Nanoparticles as a Physical Stressor of the Cellular Membrane

This conceptual essay proposes that nanoparticles affect cells primarily as physical stressors rather than as biochemical toxins or signaling agents. It argues that nanoparticles modify the physical state of the cellular membrane by altering properties such as fluidity, permeability, curvature, and mechanical stability. These changes interfere with the cellular state filter, thereby reshaping the space of permissible intracellular processes without involving receptors, ligands, or canonical signaling pathways. From this perspective, biological effects of nanoparticles emerge from state-dependent physical constraints rather than from transmitted biochemical information. This framework provides a prebiotic and physical basis for understanding chronic, sub-threshold, and non-specific cellular responses to nanoparticle exposure.