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Application of optically-induced-dielectrophoresis in microfluidic system for purification of circulating tumour cells for gene expression analysis- Cancer cell line model

View Article: PubMed Central - PubMed

ABSTRACT

Circulating tumour cells (CTCs) in a blood circulation system are associated with cancer metastasis. The analysis of the drug-resistance gene expression of cancer patients’ CTCs holds promise for selecting a more effective therapeutic regimen for an individual patient. However, the current CTC isolation schemes might not be able to harvest CTCs with sufficiently high purity for such applications. To address this issue, this study proposed to integrate the techniques of optically induced dielectrophoretic (ODEP) force-based cell manipulation and fluorescent microscopic imaging in a microfluidic system to further purify CTCs after the conventional CTC isolation methods. In this study, the microfluidic system was developed, and its optimal operating conditions and performance for CTC isolation were evaluated. The results revealed that the presented system was able to isolate CTCs with cell purity as high as 100%, beyond what is possible using the previously existing techniques. In the analysis of CTC gene expression, therefore, this method could exclude the interference of leukocytes in a cell sample and accordingly contribute to higher analytical sensitivity, as demonstrated in this study. Overall, this study has presented an ODEP-based microfluidic system capable of simply and effectively isolating a specific cell species from a cell mixture.

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Related in: MedlinePlus

(a) Simulated flow patterns of T-shaped microchannel with three different side microchannel widths [(I) 400, (II) 700, and (III) 1,000 μm] under a given flow rate of 1 μl min−1 in the main microchannel (the left column); simulated flow velocity profiles along with the distance from the central start point of the side microchannel under three different side microchannel widths [(I) 400, (II) 700, and (III) 1,000 μm] and three different flow rate conditions (1.0, 2.5, and 5.0 μl min−1) in the main microchannel (the right column); (b) microscopic observations of the travel distance of a cell from the main to the side microchannel under three different flow rate conditions [(I) 1.0, (II) 2.5, and (III) 5.0 μl min−1)] in the main microchannel (given side microchannel width: 400 μm); (IV) the quantitative relationship between the measured travel distance of a cell from the main to side microchannel and the flow rate conditions (1.0, 2.5, and 5.0 μl min−1) in the main microchannel.
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f3: (a) Simulated flow patterns of T-shaped microchannel with three different side microchannel widths [(I) 400, (II) 700, and (III) 1,000 μm] under a given flow rate of 1 μl min−1 in the main microchannel (the left column); simulated flow velocity profiles along with the distance from the central start point of the side microchannel under three different side microchannel widths [(I) 400, (II) 700, and (III) 1,000 μm] and three different flow rate conditions (1.0, 2.5, and 5.0 μl min−1) in the main microchannel (the right column); (b) microscopic observations of the travel distance of a cell from the main to the side microchannel under three different flow rate conditions [(I) 1.0, (II) 2.5, and (III) 5.0 μl min−1)] in the main microchannel (given side microchannel width: 400 μm); (IV) the quantitative relationship between the measured travel distance of a cell from the main to side microchannel and the flow rate conditions (1.0, 2.5, and 5.0 μl min−1) in the main microchannel.

Mentions: In terms of design, a simple microfluidic system with a T-shaped microchannel was fabricated [Fig. 1(a)]. As described in Fig. 2, a cell suspension was transported through the main microchannel, during which the cancer cells were identified and then selectively delivered to the side microchannel for collection. To avoid contamination from the leukocytes in the sample flow to the side microchannel, CFD-based simulations and experimental validations were conducted. This was to determine the appropriate width of the side microchannel and working flow rate of the cell suspension flow. Figure 3(a) (the left column) illustrates the simulated flow patterns of a T-shaped microchannel with three different side microchannel widths [(I) 400, (II) 700, and (III) 1,000 μm] under a given cell suspension flow rate of 1 μl min−1 in the main microchannel. To further evaluate the fluidic interference to the side microchannel, Fig. 3(a) (the right column) quantitatively shows the flow velocity profiles along with the distance from the central starting point of the side microchannel for three different side microchannel widths [(I) 400, (II) 700, and (III) 1,000 μm] and three different sample flow rate conditions (1.0, 2.5, and 5.0 μl min−1) in the main microchannel. Overall, it can be clearly seen from Fig. 3(a) that the narrower side microchannel or lower sample flow rate in the main microchannel resulted in less fluidic interference to the side microchannel under the conditions compared. Therefore, the proposed microfluidic system with a side microchannel width of 400 μm was designed. At a given side microchannel width of 400 μm, the sample flow rate issue discussed above was further experimentally validated as shown in Fig. 3(b). The travel distance of a cell from the main to side microchannel increased with the increasing sample flow rate in the main microchannel. In the results, the abovementioned travel distances were measured to be 37.1 ± 10.7, 110.2 ± 11.6, and 153.0 ± 13.7 μm under three different sample flow rate conditions (1.0, 2.5, and 5.0 μl min−1, respectively) in the main microchannel. For the simulation counterpart [Fig. 3(a–I) the right figure], the distances (from the central starting point of the side microchannel) where the flow velocity nearly reached zero were 40.2, 125.6, and 170.9 μm for the sample flow rate conditions of 1.0, 2.5, and 5.0 μl min−1, respectively. As a whole, the experimental results [Fig. 3(b)] correspond well to the simulation results [Fig. 3(a–I) the right figure]. Based on the fundamental investigations, therefore, a 2.5 μl min−1 sample flow rate was selected for operation as a compromise between the fluidic interference issue and working throughput.


Application of optically-induced-dielectrophoresis in microfluidic system for purification of circulating tumour cells for gene expression analysis- Cancer cell line model
(a) Simulated flow patterns of T-shaped microchannel with three different side microchannel widths [(I) 400, (II) 700, and (III) 1,000 μm] under a given flow rate of 1 μl min−1 in the main microchannel (the left column); simulated flow velocity profiles along with the distance from the central start point of the side microchannel under three different side microchannel widths [(I) 400, (II) 700, and (III) 1,000 μm] and three different flow rate conditions (1.0, 2.5, and 5.0 μl min−1) in the main microchannel (the right column); (b) microscopic observations of the travel distance of a cell from the main to the side microchannel under three different flow rate conditions [(I) 1.0, (II) 2.5, and (III) 5.0 μl min−1)] in the main microchannel (given side microchannel width: 400 μm); (IV) the quantitative relationship between the measured travel distance of a cell from the main to side microchannel and the flow rate conditions (1.0, 2.5, and 5.0 μl min−1) in the main microchannel.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5016898&req=5

f3: (a) Simulated flow patterns of T-shaped microchannel with three different side microchannel widths [(I) 400, (II) 700, and (III) 1,000 μm] under a given flow rate of 1 μl min−1 in the main microchannel (the left column); simulated flow velocity profiles along with the distance from the central start point of the side microchannel under three different side microchannel widths [(I) 400, (II) 700, and (III) 1,000 μm] and three different flow rate conditions (1.0, 2.5, and 5.0 μl min−1) in the main microchannel (the right column); (b) microscopic observations of the travel distance of a cell from the main to the side microchannel under three different flow rate conditions [(I) 1.0, (II) 2.5, and (III) 5.0 μl min−1)] in the main microchannel (given side microchannel width: 400 μm); (IV) the quantitative relationship between the measured travel distance of a cell from the main to side microchannel and the flow rate conditions (1.0, 2.5, and 5.0 μl min−1) in the main microchannel.
Mentions: In terms of design, a simple microfluidic system with a T-shaped microchannel was fabricated [Fig. 1(a)]. As described in Fig. 2, a cell suspension was transported through the main microchannel, during which the cancer cells were identified and then selectively delivered to the side microchannel for collection. To avoid contamination from the leukocytes in the sample flow to the side microchannel, CFD-based simulations and experimental validations were conducted. This was to determine the appropriate width of the side microchannel and working flow rate of the cell suspension flow. Figure 3(a) (the left column) illustrates the simulated flow patterns of a T-shaped microchannel with three different side microchannel widths [(I) 400, (II) 700, and (III) 1,000 μm] under a given cell suspension flow rate of 1 μl min−1 in the main microchannel. To further evaluate the fluidic interference to the side microchannel, Fig. 3(a) (the right column) quantitatively shows the flow velocity profiles along with the distance from the central starting point of the side microchannel for three different side microchannel widths [(I) 400, (II) 700, and (III) 1,000 μm] and three different sample flow rate conditions (1.0, 2.5, and 5.0 μl min−1) in the main microchannel. Overall, it can be clearly seen from Fig. 3(a) that the narrower side microchannel or lower sample flow rate in the main microchannel resulted in less fluidic interference to the side microchannel under the conditions compared. Therefore, the proposed microfluidic system with a side microchannel width of 400 μm was designed. At a given side microchannel width of 400 μm, the sample flow rate issue discussed above was further experimentally validated as shown in Fig. 3(b). The travel distance of a cell from the main to side microchannel increased with the increasing sample flow rate in the main microchannel. In the results, the abovementioned travel distances were measured to be 37.1 ± 10.7, 110.2 ± 11.6, and 153.0 ± 13.7 μm under three different sample flow rate conditions (1.0, 2.5, and 5.0 μl min−1, respectively) in the main microchannel. For the simulation counterpart [Fig. 3(a–I) the right figure], the distances (from the central starting point of the side microchannel) where the flow velocity nearly reached zero were 40.2, 125.6, and 170.9 μm for the sample flow rate conditions of 1.0, 2.5, and 5.0 μl min−1, respectively. As a whole, the experimental results [Fig. 3(b)] correspond well to the simulation results [Fig. 3(a–I) the right figure]. Based on the fundamental investigations, therefore, a 2.5 μl min−1 sample flow rate was selected for operation as a compromise between the fluidic interference issue and working throughput.

View Article: PubMed Central - PubMed

ABSTRACT

Circulating tumour cells (CTCs) in a blood circulation system are associated with cancer metastasis. The analysis of the drug-resistance gene expression of cancer patients’ CTCs holds promise for selecting a more effective therapeutic regimen for an individual patient. However, the current CTC isolation schemes might not be able to harvest CTCs with sufficiently high purity for such applications. To address this issue, this study proposed to integrate the techniques of optically induced dielectrophoretic (ODEP) force-based cell manipulation and fluorescent microscopic imaging in a microfluidic system to further purify CTCs after the conventional CTC isolation methods. In this study, the microfluidic system was developed, and its optimal operating conditions and performance for CTC isolation were evaluated. The results revealed that the presented system was able to isolate CTCs with cell purity as high as 100%, beyond what is possible using the previously existing techniques. In the analysis of CTC gene expression, therefore, this method could exclude the interference of leukocytes in a cell sample and accordingly contribute to higher analytical sensitivity, as demonstrated in this study. Overall, this study has presented an ODEP-based microfluidic system capable of simply and effectively isolating a specific cell species from a cell mixture.

No MeSH data available.


Related in: MedlinePlus