An official website of the United States government
Abstract The efficient isolation of viable and intact circulating tumor cells (CTCs) from blood is critical for the genetic analysis of cancer cells, prediction of cancer progression, development of drugs, and evaluation of therapeutic treatments. While conventional cell separation devices utilize the size difference between CTCs and other blood cells, they fail to separate CTCs from white blood cells (WBCs) due to significant size overlap. To overcome this issue, we present a novel approach that combines curved contraction–expansion (CE) channels with dielectrophoresis (DEP) and inertial microfluidics to isolate CTCs from WBCs regardless of size overlap. This label‐free and continuous separation method utilizes dielectric properties and size variation of cells for the separation of CTCs from WBCs. The results demonstrate that the proposed hybrid microfluidic channel can effectively isolate A549 CTCs from WBCs regardless of their size with a throughput of 300 μL/min, achieving a high separation distance of 233.4 μm at an applied voltage of 50 Vp–p. The proposed method allows for the modification of cell migration characteristics by controlling the number of CE sections of the channel, applied voltage, applied frequency, and flow rate. With its unique features of a single‐stage separation, simple design, and tunability, the proposed method provides a promising alternative to the existing label‐free cell separation techniques and may have a wide range of applications in biomedicine.
more »
« less
Numerical study of dielectrophoresis‐modified inertial migration for overlapping sized cell separation
Abstract Circulating tumor cells (CTCs) have been proven to have significant prognostic, diagnostic, and clinical values in early‐stage cancer detection and treatment. The efficient separation of CTCs from peripheral blood can ensure intact and viable CTCs and can, thus, give proper genetic characterization and drug innovation. In this study, continuous and high‐throughput separation of MDA‐231 CTCs from overlapping sized white blood cells (WBCs) is achieved by modifying inertial cell focusing with dielectrophoresis (DEP) in a single‐stage microfluidic platform by numeric simulation. The DEP is enabled by embedding interdigitated electrodes with alternating field control on a serpentine microchannel to avoid creating two‐stage separation. Rather than using the electrokinetic migration of cells which slows down the throughput, the system leverages the inertial microfluidic flow to achieve high‐speed continuous separation. The cell migration and cell positioning characteristics are quantified through coupled physics analyses to evaluate the effects of the applied voltages and Reynolds numbers (Re) on the separation performance. The results indicate that the introduction of DEP successfully migrates WBCs away from CTCs and that separation of MDA‐231 CTCs from similar sized WBCs at a highReof 100 can be achieved with a low voltage of magnitude 4 ×106 V/m. Additionally, the viability of MDA‐231 CTCs is expected to be sustained after separation due to the short‐term DEP exposure. The developed technique could be exploited to design active microchips for high‐throughput separation of mixed cell beads despite their significant size overlap, using DEP‐modified inertial focusing controlled simply by adjusting the applied external field.
more »
« less
- Award ID(s):
- 1917299
- PAR ID:
- 10446149
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ELECTROPHORESIS
- Volume:
- 43
- Issue:
- 7-8
- ISSN:
- 0173-0835
- Format(s):
- Medium: X Size: p. 879-891
- Size(s):
- p. 879-891
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Circulating tumor cells (CTCs) are shed from primary tumors, circulate in the bloodstream and are capable of initiating metastasis at distant anatomical sites. The detection and molecular characterization of CTCs are pivotal for early-stage cancer diagnosis and prognosis. Recently, microfluidic technology has achieved significant progress in the separation of cells from complex and heterogeneous mixtures for many biomedical applications. Conventional microfluidic platforms exploit the difference in size between the particles to achieve separation, which makes them ineffective for sorting overlapping-sized CTCs. To address this issue, we propose a method using a spiral channel for label-free, and high throughput separation of CTCs coupling Dielectrophoresis (DEP) with inertial microfluidics. A numerical model has been developed to investigate the separation effectiveness of the device over a range of electrical voltage and flow rates. The presented channel is shown to effectively isolate similar-sized CTCs from the white blood cells (WBCs) in a single-stage separation process. Subsequently, optimum working parameters to enhance separation efficiency have been proposed. The hybrid microfluidic device can provide valuable insight into the development of a robust, inexpensive, and efficient platform for cell separation with reduced analysis time for future cancer research and treatment.more » « less
-
Abstract Isolation and detection of circulating tumor cells (CTCs) hold significant importance for the early diagnosis of cancer and the assessment of therapeutic strategies. However, the scarcity of CTCs among peripheral blood cells presents a major challenge to their detection. Additionally, a similar size range between CTCs and white blood cells (WBCs) makes conventional microfluidic platforms inadequate for the isolation of CTCs. To overcome these challenges, in this study, a novel inertial‐dielectrophoretic microfluidic channel for size‐independent, single‐stage separation of CTCs from WBCs has been presented. The proposed device utilizes a spiral microchannel embedded with interdigitated electrodes. A numerical model is developed and validated to investigate the influence of various parameters related to the channel design, fluid flow, and electrode configuration. It was found that optimal separation of CTCs could be obtained at a relatively low voltage, termed the critical voltage. Furthermore, at the critical voltage of 7.5 V, the hybrid microchannel is demonstrated to be capable of separating CTCs from different WBC subtypes including granulocytes, monocytes, T‐, and B‐lymphocytes. The unique capabilities of the hybrid spiral microchannel allow for this size‐independent isolation of CTCs from a mixture of WBCs. Overall, the proposed technique can be readily utilized for continuous and high‐throughput separation of cancer cells.more » « less
-
Abstract A simple, low‐cost, three‐dimensional (3D) lab‐on‐a‐foil microfluidic device for dielectrophoretic separation of circulating tumor cells (CTCs) is designed and constructed. Disposable thin films are cut by xurography and microelectrode array are made with rapid inkjet printing. The multilayer device design allows the studying of spatial movements of CTCs and red blood cells (RBCs) under dielectrophoresis (DEP). A numerical simulation was performed to find the optimum driving frequency of RBCs and the crossover frequency for CTCs. At the optimum frequency, RBCs were lifted 120 µm inz‐axis direction by DEP force, and CTCs were not affected due to negligible DEP force. By utilizing the displacement difference, the separation of CTCs (modeled with A549 lung carcinoma cells) from RBCs inz‐axis direction was achieved. With the nonuniform electric field at optimized driving frequency, the RBCs were trapped in the cavities above the microchannel, whereas the A549 cells were separated with a high capture rate of 86.3% ± 0.2%. The device opens not only the possibility for 3D high‐throughput cell separation but also for future developments in 3D cell manipulation through rapid and low‐cost fabrication.more » « less
-
Abstract Circulating Tumor Cells (CTCs), which migrate from original sites in a body to distant organs through blood, are a key factor in cancer detection. Emerging Label-free techniques owing to their inherent advantage to preserve characteristics of sorted cells and low consumption of samples can be promising to the prediction of cancer progression and metastasis research. Deterministic Lateral Displacement (DLD) is one of the label-free separation techniques employing a specific arrangement of micro-posts for continuous separation of suspended cells in a buffer based on the size of cells. Separation based solely on size is challenging since the size distributions of CTCs might overlap with those of normal blood cells. To address this problem, DLD can be combined with dielectrophoresis (DEP) technique which is the phenomenon of particle movement in a non-uniform electric field owing to the polarization effect. Although, DLD devices employ the laminar flow in low Reynolds number (Re) fluid flow due to predictability of such flow regimes, they should be improved to work in higher Re flow regime so as to attain high throughput devices. In this paper, a particle tracing simulation is developed to study the effects of different post shapes, shift fraction of micropost arrays, and dielectrophoresis forces on separation of CTCs from peripheral blood cells. Our numerical model and results provide a groundwork for design and fabrication of high-throughput DLD-DEP devices for improvement of CTC separation.more » « less
