This lecture covers the structure and function of the extracellular matrix (ECM), including collagen, fibronectin, laminin, and proteoglycan. It explores integrins as key receptors connecting cells to the ECM, and the role of ECM in cell adhesion, migration, and survival. The presentation delves into the organization of epithelial cells, basement membrane components, and the critical role of laminin in cell differentiation and adhesion. Additionally, it discusses the impact of ECM-mimicking biomaterials on cell behavior and the dynamic reciprocity between cells and their surroundings. The lecture concludes with insights into bacterial systems, biofilms, and the brain-gut connection.