TABLE II.
Recent advances of inertial contraction–expansion microfluidics.
| Structure of contraction–expansion microfluidics | Role of contraction–expansion channels | Targets | Applications | Performance | Reference |
|---|---|---|---|---|---|
| Single large symmetrical contraction–expansion chamber | Capture large particles | CTCs | Enrichment of cancer cells from spiked blood samples | Throughput: ∼5 ml/min | 19 |
| MCF-7 cells | Separation of larger cancer cells from the blood cells | Processing rate: 7.5 × 106 cells/s | 47 | ||
| Rare cells | Selective isolation and trapping of large rare cells | The best performance: concentrations below 102 particles/ml | 48 | ||
| Large symmetrical contraction–expansion chamber with two side outlets | Capture large particles | 21 μm particles | Separation of 21 μm particles from human blood | Capture efficiency: 86% | 49 |
| 21/18.5/15 μm particles | Secondary separation of ternary mixture | Purity: 89.4% (21 μm) 80.7% (18.5 μm) 95.9% (15 μm) | 50 | ||
| HuSLCs | Sorting of HuSLCs from RBCs | Sorting efficiency: ∼90% RBCs removal efficiency: ∼99.97% | 20 | ||
| 15 μm beads | Sorting of 15 μm particle from 6 μm ones | Capture efficiency: >80% | 52 | ||
| Multiple large symmetrical contraction–expansion chamber in series and parallel | Capture large particles | MCF-7 cells | High-purity extraction of CTCs from blood samples | Processing time: <7.5 ml sample per 20 min | 53 |
| CTCs | Enrichment and concentration of rare cells. | Capture efficiency: 83% Throughput: 8 ml/min |
55 | ||
| CTCs | Enrichment and enumeration of CTCs from blood | Enumeration processing time: <1 h | 56 | ||
| CTCs | Sorting of rare cells from blood | Trapping efficiency: 67% Throughput: 5 ml/min |
57 | ||
| Direct symmetric contraction–expansion array channel | Produce inertial forces (secondary flow) to affect the lateral migration of particles (large particles were focused at the channel center while small particles were close to the two sidewalls) | 15 μm/7 μm particles | Size-based separation | Recovery: 75.2% (15 μm) 93.7% (7 μm) Throughput: 1 ∼ 5 × 104 particles/s |
58 |
| 15 μm particles | Size-based separation | Recovery: 88.7% Purity: 89.1% |
59 | ||
| MCF-7 cells | Separation of breast cancer cells from blood cells | Recovery: 98.9% Blood cells removal rate: 93.3% |
22 | ||
| MCF-7/MDA_MB_231 cells | Separation and collection of breast cancer cells from the whole blood | Recovery: 93.75% (MCF-7) 91.60% (MDA_MB_231) | 60 | ||
| MCF-7 cells | Enrichment of rare cells from blood | Separation efficiency: ∼80% Throughput: ∼0.4 ml/min |
61 | ||
| Malaria parasites | Separation and collection of malaria parasites from WBCs | Collection yield: 70.9 ± 11.4% WBCs depletion: 99.99% |
62 | ||
| WBCs/RBCs | Size-based separation | Purity: 91.0% (WBCs) 99.6% (RBCs) Separation efficiency: 89.7%(WBCs) 99.8% (RBCs) Throughput: 10.8 ml/min |
63 | ||
| Plasma NCI-H1299 cells | Separation of plasma, RBCs, and NCI-H1299 cancer cells from blood in different shape CEA channels | Separation efficiency: 96.0% (plasma) >95% (NCI-H1299) | 64 | ||
| Unilateral contraction–expansion array channel with a sheath flow | Produce Dean drag force (induced by the secondary flow) combined with inertial lift force to achieve size-based separation (large particles were close to the side of the contraction–expansion wall while small particles were close to the side of the straight wall) | 10/4 μm particles | Separation of different-sized particles | Purity: 100% (10 μm) 99%(4 μm) Throughput: 111 particles/s |
73 |
| Plasma | Separation of plasma from RBCs | Separation efficiency: 62% Throughput: 1.2 ml/h |
74 | ||
| Plasma | Separation of plasma from human whole blood | Separation efficiency: 69.5% Blood cell rejection ratio: 92.6% Throughput: 5.4 × 1011 cells/min |
95 | ||
| CTCs | Separation of cancer cells from human whole blood | Recovery: 99.1% Blood cell rejection ratio: 88.9% Throughput: 1.1 × 108 cells/min |
24 | ||
| MCF-7 cells U937 cells | Separation of immune-specifically labeled cells from other cells | Recovery: 97.6% (MCF-7) Rejection ratio: 95% (U937) Purity: 73.8% (U937) Throughput: 8.75 ml/h |
75 | ||
| Unilateral contraction–expansion array channel on the top surface of low aspect ratio channel | Induce fluid helical rotation to promote particle focusing position from the original two (caused by inertial lift force) to a single one | 9.9 μm particles | Three-dimensional single-stream particle focusing | Focusing efficiency: 99.77% Throughout: 36 000 particles/s | 77 |
| Euglena gracilis | Three-dimensional single-stream particle focusing | High aspect ratio particles have better focusing performance at higher Re | 78 | ||
| A series of repeated sharp corner structures | Produce inertial forces to affect the lateral migration of particles | 9.94 μm particles | Three-dimensional single-stream particle focusing | Throughput: 0.7 ml/min | 79 |
| 7.32 μm particles | Three-dimensional single-stream particle focusing | Throughput: 66.7 μl/min (sample flow) 400 μl/min (sheath flow) | 80 | ||
| 7.32 ∼ 15.5 μm particles | Three-dimensional single-stream particle focusing | Single-stream particle focusing over a wide range of Re from 19.1 to 142.9 | 25 | ||
| Nonorthogonal groove array structure | Produce hydrophoresis effect and combine with inertial lift force to realize particle manipulation | K562 cells | Size-based cell sorting and focusing. | Optimal width for cell sorting (3 × cell diameter) and focusing (>400 μm) | 82 |
| 12.4/15.6 μm particles | Size-based particle sorting and focusing | Particle sorting at Re = 2.4 Particle focusing at Re = 50.8 | 83 | ||
| Blood cells | Particle ordering and liquid-medium recovery from blood cells | Rejection efficiency: 99.3% Throughput: 1.63 × 106 cells/s | 84 | ||
| G1 cells | Size-based cell sorting | Purity: 90.3% Throughput: 1.2 × 105 cells/s |
29 | ||
| 13/4.8 μm particles | Size-based particle separation and filtration | Recovery: >99.9% (13 μm) ∼80% (4.8 μm) Purity: ∼35% (13 μm) >99.9% (4.8 μm) |
88 | ||
| Jurkat cells | Separation of Jurkat cells from undiluted blood | Recovery: ∼83.4% | 89 | ||
| PBMCs/ platelets | Extraction of peripheral blood mononuclear cells (PBMCs) from platelets | Purity: 10.4% (PBMCs) ∼100% (platelets) | 90 | ||
| Plasma | Manipulation of small-sized particles (<8 μm) with the assistance of sheath flow | Purity: ∼99% Throughput: 0.7 ml/min |
91 | ||
| Combination of slanted groove array and contraction–expansion array | To obtain the enhanced particle focusing | 10 μm particles | Three-dimensional single-stream particle focusing | Focusing efficiency: >95% Particle focusing over a wide range of flow rate from 50 to 500 μl/min |
92 |
| Others (add obstacles, or combine with other channels) | Make the devices more stable and efficient for particle manipulation | 19 μm particles | Three-dimensional single-stream particle focusing by adding a series of cylindrical obstacles | Focusing efficiency: 91.65% | 93 |
| 15.5/9.9/7.3 μm particles | The fast, high-throughput and high-efficient particle focusing and sorting by adding obstacles to the spiral microchannel | Focusing efficiency: 99.8% (15.5 μm) 98.6% (9.9 μm) 90.9% (7.3 μm) Recovery: 98.7% (15.5 μm) 97.8% (9.9 μm) 85.8% (7.3 μm) Purity: 97.5% (15.5 μm) 86.1% (9.9 μm) 98.4% (7.3 μm) |
31 | ||
| MCF-7 cells Hela cells A549 cells | Separation of rare cancer cells from the blood sample by a spiral microchannel combined with CEA | Recovery: 93.5% (MCF-7) 89.5% (HeLa) 88.6% (A549) | 32 | ||
| CTCs | Separation and cell Lysis of CTCs by a centrifugal microfluidic platform integrating CEA and serpentine channel | Separation efficiency: ∼90% Mixing quality: ∼98% |
33 |