Abstract
Biofilms are widely present in any environment with water and a substrate, posing microbial contamination risks to flow pipelines. This study established a bacterial biofilm flow growth model based on the experimental phenomena of Bacillus subtilis biofilm in microfluidic channels, combining the principles of cellular automata with the finite element method. In the model, the hydrodynamic model was developed using the COMSOL platform to analyze the flow field distribution characteristics induced by micropost. A cellular automata model was developed in MATLAB, innovatively incorporating a flow direction weight algorithm and a filamentous growth mode. The study focused on the attachment behavior of biofilms in microfluidic channels, and simulations of biofilm growth in microfluidic channels with different micropost structures were conducted. The model successfully reproduced key experimental phenomena, such as the attachment and growth of filamentous structures and the aggregation of streamer-like biofilms. By combining real-time flow field analysis with the model, the attachment and growth mechanism of biofilm in the micropillar-flow system was revealed. The spatial arrangement of microposts affects the flow paths of free bacteria by altering streamline distribution. The secondary flow induced by the micropillars promotes bacterial attachment, and its spatial distribution characteristics determine the initial attachment sites of bacteria. This study provides a reference for preventing biofilm formation in flow pipelines and reducing the risk of microbial contamination in similar devices.