Abstract
Capillary microfluidic chips (CMCs) enable passive liquid transport via surface tension and wettability gradients, making them central to point-of-care diagnostics and biomedical sensing. However, accurate analysis of capillary-driven flow experiments remains constrained by the labour-intensive, time-consuming, and inconsistent nature of manual fluid path tracking. Here, we present AI-CMCA, an artificial intelligence framework designed for capillary microfluidic chip analysis, which automates fluid path detection and tracking using deep learning-based segmentation. AI-CMCA combines transfer learning-based feature initialization, encoder-decoder-based semantic segmentation to recognize fluid in each frame, and sequential frame analysis to track then quantify fluid progression. Among the five tested architectures, including U-Net, PAN, FPN, PSP-Net, and DeepLabV3+, the U-Net model with MobileNetV2 achieved the highest performance, with a validation IoU of 99.24% and an F1-score of 99.56%. Its lightweight design makes it well suited for smartphone or edge deployment. AI-CMCA demonstrated a strong correlation with manually extracted data while offering superior robustness and consistency in fluid path analysis. AI-CMCA performed fluid path analysis up to 100 times faster and over 10 times more consistently than manual tracking, reducing analysis time from days to minutes while maintaining high precision and reproducibility across diverse CMC architectures. By eliminating the need for manual annotation, AI-CMCA significantly enhances efficiency, precision, and automation in microfluidic research.