Nanoplastics as a return to the prebiotic dimensional regime: A dimensional perspective on interactions with biological membranes

Abstract Nanoplastics represent a distinct class of environmental particles whose relevance lies not primarily in their chemical toxicity, but in their size and the physical regime they occupy. With characteristic dimensions ranging from a few to tens of nanometers, nanoplastics enter the same dimensional space in which key processes of prebiotic evolution occurred billions of years ago. During this period, the dominant structures—fatty acids, primitive membranes, simple vesicles, and prebiotic membrane domains—existed predominantly below the ~100 nm scale, where surface forces, membrane curvature, thermal fluctuations, and local energy minima governed system behavior.This conceptual and dimensional perspective argues that interactions between nanoplastics and biological systems cannot be adequately understood without explicitly considering this nanometer-scale regime. Rather than acting as classical toxins, nanoplastics function as physical perturbations within membrane environments, interacting with domains and structures that are evolutionarily ancient in origin. By systematically mapping the characteristic sizes of key biological and prebiotic structures, this work proposes that nanoplastics effectively reintroduce prebiotic physical conditions into modern biological systems, highlighting the need to complement chemical toxicity frameworks with a dimensionally grounded, biophysical approach.