Trapping metastatic cancer cells with mechanical ratchet arrays

Current treatments for cancer, such as chemotherapy, radiotherapy, immunotherapy, and surgery, have positive results but are generally ineffective against metastatic tumors. Treatment effectiveness can be improved by employing bioengineered cancer traps, typically utilizing chemoattractant-loaded materials, to attract infiltrating cancer cells preventing their uncontrolled spread and potentially enabling eradication. However, the encapsulated chemical compounds can have adverse effects on other cells causing unwanted responses, and the generated gradients can evolve unpredictably. Here, we report the development of a cancer trap based on mechanical ratchet structures to capture metastatic cells. The traps use an array of asymmetric local features to mechanically attract cancer cells and direct their migration for prolonged periods. The trapping efficiency was found to be greater than isotropic or inverse anisotropic ratchet structures on either disseminating cancer cells and tumor spheroids. Importantly, the traps exhibited a reduced effectiveness when targeting non-metastatic and non-tumorigenic cells, underscoring their particular suitability for capturing highly invasive cancer cells. Overall, this original approach may have therapeutic implications for fighting cancer, and may also be used to control cell motility for other biological processes. STATEMENT OF SIGNIFICANCE: Current cancer treatments have limitations in treating metastatic tumors, where cancer cells can invade distant organs. Biomaterials loaded with chemoattractants can be implanted to attract and capture metastatic cells preventing uncontrolled spread. However, encapsulated chemical compounds can have adverse effects on other cells, and gradients can evolve unpredictably. This paper presents an original concept of "cancer traps" based on using mechanical ratchet-based structures to capture metastatic cancer cells, with greater trapping efficiency and stability than previously studied methods. This innovative approach has significant potential clinical implications for fighting cancer, particularly in treating metastatic tumors. Additionally, it could be applied to control cell motility for other biological processes, opening new possibilities for biomedicine and tissue engineering.