A low-cost and high-throughput benchtop cell sorter for isolating white blood cells from whole blood

Label-free microfluidic cell sorting and detection for rapid blood analysis

Blood tests are considered as standard clinical procedures to screen for markers of diseases and health conditions. However, the complex cellular background (>99.9% RBCs) and biomolecular composition often pose significant technical challenges for accurate blood analysis. An emerging approach for point-of-care blood diagnostics is utilizing "label-free" microfluidic technologies that rely on intrinsic cell properties for blood fractionation and disease detection without any antibody binding. A growing body of clinical evidence has also reported that cellular dysfunction and their biophysical phenotypes are complementary to standard hematoanalyzer analysis (complete blood count) and can provide a more comprehensive health profiling. In this review, we will summarize recent advances in microfluidic label-free separation of different blood cell components including circulating tumor cells, leukocytes, platelets and nanoscale extracellular vesicles. Label-free single cell analysis of intrinsic cell morphology, spectrochemical properties, dielectric parameters and biophysical characteristics as novel blood-based biomarkers will also be presented. Next, we will highlight research efforts that combine label-free microfluidics with machine learning approaches to enhance detection sensitivity and specificity in clinical studies, as well as innovative microfluidic solutions which are capable of fully integrated and label-free blood cell sorting and analysis. Lastly, we will envisage the current challenges and future outlook of label-free microfluidics platforms for high throughput multi-dimensional blood cell analysis to identify non-traditional circulating biomarkers for clinical diagnostics.

Trapping and releasing of single microparticles and cells in a microfluidic chip

A microfluidic device was designed and fabricated to capture single microparticles and cells by using hydrodynamic force and selectively release the microparticles and cells of interest via negative dielectrophoresis by activating selected individual microelectrodes. The trap microstructure was optimized based on numerical simulation of the electric field as well as the flow field. The capture and selective release functions of the device were verified by multi-types microparticles with different diameters and K562 cells. The capture efficiencies/release efficiencies were 95.55% ± 0.43%/96.41% ± 1.08% and 91.34% ± 0.01%/93.67% ± 0.36% for microparticles and cells, respectively. By including more traps and microelectrodes, the device can achieve high throughput and realize the visual separation of microparticles/cells of interest in a large number of particle/cell groups.

Automatic Microfluidic Cell Wash Platform for Purifying Cells in Suspension: Puriogen

Cell wash is an essential cell sample preparation procedure to eliminate or minimize interfering substances for various subsequent cell analyses. The commonly used cell wash method is centrifugation which separates cells from other biomolecules in a solution with manual pipetting and has many drawbacks such as being labor-intensive and time-consuming with substantial cell loss and cell clumping. To overcome these issues, a centrifuge-free and automatic cell wash platform for cell purity generation, termed Puriogen, has been developed in this work. Compared with other developed products such as AcouWash, Puriogen can process samples with a high throughput of above 500 μL/min. Puriogen utilizes a uniquely designed inertial microfluidic device to complete the automatic cell wash procedure. One single-cell wash procedure with the Puriogen platform can remove more than 90% ambient proteins and nucleic acids from the cell sample. It can also remove most of the residual fluorescent dye after cell staining to significantly reduce the background signals for subsequent cell analysis. By removing the dead cell debris, it can increase the live cell percentage in the sample by 2-fold. Moreover, the percentage of single-cell population is also increased by 20% because of further disassociation of small-cell aggregates (e.g., doublets and triplets) into singlets. To freely adjust cell concentrations, the Puriogen platform can concentrate cells 5 times in a single flow-through process. The presented Puriogen cell wash solution has broad applications in cell preparation with its excellent simplicity in operation and wash efficiency, especially in single-cell sequencing.