University of Louisville
Efficacy of Stretched Membrane Immunoaffinity Capture of Circulating Tumor Cells (CTCs)
Institution
University of Louisville
Faculty Advisor/ Mentor
Palaniappan Sethu
Abstract
This project examined how immunoaffinity capture techniques can help isolate circulating tumor cells (CTCs) using microfluidic devices. CTCs are cells that originate from a primary tumor, travel within the bloodstream, and can often lead to metastasis. These cells are prevalent in small amounts (about 1-10 cells per 109 blood cells) and have been difficult to detect. Therefore, the researcher hypothesized that stretching and relaxing a polydimethylsiloxane (PDMS) membrane during each step of the functionalization process would increase the available surface area for modification, thus increasing the number and proximity of antibodies. To validate this hypothesis, model cell lines were used to represent both CTCs (MCF-7 cells, represent CTCs of epithelial origin) and blood cells (MOLT-3 cells, T-lymphoblast cell line). Stretching was achieved by clamping the outflow tubing of one of the devices and injecting an additional 0.35 mL of solution at each step of the surface modification process to increase the surface area by 5% via stretch. The membranes were evaluated by counting the amount of MCF-7 cells captured on each type of membrane. Results across four trials indicated that the amount of MCF-7 cells present on stretched membranes (109.3 ± 1.69) was ~ 5-fold greater than on non-stretched membranes (21.9 ± 26.6). No statistically significant difference was found in the non-specific binding of MOLT-3 in stretched (4.25 ± 0.306) and non-stretched (4.38 ± 0.161) devices. These results validate the hypothesis and have potential to be further developed into a point-of-care diagnostic device for health-care professionals, such as one that would spare cancer patients from invasive biopsies.
Efficacy of Stretched Membrane Immunoaffinity Capture of Circulating Tumor Cells (CTCs)
This project examined how immunoaffinity capture techniques can help isolate circulating tumor cells (CTCs) using microfluidic devices. CTCs are cells that originate from a primary tumor, travel within the bloodstream, and can often lead to metastasis. These cells are prevalent in small amounts (about 1-10 cells per 109 blood cells) and have been difficult to detect. Therefore, the researcher hypothesized that stretching and relaxing a polydimethylsiloxane (PDMS) membrane during each step of the functionalization process would increase the available surface area for modification, thus increasing the number and proximity of antibodies. To validate this hypothesis, model cell lines were used to represent both CTCs (MCF-7 cells, represent CTCs of epithelial origin) and blood cells (MOLT-3 cells, T-lymphoblast cell line). Stretching was achieved by clamping the outflow tubing of one of the devices and injecting an additional 0.35 mL of solution at each step of the surface modification process to increase the surface area by 5% via stretch. The membranes were evaluated by counting the amount of MCF-7 cells captured on each type of membrane. Results across four trials indicated that the amount of MCF-7 cells present on stretched membranes (109.3 ± 1.69) was ~ 5-fold greater than on non-stretched membranes (21.9 ± 26.6). No statistically significant difference was found in the non-specific binding of MOLT-3 in stretched (4.25 ± 0.306) and non-stretched (4.38 ± 0.161) devices. These results validate the hypothesis and have potential to be further developed into a point-of-care diagnostic device for health-care professionals, such as one that would spare cancer patients from invasive biopsies.