtration to exclude cells from plasma, and is convenient, easy to use, and cost-effective. Most of the RBCs can be captured and immobilized by antibody which coated in separation matrix, and residue cells can be totally removed from the sample by a commercially plasma purification membranes. A 400 µL anti-coagulated whole blood sample with 65% hematocrit (Hct) can be separated by the device in 5 min with only one pipette. Up to 97% of the plasma can be recovered from the raw blood sample with a separation efficiency at 100%. The recovery rate of small molecule compounds, proteins, and nucleic acid biomarkers is evaluated; there are no obvious differences from the centrifuge method. The results demonstrate that this method is an excellent replacement for traditional plasma preparation protocols.

A rapid, sensitive and quantitative biomarker detection platform is of great importance to the small clinic or point-of-care (POC) diagnosis. In this work, we realize that an automated diagnostic platform mainly includes two components: (1) an instrument that can complete all steps of the chemiluminescence immunoassay automatically and (2) an integrated microfluidic chip which is disposable and harmless. In the instrument, we adopt vacuum suction cups which are driven by linear motor to realize a simple, effective and convenient control. The method of acridine esterification chemiluminescence is adopted to achieve a quantitative detection, and a photomultiplier tube is used to detect photons from acridine ester producing in alkaline conditions. We use the laser cutting machine and hot press machine to accomplish the product of microfluidic chips. The automated microfluidics-based system is demonstrated by implementation of a chemiluminescence immunoassay for quantitative detection of ferritin. We observe alinear relationship between CL intensity and the concentration of ferritin from 5.1 to 1300 ng mL −1 and the limit of detection (LoD) is 2.55 ng mL −1 . At the same time, we also used the automated microfluidics-based system to test clinical serum samples. The whole process of chemiluminescence experiment can complete within 45 min. We realize that this lab-on-a-chip chemiluminescence immunoassay platform with features of automation and quantitation provides a promising strategy for POC diagnosis.

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