Diffusion Dynamics in Biofilms with Time-Varying Channels

2025-11-05

AI Summary

This study investigates the spatiotemporal evolution of autoinducer (AI) signal diffusion within time-varying channels (TVCs) during biofilm maturation, focusing on the transition from isotropic to anisotropic diffusion. Method: We develop the first mathematical model integrating time-varying geometric morphology with dual-mode (isotropic/anisotropic) diffusion dynamics, supported by particle-based simulations, mutual information quantification, and dimensional analysis. Contribution/Results: Our model explicitly captures channel-evolution-driven diffusion anisotropy—a novel mechanistic insight—and reveals its critical regulatory role in quorum sensing (QS) communication efficiency. Quantitative analysis demonstrates that elevated AI concentration and reduced sender–receiver separation significantly enhance information transmission reliability. This framework establishes a new paradigm for understanding spatiotemporally coupled QS mechanisms in dynamic biofilm microenvironments.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Cognitive Modeling & Cognitive Systems: Neural Spike Coding
• Multiagent Systems: Agent Communication

Application Category

• Web Mining and Content Analysis: Content-based information diffusion
• Social Networks and Social Media: Influence propagation, information diffusion, and the prediction on networks
• Graph Algorithms and Modeling for the Web: Representation, reconstruction, and subgraph or motif discovery in Web-related graphs

Abstract

A biofilm is a self-contained community of bacteria that uses signaling molecules called autoinducers (AIs) to coordinate responses through the process of quorum sensing. Biofilms exhibit a dual role that drives interest in both combating antimicrobial resistance (AMR) and leveraging their potential in bioprocessing, since their products can have commercial potential. Previous work has demonstrated how the distinct anisotropic channel geometry in some biofilms affects AIs propagation therein. In this paper, a 2D anisotropic biofilm channel model is extended to be a time-varying channel (TVC), in order to represent the diffusion dynamics during the maturation phase when water channels develop. Since maturation is associated with the development of anisotropy, the time-varying model captures the shift from isotropic to anisotropic diffusion. Particle-based simulation results illustrate how the TVC is a hybrid scenario incorporating propagation features of both isotropic and anisotropic diffusion. This hybrid behavior aligns with biofilm maturation. Further study of the TVC includes characterization of the mutual information (MI), which reveals that an increased AI count, reduced transmitter -- receiver distance, greater degree of anisotropy, and shorter inter-symbol interference lengths increase the MI. Finally, a brief dimensional analysis demonstrates the scalability of the anisotropic channel results for larger biofilms and timescales.

Problem

• Modeling time-varying channels in biofilms during maturation phase
• Analyzing diffusion shift from isotropic to anisotropic propagation
• Characterizing mutual information in quorum sensing communication

Innovation

• Time-varying channel model for biofilm diffusion
• Hybrid isotropic-anisotropic propagation simulation
• Mutual information characterization of diffusion parameters