A novel radial co-culture microfluidic device for parallel and control detection of tumor cell invasiveness

Metastasis is responsible for the majority of cancer-related deaths, and tumor cell invasion is a critical step in the cancer metastatic cascade. Traditional invasion analysis using transwell assays and immunodeficient mouse models struggles to control tumor microenvironment factors, such as various biochemical signals and cell types. A microfluidic chip system has emerged as an important tool for invasion analysis, but the simultaneous parallel and controlled experiments within the same group of tumor cells remain challenging. Here, we developed a new three-dimensional co-culture microfluidic device to investigate tumor invasion. This device consists of three concentric circles and is divided into four identical regions. Each region includes a tumor cell region, an invasion channel and a co-culture channel. Additionally, the four identical regions allow for four specific groups of parallel or control analysis surrounding the same group of tumor cells. Thus, our device enables the comparison of invasion among the same group of cells under different conditions, avoiding the discrepancies in invasion that arise when the treatment factors differ across different groups of tumor cells. Using experimental examinations and numerical simulations, we verified the capability of the device for parallel and controlled analysis of tumor invasion in response to different stimuli, including chemokines, drugs and cellular factors secreted from co-cultured cells. Furthermore, we found that in a co-culture environment with cancer-associated fibroblasts, the invasiveness of LoVo cells and their resistance to 5-fluorouracil treatment were enhanced. This innovative approach allows for easy, parallel and controlled assays to study tumor cell invasion with the advantages of multiplexing and simplicity. The method provides straightforward, repeatable control over cell-biochemical signals and cell-cell interactions, making it a valuable tool for accurately evaluating tumor invasion in metastasis studies.