O13 - Modeling Channel Diameter in a Wicking Fiber Cancer Diagnostic Device

Introduction: : Current canine cancer diagnostic methods are limited by high costs, inefficiencies, and subjective interpretations, contributing to suboptimal patient outcomes. These factors have driven the need to develop a rapid cancer diagnostic capable of processing a cellular sample during a routine veterinary appointment. Cancer cells are generally less stiff than the non-malignant cells [1], contributing to higher motility and faster migration rate [2]. Therefore, capillary action may be leveraged to achieve cancer cell separation. Previous work has shown that polylactide (PL) wicking, channeled fibers are effective in facilitating cell separation in heterogeneous liquid cell samples. [3] However, the PL fiber bundles used in past experiments were difficult to standardize to produce replicable results. This was due to inconsistencies in the shape of the bundle along with the gap sizes between the bundled fibers. In an attempt to standardize the procedure, a series of experiments was conducted to assess the efficacy of glass capillary tubes, rather than channeled fibers, in repeatably inducing wicking. The experiments analyzed the movement of MCF-7 cells within the capillary tubes to better characterize and optimize the cell separation. The results lay groundwork for the optimization of the more complex PL wicking fiber bundles.

Materials and

Methods: : Cell Tracker Red was used to stain MCF-7 (cancer cells). Once stained, a 2,000 cell/mL concentration of MCF-7 medium was prepared and introduced at the bottom of glass capillary tubes positioned vertically. The cells moved along the vertical tube via capillary action. An EVOS fluorescence microscope was rotated 90o (Fig 2) to accommodate imaging the length of the vertical wicking tube to visualize and track cell movement. Fluorescent images were captured across three defined zones along the capillary tubes to assess distribution patterns and migrations of MCF-7s.

Results, Conclusions, and Discussions:: The data collected from the MCF-7 wicking experiments show that the cell count is the greatest inside zone 3 of the capillary tube. A one-way ANOVA revealed a significant difference in cancer cell counts across spatial zones (p < 0.001). Follow-up t-tests showed significantly higher counts in Zone 3 compared to Zone 1 (p = 0.004) and Zone 2 (p = 0.003), while no significant difference was observed between Zones 1 and 2 (p = 0.778).

The glass capillary effectively modeled the deep grooves of the PL wicking fiber, allowing the analysis of MCF-7 migration patterns. The MCF-7 migration data is statistically significant and indicates the potential that various cell types may wick at different rates or settle at different locations along the wicking fiber. Limitations of this study include the investigation of migration patterns for one cell type only. Additionally, the height of Zone 3 was variable based on solution wicking height. To address this point, future work will explore testing of multiple cell types with a greater number of capillary zones. Ultimately, refining these techniques will enhance optimization of the wicking fiber, thus paving the way for a low-cost, rapid cancer diagnostic tool.

Acknowledgements and/or References (Optional):: Acknowledgements: This work was funded by the Harbor Lights Endowment.

References
1. Daniel C. et al., BMC Cancer. 23:862 (2023)
2. Liu Z. et al., FASEB J. 34:9307–9315 (2021)
3. Tabbaa S. et al., Ann. Biomed. Eng. 45:12 (2017)